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  • 1990-1994  (66)
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  • 1
    Electronic Resource
    Electronic Resource
    Light microscopical study of dendrites and perikarya of interneurones mediating la reciprocal inhibition of cat lumbar alpha-motoneurones (1990)
    Springer
    Anatomy and embryology 181 (1990), S. 381-388 
    Details
    ISSN: 1432-0568
    Keywords: Ia interneurones ; Dendrites ; Horseradish peroxidase ; Intracellular injection ; Light microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Interneurones which mediate disynaptic inhibition from la muscle spindle afferents of the quadriceps nerve to lumbar alpha-motoneurones were stained with intracellular injection of horseradish peroxidase. Seven best stained and most satisfactorily preserved cells were selected for analysis, and the light microscopic morphology of their cell bodies and dendrites were quantitatively investigated in parasagittal sections. The perikarya were located dorsal or dorso-medial to the motoneurones; they had mean diameters of 51 × 27 μm and a mean volume of 35820 μm3. The cells had 3 to 7 dendrites, which were arranged asymmetrically around the parent somata. The dendrites extended mainly in the dorso-ventral direction, in which the mean tip to tip distance for each cell was 1742 μm. The dendrites had few spines and they branched almost only in bifurcations. On the average, each process divided 3.5 times and in each cell they gave rise to 14.9 branching points as well as a total combined length of more than 7000 μm. Primary dendrites had a mean length of 193 μm which was generally shorter than the lengths of the branches of higher order. A more detailed analysis of two cells revealed the mean width of primary dendrites to be 5.6 μm while that of the 5th order processes was 1.5 μm. The mean tapering of individual dendritic branches per unit length was 17%, being somewhat more pronounced for the distally located segments, while at branching points the sum of daughter processes approximately equalled the diameter of the parent process. The surface area and volume of the dendrites constituted 90% and 83% of the total surface area and 46% and 37% of the total volume of the two cells, respectively, excluding the axons. The Ia interneurones differed considerably among themselves with respect to the quantitively investigated parameters. They resembled the inhibitory Renshaw cells of the cat with regard to the number of dendrites, the poverty of spines, and the relationships between cell body diameter and width of primary dendrites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186910
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  • 2
    Electronic Resource
    Electronic Resource
    Pattern of neuronal vulnerability in the cat hippocampus after one hour of global cerebral ischemia (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 444-455 
    Details
    ISSN: 1432-0533
    Keywords: Ischemia ; Cat ; Selective vulnerability ; Immunohistochemistry ; Glial fibrillary acidic protein (GFAP)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The dorsal hippocampus of cat was investigated by light microscopy and immunohistochemistry following 1 h global cerebral ischemia and various recirculation times from 1 day to 1 year. Complete ischemia was produced by combining hypotension with intrathoracic occlusion of major arteries. Postischemic resuscitation was carried out using an intensive care regimen with continuous neurophysiological monitoring. Brains of controls (n=4) and postischemic animals (n=12) were fixed in formaldehyde and prepared for histology and immunohistochemistry of glial fibrillary acidic protein (GFAP). In all post-ischemic animals the hilus and the regio superior of dorsal hippocampus which encompasses the CA1 subfield were severely damaged. Neurons in these regions exhibited the typical sequela of neuronal death. GFAP staining revealed vivid astroglial proliferation in stratum lacunosum-moleculare and stratum oriens. Changes in the regio inferior of dorsal hippocampus, i.e., CA3 subfield, and in dentate gyrus granular layer, were variable. Although most animals exhibited moderate to severe neuronal and glial alterations, groups of surviving cells were observed in the stratum oriens and in the granular layer of dentate gyrus. In one animal the majority of CA3 pyramidal cells and granule cells was preserved. These findings demonstrate that after 1 h of complete cerebral ischemia dorsal hippocampus exhibits two different types of injury: a consistent pattern of selective vulnerability in the hilus and the regio superior, and a variable pattern of non-selective injury in the regio inferior and dentate gyrus. The two patterns can be best explained by intrinsic (pathoclitic) and extrinsic (hemodynamic/edema) factors, respectively and are likely to represent basically different mechanisms of ischemic injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308722
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  • 3
    Electronic Resource
    Electronic Resource
    Immunoreactivity of canine and feline polyglucosan bodies for monoclonal antibody against human polyglucosan (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 217-218 
    Details
    ISSN: 1432-0533
    Keywords: Immunohistochemistry ; Polyglucosan bodies ; Dog ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With the use of monoclonal antibodies, raised against the human polyglucosan, positive staining of polyglucosan bodies (PGB) was detected in the brain, spinal cord and cecum of aged dogs. PGB in feline brain were also positively stained with these antibodies. These findings indicate that animal PGB share common antigenicity with human PGB.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334511
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  • 4
    Electronic Resource
    Electronic Resource
    Changes in extracellular potassium concentration in cat spinal cord in response to innocuous and noxious stimulation of legs with healthy and inflamed knee joints (1990)
    Springer
    Experimental brain research 79 (1990), S. 283-292 
    Details
    ISSN: 1432-1106
    Keywords: [K+]0 Spinal cord ; Posterior articular nerve ; Knee joint ; Inflammation ; Pain ; Arthritis ; Nociception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 20 cats anaesthetized with alpha-chloralose and spinalized at the thoracolumbar junction we investigated the role of stimulation induced accumulation of extracellular potassium in the spinal cord in the processing of nociceptive discharges from the knee joint. For that we electrically stimulated the posterior articular nerve of the knee. We further performed innocuous and noxious stimulation of the knee and of other parts of the leg and studied the effect of an acute inflammation of the knee on [K+]0 in the spinal cord. Innocuous stimulation of the skin (brushing or touching) and innocuous movements in the knee joint all induced rises in [K+]0 which were maximal at recording depths of 1500 to 2200 μm below the surface of the cord dorsum. Peak increases were 0.4 mM for touching the leg and 1.7 mM during rhythmic flexion/ extension of the knee joint. Noxious stimulation of the skin, the paw, the tendon and noxious movements of the knee joint also produced rises in [K+]0, which were somewhat larger for the individual types of stimuli than those produced by innocuous intensities. Electrical stimulation of the posterior articular nerve induced rises in [K+]0 by up to 0.6 mM. Stimulus intensities sufficient to activate unmyelinated group IV fibers were only slightly effective in raising [K+]0 above the levels reached during stimulation of myelinated group II and III fibers. During development of an acute inflammation of the knee joint (induced by kaolin and carrageenan), increases in [K+]0 and associated field potentials became larger by about 25%. We assume that this reflects an increase in neuronal responses. In conclusion, changes in [K+]0 in the spinal cord are some-what larger during noxious stimulation than during innocuous stimulation. The absolute level reached depended more on the site and type of stimulation than on the actual stimulus intensity itself. Hence a critical role of spinal K+ accumulation for nociception is unlikely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608237
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  • 5
    Electronic Resource
    Electronic Resource
    Topographic variations in W-cell input to cat superior colliculus (1990)
    Springer
    Experimental brain research 79 (1990), S. 459-466 
    Details
    ISSN: 1432-1106
    Keywords: Retinotectal ; Topography ; Superior colliculus ; W-cell ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Most of the retinal input to the cat's superior colliculus (SC) arises from W-cells of the contralateral eye and terminates just below the tectal surface. The goal of this study was to determine whether the strength of this input is uniform over the collicular map or, instead, exhibits topographic variations as has been reported for the retinotectal Y-cell projection (McIlwain and Lufkin 1976). Monosynaptic inputs from the principal W-cell projection mediate the late negative potential (LNP), a collicular field potential that can be evoked by shocks to the optic pathway. We assumed that the amplitude of the potential provided a measure of the strength of the W-cell input to the upper superficial gray layer. Using a fixed stimulus, we measured the maximal amplitude of the LNP at 90 topographically identified tectal sites in 5 cats. The amplitude of the LNP varied as much as 5-fold over the SC and was systematically related to the azimuthal position of the recording site. LNP amplitudes were consistently smallest in the representation of the area centralis and vertical meridian and largest in the representations of the contralateral hemifield periphery and the ipsilateral hemifield. There was little systematic variation in LNP amplitude as a function of elevation in the map. The observed variations did not result from non-uniform activation of retinal afferents or drift in properties of the recording electrodes, stimuli, or preparation. The results suggest that the principal W-cell input to the SC is weaker in the representation of the area centralis than elsewhere in the map. These topographic variations are similar to those reported for the retinotectal Y-cell projection (McIlwain and Lufkin 1976) and are consistent with anatomical evidence for thinning of retinal input in the area-centralis representation (Graybiel 1975; Harting and Guillery 1976; Mize 1983). An important implication of these results is that the scaling of the collicular retinotopic map may not be proportional to the spatial density of tectally projecting W-cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229316
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  • 6
    Electronic Resource
    Electronic Resource
    Sensitivity of monosynaptic test reflexes to facilitation and inhibition as a function of the test reflex size: a study in man and the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 35-45 
    Details
    ISSN: 1432-1106
    Keywords: Spinal cord ; Spinal reflexes ; Monosynaptic reflex ; Motor control ; Man ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In parallel experiments on humans and in the cat it was investigated how the sensitivity of monosynaptic test reflexes to facilitation and inhibition varies as a function of the size of the control test reflex itself. In man the monosynaptic reflex (the Hoffmann reflex) was evoked in either the soleus muscle (by stimulation of the tibial nerve) or the quadriceps muscle (by stimulation of the femoral nerve). In the decerebrate cat monosynaptic reflexes were recorded from the nerves to soleus and medial gastrocnemius muscles; they were evoked by stimulation of the proximal ends of the sectioned L7 and S1 dorsal roots. Various excitatory and inhibitory spinal reflex pathways were used for conditioning the test reflexes (e.g. monosynaptic Ia excitation, disynaptic reciprocal inhibition, cutaneous inhibition, recurrent inhibition, presynaptic inhibition of the Ia fibres mediating the test reflex). It was shown that the additional number of motoneurones recruited in a monosynaptic test reflex by a constant excitatory conditioning stimulus was very much dependent on the size of the test reflex itself. This dependency had the same characteristic pattern whatever the conditioning stimulus. With increasing size of the test reflex the number of additionally recruited motoneurones first increased, then reached a peak (or plateau) and finally decreased. A similar relation was also seen with inhibitory conditioning stimuli. The basic physiological factors responsible for these findings are discussed. Finally, the implications for the interpretation of experiments in man with the H-reflex technique are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230098
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  • 7
    Electronic Resource
    Electronic Resource
    Organization of the auditory area in the posterior cerebellar vermis of the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 377-383 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Auditory ; Hearing ; Granule cells ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We mapped the topographic distribution of auditory responses in the posterior cerebellar vermis of the cat under barbiturate anesthesia. Auditory neurons in the granule cell layer of lobules VI and VII appeared to be arranged in columns perpendicular to the surface of the cerebellar cell layers. Mapping the surface of the cerebellum, auditory responses were found as separated patches of the order of a square millimeter. Neurons on these patches responded to auditory stimuli but neurons between patches did not respond to sound. In decerebrated cats, the entire granule cell layer within the cerebellar auditory area responded to acoustic stimulation without a patchy pattern. Responses to tonal stimuli from single neurons in the granule cell layer were studied before and after the induction of barbiturate anesthesia. Some neurons showed no change in their responses to sound before and under barbiturate. But other neurons showed dramatically attenuated responses or essentially stopped responding as a result of barbiturate anesthesia. These results suggest that there may be two types of granule cells distinguishable in their auditory responses and therefore possibly in function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228129
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  • 8
    Electronic Resource
    Electronic Resource
    Contribution of area 19 to the foreground-background-interaction of the cat: an analysis based on single cell recordings and behavioural experiments (1990)
    Springer
    Experimental brain research 82 (1990), S. 107-112 
    Details
    ISSN: 1432-1106
    Keywords: Area 19 ; Visual noise ; Detection performance ; Signal-to-noise thresholds ; S/N profiles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The contribution of area 19 to pattern discrimination in the cat was studied by single cell recordings in this area and by behavioural experiments before and after bilateral lesions. In order to make quantitative comparisons between behavioural performance and that of cell systems, we introduced a new parameter that characterizes visual neurons by their signal-to-noise (S/N) thresholds. A structured visual background made up of Gaussian visual broadband noise which could be moved was superimposed on the signal (moving bars or outline patterns) and the S/N characteristics of the response were determined by varying the signal intensity. The detection performance of cats after bilateral lesion of area 19 showed no deficits. Only for slowly (11 deg/s) or quickly (110 deg/s) moving patterns, or when the background was moved relative to stationary patterns, did we find slight, but significant deficits in the low S/N range. However, when the S/N ratios were higher than 5, all cats achieved their full preoperative performances and no deficits remained. The S/N thresholds of neurons in area 19 were much higher than those found for neurons in areas 17 and 18. The lowest thresholds were found with a stationary background. Introduction of relative velocity between background and bar resulted in intermediate thresholds and the highest thresholds were observed for stimulus configurations lacking relative velocity. These effects correspond to the performance of the intact animal, in which introduction of relative motion increases the performance. The S/N thresholds did not correlate with levels of spike rate recorded at high S/N ratios, direction selectivity or speed preference, indicating that S/N threshold measurements provide a significant additional description of visual neurons. A limited number of area 19 cells recorded in area 17/18 lesioned animals showed very similar thresholds suggesting that this property may be independent of the intactness of areas 17 and 18. The residual performance by 17/18 lesioned cats in detecting small patterns corresponds well to the characteristics of the single cells of area 19. This suggests that area 19 might be able to make a considerable contribution to this task when areas 17/18 are eliminated, though by itself it seems not to be able to sustain the level of performance mediated by them. The contribution of area 19 is restricted to performances at high S/N ratios only. In contrast to what was found for areas 17 and 18, area 19 makes no essential contribution to lowering the S/N ratio at which the system is able to detect the presence of a pattern in a background of irrelevant detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230843
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  • 9
    Electronic Resource
    Electronic Resource
    Extensive monosynaptic inhibition of ventral respiratory group neurons by augmenting neurons in the Bötzinger complex in the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 639-648 
    Details
    ISSN: 1432-1106
    Keywords: Respiratory neurons ; Antidromic mapping ; Spike-triggered averaging ; Respiratory control ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Axonal projections and synaptic connectivity of expiratory Bötzinger neurons with an augmenting firing pattern (Bot-Aug neurons) to neurons in the ipsilateral ventral respiratory group (VRG) were studied in anaesthetized cats. Antidromic mapping revealed extensive axonal arborizations of Bot-Aug neurons (24 of 45) to the rostral or caudal VRG, with some having arbors in both regions. Of 234 pairs of neurons studied with intracellular recording and spike-triggered averaging, monosynaptic inhibitory postsynaptic potentials (IPSPs) were evoked in 49/221 VRG neurons by 38/98 Bot-Aug neurons. The highest incidence of monosynaptic inhibition was found in inspiratory bulbospinal neurons (10 of 23 tested). Evidence was also found for monosynaptic inhibition, by a separate group of Bot-Aug neurons, of expiratory bulbospinal neurons (12/58), while excitatory postsynaptic potentials (EPSPs) were identified in another two of these neurons. In addition, monosynaptic IPSPs were recorded from 13 of 53 identified laryngeal motoneurons, and from 14 of 100 respiratory propriobulbar neurons. Presumptive disynaptic IPSPs were recorded from 11 of the 221 VRG neurons. We conclude that Bot-Aug neurons exert widespread inhibition on all major neuron categories in the ipsilateral VRG, and should be regarded as an important element in shaping the spatiotemporal output pattern of both respiratory motoneurons and premotor neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423514
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  • 10
    Electronic Resource
    Electronic Resource
    A specific subgroup of non-length tuned relay cells in the feline dorsal lateral geniculate nucleus (1990)
    Springer
    Experimental brain research 82 (1990), S. 33-39 
    Details
    ISSN: 1432-1106
    Keywords: Dorsal lateral geniculate nucleus ; Non-length tuned cells ; Acetylcholine ; Relay cells ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Length tuning was first described for the “hypercomplex cell category” in the visual cortex. However it has subsequently become apparent that cells in the dorsal lateral geniculate nucleus (dLGN) also exhibit a high degree of length tuning and that for the majority of the population this matches or exceeds that associated with cortical hypercomplex cells (Cleland et al. 1983; Jones and Sillito 1987). In this paper we describe a distinct subpopulation of dLGN Y cells that lack length tuning. These cells were also characterised by poor centre-surround antagonism, and tended to be located close to laminar borders. They appeared to constitute 25% of the Y cell population. Following recent evidence showing relay cells to be powerfully excited by acetylcholine, and inhibitory interneurones to be inhibited, we have examined the responses of these non-length tuned cells to iontophoretic application of acetylcholine. Their brisk excitatory responses suggest that these cells are in fact relay cells. Their presence raises the possibility of a discrete non-length tuned component to the geniculate input to the cortex, and has potentially important implications for the way in which synaptic processes contributing to the length tuning profiles of visual cortical cells are modelled.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230835
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  • 11
    Electronic Resource
    Electronic Resource
    Retrograde transneuronal transport of wheat-germ agglutinin to the retina from visual cortex in the cat (1990)
    Springer
    Experimental brain research 82 (1990), S. 67-76 
    Details
    ISSN: 1432-1106
    Keywords: Retina ; Visual cortex ; Retrograde transneuronal transport ; Wheat-germ agglutinin ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Injections of peroxidase-conjugated wheatgerm agglutinin (WGA-HRP) were made into areas 17 or 18 of cats. After survivals of 3–7 days, foci of HRP-labeled ganglion cells were found at the appropriate topographic locations in the retinas. The labeling was interpreted as resulting from retrograde transneuronal transport through the lateral geniculate nucleus. This phenomenon offers a new and simple technique for the study of retinotopic maps in visual cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230839
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  • 12
    Electronic Resource
    Electronic Resource
    Anatomy of soleus α-motoneurone dendrites in normal cats and in cats subjected to chronic postnatal tenotomy or overload of the soleus muscle (1990)
    Springer
    Experimental brain research 80 (1990), S. 34-43 
    Details
    ISSN: 1432-1106
    Keywords: α-motoneurones ; Dendrites ; Tenotomy ; Overload ; Development ; Plasticity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The anatomy of intracellularly HRP-labeled soleus α-motoneurone dendrites was studied both in normal adult cats (“normal soleus”, NS) and in adult cats which at a postnatal age of 5–7 days had been subjected to chronic tenotomy of either the soleus muscle (“tenotomized soleus”, TS), or all the soleus synergists contributing to the achilles tendon (“overloaded soleus”, OS). A set of “structural rules” seemed to govern the architecture of normal soleus α-motoneurone dendrites. Thus, the dendrites branched dichotomously and the number of daughter branches originating from a preterminal branch was proportional to the diameter of that parent branch. Branch diameter decreased across branching points according to the “3/2 power rule” of Rall (1959). Branching occurred down to a preterminal branch diameter of about 0.8 μm. Through all branch orders there existed a quite precise relation between the diameter of a preterminal branch and the membrane area of its distal dendritic arborization. The average dendritic path distance from soma to termination was not closely related to the diameter of the stem dendrite, since thick stem dendrites rather generated more profusely branched arborizations than thin stem dendrites. As a corollary of these characteristics close relations existed between the dendritic stem diameter on one hand, and the total number of branches, combined dendritic length, total dendritic membrane area and total volume, on the other. In the OS material, the dendrites were not different from those of normal soleus motoneurone dendrites. In the TS material, the dendrites were less branched and had greater dendritic path lengths, although the relations between various size-parameters within the dendrites were not significantly altered compared with normal dendrites. It was concluded that the change in branching pattern was due to a net elimination of dendritic branches following the muscle tenotomy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228844
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  • 13
    Electronic Resource
    Electronic Resource
    Release of glutamate and aspartate from the visual cortex of the cat following activation of afferent pathways (1990)
    Springer
    Experimental brain research 80 (1990), S. 447-455 
    Details
    ISSN: 1432-1106
    Keywords: Glutamate ; Visual cortex ; HPLC ; Pushpull cannula ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To test the possibility that glutamate (Glu) and aspartate (Asp) are transmitters at geniculo-cortical synapses in the visual cortex of the cat, we studied the release of amino acids from the striate cortex consequent upon visual and electrical stimulation of the dorsal lateral geniculate nucleus (LGN) and of the optic tract, using push-pull cannulae. We perfused a discrete region that included layer IV of the cortex with an artificial cerebrospinal fluid (aCSF) and analysed the amino acid content of these perfusates by high-performance liquid chromatography (HPLC). Significant increases only of Glu and Asp were obtained among all 17 amino acids measured, except for gamma-aminobutyric acid (GABA), during electrical stimulation of the afferent pathways. Visual stimulation by stroboscopic diffuse flashes of light increased the level of Glu released, but did not change that of Asp significantly. The level of GABA released did not change during diffuse flash stimulation, suggesting that the increase in Glu was not derived from cortical neurons. The increases in release of Glu/Asp were not seen when the perfusion medium was replaced with a Ca2+-free, high-Mg2+-containing solution. The basal (resting) release of Glu/Asp in the absence of stimulation also was decreased during perfusion with Ca2+-free/high-Mg2+ solutions. Intraocular injections of a sodium channel blocker, tetrodotoxin (TTX), resulted in a remarkable decrease in the basal release of Glu. These results suggest that Glu is released as an excitatory synaptic transmitter at least from terminals of geniculo-cortical afferents and Asp from axons of a certain type of visual cortical neuron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227986
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  • 14
    Electronic Resource
    Electronic Resource
    Texture discrimination by cells in the cat lateral geniculate nucleus (1990)
    Springer
    Experimental brain research 82 (1990), S. 48-66 
    Details
    ISSN: 1432-1106
    Keywords: Texture segregation ; Textons ; Lateral geniculate nucleus ; Figure ground discrimination ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The spontaneous segregation of texture areas is an impressive perceptual phenomenon, the neural basis of which is not yet understood. In the texton concept (Julesz and Bergen 1983; Julesz 1984, 1986) it is assumed that the visual system analyzes a stimulus for certain features (‘textons’) the spatial distribution of which is pre-attentively registered and may provide the percept of dissected texture areas. Supposed textons are blobs of a given size, oriented lines, line intersections and line terminators, suggesting that texture analysis is exclusively mediated by form-specific filters at higher, e.g. cortical, processing levels. This paper investigates the contribution of cells in the cat lateral geniculate nucleus (LGN) to segregation of typical texton differences. The results indicate that LGN cells, though not resembling the supposed texton filters, often distinguished textured arrangements of such features on the basis of a variety of other visual cues, such as global or local variations in mean luminance or differences in spatial frequency composition. Thus, cells responded to texture borders between areas differing in the size or the density of texture elements and often revealed differential firing rates to textures differing by the crossing or the terminator feature. For textures with differences in line orientation, however, only small variations of the firing rate were seen. In summary, the observations suggest a means of texture representation in the cat LGN which is different from recent concepts of texture segregation in man. For given pair of textures, cells with receptive fields larger than, or similar to the texture raster respond to global and local luminance variations between areas and, in particular, to differences in their spatial frequency composition. These cells, hence, may signal the global texture difference without encoding spatial details of the pattern from which texton features could be identified. Cells with receptive fields small in comparison to texture elements transfer all the information necessary for analyzing these elements in detail, but themselves are relatively insensitive to global texture differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230837
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  • 15
    Electronic Resource
    Electronic Resource
    Effects of alternating monocular occlusion on the development of visual callosal connections (1990)
    Springer
    Experimental brain research 83 (1990), S. 200-209 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Development ; Vision ; Alternating monocular occlusion ; Cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During normal postnatal development there is a partial elimination of the callosal projections of cortical areas 17 and 18 in the cat. Visual experience early in life can modulate this process. In the present study, we investigated how restricting visual experience to alternating monocular occlusion affects the development of the callosal connections of cortical areas 17 and 18. Alternating monocular occlusion exaggerates the normally occurring partial elimination of immature callosal projections: it causes a significant reduction in the total number of neurons in the supragranular layers that send an axon through the corpus callosum and marginally increases the distribution of these neurons across areas 17 and 18. Examination of these data in the context of the effects of other types of abnormal early visual experience on the corpus callosum and on the anatomy and physiology of areas 17 and 18 indicates that the postnatal development of the corpus callosum is under the control of multiple, interacting influences which differ in the magnitude and quality of their effects. The data also support the conclusion, drawn from our results in prior studies, that normal visual stimulation is necessary for the stabilization of the normal complement of callosal projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232209
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  • 16
    Electronic Resource
    Electronic Resource
    Frequency dependent corticofugal excitation of principal cells in the cat's dorsal lateral geniculate nucleus (1990)
    Springer
    Experimental brain research 79 (1990), S. 313-318 
    Details
    ISSN: 1432-1106
    Keywords: Dorsal lateral geniculate nucleus ; Principal cells ; Cortico-geniculate system ; Frequency enhancement ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Excitatory postsynaptic potentials (EPSPs) were evoked in principal cells of the cat's dorsal lateral geniculate nucleus by electrical stimulation of cortico-geniculate fibres. The EPSPs had a pronounced frequency sensitivity. They were barely detectable at stimulation frequencies below 3 Hz but increased dramatically in size at higher frequencies. At 30–50 Hz their amplitude typically exceeded that of EPSPs from optic tract fibres. A prominent EPSP potentiation was also obtained with pair pulse stimulation. The findings are discussed in relation to the hypothesis that the cortico-geniculate system serves as a variable gain regulator for the visual input to the cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608240
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  • 17
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    Electronic Resource
    Movement and muscle activity during contact placing of the forelimb and their relations to other postural reactions in the cat (1990)
    Springer
    Experimental brain research 79 (1990), S. 373-382 
    Details
    ISSN: 1432-1106
    Keywords: Contact placing ; Forelimb muscles ; Forelimb movements ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Forelimb trajectory and the activity of eight muscles operating at the elbow, wrist and digit joints were compared during the contact placing reaction, during the swing phase of locomotion and during reactions induced by swing perturbations, to verify the hypothesis that common neural mechanisms are involved in these reactions. Both the patterns of muscle activation and forelimb kinetics during the placing reaction greatly differed from those during the swing phase of locomotion. Both similarities and differences have been found between the placing reaction and the reaction to swing perturbations. Similar latencies, patterns of muscle activation and trajectories have been found for elbow movements while considerable differences were seen in the movements of distal joints. Both reactions started with a backward and upward movement at the proximal joints which was accompanied by a locking at the elbow. At the distal joints, tactile stimuli evoked first a wrist ventroflexion during the placing reaction, whereas they induced wrist dorsiflexion to swing perturbations. A further difference between these two reactions appeared at the beginning of the extension which was highly passive during the reaction to swing perturbation and active during contact placing. These results suggest that some common, most likely spinal, reflexes are involved at the beginning of the two reactions while their extension phases are controlled in a different way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608247
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  • 18
    Electronic Resource
    Electronic Resource
    Corticofugal feedback influences the responses of geniculate neurons to moving stimuli (1990)
    Springer
    Experimental brain research 79 (1990), S. 441-446 
    Details
    ISSN: 1432-1106
    Keywords: LGN ; Corticofugal feedback ; Moving stimuli ; Texture ; Velocity response curve ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Geniculate cell responses to moving bars and moving texture were compared in normal cats and in cats in which the corticofugal feedback was removed by cortical ablation. In experimental animals the response strength and the velocity upper cutoff assessed with a moving bar was reduced compared to control animals. The strength of response to texture decreased even more after cortical ablation, which also changed the response pattern of X cells to moving texture. These data suggest that corticofugal feedback contributues to the geniculate responses to moving stimuli and in particular to moving texture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608257
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  • 19
    Electronic Resource
    Electronic Resource
    Activity of interneurons within the L4 spinal segment of the cat during brainstem-evoked fictive locomotion (1990)
    Springer
    Experimental brain research 80 (1990), S. 290-295 
    Details
    ISSN: 1432-1106
    Keywords: Interneurons ; Locomotion ; Group II afferents ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular recordings from interneurons located in the L4 spinal segment were made during fictive locomotion produced by electrical stimulation of the mesencephalic locomotor region (MLR) in the paralysed decerebrate cat. Only interneurons within the L4 segment which received group II input from quadriceps, sartorius or the pretibial flexor muscle afferents and which had axonal projections to motor nuclei in L7 were selected for analysis. During the fictive step cycle two thirds of these interneurons fired action potentials during the time of activity in the ipsilateral hindlimb flexor neurograms. These cells were also less responsive to peripheral input during the extension phase of the fictive locomotion cycle. The remaining one third of the interneurons examined were not rhythmically active during locomotion. The possible contributions of the midlumbar interneurons to motoneuron activity during locomotion are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228156
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  • 20
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    Electronic Resource
    Interconnections of the auditory cortical fields of the cat with the cingulate and parahippocampal cortices (1990)
    Springer
    Experimental brain research 80 (1990), S. 501-511 
    Details
    ISSN: 1432-1106
    Keywords: Auditory cortex ; Corticocortical connections ; Cingulate cortex ; Parahippocampal cortex ; Limbic system ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The interconnections of the auditory cortex with the parahippocampal and cingulate cortices were studied in the cat. Injections of the anterograde and retrograde tracer WGA-HRP were performed, in different cats (n = 9), in electrophysiologically identified auditory cortical fields. Injections in the posterior zone of the auditory cortex (PAF or at the PAF/AI border) labeled neurons and axonal terminal fields in the cingulate gyrus, mainly in the ventral bank of the splenial sulcus (a region that can be considered as an extension of the cytoarchitectonic area Cg), and posteriorly in the retrosplenial area. Labeling was also present in area 35 of the perirhinal cortex, but it was sparser than in the cingulate gyrus. Following WGA-HRP injection in All, no labeling was found in the cingulate gyrus, but a few neurons and terminals were labeled in area 35. In contrast, no or very sparse labeling was observed in the cingulate and perirhinal cortices after WGA-HRP injections in the anterior zone of the auditory cortex (AI or AAF). A WGA-HRP injection in the cingulate gyrus labeled neurons in the posterior zone of the auditory cortex, between the posterior ectosylvian and the posterior suprasylvian sulci, but none was found more anteriorly in regions corresponding to AI, AAF and AII. The present data indicate the existence of preferential interconnections between the posterior auditory cortex and the limbic system (cingulate and parahippocampal cortices). This specialization of posterior auditory cortical areas can be related to previous observations indicating that the anterior and posterior regions of the auditory cortex differ from each other by their response properties to sounds and their pattern of connectivity with the auditory thalamus and the claustrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227991
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  • 21
    Electronic Resource
    Electronic Resource
    Brainstem genesis of reserpine-induced ponto-geniculo-occipital waves: An electrophysiological and morphological investigation (1990)
    Springer
    Experimental brain research 81 (1990), S. 533-544 
    Details
    ISSN: 1432-1106
    Keywords: Ponto-geniculo-occipital (PGO) waves ; Peribrachial area ; Central tegmental field ; Superior colliculus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Several experimental results indicate that the peribrachial (PB) cholinergic area of the pedunculopontine nucleus is the final relay for the transfer of brainstem-generated pontogeniculo-occipital (PGO) waves to the thalamus. However, the mechanisms underlying the PGO-related activity of PB neurons remain unknown. In order to study these mechanisms, single unit recordings in the PB area were performed in reserpinized cats. Because PGO waves are closely related to rapid eye movements, our microelectrode explorations were also aimed to some structures of the preoculomotor network, namely, the superior colliculus (SC) and parts of the central tegmental field (FTC). We have found several classes of PGO-on cells in the PB area, most of them descharging 80 ms or less before the peak of PGO waves. These cell-classes comprised high-frequency bursting cells, slow-frequency bursting cells, and neurons discharging single spikes or doublets. Intracellular recordings showed that PGO-on single spikes arise from conventional excitatory postsynaptic potentials. Among PGO-related cells in structures outside the PB limits, it was found that most SC cells discharge during or after the PGO, whereas FTC cells increase their discharge rate several hundreds of ms before PGO waves, thus indicating that PGO waves are elaborated long before the activition of PB neurons. Massive retrograde labeling was found in FTC following horseradish peroxidase injections into the PB area. We suggest that long-lead FTC neurons provide an excitatory input to PGO-on PB neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423502
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  • 22
    Electronic Resource
    Electronic Resource
    The vestibular nuclei of the cat receive a primary afferent projection from receptors in extraocular muscles (1990)
    Springer
    Experimental brain research 81 (1990), S. 654-658 
    Details
    ISSN: 1432-1106
    Keywords: Eye muscle receptors ; Ganglionic cells ; Central projection ; Vestibular nuclei ; WGA-HRP ; Double labelling ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The vestibular nuclei of adult cat were injected with retrogradely transported tracers, WGA-HRP or fluorescent Diamidino-Yellow. Labelled cells were found in the caudal half of the ipsilateral mesencephalic trigeminal nucleus, in the area where ganglionic cells of the sensory receptors in the extraocular muscles have previously been described. Double labelling experiments were carried out with Diamidino Yellow injected in vestibular nuclei and Fast Blue in extraocular muscles. Some cells in the mesencephalic trigeminal nucleus were found to contain both tracers, providing evidence that vestibular neurons do receive direct afferent signals from extraocular muscles. Therefore, this anatomical demonstration suggests a direct feed-back control between the extraocular muscle receptors and the vestibular nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423516
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  • 23
    Electronic Resource
    Electronic Resource
    Directionality of cat striate cortical neurones: contribution of suppression (1990)
    Springer
    Experimental brain research 81 (1990), S. 417-425 
    Details
    ISSN: 1432-1106
    Keywords: Direction selectivity ; Directional tuning ; Visual cortex ; Area 17 ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Direction-selective or direction-biased striate cortical neurones were assessed for absence or incidence of suppression of firing, maximal at 90° or 180° (“null” suppression) to the optimal direction, in 327 neurones recorded from the striate cortex of cats anaesthetized with N2O/O2/halothane. Stimuli were light or dark bars moving over uniform or stationary textured back-grounds; or square-wave gratings of optimal spatial frequency and velocity. Five identified directionality groups were correlated with neuronal class and a range of other receptive field properties. Suppression maximal at 90° to optimum was common amongst direction-biased neurones, rare amongst direction-selective neurones. In the latter group, null suppression (maximal at 180° to optimum) was more prevalent than at 90°. Standard complex cells constituted the majority of complex neurones. They were more commonly direction-biased and less commonly showed suppression than special complex cells. The latter comprised the majority of direction-selective neurones with 180° suppression. Endstopping was seen more frequently in special complex cells, but for each functional class was similarly distributed between the different directionality groups. Based on the mean and mode of partially overlapping distributions, for all neuronal classes direction-selective neurones were more broadly tuned than direction-biased neurones. Special complex neurones were appreciably more broadly tuned than standard complex neurones; those with suppression at 180° were the most broadly tuned neurones in the cortex. Direction-biased neurones with suppression at 90° to optimum were more sharply tuned than those lacking such suppression. Direction-selective neurones had larger receptive fields than direction-biased neurones. In both groups receptive fields decreased in size in the sequence: intermediate complex 〉 standard complex 〉 special complex 〉 simple. Resting discharge was highest amongst direction-selective neurones with 180° suppression, lower in those with 90° suppression or those lacking it, and lowest amongst direction-biased neurones. With the possible exception of the minority of neurones that were silent, low levels of resting discharge have not seriously prejudiced either neuronal categorization or comparisons of tuning selectivity. The pattern which emerges is that suppression maximal in directions orthogonal to the preferred direction/orientation is more commonly associated with sharp tuning and directionbias, whereas “null” suppression, in the direction opposite that preferred, is associated with broad tuning, direction-selectivity, high resting discharge levels and strong texture sensitivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228135
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  • 24
    Electronic Resource
    Electronic Resource
    Integration in descending motor pathways controlling the forelimb in the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 447-461 
    Details
    ISSN: 1432-1106
    Keywords: C3-C4 propriospinal neurones ; Forelimb segments ; Lateral reticular nucleus ; Pyramid ; Motoneurones ; Ia inhibitory interneurones ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Collateralization and termination of single C3-C4 propriospinal neurones (PNs) have been studied in the C6-Th1 segments of the cat using two methods: threshold mapping for antidromic activation of C3-C4 PNs and intra-axonal injection of horseradish peroxidase. Low threshold points for antidromic activation of C3-C4 PNs were found in the region of different motor nuclei in lamina IX both at one level and at different segmental levels, in all parts of lamina VII, in the lateral part of lamina VI and in the dorsal and ventral parts of lamina VIII. Collaterals were found from C6 to Th1. A marked decrease of conduction velocity of the stem axon occurred in the caudal region of termination, while it was almost constant in the rostral region of termination. HRP was injected iontophoretically in C6-Th1 into stem axons of neurones, which were activated antidromically from the ventral part of the lateral funiculus in C5/C6, from the lateral reticular nucleus (LRN) and monosynaptically from the corticospinal fibres (stimulated in the contralateral pyramid) which were transected in C5/C6. Reconstruction of successfully stained stem axons, revealed collaterals with terminals on presumed motoneurones in different parts of lamina IX and on interneurones in laminae IV–VIII. These findings confirm previous results which showed monosynaptic projections from C3-C4 PNs to forelimb motoneurones and Ia inhibitory interneurones. With respect to termination in the region of the motoneurones in lamina IX and in the region of Ia inhibitory interneurones in lamina VII, three patterns were found: 1) termination mainly in lamina IX (n=1) 2) termination in laminae IX and VII (n=15) and 3) termination mainly in lamina VII (n=2). However, in some cases the same stem axon gave off collaterals which terminated either on motoneurones in lamina IX or on presumed Ia inhibitory interneurones in lamina VII. Furthermore, when the stem axons had collaterals which terminated in different motor nuclei only some of these collaterals had additional terminations on presumed Ia inhibitory interneurones. This result suggest that C3-C4 PNs do not follow a strict Ia pattern of reciprocal innervation. It is tentatively proposed that the difference of innervation may be related to the type of multi-joint movement, such as target-reaching with the forelimb, which has been shown to be controlled by the C3-C4 PNs. Termination in laminae VI, VIII and different parts of lamina VII indicates that C3-C4 PNs also project to other types of neurones than motoneurones and Ia inhibitory interneurones. Injection of wheat germ agglutinated horseradish peroxidase (WGA-HRP) laterally in laminae VI-VII in C3 and C4 caused anterograde labelling of axonal bundles from neurones in these segments. Labelled axons were found mainly in the lateral funiculus with the highest density in the ventral part. These axons could be traced throughout the forelimb segments and also to the LRN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423494
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  • 25
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    Electronic Resource
    Axonal trajectories of inhibitory vestibulocollic neurons activated by the anterior semicircular canal nerve and their synaptic effects on neck motoneurons in the cat (1990)
    Springer
    Experimental brain research 82 (1990), S. 14-24 
    Details
    ISSN: 1432-1106
    Keywords: Anterior semicircular canal ; Vestibular nuclei ; Vestibulocollic ; Neck motoneuron ; Unitary IPSP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Somatic location, axonal trajectories and synaptic effects of inhibitory vestibulocollic neurons which were activated by selective stimulation of the anterior semicircular canal nerve (ACN) were studied in the anesthetized cat. ACN stimulation evoked disynaptic inhibitory postsynaptic potentials (IPSPs) in neck flexor motoneurons. This was seen in all the (64/64) tested motoneurons innervating the ipsilateral (i-) longus capitis (LC) and the i-sternocleidomastoideus (SCM) muscles and in 86% (38/44) of the motoneurons innervating the contralateral (c-) LC muscle. The inhibitory relay neurons, identified by orthodromic and antidromic responses to stimulation of the ACN and the i- and c-LC motoneuron pools, were classified as VCi (vestibulocollic neurons sending an axon to the i-LC motoneuron pool) and VCc (vestibulocollic neurons sending an axon to the c-LC motoneuron pool) neurons. Neither VCi nor VCc neurons were activated antidromically by localized stimulation of the ascending medial longitudinal fasciculus (asc. MLF) or the 3rd nuclei. They were located in the medial, descending and ventral lateral vestibular nuclei. It was also observed that VCi neurons produced unitary IPSPs in i-LC and i-SCM motoneurons in the C1 segment. Inhibitory synapses were estimated to be on the cell somata and/or the proximal dendrites of the motoneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230833
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  • 26
    Electronic Resource
    Electronic Resource
    Interlimb coordination during fictive locomotion in the thalamic cat (1990)
    Springer
    Experimental brain research 82 (1990), S. 536-546 
    Details
    ISSN: 1432-1106
    Keywords: Locomotion ; Interlimb coordination ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Efferent discharges in muscle nerves of the four limbs were recorded simultaneously during spontaneous fictive locomotion in thalamic cats with the goal of understanding how the central nervous system controls interlimb coordination during stepping. The onset of the bursts of activity in the nerve of a selected flexor muscle in each limb allowed the temporal and the phase relationships between the fictive step cycle of a pair of limbs to be determined. Our main results are the following: 1) the fictive step cycles of the two forelimbs are always strictly alternated whereas the phasing of the step cycles of either the two hindlimbs or pairs of homolateral or diagonal limbs is more variable; 2) the time interval between the onsets of the flexor bursts of one of the two pairs of diagonal limbs is independent of the step cycle duration; 3) distinct patterns of interlimb coordination exist during fictive locomotion; a small number of patterns of coordination involving all four limbs, which correspond to the walking and the trotting gaits in the intact cat, occur very frequently. The results demonstrate that the central nervous system deprived of phasic afferent inputs from the periphery has the capacity to generate most of the patterns of interlimb coordination which occur during real locomotion. They further support the view that the central pattern of interlimb coordination essentially results from diagonal interactions between a forelimb generator for locomotion and a hindlimb one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228795
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  • 27
    Electronic Resource
    Electronic Resource
    Spatial properties of vertical eye movement-related neurons in the region of the interstitial nucleus of Cajal in awake cats (1990)
    Springer
    Experimental brain research 79 (1990), S. 25-42 
    Details
    ISSN: 1432-1106
    Keywords: Vestibulo-ocular reflex ; Vertical semicircular canals ; Spatial transformation ; Null point analysis ; Interstitial nucleus of Cajal ; Burst-tonic neuron ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Maximal activation directions of vertical burst-tonic and tonic neurons in the region of the interstitial nucleus of Cajal (INC) were examined in alert cats during vertical vestibulo-ocular reflex induced by sinusoidal rotation (at 0.11 Hz±10 deg, or 0.31 Hz±5 deg) in a variety of vertical planes using a null point analysis. The results were compared with the angles of anatomical and functional planes of vertical canals reported by Blanks et al. (1972) and Robinson (1982), and with the angles of vertical eye muscles measured in this study and by Ezure and Graf (1984). 2. Maximal activation directions of 23 cells (21 burst-tonic and 2 tonic neurons) were determined from their responses during rotation in 4 or more different vertical planes. All cells showed sinusoidal gain curves and virtually constant phase values except near the null regions, suggesting that their responses were evoked primarily by canal inputs. Phase values of 5 cells near the null regions depended on the rotation plane, suggesting additional otolith inputs. We used a measurement error range of ±10 deg for calculating the maximal activation directions from the null regions of individual cells and the values of error ranges of null calculation. Of the 23, the maximal activation directions of 7 cells were outside the measurement error ranges of vertical eye muscle angles and within the ranges of vertical canal angles (class A), those of 5 cells were within the ranges of eye muscle angles and outside the ranges of vertical canal angles (class B), and those of the remaining 11 cells were in the overlapping ranges for both angles (class C). Even if only the cells in which 5 or more measurement points were taken to determine maximal activation directions (n = 15), the results were similar. During vertical rotation with the head orientation +60 deg off the pitch plane, dissociation of cell activity and vertical compensatory eye movement was observed in 5 cells in class A or C that had null angles near +45 deg. These results suggest that the cells in class A and B carried individual vertical canal and oculomotor signals, respectively, although it is difficult to tell for the majority of cells (class C) which signals they reflected. Some cells in class A and C were antidromically activated from the medial longitudinal fasciculus at the level of abducens nucleus, suggesting that the signals carried by these cells may be sent to the lower brainstem. 3. Most burst-tonic neurons did not respond to horizontal rotation; significant responses were obtained in only 3 of 10 cells tested for which the gain was only 14–17% of their maximal vertical gain. There was no clear difference in gain or phase values of the responses to vertical rotation, or in eye position sensitivity (during spontaneous saccades) between cells whose responses coincided with individual vertical canal angles and those matching the angles of vertical recti muscles. The values of phase lag (re head acceleration during pitch rotation) and eye position sensitivity of these cells are still smaller compared to those of extraocular motoneurons reported by Delgado-Garcia et al. (1986), although they were larger than those of secondary vestibulo-ocular neurons (Perlmutter et al. 1988). All these results suggest that the signals carried by burst-tonic and tonic neurons in the INC region are different from oculomotor signals. 4. Similar analysis was done for comparison for 19 other cells that did not show close correlation with spontaneous eye movement but whose activity was clearly modulated by pitch rotation (pitch cells). More than a half (10/19) had maximal activation directions outside the measurement error ranges of individual vertical canal angles, and many shifted towards roll. Horizontal rotation produced responses with higher gain than burst-tonic neurons, suggesting a difference in the spatial response properties of burst-tonic and tonic neurons on one hand and pitch cells on the other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228871
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  • 28
    Electronic Resource
    Electronic Resource
    Neuronal activity related to vertical eye movement in the region of the interstitial nucleus of Cajal in alert cats (1990)
    Springer
    Experimental brain research 79 (1990), S. 43-64 
    Details
    ISSN: 1432-1106
    Keywords: Vertical eye movement ; Burst-tonic neuron ; Tonic neuron ; Interstitial nucleus of Cajal ; Saccade ; Vestibulo-ocular reflex ; Temporal conversion ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary (1) Discharge characteristics of neurons in the region of the interstitial nucleus of Cajal (INC) were studied in alert cats during spontaneous or visually induced eye movement and sinusoidal vertical (pitch) rotation. Activity of a majority of cells (n = 68) was closely related to vertical eye position with or without bursting activity during on-direction saccades. They were called vertical burst-tonic (n = 62) and tonic (n = 6) neurons. Mean discharge rates for individual cells when the eye was near the primary position ranged from 35 to 133 (mean 75) spikes/s with a coefficient of variation (CV) ranging from 0.04 to 0.29 (mean 0.15). Average rate position curves were linear for the great majority of these cells with a mean slope of 3.9 ± 1.2 SD spikes/s/deg. (2) The burst index was defined as the difference in discharge rate between maximal rate during an on-direction saccade and the tonic rate after the saccade. The values of mean burst index for individual cells ranged from 8 to 352 (mean 135) spikes/s. Tonic neurons had a burst index lower than 60 spikes/s and were distributed in the lower end of the continuous histogram, suggesting that burst-tonic and tonic neurons may be a continuous group with varying degrees of burst components. During off-direction saccades, a pause was not always observed, although discharge rate consistently decreased and pauses were seen when saccades were made further in the off-direction toward recruitment thresholds. Significant positive correlation was observed between average discharge rate during off- as well as on-direction saccades and tonic discharge rate after saccades for individual cells, which was not due to cats making saccades mainly from the primary position. (3) During pitch rotation at 0.11 Hz (±10 deg), burst-tonic and tonic neurons had mean phase lag and gain of 128 (±13 SD) deg and 4.2 (±1.7 SD) spikes/s/deg/s2 relative to head acceleration. During pitch rotation of a wide frequency range (0.044–0.495 Hz), the values of phase lag were mostly constant (120–140 deg), while simultaneously recorded vertical VOR showed the mean phase lag of 178 deg. Vertical eye position sensitivity and pitch gain (re head position) showed significant positive correlation. (4) Comparison of the discharge characteristics of vertical burst-tonic and tonic neurons with those of secondary vestibulo-ocular neurons (Perlmutter et al. 1988) and extraocular motoneurons (Delgado-Garcia et al. 1986) in alert cats suggests that signals carried by burst-tonic and tonic neurons are partially processed signals in vertical VOR and saccades, and different from oculomotor signals. (5) The INC region also contained many cells that did not belong to the above groups but whose activity was clearly modulated by pitch rotation (called pitch cells for the present study, n = 44). Many (n = 23) showed some correlation with vestibular quick phases, and some (n = 12) with visually elicited eye movement, although they showed significantly lower and more irregular discharge rates than burst-tonic and tonic neurons (mean discharge rate when the eye was near the primary position 34, range 3–91, spikes/s; mean CV 0.61, range 0.15–1.7). During pitch rotation they showed the mean phase lag and gain of 119(±26 SD) deg and 3.2(±2.1 SD) spikes/s/deg/s2. Some cells showed a much lower phase lag of about 90 deg. (6) More than half the burst-tonic, tonic and pitch cells tested were antidromically activated by stimuli applied to the ponto-medullary medial longitudinal fasciculus at the level of abducens nucleus, while none of them were activated from the inferior olive, suggesting that vertical eye position signals carried by some burst-tonic and tonic neurons are carried to the lower brainstem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228872
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    Electronic Resource
    The laminar distribution and postnatal development of serotonin-immunoreactive axons in the cat primary visual cortex (1990)
    Springer
    Experimental brain research 81 (1990), S. 257-266 
    Details
    ISSN: 1432-1106
    Keywords: Serotonin ; Area 17 ; Postnatal development ; Immunohistochemistry ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The laminar distribution and postnatal development of profiles immunoreactive to antibodies directed against serotonin (5-hydroxytryptamine, 5-HT) have been investigated in the primary visual cortex (striate cortex, area 17) of cats. In the adult cat, profiles with serotonin-like immunoreactivity consist exclusively of fibers which exhibit laminar differences in density and predominant orientation. Immunoreactive fibers are dense in layers I–III, less dense in layer V, and sparse in layers IV and VI. In layers I and VI the trajectories of these fibers are mainly tangential to the pial surface; in layers II–V they are predominantly radial and more irregular. The vast majority of immunoreactive fibers consists of fine axons with frequent small varicosities. In addition, there are a few thick axons. In 2-week-old cats, immunoreactive fibers are sparsely distributed through layers II–V. By 4 weeks, fiber density has decreased still further in layer IV and increased in layers I–III. By 6 weeks, the laminar pattern resembles that of adult cats except that fiber density is still lower than in adults. At three months of age, the mature pattern is established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228114
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  • 30
    Electronic Resource
    Electronic Resource
    Spatial frequency thresholds of single striate cortical cells in neonatal corpus callosum sectioned cats (1990)
    Springer
    Experimental brain research 82 (1990), S. 617-627 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Visual acuity ; Spatial frequency threshold ; Striate cortex ; Development ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following section of the corpus callosum at 1–6 postnatal weeks in cats, behavioral visual acuity was measured binocularly and monocularly from 6–29 postnatal weeks; physiological determination of spatial frequency thresholds of single striate cortical cells was performed when the cats were at least 8 months old. Results were compared between cats with callosum section at each postnatal week, as well as with normal cats. Cats with callosotomy at 1–3 postnatal weeks had deficits in behavioral visual acuity, and the deficits were greatest in the youngest operated cats. Cats with callosotomy at 1–2 postnatal weeks failed to resolve as high spatial frequencies as did normal cats, and the resolution of the 1 week operated cats was lower than the resolution of the 2 week operated cats. Cats with callosotomy at 3–6 postnatal weeks had spatial frequency thresholds that were equivalent to those of normal cats. To determine what kinds of striate cells had reduced spatial resolution following neonatal corpus callosum section, cells were categorized according to class (Simple, Complex), receptive field location (Central, Peripheral), and monocular behavioral acuity eye performance (Better Eye, Worse Eye). Cats with corpus callosum section during postnatal week 1 had the lowest spatial resolution for all cell categories compared to all groups tested. However, cats with callosum section during postnatal week 2 had normal spatial frequency thresholds for Simple, Central and Better Eye categories. The cats with callosum section in postnatal weeks 3–6 had normal spatial frequency thresholds for all cell categories. For corpus callosum sectioned cats with and without visual deficits, and for normal cats, visual acuity measured behaviorally is significantly related to visual acuity measured physiologically. The results show that neonatal corpus callosum section in cats can affect behavioral visual acuity, as well as the spatial frequency thresholds of many categories of striate cortical cells. However, callosum section at different ages affects different populations of cortical cells. Furthermore, the results suggest that neonatal corpus callosum section may directly affect a single fundamental property of cells in primary visual cortex with a resulting disruption of many visual functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228803
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    Morphological and physiological identification of neurons in the cat motor cortex which receive direct input from the somatic sensory cortex (1990)
    Springer
    Experimental brain research 80 (1990), S. 209-212 
    Details
    ISSN: 1432-1106
    Keywords: Pyramidal cells ; Nonpyramidal cells ; Cortico cortical fibers ; Sensory-motor ; Intracellular recording ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The population of neurons in the cat motor cortex which receives monosynaptic input from a specific functional region of the somatic sensory cortex was identified with the techniques of intracellular recording and staining with HRP. Both pyramidal and nonpyramidal cells located in the superficial layers of the pericruciate cortex responded to stimulation of the sensory cortex with short latency, excitatory postsynaptic potentials. More than half of the labeled cells were classified as pyramidal cells and the remainder as sparsely spinous or aspinous nonpyramidal cells. The characteristics of the EPSP's of the 2 groups of cells, ie. latency, time from beginning to peak and amplitude were found to vary only slightly. The results suggest that input from the sensory cortex impinges upon neurons which may in turn have an excitatory or inhibitory effect on corticofugal neurons in the motor cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228864
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  • 32
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    Electronic Resource
    Topographical organisation within the cerebellar nucleocortical projection to the paravermal cortex of lobule Vb/c in the cat (1990)
    Springer
    Experimental brain research 80 (1990), S. 415-428 
    Details
    ISSN: 1432-1106
    Keywords: Nucleocortical ; Corticonuclear ; Cerebellar nuclei ; Cerebellar zonation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The projection from the intracerebellar nuclei to the paravermal (intermediate) cerebellar cortex of lobule Vb/c has been investigated in the cat using a combined electrophysiological and neuroanatomical technique. A small (10–30 nl) injection of WGA-HRP was made into one of the three paravermal zones (c1, c2 or c3) after the mediolateral boundaries of the zones had been delimited on the cerebellar surface by recording climbing fibre field potentials evoked in response to percutaneous stimulation of one or more paws. The distribution of retrogradely labelled cell bodies within the intracerebellar nuclei was compared with the distribution of terminal labelling arising from anterograde transport by cerebellar Purkinje cells. The three paravermal zones displayed marked heterogeneity in their receipt of a projection from the intracerebellar nuclei. The c1 and c3 zones received virtually no such input, although injections in either zone resulted in significant terminal labelling (which was largely restricted to nucleus interpositus anterior). By contrast, the intervening c2 zone received a much heavier nucleocortical input which arose almost exclusively from nucleus interpositus posterior (to which the zone also projected). A sparse contralateral nucleocortical input to the c2 zone was also demonstrated. This arose primarily from nucleus fastigius. It is concluded that the nucleocortical projection to the paravermal cortex of lobule Vb/c displays marked topographical specificity and some functional implications of this are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228169
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  • 33
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    Electronic Resource
    Peripheral nerve section induces increased levels of calcitonin gene-related peptide (CGRP)-like immunoreactivity in axotomized motoneurons (1990)
    Springer
    Experimental brain research 79 (1990), S. 212-216 
    Details
    ISSN: 1432-1106
    Keywords: Neuropeptide ; Plasticity ; Nerve injury ; Spinal cord ; Immunohistochemistry ; Cat ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By use of fluorescence immunohistochemistry it is shown that sciatic nerve section in cat and rat induces increased levels of immunoreactive calcitonin gene-related peptide (CGRP) in axotomized motoneurons. In the rat, this effect was clearly seen at 2–5 days postoperatively, but could not be demonstrated after 11–21 days. These findings are discussed in relation to previously proposed roles for CGRP in motoneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228891
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  • 34
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    The effects of contrast on the linearity of spatial summation of simple cells in the cat's striate cortex (1990)
    Springer
    Experimental brain research 79 (1990), S. 582-588 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Contrast ; Spatial summation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Non-linearities of spatial summation were examined in simple cells in the cat's striate cortex. The degree of non-linearity was assessed from an examination of the waveforms of the responses to moving sinusoidal gratings and was quantified by a measure called relative modulation. Relative modulation was affected little by changes in contrast at either optimal or non-optimal spatial frequencies. The non-linearities of spatial summation exhibited by some simple cells are, therefore, essential. Those simple cells which exhibit linear spatial summation are no less linear at high stimulus contrasts. These results support a ‘push-pull’ model of simple cell receptive field organization in which ON and OFF centre l.g.n. input is combined both additively and subtractively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229326
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  • 35
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    Electronic Resource
    Optokinetic nystagmus in the ferret: including selected comparisons with the cat (1990)
    Springer
    Experimental brain research 79 (1990), S. 623-632 
    Details
    ISSN: 1432-1106
    Keywords: Optokinetic nystagmus ; Ferret ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to evaluate the functional significance of similarities observed in the anatomy and the physiology of cat and ferret visual systems. Optokinetic nystagmus (OKN) in response to movement of the entire visual field, and optokinetic after nystagmus (OKAN) were measured in 8 ferrets with binocular stimulation. A shift of the beating field in the same direction as the fast phase of eye movements was observed both in ferret and cat. The absence of a fast rise in slow phase velocity (SPV) and similarities in the time constant to reach the steady state OKN gain, using step velocity stimuli are noted. As in the cat, primary OKAN was observed with a gradual decrease in its SPV. Following termination of stimulation, no sudden fall in SPV was noted for either species. However, for the ferret, the decrease was more rapid. With monocular stimulation, small differences were observed in OKN gain when responses to temporonasal and nasotemporal directions of the stimulus were compared in the two species. In contrast, the ferret displays a OKN gain which is approximatively twice that of the cat at stimulus velocities of 100°/sec. Even at 200°/sec., visual movement still induces a discernable OKN response (gain.0.07). Secondary OKAN, always present in the cat, was observed in only 43% of ferret records. Taken together with other considerations, these findings recommend the ferret as an alternative to the cat for the study of OKN and of other visuo-motor capacities in carnivores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229330
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  • 36
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    Electronic Resource
    Transneuronal transport of wheat germ agglutinin conjugated horseradish peroxidase into last order spinal interneurones projecting to acromio- and spinodeltoideus motoneurones in the cat (1990)
    Springer
    Experimental brain research 80 (1990), S. 96-103 
    Details
    ISSN: 1432-1106
    Keywords: Target-reaching ; Walking ; Transneuronal transport ; Wheat germ agglutinin conjugated horseradish peroxidase ; Last order interneurones ; Motoneurones ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Transneuronal transport of wheat germ agglutinin conjugated horseradish peroxidase was used to define the location of last order spinal interneurones projecting to deltoideus motoneurones during voluntary target-reaching and/or in unrestricted walking on the ground. Labelled interneurones were found bilaterally from C2 to Th1 in target-reaching cats and almost exclusively in the C5-Th1 segments in walking cats, although the total number of labelled interneurones in these cats was considerably higher than in the target-reaching cats. These results confirm the previous finding that propriospinal neurones in the C3–C4 segments can mediate the descending command for target-reaching movements with the forelimb. In both groups of cats labelled interneurones were found ipsilaterally in laminae V–IX, while contralaterally they were mainly restricted to lamina VIII. In the forelimb segments there was a larger number of labelled interneurones in the walking cats in the lateral part of laminae V–VII and in laminae VIII and IX. There was a positive, almost linear correlation between the total number of labelled interneurones and motoneurones in all cats. The results suggest that both excitatory and inhibitory last order interneurones can be transneuronally labelled. It is concluded that this method can be used for functional identification of last order interneurones active during the preparation and/or execution of different movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228851
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  • 37
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    Electronic Resource
    Areal influences on complex cells in cat striate cortex: stimulus-specificity of width and length summation (1990)
    Springer
    Experimental brain research 80 (1990), S. 135-147 
    Details
    ISSN: 1432-1106
    Keywords: Vision ; Striate cortex ; Receptive field specificity ; Spatial summation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In single neurones recorded from the striate cortex of cats anaesthetized with N2O/O2/halothane, receptive field dimensions, length specificity and areal extent of drive were assessed for different classes of visual stimuli. Receptive fields were mapped as rectangular minimum response fields (MRFs). Spatial summation along the axis of preferred orientation was assessed: for moving bars whose length was varied (length summation); and for height variation of a square-wave grating patch against a uniform grey background, or a patch of moving texture against a stationary background of similar texture. In complementary tests a moving square-wave grating background was progressively occluded by a uniform grey foreground mask of variable height; or a mask of stationary texture of variable height progressively occluded a background of moving texture. In parallel measurements, the width of grating or textured patches or masks was varied whilst maintaining height constant. Broadly speaking, the areal influence of each class of stimulus was comparable, and distinct from extra-receptive field phenomena in evoking responses from within the receptive field, but not from surrounding areas. The masking paradigm provided the most sensitive measure of receptive field height and width. However, in some neurones length summation, the degree of endstopping, and the directional bias depended critically on the stimulus configuration used. Length summation tended to be more dramatic for short bars than for gratings. Length summation for texture was significantly more pronounced than for an oriented bar in special and in intermediate complex neurones. By contrast, endstopping was typically less intense for gratings than for bars, and least pronounced for texture. Because of stimulus specificity, complex neurones assigned to particular functional subgroups on the basis of their response to oriented bars may exhibit quite different patterns of behaviour for other classes of stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228855
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  • 38
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    Transneuronal transport of wheat germ agglutinin conjugated horseradish peroxidase into last order spinal interneurones projecting to acromio- and spinodeltoideus motoneurones in the cat (1990)
    Springer
    Experimental brain research 80 (1990), S. 83-95 
    Details
    ISSN: 1432-1106
    Keywords: Motoneurones ; Last order interneurones ; Transneuronal transport ; Wheat germ agglutinin conjugated horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Transneuronal transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) was used to define the location of last order spinal interneurones projecting to deltoideus motoneurones in C5–C8 of the cat. Labelled interneurones were found bilaterally from rostral C1 to caudal Th5 and from L3 to the L4/5 border. Ipsilaterally they were located in laminae V–IX, while contralaterally they were confined to lamina VIII except for a few cells in laminae VII and IX. To estimate the degree to which inter-neuronal activity facilitates the transneuronal transport from deltoideus motoneurones, the numbers of labelled interneurones were compared under different experimental conditions after WGA-HRP injection. The number of labelled last order interneurones was larger in one awake and active cat than in one awake but inactive cat and also larger in six anaesthetized animals in which spinal pathways were stimulated to evoke antidromic and synaptic activation of the interneurones, than in two anaesthetized animals without stimulation. It is concluded that the transneuronal transport of WGA-HRP is considerably facilitated by increased activity in the last order interneurones. An overall tendency was observed for a positive correlation between the number of labelled interneurones and the number of primarily stained deltoideus motoneurones. In order to reach a detectable concentration of WGA-HRP in the last order interneurones a certain number of motoneurones has to be labelled to the extent that they appear homogenously black.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228850
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  • 39
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    Electronic Resource
    An analysis of neural spike-train distributions: determinants of the response of visual cortex neurons to changes in orientation and spatial frequency (1990)
    Springer
    Experimental brain research 80 (1990), S. 129-134 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Spike train analysis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A previously unexploited method of examining neural spike-trains was applied to data obtained from cells in the visual cortex. Distributions of interspike intervals recorded extracellularly from cat visual cortex under four conditions were analyzed. Stimuli were gratings differing in orientation and spatial frequency. The probability density function of first passage time for a random walk with drift process, which is defined by its barrier height and drift coefficient, was used to characterize the generating process of axonal discharge under resting and stimulus conditions. Drift coefficient and barrier height were derived from the sample mean and standard deviation of the measured inter-spike intervals. For cells with simple receptive fields, variations in the drift coefficient were produced by changes in orientation and spatial frequency. Variations in barrier height were produced only by changes in orientation of the stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228854
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  • 40
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    Electronic Resource
    Monosynaptic excitatory connexions of reticulospinal neurones in the nucleus reticularis pontis caudalis with dorsal neck motoneurones in the cat (1990)
    Springer
    Experimental brain research 80 (1990), S. 277-289 
    Details
    ISSN: 1432-1106
    Keywords: Recticulospinal neurones ; Pons ; Neck ; Tectum ; Cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Projections of reticulospinal neurones (RSNs) in the nucleus reticularis pontis caudalis (N.r.p.c.) to dorsal neck motoneurones supplying splenius (SPL, lateral head flexor) and biventer cervicis and complexus (BCC, head elevator) muscles were studied in the cat anaesthetized with pentobarbiturate or α-chloralose. 2. Threshold mapping for evoking antidromic spikes revealed that most of RSNs tested projecting down to brachial segments but not to lumbar segments (C-RSNs) gave off collaterals to the gray matter of the upper spinal cord in C2–C3 segments. 3. Spike triggered averaging showed that negative field potentials were evoked after firing of a single C-RSN (single fibre focal synaptic potentials, FSPs) in the region of C2–C3 where large antidromic field potentials from nerves supplying SPL or BCC muscles were evoked. The single fibre FSPs ranged between 1 and 10 μV in amplitude and had latencies between 0.7 and 1.2 ms from the onset of the triggering spike. In most cases, a presynaptic spike preceded the negative potential by 0.3 ms. These results indicated that C-RSNs project to the SPL or BCC motor nucleus. 4. Spike triggered averaging of postsynaptic potentials revealed EPSPs (single fibre EPSPs) in 36 dorsal neck motoneurones, predominantly in SPL (25) and less in BCC (11) motoneurones, evoked from 15 C-RSNs. The amplitude of the single fibre EPSPs ranged from 5 to 310 μV, and had latencies of 0.8–2.0 ms from the onset of the triggering spikes of C-RSNs, or 0.3–0.5 ms from the presynaptic spike when recorded. The results indicated monosynaptic excitatory connexions of C-RSNs to dorsal neck motoneurones. 5. Single fibre EPSPs from a C-RSN were usually recorded from either BCC or SPL motoneurones but not from both types of motoneurones, when tested in many motoneurones. This showed that connexions of C-RSNs with dorsal neck motoneurones were muscle specific. 6. RSNs projecting down to the lumbar segment (L-RSN) also showed branching in C2–C3 segments. Excitatory monosynaptic connexion of L-RSNs with neck motoneurones were demonstrated by recording single fibre postsynaptic population potentials (p.s.p.p.s.) from the C2 ventral root perfused with sucrose. The probability of evoking monosynaptic single fibre p.s.p.p.s. was less (19%) than for C-RSNs (59%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228155
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  • 41
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    Electronic Resource
    Spatio-temporal interactions and the spatial phase preferences of visual neurons (1990)
    Springer
    Experimental brain research 80 (1990), S. 441-445 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Visual cortex ; Receptive field ; Spatial phase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We recorded single neuron responses in the cat's lateral geniculate nucleus (LGN) and visual cortex to compound stimuli composed of two sinusoidal gratings in a 2∶1 frequency ratio. To probe visual receptive field symmetry, we varied the relative spatial phase of the two components and measured the effect on neuronal responses. We expected that on-center LGN neurons would respond best to gratings combined in positive cosine (bright bar) phase, while off-center LGN neurons would respond best to gratings combined in negative cosine (dark bar) phase. When drifting stimuli were used, cells' phase preferences were roughly 90 deg away from the expected values; when stationary, contrast-modulated stimuli were used, phase preferences were as originally predicted. Computer simulations showed that this discrepancy could be explained by taking into account the cells' temporal properties. Thus, tests using drifting stimuli confound the spatial structure of visual neural receptive fields with their temporal response characteristics. A small sample of data from cortical neurons reveals the same confound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228172
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  • 42
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    Electronic Resource
    Horizontal optokinetic responses under stroboscopic illumination in cat, monkey and man (1990)
    Springer
    Experimental brain research 81 (1990), S. 59-69 
    Details
    ISSN: 1432-1106
    Keywords: Optokinetic reflex ; Stroboscopic illumination ; Cat ; Monkey ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The horizontal optokinetic reflex (OKN) was studied in cat, monkey and man under conditions of steady or stroboscopic illumination. In all species, there was an abrupt decrease in OKN gain for a given spatial displacement of the stimulus between two consecutive stroboscopic flashes. The upper limit of spatial displacement which preserved optimal OKN gain was independent of stimulus velocity and flash frequency. The value of this limit differed in the three species studied. In the cat, OKN gain was affected when the spatial displacement between two stimuli exceeded 0.55° of visual angle. In monkey and man, these limits were 1.48° and 2.87°, respectively. When human subjects were asked to voluntary track the stimulus, the limit value reached 4.3°. This result is discussed in the context of the evolution of the smooth pursuit system and its contribution to optokinetic response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230101
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  • 43
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    Electronic Resource
    Properties of single neurons in the cat midsuprasylvian gyrus (1990)
    Springer
    Experimental brain research 79 (1990), S. 515-529 
    Details
    ISSN: 1432-1106
    Keywords: Parietal cortex ; Thalamo-cortical projection ; Tooth pulp ; Nociception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of cells in the midsuprasylvian gyrus (MSSG) of cats were investigated following electrical stimulation of the central lateral nucleus (CL) of the thalamus and tooth pulp, low-threshold cutaneous or visual afferents. Electrical stimulation in CL induced excitation in many cells located in cortical areas 5 and 7. Cells in these areas also received input from somato-sensory and visual afferents. Cells in MSSG showed a wide convergence from tooth pulp, low-threshold cutaneous afferents and from the CL. The majority of wide convergent cells in area 5 were found in layers IV and V, while cells excited by CL and tooth pulp were found in layers II and III. Similarities were found between CL and tooth pulp evoked responses with regard to the excitation-inhibition pattern. The excitation evoked from CL and tooth pulp was less often followed by a hyperpolarizing potential compared to that seen after low-threshold lip, paw and visual afferent stimulation. Stimulation sites in the lateral parts of CL-evoked responses with the shortest latencies in area 5. In this part of the cortex, short latency synaptic potentials were found in cells in superficial layers. In the same area, synaptic potentials of short latency were also evoked by electrical stimulation of tooth pulp, lip and paw. Light-flash stimulation evoked responses with the shortest latencies in area 7. The results of this study demonstrate that putative nociceptive information reaches the parietal association cortex and that part of this input may be relayed via CL. We suggest that the excitatory influences of nociceptive and CL stimulation is related to behavioral arousal and attention mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229321
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  • 44
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    Electronic Resource
    GABA, glycine, aspartate, glutamate and taurine in the vestibular nuclei: an immunocytochemical investigation in the cat (1990)
    Springer
    Experimental brain research 79 (1990), S. 547-563 
    Details
    ISSN: 1432-1106
    Keywords: Neurotransmitter ; Colocalization ; Vestibular nuclei ; Immunocytochemistry ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distributions of five amino acids with well-established neuroexcitatory or neuroinhibitory properties were investigated in the feline vestibular complex. Consecutive semithin sections of plastic-embedded tissue were incubated with antisera raised against protein-glutaraldehyde conjugates of GABA, glycine, aspartate, glutamate and taurine. This approach allowed us to study the relative densities of the different immunoreactivities at the level of individual cell profiles. The results indicate that in the vestibular nuclei, neuronal colocalization of two or more neuroactive amino acids is the rule rather than an exception. Colocalization was found of immunoreactivities for GABA and glycine; glycine, aspartate and glutamate; glycine and aspartate, and glutamate and aspartate. GABA immunoreactive neurons were generally small and were found scattered throughout the vestibular complex. Glycine immunoreactive neurons were similarly distributed, except in the superior nucleus where the latter type of neuron could not be detected. Neuronal profiles colocalizing immunoreactivities for GABA and glycine occurred in all nuclei, but were most numerous in the lateral nucleus. The vast majority of the neurons showed noteworthy staining for glutamate and aspartate, although the level of immunoreactivities varied (e.g., the large neurons in the lateral and descending nuclei were more intensely aspartate immunoreactive than the smaller ones). Taurine-like immunoreactivity did not occur in neuronal cell bodies but appeared in Purkinje cell axons and in glial cell profiles. The functional significance of the complex pattern of amino acid colocalization remains to be clarified. In particular it needs to be distinguished between metabolic and transmitter pools of the different amino acids. The present results call for caution when attempts are made to conclude about transmitter identity on the basis of amino acid contents alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229324
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  • 45
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    Electronic Resource
    Neural site of strabismic amblyopia in cats: spatial frequency deficit in primary cortical neurons (1990)
    Springer
    Experimental brain research 79 (1990), S. 615-622 
    Details
    ISSN: 1432-1106
    Keywords: Strabismic amblyopia ; Visual cortex ; Acuity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The acuities of cells in the primary visual cortex of five tenotomized strabismic cats were measured. Previous behavioural studies have shown such animals to possess a severe amblyopia of approximately 1.5 octaves of spatial frequency, yet the acuities of both retinal ganglion and lateral geniculate X-cells are normal. The receptive fields of the cortical cells sampled were within 5° of the area centralis projection. On average, the acuities of cortical cells driven by the amblyopic eye were nearly 1 octave less than those for the non-deviating eye. However, the best cell acuities for each eye were nearly the same. The relationship between ocular dominance and cell acuity was found to be different for the two eyes despite a symmetrical ocular dominance distribution. The acuity deficit for cells driven through the amblyopic eye was present at all depths along the electrode tracks. We conclude that in this model amblyopia, the initial spatial processing deficit lies in the visual cortex, and most probably in the cells of layer IV. Further-more, the presence of a few cells driven by the amblyopic eye which can perform nearly as well as those from the fellow eye in processing high spatial frequencies gives new insight into the way in which strabismic and deprivation amblyopias differ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229329
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  • 46
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    Electronic Resource
    The mode of synaptic activation of pyramidal neurons in the cat primary somatosensory cortex: an intracellular HRP study (1990)
    Springer
    Experimental brain research 80 (1990), S. 12-22 
    Details
    ISSN: 1432-1106
    Keywords: Somatosensory cortex ; VPL ; Intracellular recording ; Pyramidal neuron ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A total of 141 pyramidal neurons in the cat primary somatosensory cortex (SI) were recorded intracellularly under Nembutal anesthesia (7 in layer II, 43 in layer III, 8 in layer IV, 58 in layer V and 25 in layer VI). Most neurons were identified by intracellular staining with HRP, though some layer V pyramidal neurons were identified only electrophysiologically with antidromic activation of medullary pyramid (PT) or pontine nuclear (PN) stimulation. Excitatory synaptic potentials (EPSPs) were analyzed with stimulation of the superficial radial nerve (SR), the ventral posterolateral nucleus (VPL) in the thalamus and the thalamic radiation (WM). The pyramidal neurons in layers III and IV received EPSPs at the shortest latency: 9.1±2.1 ms (Mean+S.D.) for SR and 1.6±0.7 ms for VPL stimulation. Layer II pyramidal neurons also responded at a short latency to VPL stimulation (1.7±0.5 ms), though their mean latencies for SR-induced EPSPs were relatively longer (10.6±1.9 ms). The mean latencies were much longer in layers V and VI pyramidal neurons (10.2±2.4 ms and 2.9±1.5 ms in layer V pyramidal neurons and 9.9±2.5 ms and 2.8±1.6 ms in layer VI pyramidal ones, respectively for SR and VPL stimulation). The comparison of the latencies between VPL and WM stimulation indicates that most layer III–IV pyramidal neurons and some pyramidal cells in layers II, V and VI received monosynaptic inputs from VPL. These findings are consistent with morphological data on the laminar distribution of thalamocortical fibers, i.e., thalamocortical fibers terminate mainly in the deeper part of layers III and IV with some collaterals in layers V, VI and II-I. The time-sequences of the latencies of VPL-EPSPs indicate that corticocortical and/or transcallosal neurons (pyramidal neurons in layers II and III) fire first and are followed by firing of the output neurons projecting to the subcortical structures (pyramidal neurons in layers V and VI).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228842
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    Electronic Resource
    Disynaptic tectal and pyramidal excitation of hindlimb motoneurons mediated by pontine reticulospinal neurons in the cat (1990)
    Springer
    Experimental brain research 79 (1990), S. 175-186 
    Details
    ISSN: 1432-1106
    Keywords: Reticulospinal neurons ; Spinal projection ; Tectum ; Cerebral peduncle ; Hindlimb motoneurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1 The pathway mediating disynaptic tectal and pyramidal excitation of hindlimb motoneurons was analyzed in cats anesthetized with αchloralose or pentobarbital. Stimulation of the contralateral tectofugal fibers induced EPSPs in flexor and extensor hindlimb motoneurons (118/171). EPSP latencies, measured from the monosynaptically evoked descending volley, were 0.8 ms or less in 34 of the 118 motoneurons, suggesting disynaptic linkage from the tectum. The latencies tended to be shorter in motoneurons innervating proximal muscles than in those innervating distal muscles. 2. Stimulation of the cerebral peduncle induced EPSPs only in a small proportion of motoneurons (7/32). But the peduncular stimulation exhibited a marked facilitatory effect on the tectal EPSPs in most of the tested motoneurons (23/27), showing convergence of tectal and peduncular inputs onto relay cells. 3. In animals whose pyramid was transected, the tectal EPSPs were still facilitated by peduncular stimulation in 45 of 48 tested motoneurons. The time course of facilitation indicated convergence of tectofugal and corticofugal fibers onto brainstem relay neurons. 4. Projection of single neurons in the nucleus reticularis pontis caudalis (NRPC) to the gray matter of the hindlimb segments was examined by mapping thresholds of antidromic activation. Twelve of 13 tested neurons were excited by contralateral tectal stimulation at short latencies, probably monosynaptically. Four of them were found to project to lamina IX. Two of the 3 tested neurons projecting to lamina IX were found to receive excitatory input from the cerebral peduncle. 5. Stimulation of NRPC induced monosynaptic EPSPs in hindlimb motoneurons. In 19 motoneurons, the NRPC-induced monosynaptic EPSPs were facilitated by a conditioning tectal shock. This indicated that the tectal stimulus lowered thresholds of direct activation of cell bodies of premotor NRPC neurons. The time course of the facilitation indicated that the NRPC neurons received monosynaptic tectal excitation. The results provide strong evidence that NRPC neurons are involved in mediating disynaptic tectal excitation of hindlimb motoneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228887
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    Electronic Resource
    Functional organization of the cortical 17/18 border region in the cat (1990)
    Springer
    Experimental brain research 79 (1990), S. 271-282 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; 17/18 border ; Retino-topic map ; Orientation map ; Ocular dominance map ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The representation of the visual field in the 17/18 border region of the cat's visual cortex, and the layout of orientation and ocular dominance columns, were studied by making many closely spaced electrode penetrations into the superficial layers of the flattened dorsal region of the marginal gyrus and recording response properties at each location. The 17/18 border region was defined by measuring the change in the horizontal component of receptive field position within the gyrus: as the position of the recording electrode moved from medial to lateral, the receptive fields moved towards the vertical midline, indicating that the electrode was in area 17; as penetrations were made in increasingly lateral positions, the trend reversed, and receptive field positions moved away from the midline, indicating that the electrode was in area 18. The receptive fields of cells close to the border straddled, or lay within 2°–3° on either side of the vertical midline. In addition, patches of cortex were sometimes encountered in which cells had receptive field centers located up to 7° in the ipsilateral visual field. Experiments in which maps were made in the left and right hemispheres of a single animal showed that these patches had a complementary distribution in the two hemispheres. Cells within the patches behaved as though driven by Y-cell inputs: they usually had large receptive fields and responded to rapidly-moving stimuli. They were broadly tuned for orientation and strongly dominated by the contralateral eye. Fourier spectral analysis of orientation selectivity maps showed that iso-orientation bands had an average spacing of 1.14 ± 0.1 mm and tended to be elongated in a direction orthogonal to the 17/18 border. Individual bands crossed the border without obvious interruption, although singularities (points of discontinuity in the layout of orientations) were more frequently observed in the border region than in adjacent areas. Two dominant periodicities could be measured in the maps of ocular dominance, one at around 0.8 ± 0.2 mm and a second at 2.0 ± 0.3 mm. No constant direction of elongation was noted. These are close to the periods present within areas 17 and 18 respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608236
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  • 49
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    Electronic Resource
    Spatio-temporal organization of the somaesthetic projections in the red nucleus transmitted through the spino-rubral pathway in the cat (1990)
    Springer
    Experimental brain research 79 (1990), S. 412-426 
    Details
    ISSN: 1432-1106
    Keywords: Red nucleus ; Sensori-motor control ; Spino-rubral pathway ; Intracellular recordings ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Although it has been known for a long time that in awake cats, natural stimulation of the skin induces short latency responses in rubrospinal cells, the pathway possibly involved has been identified only recently (Padel et al. 1988). This tract, which was described in acute, chloralose anaesthetized cats, ascends in the ventromedial spinal cord and is activated via collaterals of primary afferent fibres running in the dorsal columns of the spinal cord. The present study demonstrates that this newly described spino-rubral tract is able to send detailed somaesthetic information to the red nucleus. After lesions leaving intact only the spino-rubral pathway, excitatory and inhibitory responses to natural peripheral stimulations were recorded in identified rubral efferent cells. The most effective stimuli were touching the skin, passive joint rotation and hair displacement. Each cell was found to possess a particular receptive field. These fields which could be ipsi-, contra-, or bi-lateral were generally located on a single limb, although they could include two or more limbs, or even exceptionally the whole body with or without preferential zones. The topographic organization of receptive fields was arranged somatotopically in the red nucleus and overlapped the motor representation. The somaesthetic inputs transmitted through the spino-rubral pathway to the red nucleus are very similar to those previously observed in the intact cat, which supports the idea that this pathway may play a functional role in motor control. The spino-rubro-spinal loop may provide a fast adaptation of the descending motor command, thus producing a fine and harmonious tuning between the changing surroundings and the animal's movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608253
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  • 50
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    Electronic Resource
    Speed-related changes in hindlimb intersegmental dynamics during the swing phase of cat locomotion (1990)
    Springer
    Experimental brain research 79 (1990), S. 651-660 
    Details
    ISSN: 1432-1106
    Keywords: Inverse dynamics ; Step-cycle kinematics ; Swing-phase kinetics ; Coordination ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine speed-related changes in hindlimb motion that might account for the mutability of bifunctional (hip extensor/knee flexor) muscle activity during the E1 phase of swing, we studied hip and knee joint kinematics and kinetics during swing over a ten-fold increase in locomotor speed (0.35 to 3.5 m/s). Three cats were filmed (100 frames/s) while locomoting on a motorized treadmill; kinematics were analyzed for the entire step cycle and kinetics for the swing phase. During swing, angular excursions at the hip and knee joints were similar for walking and trotting, but hip flexion and extension were significantly less after the transition from trot to gallop, while knee-angle range of motion increased during gallop phases E1, E2, and E3. During swing, knee-extension velocity peaked early in E1 and increased linearly with speed, while hip-flexion velocity peaked late in the flexion (F) phase and also increased linearly, but decreased precipitously at the trotgallop transition and remained constant as speed of galloping increased. Muscle torque directions during E1, flexor at the knee and extensor at the hip, were consistent with the proposed role of bifunctional posterior thigh muscles to decelerate thigh and leg segments for paw contact. At the knee joint, muscle torque during E1 counteracted a large interactive torque due to leg angular acceleration; the magnitudes of both torques were speed related with maximal values at the fastest speed tested (3.5 m/s). At the hip joint, muscle torque during E1 also counteracted a large interactive torque due to leg angular acceleration; the magnitudes of these two torques were speed related during the walk and trot, and like hip flexion velocity, decreased at the trot-gallop transition. Our data on speed-related changes in hindlimb dynamics suggest that the E1 burst amplitude (and perhaps duration) of posterior thigh muscles will be speed related during the walk and trot. After the trot-gallop transition at about 2.5 m/s, the recruitment of these bifunctional muscles may decline due to the changes in hindlimb dynamics. Because activity of these muscles counteracts interactive torques primarily related to leg angular acceleration, we suggest that motion-related feedback decoding this action may be important for regulating recruitment during E1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229333
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    Formation of new synapses in the cat motor cortex following lesions of the deep cerebellar nuclei (1990)
    Springer
    Experimental brain research 80 (1990), S. 23-33 
    Details
    ISSN: 1432-1106
    Keywords: Synaptic plasticity ; Sprouting ; Corticocortical synapses ; Functional recovery ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of unilateral lesions of the deep cerebellar nuclei on the corticocortical (CC) projection from the somatosensory to the motor cortex were studied in adult cats, utilizing electrophysiological and electron microscopical methods. Axon terminals in the motor cortex belonging to CC afferents were labeled by degeneration induced by lesions of the somatosensory cortex; neurons in the motor cortex were labeled by the Golgi/EM method. In each cat, data from the motor cortex (MCx) contralateral (experimental) and ipsilateral (control) to the cerebellar lesion were compared. Cerebellar lesions produced marked motor deficits, which receded gradually and disappeared after 30 to 40 days. Subsequent lesions of the somatosensory cortex (area 2) contralateral to the cerebellar lesions resulted in the reappearance of the cerebellar symptoms. The number of CC synapses per unit area in experimental MCx was significantly higher than in control MCx. The increase in the number of CC synapses was apparent throughout layers II–V of the MCx, but was most prominent in layers II/III. The increase in the number of CC synapses in experimental MCx was due mainly to an increase of axon terminals synapsing with dendritic spines belonging to pyramidal neurons. In comparison, the numbers and spatial distribution of CC synapses with aspinous, nonpyramidal neurons from both experimental and control MCx were similar. Field potentials in the experimental MCx, evoked by stimulation of area 2, were altered following cerebellar lesions. In experimental MCx, the polarity of the early component of the field potentials reversed at cortical depths corresponding to layers II–III, whereas this reversal was not observed in control MCx. These findings suggest that lesions of the cerebellar nuclei induced sprouting of axon terminals in the MCx to establish a new function. The results provide the first anatomical evidence for the generation of new synapses in the adult CNS which is not induced by elimination of existing synapses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228843
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    A quantitative analysis of the distribution of Purkinje cell axonal collaterals in different zones of the cat's cerebellum: an intracellular HRP study (1990)
    Springer
    Experimental brain research 80 (1990), S. 63-71 
    Details
    ISSN: 1432-1106
    Keywords: Local circuits ; Recurrent collaterals ; Axonal varicosities ; Zones ; Lobule V ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Purkinje cells in zones a and b of the vermis and zone c in the intermediate cortex of the anterior lobe were intracellularly injected with horseradish peroxidase and the distribution patterns of the varicosities present on their axonal collaterals were quantified and compared at the light microscopic level. The data derived from this study reveal that each individual axonal arbor had a unique pattern of distribution. However, certain principles of distribution could be applied to the collaterals regardless of the cortical location of the parent cell, including the following: 1) the total number of varicosities derived from the axonal collaterals of individual Purkinje cells is relatively uniform; 2) the collateral plexi have a greater extent in the sagittal plane as compared to the transverse plane; 3) the majority of varicosities remain within 200–300 μm of the parent cell in both the sagittal and transverse planes; 4) there is a heterogenous distribution of varicosities within the area traversed by the axonal branches; and 5) the majority of varicosities are located within the Purkinje cell layer. Although there were similarities in the pattern of distribution for collaterals, there were also variations which distinguished the plexi in the three zones. The collaterals of zone a cells tended to be the most confined in both the sagittal and transverse planes. In contrast, several cells in zone b and c had branches that extended for relatively long distances in the sagittal plane. In zone b the collaterals have an asymmetric distribution around the cell of origin in the transverse plane. In zones a and c there is a tendency for a more symmetric pattern of distribution in this plane. The similarities in the number and laminar distribution of varicosities, as well as the predominantly sagittal orientation of the collaterals in all zones of the cerebellar cortex suggest that the collaterals subserve a common function throughout the cerebellar cortex. However, variations indicate that there may be subtle differences in the way recurrent collaterals process information in the cerebellar cortex that may be related to the functional heterogeneity or the location of the targets of the collaterals in the three zones analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228848
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    Input-output organization of reticulospinal neurones, with special reference to connexions with dorsal neck motoneurones in the cat (1990)
    Springer
    Experimental brain research 80 (1990), S. 260-276 
    Details
    ISSN: 1432-1106
    Keywords: Reticulospinal neurones ; Tectum ; Cortex ; Neck ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dorsal neck motoneurones receive disynaptic tectal and pyramidal EPSPs via common reticulospinal neurones (RSNs). This study was aimed at identification of the RSNs projecting directly to neck motoneurones and mediating these EPSPs. 1. Stimulation of the tectum and the cerebral peduncle evoked monosynaptic descending volleys in the spinal cord, which were chiefly mediated by reticulospinal neurones in the pons and the medulla. Systematic tracking of the C3 and C7 segments was made to locate descending volleys in the spinal funiculi. The tectal monosynaptic volley was largest in the medial part of the ventral funiculus and decreased gradually as the recording electrode was moved to the lateral part of the ventral funiculus and the lateral funiculus. In contrast, the peduncle-evoked monosynaptic volley was distributed rather evenly in the ventral funiculus and the ventral half of the lateral funiculus. 2. Differences in funicular distribution of the two descending volleys suggest the existence of subgroups of RSNs which differed in strength of inputs from the two descending fibre systems and in the funicular location of descending axons. 3. The RSNs were classified into the following four groups; (1) mRSNs which descended in the medial part of the ventral funiculus, (2) in RSNs which descended in the ventrolateral funiculus, (3) 1RSNs which descended in the dorsal 2/3 of the lateral funiculus and (4) coRSNs which descended in the contralateral funiculi. The mRSNs were located in a fairly localized region corresponding to the nucleus reticularis pontis caudalis (N.r.p.c.), while inRSNs, 1RSNs and coRSNs were mainly in the nucleus reticularis gigantocellularis (N.r.g.), in the nucleus reticularis magnocellularis (N.r.m.) and in the nucleus reticularis ventralis (N.r.v.). RSNs were further divided into three types depending on the levels of projection. L-RSNs projected to the lumbar spinal segments. C-RSNs descended to the C6–C7 spinal segment but not to the lumbar segments. N-RSNs projected to the C3 but not to the C6–C7 segments. 4. Stimulation of the tectum and the cerebral peduncle produced monosynaptic negative field potentials in the medial two thirds of the reticular formation in the pons and medulla. Tectal field potentials were largest in the N.r.p.c. and the rostral part of the N.r.g., while pyramidal field potentials were largest in the N.r.g. Correspondingly, RSNs in the N.r.p.c. (mRSNs) received larger monosynaptic EPSPs from tectal than from pyramidal volleys, while RSNs in the N.r.g. (in-, 1- and coRSNs) received stronger input from the peduncle than from the tectum. 5. Stimulation of the C7 ventral but not the lateral funiculus evoked monosynaptic EPSPs on all the dorsal neck motoneurones tested. Stimulation of the L1 segment only produced monosynaptic EPSPs in 35% of the motoneurones. The L1 evoked EPSPs were much smaller than C7 evoked EPSPs. 6. The C7 evoked EPSPs (C7 EPSP) showed complete occlusion (collision) with the tectal or pyramidal disynaptic EPSPs. Similar results were obtained with L1 EPSPs. These results indicate that tectal and pyramidal disynaptic EPSPs in dorsal neck motoneurones were mediated chiefly by C-mRSNs and C-inRSNs and partly by L-RSNs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228154
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    Electronic Resource
    Functional differentiation between the anterior and posterior Clare-Bishop cortex of the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 221-233 
    Details
    ISSN: 1432-1106
    Keywords: Vision ; Motion perception ; Photic responsiveness ; Extrastriate cortex ; Suprasylvian cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A total of 783 cells were studied extracellularly in anterior (A10–13), posterior (A4–8), and intermediate regions (A8. 1–9.9) of Clare-Bishop (CB) cortex of the cat, which were defined according to the anteroposterior coordinate of the stereotaxic axis and probably corresponded to the antero- (AMLS), postero-medial lateral suprasylvian cortex (PMLS), and the border region between the two subareas, respectively. The study was conducted under N2O anesthesia supplemented with continuous infusion of short-lasting anesthetics (Saffan, Glaxo or Etomidate, Janssen), using three types of visual stimulators presenting two- (2D) and three-dimensional (3D) motion stimuli, and visual cues contained in the 3D motion. Neuronal responsiveness was essentially similar between the anterior and posterior CB subdivisions. Both areas contained 1) AP, 2) RC and 3) FP cells, selectively responsive to approaching, recessive and fronto-parallel motion, and 4) NS and 5) U cells, nonselectively responsive and unresponsive to any of these motions. However, a quantitative difference was found: 1) In the posterior CB the FP cell population was the largest, and the frequency reduced in the order of AP, NS, RC and U cells, while the largest population in the anterior CB consisted of the AP and U cells, and the frequency reduced in the order of FP, RC and NS cells. 2) 3D (AP and RC) cells in the posterior CB responded preferentially to approaching motion at a distal range, while those in the anterior CB preferred motion at a proximal range. 3) The 3D cells in the posterior CB were more sensitive to the motion cue and demonstrated lower thresholds for the size cue than the anterior CB cells. 4) The anterior CB cells generally demonstrated high-pass velocity tuning (cut-off around 10°/s) for monocular 2D stimulation, while the posterior CB cells demonstrated a broad band-pass tuning (4–120°/s). These findings suggest functional differentiation in neuronal representation of 3D motion signals between the two subdivisions of CB cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228111
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    Mono- and disynaptic excitatory inputs from the superior colliculus to vertical saccade-related neurons in the cat Forel's field H (1990)
    Springer
    Experimental brain research 82 (1990), S. 222-226 
    Details
    ISSN: 1432-1106
    Keywords: Vertical saccade ; Forel's field H ; Saccaderelated neuron ; Mono- and disynaptic excitatory input ; Superior colliculus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Excitatory inputs to neurons in the Forel's field H (FFH) related to visually induced vertical saccades from the ipsilateral superior colliculus (SC) were investigated in chronically prepared alert cats. By stimulation of the deep or intermediate layer of the SC, upward augmenting neurons (ANs) and one long-lead downward burst neuron (BN) were found to be activated monosynaptically, while medium-lead BNs were activated disynaptically. The monosynaptically activated neurons were not antidromically activated from the oculomotor nucleus, whereas disynaptically activated neurons were also activated antidromically from the inferior rectus subdivision of the nucleus. These results suggest that an excitatory input to the FFH from the SC for inducing vertical saccades of visual origin first reaches upward ANs and/or long-lead downward BNs in the FFH, which in turn drive medium-lead BNs in the same area synapsing with motoneurons related to vertical eye movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230857
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  • 56
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    Neuronal cell types in the thalamic intralaminar central lateral nucleus of the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 491-499 
    Details
    ISSN: 1432-1106
    Keywords: Intralaminar thalamus ; Interneurons ; Projection neurons ; Golgi impregnation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The existence of Golgi type II neurons was verified in the anterior intralaminar central lateral (CL) nucleus of the cat thalamus, and its projection cell types were identified, by means of Golgi impregnation. CL principal neurons were found to display a large- or medium-sized cell body and a radiate dendritic pattern. Their primary dendrites were limited in number, and had a rather long course; they were poorly ramified. The axons of principal neurons were impregnated only occasionally and for a short distance. Projection neurons of the ‘bushy’ or tufted type, described in the main thalamic sensory nuclei, were not identified in the CL in the present study. Typical Golgi type II neurons were found throughout CL. They were mainly small-sized, and displayed a rich dendritic arborization characterized by dendritic appendages. The axons of Golgi type II neurons were seen to give rise to extensive local arborizations. The present findings indicate that in the cat CL, principal cells are mainly represented by radiate neurons. Typical local circuit neurons also are evident in CL, suggesting that the activity of anterior intralaminar structures is regulated by intrinsic mechanisms similar to those operating in the main thalamic relay nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423497
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    GABAergic mechanisms in the cat red nucleus: Effects of intracerebral microinjections of muscimol or bicuculline on a conditioned motor task (1990)
    Springer
    Experimental brain research 81 (1990), S. 523-532 
    Details
    ISSN: 1432-1106
    Keywords: GABA ; Microinjection ; Red nucleus ; Motor control ; Reaction time ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Interneurons in the Red Nucleus (RN) are known to be under cortical control and to exert an inhibitory action, mediated by GABAergic mechanisms, on the main output towards the spinal cord. The effects of discrete injections of a GABA receptor agonist (muscimol) or an antagonist (bicuculline) in the Red Nucleus were tested on a motor task performed by seven cats. The subjects were trained to release a lever with a flexion movement of the forelimb controlled by a reaction time (RT) paradigm. Muscimol as well as bicuculline increased RTs in a dose-dependent manner at doses below 100 ng. However the parameters of the force exerted on the lever were differentially altered by the two drugs. Muscimol increased RTs by slowing down the force change preceding movement as well as slightly delaying its latency. While bicuculline increased drastically the force change latency. It could also speed up the force change velocity for low doses. At higher doses (up to 500 ng) both drugs produced an arrest of the performance either associated with anxiety signs (bicuculline) or dystonic movements of the head followed by body rotations (muscimol). The strong motor impairments as well as the disruption of the conditioned performances following muscimol or bicuculline microinjection in the RN suggest an important functional role for GABAergic interneurons. Under the control of cortical afferences they can modulate rubrospinal activity and participate in the triggering of a conditioned movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423501
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    Slowing of the discharge of secondary endings of cat muscle spindles during fusimotor stimulation (1990)
    Springer
    Experimental brain research 83 (1990), S. 164-171 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Fusimotor ; Afferent ; Intrafusal contraction ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of secondary endings of muscle spindles of the peroneus tertius muscle of the anaesthetized cat have been recorded during repetitive stimulation of functionally single fusimotor fibres that produced slowing of the discharge. In a sample of 125 pairs of single fusimotor fibres and secondary spindle afferents 5 examples of slowing were seen. The amount of slowing became less at longer muscle lengths. Conditioning the spindle by stimulating the muscle nerve at fusimotor strength, at a length 2.5 mm longer than the test length, and then returning to the test length 3 seconds later led to a greater degree of slowing of the discharge than after conditioning stimulation at the test length. With one exception, responses to muscle stretch were reduced during stimulation of a fusimotor fibre that produced slowing. On two occasions stimulating a fusimotor fibre that produced slowing of the response of one secondary ending, led to excitation of two other endings. Two possible explanations for the generation of slowing responses have been considered. The first is that the slowing is the result of contraction of the region of intrafusal fibre directly underlying the secondary sensory ending. The second, which we favour since it accounts for the facts more adequately, is that slowing is the result of shortening of the region of nuclear chain fibres on which the sensory ending lies, produced by movement in an adjacent nuclear bag fibre.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232205
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  • 59
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    GABA-induced remote inactivation reveals cross-orientation inhibition in the cat striate cortex (1990)
    Springer
    Experimental brain research 80 (1990), S. 626-630 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Orientation tuning ; Inhibition ; Local inactivation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated the contributions of lateral intracortical connections to the orientation tuning of area 17 cells using micro-iontophoresis of the inhibitory transmitter gamma-aminobutyric acid (GABA) to inactivate small cortical sites in the vicinity of a recorded cell. GABA was ejected from an array of micropipettes each with an average horizontal distance of 500 μm from the recording site. Of 54 cells tested, 33 showed a reduction and 3 a loss of orientation selectivity due to an increase in responses to non-optimal orientations during GABA inactivation. The response to the optimal orientation remained constant in more than half of the cells and increased or decreased in others. Given that a complete cycle of orientations occupies a tangential distance of 1000 μm, the observed broadening of orientation tuning is presumably due to GABA-mediated inactivation of inhibitory interneurones with different preferred orientations from those of their target cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228003
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    Stimulation of cranial vessels excites nociceptive neurones in several thalamic nuclei of the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 552-566 
    Details
    ISSN: 1432-1106
    Keywords: Superior sagittal sinus ; Middle meningeal artery ; Craniovascular ; Nociception ; Single units ; Thalamus ; Ventroposteromedial nucleus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular recordings were made in the thalamus of cats anaesthetized with chloralose and urethane following electrical, mechanical and chemical stimulation of the superior sagittal sinus or middle meningeal artery. Facial receptive fields were looked for using electrical and mechanical stimuli. The locations of fifty-six cells were verified histologically. Twenty six cells were located in the ventroposteromedial nucleus (VPM) and six in its ventral periphery (VPMvp). All units in VPM had facial receptive fields, usually involving the first trigeminal division. Cells with nociceptive receptive fields or responding to the craniovascular application of bradykinin were often found in the periphery or “shell” region of VPM. Other craniovascular nociceptive cells were found in VPMvp, in the posterior group and in the intralaminar complex. This study shows that craniovascular afferents in the cat project to several thalamic nuclei and implicate VPM especially in craniovascular nociception.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423504
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  • 61
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    In vivo recording of postsynaptic potentials and low threshold spikes in W cells of the cat's lateral geniculate nucleus (1990)
    Springer
    Experimental brain research 81 (1990), S. 438-442 
    Details
    ISSN: 1432-1106
    Keywords: Thalamus ; Visual system ; Calcium conductance ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We obtained good intracellular recording from 5 W cells in the C-laminae of the cat's lateral geniculate nucleus. The recordings were made from an anesthetized and paralyzed in vivo preparation. We found a consistent pattern for the postsynaptic potentials evoked from activation of the optic chiasm: first was an IPSP followed by an EPSP. This is very different from the pattern seen in X and Y cells, for which an EPSP always appears first and is then followed by an IPSP. We interpret the pattern for W cells as follows. The initial IPSP is disynaptic; this involves retinogeniculate conduction over very fast Y axons and a relay through an interneuron. The EPSP is monosynaptic, reflecting retinogeniculate conduction over very slow W axons. A possible implication for this is that activity over the Y pathway may generally inhibit geniculate W cells before these W cells can be excited by their retinal afferents. Finally, we elicited from each of these W cells voltage-dependent, low threshold spikes, which are very similar to those displayed by X and Y cells. These spikes can interrupt normal retinogeniculate transmission, and they are prevented by maintaining relatively depolarized membrane potentials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228138
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  • 62
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    Relations between identified tendon organs and motor units in the medial gastrocnemius muscle of the cat (1990)
    Springer
    Experimental brain research 81 (1990), S. 602-608 
    Details
    ISSN: 1432-1106
    Keywords: Golgi tendon organ ; Motor unit ; Gastrocnemius ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In one medial gastrocnemius muscle of each of several cats, the response was recorded of a single tendon organ to the contraction of a single motor unit which strongly excited the receptor. The motor unit was depleted of its glycogen and the depleted muscle fibres identified in PAS-stained transverse sections. The site of maximum tendon organ sensitivity was marked and the tendon organ identified in the same sections. Five pairs of tendon organs and motor units were studied completely. Each tendon organ was found to have one or two (mean 1.6) depleted muscle fibres attached to it, included in the bundle of fibres attached to the end (mean no. 14.4) and side (mean no. 5.6) of the tendon organ. A correlation was found between tendon organ discharge rate and the tension calculated from cross-sectional area measurements of the depleted muscle fibres attached to the tendon organ, with variation between individual pairs of tendon organs and motor units. One estimate of the average sensitivity of the sample was 28 imp/s/mN. A nearly linear discharge rate vs. tension relation was found for single tendon organ and motor unit pairs when tension was graded during a series of fatiguing contractions. Under these conditions the sensitivity, measured as the slope of the relation between discharge rate and motor unit tension recorded at the common tendon, varied between 0.11 and 0.30 imp/s/mN for 6 pairs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02423510
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  • 63
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    Electronic Resource
    Spatial coordination by descending vestibular signals (1990)
    Springer
    Experimental brain research 105 (1990), S. 345-362 
    Details
    ISSN: 1432-1106
    Keywords: Vestibulospinal reflexes ; Vestibulocollic reflex ; Cervicocollic reflex ; Directionality ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Electromyographic activity of dorsal neck muscles and neck torques was recorded to study vestibulocollic, cervicocollic, and combined reflexes in alert and decerebrate cats during rotations of the whole body, the body except for the head, and the head but not the rest of the body. Cats were rotated about many axes that lay in the frontal, sagittal, and horizontal planes using sinusoidal 0.25-Hz waveforms or sum-of-sinusoid waveforms. Robust electromyographic responses were recorded from six muscles, with response directionality that in most cases did not show strong dependence on the reflex tested or on other factors including exact neck angle, stimulus amplitude from 5° to 60°, and intact versus decerebrate state. Based on the strength of responses to rotations about all the tested axes, neck muscles could be characterized by maximal activation direction vectors representing the axis and direction of rotation in threedimensional space that was most excitatory during reflex responses. Responses to rotations about axes that lay in a coordinate plane were predicted by a cosine function of the angle between the axis under test and the maximally excitatory axis in the plane. All muscles were excited by the nose down phase of pitch rotation and by yaw and roll away from the side on which the muscle lay. Biventer cervicis was best activated by rotations with axes near nose-down pitch, and its axis of maximal activation also had small, approximately equal components of yaw and roll toward the contralateral side. Complexus was best excited by rotations with axes nearest roll, but with large components along all three axes. Occipitoscapularis was best excited by rotations about axes near pitch, but with a moderately large contralateral yaw component and a smaller but significant contralateral roll component. Splenius was best excited by rotations with a large component of contralateral yaw, considerable nose-down pitch, and a smaller component of contralateral roll. Rectus major was best excited by rotations near nose-down pitch, but with a substantial contralateral yaw component and smaller contralateral roll component. Obliquus inferior was best excited by rotations with a large component of contralateral yaw, but with considerable contralateral roll and nose-down pitch components. All muscles responded as though they received convergent input from all three semicircular canals. Vestibulocollic and combined reflex responses in alert cats and vestibulocollic, cervicocollic, and combined responses in decerebrate cats appeared to have the same directionality, as evidenced by insignificant shifts in maximal activation vectors. Cervicocollic responses in alert cats were inconsistent and often absent, but appeared upon decerebration, suggesting that higher centers suppress the cervicocollic reflex in intact animals. Decerebration and partial cerebellectomy had no significant effect on maximal activation directions, although electromyographic response magnitudes increased after each. The results suggest that common circuits or strategies are used by neck stretch and vestibular-neck reflexes. The reflex excitation directions do not match the mechanical actions of the neck muscles but agree fairly well with previously published predictions of a mathematical model of neck motor control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233035
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  • 64
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    Electronic Resource
    Action of tianeptine on focalization of attention in cat (1990)
    Springer
    Psychopharmacology 102 (1990), S. 227-233 
    Details
    ISSN: 1432-2072
    Keywords: Tianeptine ; Amitriptyline ; Attention ; Beta rhythms ; Frontoparietal cortex ; Quantitative ECoG ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Tianeptine, an antidepressant substance devoid of sedative action, was investigated for its effects on focalization of attention in cats, using combined behavioural and electrocorticographic (ECoG) observations. The ECoG index was the presence of 40 Hz frontoparietal rhythmic cortical activities, developing while the animal displayed a behaviour suggesting focused attention. Cats were observed in two conditions: a “neutral” one, with no specific target, and another one, “of focused attention” where a live mouse placed in a transparent box was present in the recording room, each test lasting for 90 min. After treatment the animals displayed increased attention even in the neutral situation, where the cat, instead of sleeping like during control sessions, payed sustained attention to its environment. Conversely, at corresponding doses, amitriptyline, another antidepressant drug chosen as a reference, induced uninterrupted slow sleep even in the situation of focused attention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245926
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  • 65
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    Slow inward and late slow outward currents induced by hyperpolarizing pre-pulses in cat bladder parasympathetic neurones (1990)
    Springer
    Pflügers Archiv 416 (1990), S. 322-334 
    Details
    ISSN: 1432-2013
    Keywords: Cat ; Urinary bladder ; Parasympathetic ganglion neurone ; Slow inward current ; Late slow outward current
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Single-electrode voltage-clamp techniques were used to examine membrane currents recorded as a result of hyperpolarizing pre-pulses in cat bladder parasympathetic neurones. In 84 ganglion cells examined, two types of current were observed in response to hyperpolarizing pre-pulses of 10 ms to 1 s duration from holding potentials of −30 to −60 mV to test potentials of −90 to −130 mV. In 46 cells, a short-duration pulse induced a slow inward current (SIC); with longer pulse durations, an outward current was superimposed on the SIC, resulting in a late slow outward current (LSOC). In the remaining cells, either a SIC (n=12) or an LSOC (n=26) was recorded over a range of hyperpolarizing pre-pulse durations. The more depolarized the holding potential, the more hyperpolarized the test potential and the longer the pulse duration, the larger the amplitude of the SIC and LSOC. The SIC and LSOC were associated with an increase in input conductance. The extrapolated reversal potential (V rev) for the LSOC obtained at a holding potential of −60 mV (where the LSOC seemed to be less contaminated with the SIC) was −89±4 mV (mean ± standard error of the mean; n=5), which is close to the equilibrium potential for the K ion. The LSOC was depressed by a high-K (10–20 mM) solution and potentiated by a low-K (0.47 mM) solution. The SIC was depressed by a low-Na (26.2 mM) solution, but was not affected significantly by a low-Cl (12.2 mM) solution. A low-Ca (0.1 mM)/high-Mg (5 mM) solution depressed the LSOC, while a high-Ca (5 mM) solution potentiated it. Cd (0.5 mM) blocked the SIC almost completely, and suppressed the LSOC. The LSOC but not the SIC was suppressed by tetraethylammonium chloride (10 mM). Superfusing Cs (3 mM) did not affect either the LSOC or the SIC. 4-Aminopyridine (1 mM) and muscarine (10 μM) depressed or replaced the SIC with an outward current, while potentiating the LSOC. These results suggest that a hyperpolarizing pre-pulse induces slow inward Na- and late slow outward Ca-dependent K currents, which are inactivated at depolarized potentials and are de-inactivated by hyperpolarizing pulses in a time-dependent manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392069
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  • 66
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    Neuropeptide Y: presence in sympathetic and parasympathetic innervation of the nasal mucosa (1990)
    Springer
    Cell & tissue research 259 (1990), S. 119-128 
    Details
    ISSN: 1432-0878
    Keywords: Nasal mucosa ; Neuropeptide Y (NPY) ; Vasoactive intestinal polypeptide (VIP) ; Peptide histidine isoleucine (PHI) ; Noradrenaline ; Sympathetic/parasympathetic innervation ; Pig ; Cat ; Guinea-pig ; Rat ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The occurrence of neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) in the sympathetic and parasympathetic innervation of the nasal mucosa was studied in various species including man. A dense network of NPY-immunoreactive (IR) fibres was present around arteries and arterioles in the nasal mucosa of all species studied. NPY was also located in nerves around seromucous glands in pig and guinea-pig, but not in rat, cat and man. The NPY-IR glandular innervation corresponded to about 20% of the NPY content of the nasal mucosa as revealed by remaining NPY content determined by radioimmunoassay after sympathectomy. These periglandular NPY-positive fibres had a distribution similar to the VIP-IR and PHI-IR nerves but not to the noradrenergic markers tyrosine hydroxylase (TH) or dopamine-β-hydroxylase (DBH). The NPY nerves around glands and some perivascular fibres were not influenced by sympathectomy and probably originated in the sphenopalatine ganglion where NPY-IR and VIP-IR ganglion cells were present. The venous sinusoids were innervated by NPY-positive fibres in all species except the cat. Dense NPY and DBH-positive innervation was seen around thick-walled vessels in the pig nasal mucosa; the latter may represent arterio-venous shunts. Double-labelling experiments using TH and DBH, and surgical sympathectomy revealed that the majority of NPY-IR fibres around blood vessels were probably noradrenergic. The NPY-positive perivascular nerves that remained after sympathectomy in the pig nasal mucosa also contained VIP/PHI-IR. The major nasal blood vessels, i.e. sphenopalatine artery and vein, were also densely innervated by NPY-IR fibres of sympathetic origin. Perivascular VIP-IR fibres were present around small arteries, arterioles, venous sinusoids and arterio-venous shunt vessels of the nasal mucosa whereas major nasal vessels received only single VIP-positive nerves. The trigeminal ganglion of the species studied contained only single TH-IR or VIP-IR but no NPY-positive ganglion cells. It is concluded that NPY in the nasal mucosa is mainly present in perivascular nerves of sympathetic origin. In some species, such as pig, glandular and perivascular parasympathetic nerves, probably of VIP/PHI nature, also contain NPY.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571436
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    Die Bestimmung der intestinalen Resorption von Herzglykosiden durch Messung der3H-markierten Glykoside im Portalvenenblut und in der Darmlymphe bei Katzen (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    Details
    ISSN: 1432-1912
    Keywords: Intestinal Absorption ; Cardiac Glycosides ; Blood of Portal Vein ; Intestinal Lymph ; Cat ; Intestinale Resorption ; Herzglykoside ; Portalvenenblut ; Darmlymphe ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The cardiac glyoosides digitoxin, ouabain, digoxin and peruvosid labelled with3H were injected into tied intestinal loops of anaesthetized cats in situ. The absorbed glycosides were measured in the blood of the portal vein and in the intestinal lymph. At the same time the3H-activity was measured in the blood of the peripheral circulation, in the bile and in the urine. 2. Calculation of the amount of glycosides totally absorbed from the3H-concentration in the blood of the portal vein and the circulation volume (bubble-flow-meter) gave the following absorption rates as a percentage of the administered dose per hour: digitoxin 56%, digoxin 42%, peruvosid 26% and ouabain 10%. 3. The amount of glycosides passing into the lymph during 1 hour was found to be only 0.006 to 0.02% of the amount offered. In lymph3H-activity cannot be measured earlier than 5 min after the administration of the labelled glycosides. The3H-concentration in the lymph did not equal that measured in the blood of the peripheral circulation until at least 1 hour after the administration and always remained below the3H-concentration of the blood in the portal vein. This proportion remained unchanged even if digitoxin was administered as an emulsion in oil instead of an aqueous solution. From the time course of3H-concentration it might be concluded that the glycosides do not pass directly to the lymph after absorption but indirectly by way of the blood. 4. The amount of glycoside excreted in the bile is for peruvosid 15,5% of the amount absorbed, for ouabain 1,9%, for digoxin 1,4% and for digitoxin 0,8%. The3H-activity excreted in urine is very small and can be disregarded. 5. Chromatographic analyses of the bile revealed, that in the case of digoxin, 4/5 of the amount excreted were unchanged, in the case of digitoxin and ouabain 2/3 and in the case of peruvosid only 1/4. In the lumen of the tied intestinal loops and in the tissue of the small intestine the glycosides were hardly metabolised.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01002379
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    Über die Gefäßversorgung des Corpus callosum der Katze (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    Details
    ISSN: 1432-0568
    Keywords: Arterial supply ; Corpus callosum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 27 Katzen beiderlei Geschlechts wurde die Blutversorgung des Corpus callosum untersucht. Dabei wurden folgende Befunde erhoben: Der Balken der Katze wird im Bereich des Rostrum und Genu sowie im vorderen und mittleren Truncuabschnitt aus der Arteria cerebri anterior versorgt und zwar über Äste, die den Arteriae pericallosae und den Arteriae genu corporis callosi entstammen. Diese Äste wurden als Arteriae callosi superiores und inferiores bezeichnet. Lediglich im hinteren Truncusabschnitt und im Splenium erfolgt die Versorgung neben Ästen der A. pericall. auch über solche der Arteriae cerebri mediae und posteriores. Die Blutgefäße treten dolchartig in den Balken ein, teilen sich dann baumartig weiter auf und gehen in ein Capillarnetz über, das in Richtung des Nervenfaserverlaufes ausgezogen ist. Auf in der Literatur bereits bekannte, aber oft vernachlässigte Besonderheiten der Arteria carotis interna und des Circulus arteriosus wird hingewiesen.
    Notes: Summary In investigations on 27 cats of both sexes, the arterial supply of the corpus callosum was studied. The findings are as follows: In the region comprising rostrum and genu as well as in the fore and middle trunk sections, blood supplied by branches of the arteriae pericallosae and the arteriae genu corporis callosi which originate from the arteria cerebri anterior. These branches were designated arteriae callosi superiores and inferiores. However, in the posterior section of the trunk and in the splenium the blood is supplied by branches of the aa. pericall. and, in addition, by branches of the arteriae cerebri media and posteriores. The blood vessels penetrate the corpus callosum in bayonet fashion, then arborise and finally become a capillary network which is elongated in the direction of the course of the nerve fibres. Attention is drawn to peculiarities of the arteria carotis interna and the circle of Willis which, although known in the literature, are rarely referred to.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00522492
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    Quantitative Untersuchungen an Gliazellen im Corpus callosum wachsender Katzen nach Perfusions- und Immersionsfixierung (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    Details
    ISSN: 1432-0568
    Keywords: Postnatal development ; Fixation ; Neuroglia ; Corpus callosum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Gehirne von Tieren aus 4 verschieden alten Würfen junger Katzen wurden teils lebensfrisch durch Perfusion, teils nach 24 Std durch Immersion fixiert und für Vergleichsuntersuchungen in Paraffin eingebettet. Bei Betrachtung der Gliazellen des Corpus callosum ergab sich: 1. Nach Perfusionsfixierung sind die Kerne der Gliazellen groß und elliptisch. Sie sind wasserklar und haben eine scharf gezeichnete Chromatinstruktur. Nach Immersionsfixierung 24 Std p.m. sind die Kerne dagegen klein und rund, homogen dunkel gefärbt und haben ein kaum zu erkennendes Chromatingerüst. 2. Nach Perfusionsfixierung sieht man im Balken der ganz jungen Tiere zahlreiche Mitosen. Sie fehlen bei den durch Immersion fixierten Geschwistertieren desselben Wurfes. 3. Die nach verschiedener Fixierung beobachteten Unterschiede in der Form der Gliazellkerne werden durch Messungen der Quer- und Längsachsen erfaßt.
    Notes: Summary In four litters of young cats, some of the brains were fixed by perfusion and the others by immersion. The material was embedded in paraffin and the neuroglia was investigated in sections through the corpus callosum. It was found that: 1. After fixation by perfusion the nuclei of the glia cells are large and elliptic. The caryoplasm is clear and there is a distinct structure of the chromatin. After fixation by immersion the nuclei of the same cells are small and round. The caryoplasm is dense and the structure of the chromatin is not clearly visible. 2. After fixation by perfusion mitotic figures are present. They are absent in the brains fixed by immersion. 3. Following different fixation, there are differences in the shape of the nuclei of the glial cells. These differences have been investigated in detail by measuring the diameters of the nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00521281
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  • 70
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    The lateral cervical nucleus in the cat IV. A light and electron microscopical study after midbrain lesions with demonstration of indirect wallerian degeneration at the ultra-structural level (1969)
    Springer
    Experimental brain research 7 (1969), S. 51-67 
    Details
    ISSN: 1432-1106
    Keywords: Lateral cervical nucleus ; Midbrain lesions ; Nauta method ; Ultrastructural investigation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The lateral cervical nucleus (LCN) has been studied with the light and electron microscope after midbrain lesions in kittens of different ages, and in adult cats. It has been shown that nerve cells remain within the contralateral LCN after hemisection of the midbrain. performed on 1 day old kittens. The estimated number of these remaining cells was 3–19% in the different cases. No fibers descending to the LCN from levels rostral to the midbrain could be demonstrated in adult cats with the Nauta technique. A combined Nauta and electron microscopical investigation was performed on kittens operated on at different ages and allowed to survive varying times postoperatively. At the operations the LCN-axons were transected at midbrain level. The Nauta investigation demonstrated silver impregnation of degenerating LCN-neurons on the affected side of the same type as has been described recently in other neuronal systems following axonal transection. The ultrastructural study revealed electron dense degenerating dendrites and probably also nerve cells within the LCN. The dense degenerative changes were very similar to the dense degeneration in terminal boutons following transection of parent axons. The potential value of the findings for electron microscopical research in neuroanatomy is discussed. The results in terms of connections of the LCN are discussed in the light of known anatomical and physiological data of the LCN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236107
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  • 71
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    Integration konvergierender Afferenzen in der bulbären Formatio Reticularis der Katze (1969)
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    Details
    ISSN: 1432-1106
    Keywords: Reticular formation ; Convergence ; Inhibition ; Cat ; Chloralose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Ein konditionierender corticaler Reiz inhibiert den somatischen Startlereflex bei Katzen unter Chloralosenarkose für eine Dauer von mehr als 200 ms. Die Interaktionen zwischen beiden Reizen laufen in der bulbären und pontinen Formatio reticularis ab. 2. Dem Startlereflex liegt eine polysynaptische Erregungsschleife zugrunde, die die bulbäre und pontine Formatio reticularis durchzieht. Die Resistenz der reticulären Neurone gegenüber repetitiver Stimulation wurde als Kriterium ihrer funktionellen Lokalisation auf dem polysynaptischen Reflexbogen gewertet. 3. Die corticale Inhibition wird im Verlaufe der polysynaptischen Erregungsschleife zunehmend stärker. Neurone, die von den Startlereflexafferenzen direkt erregt werden, werden durch den corticalen Reiz nicht inhibiert. Dies schliebt eine präsynaptische Inhibition der reticulopetalen Fasersysteme aus.
    Notes: Summary 1. The startle reflex evoked by cutaneous stimulation in cats under chloralose anesthesia is inhibited for more than 200 ms by a conditioning cortical volley. The interaction between the cutaneous and the cortical volley takes place in the bulbar and pontine reticular formation. 2. The startle reflex involves a series of reticular neurones. Resistance to repetitive stimulation has been determined to evaluate the functional localization of each neurone within this polysynaptic path. 3. Inhibition following the cortical volley becomes increasingly more effective along the course of the polysynaptic path and is completed within 5–6 ms. Reticular neurones excited directly by the spino-reticular afferents are not inhibited, thus excluding a presynaptic inhibition of the spinoreticular fibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235440
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  • 72
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    Inhibitory and excitatory factors influencing the receptive fields of lamina 5 spinal cord cells (1969)
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    Details
    ISSN: 1432-1106
    Keywords: Cutaneous receptive fields ; Spinal cord ; Cat ; Pain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Examination of cutaneous receptive fields (RFs) of lamina 5 cells in the lumbar spinal cord of decerebrate cats shows them to have three distinct zones with respect to mechanical and electrical stimulation. The mean response rate to both mechanical and electrical stimulation in zone 1 increases steadily up to the highest strengths used; in zone 2, surrounding zone 1 mainly proximally, mild stimuli reduce the mean rate, stronger stimuli increase it; in zone 3, mainly proximal to zone 2, all stimuli reduce the rate. Temporally, zone 1, electric shocks near threshold produce bursts of firing followed by inhibition. With increased stimulus strength, the bursts lengthen to a second or more. In zones 2 and 3, inhibition at all strengths is preceded at higher strengths by bursts of firing. Cold-blocking the spinal cord at lower thoracic levels reversibly increases the ongoing activity of these cells, increases the area of zones 1 and 2, and almost completely suppresses all inhibition. Stimulation of dorsal columns and threshold stimulation of distant dorsal roots inhibits ongoing and induced activity. Barbiturate decreases ongoing activity and the duration of firing produced by cutaneous electrical stimulation but does not decrease inhibition. These results are consistent with a model in which low-threshold fibres are excitatory only over a small central area of the RF of a lamina 5 cell (zone 1), high threshold fibres are excitatory over a larger area (zones 1 and 2), and low threshold fibres are inhibitory over the entire receptive field (zones 1, 2 and 3) with a slower time-course. This inhibition is tonically enhanced by descending influences in the decerebrate cat. It is suggested that the high and low threshold fibres correspond approximately to the small and large diametre fibres whose balance is the basis for the coding of pain in the theory of melzack and wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235240
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  • 73
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    Die Bedeutung der Vorderhirnkommissuren für die Koordination bilateraler EEG-Muster (1969)
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; EEG synchronization ; Homolateral sensory evoked potentials ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spontaneous EEG-patterns and evoked potentials (EP's) of symmetrical cortical areas were recorded in chronic and acute cats before and after section of the corpus callosum, the commissura anterior and posterior and the massa intermedia. The spontaneous EEG was recorded without and with anesthesia, EP's after electrical stimulation of the fore-paws only during nembutal anesthesia. — No changes in the bilateral coordination of spontaneous and evoked EEG-patterns could be seen after commissurotomy (CT). The bilateral coherence of EEG-waves as revealed by cross-correlation is low already in the normal cats and does not change significantly after CT. The values of cross-correlation coefficients at T = ± 15 msec vary during one EEG-record between -0.25 and +0.25 in the somatosensory, suprasylvian and temporal areas (mean values slightly above 0). In the visual area occasionally positive values between 0.5 and 0.8 were seen, but also here a large variation was found in all animals and the mean values were below 0.1. No consistent phase shift between both sides was observed. EEG-patterns like spindles or arousal, still occurred together in both hemispheres after CT, the variability of their exact beginning or end was the same as in controls. Spontaneous spindles often lasted longer after section of the massa intermedia. Homolateral EP's in the somato-sensory area were still present after CT. Rhythmical afterdischarges could be restricted to the contralateral somato-sensory cortex even before CT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239029
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    Functional organization of the vestibular afferents to the cerebellar cortex of frog and cat (1969)
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    Details
    ISSN: 1432-1106
    Keywords: Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Field and unitary potentials evoked in the vestibulo-cerebellum of frog and cat following vestibular nerve stimulation were recorded with microelectrodes and correlated with their site of origin in the various layers of the cerebellar cortex. 2. In the frog, primary vestibular fibers project both as mossy and as climbing fibers onto the cerebellar auricular lobe. Secondary vestibulo-cerebellar fibers seem to end exclusively as mossy fibers in the auriculum. As a consequence of this dual projection, extra- and intracellular recordings from Purkinje cells in the auricular lobe show two kinds of responses to vestibular nerve stimulation: a) graded, repetitive firing mediated through mossy fiber-granule cell-parallel fiber pathways, and b) all-or-none burst responses caused by monosynaptic impingement of vestibular climbing fibers on Purkinje cells. 3. The field and unitary potentials evoked in the cat nodulus, flocculus and uvula following vestibular nerve stimulation are shown to be generated by mossy fibers exclusively. Considerable convergence of the two labyrinthine mossy fiber inputs to a given cerebellar area was found. 4. Interaction of contralateral and ipsilateral mossy fiber input at the level of the flocculus suggests that Golgi cell inhibition might operate not only as a simple inhibitory feedback loop, but also as a complex gating operator at the granule layer. 5. No short latency climbing fiber activation of Purkinje cells was observed following VIIIth nerve stimulation. Stimulation of the contralateral inferior olive evoked short latency climbing fiber EPSPs in Purkinje cells of the vestibulo-cerebellum. Suggestions are made as to the possible role of mossy and climbing fiber inputs to this area of the cerebellum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235450
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    Pyramidal control of fusimotor neurons supplying extensor muscles in the cat's forelimb (1969)
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    Details
    ISSN: 1432-1106
    Keywords: Pyramidal tract ; Fusimotor Neurons ; Forelimb ; Extensor ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of cortical stimulation upon dynamic and static sensitivities of the sensory endings in muscle spindles have been analyzed. 63 single afferent fibers from the muscle spindles of the forelimb extensors: M. flexor carpi radialis, M. flexor digitorum communis and M. palmaris longus were isolated in dorsal root filaments in 20 adult cats under chloralose-urethane anesthesia. They were identified by their response to stimulation of the median nerve. 1. Surface anodal repetitive stimulation of the anterior sigmoid gyrus was found to produce an enhancement of static response of single Group II fibers. Effective area was localized in a restricted region which corresponded to the forelimb motor area. The effect was obtained without any concomitant muscle contraction. Similarly, the stimulation increased the resting discharges of the Group Ia fibers from the same muscles. 2. Stimulation of the same area in the cerebral cortex was also found to increase the dynamic sensitivities of primary sensory endings. The increase was revealed by an enhancement of initial burst discharge during relaxation period of a twitch contraction caused by median nerve stimulation. 3. These results indicate that stimulation of the forelimb motor area has a facilitatory effect on both the static and dynamic fusimotor neurons innervating the muscle spindles of the test muscles. 4. The effects were reproduced in pyramidal tract preparations in which the brainstem was cut either at the level of the midbrain except for the cerebral peduncle or at the level of caudal medulla oblongata sparing the pyramid. 5. The threshold for the fusimotor effects was less than 1.3–1.5 times threshold of the pyramidal tract discharge, when the best spot for eliciting the fusimotor response was chosen. These results indicate that the effects of cortical stimulation are mainly mediated by the fast conducting pyramidal tract fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238324
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    Contrôle de l'activité des fibres fusimotrices dynamiques et statiques par la formation réticulée mésencéphalique chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 307-324 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Gamma motor control ; Mesencephalic reticular formation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of repetitive stimulation of the mesencephalic reticular formation (MRF) on the static discharge and dynamic sensitivity of muscle spindle primary endings (soleus muscle) were studied in cats anaesthetized with Halothane (Fluothane). By progressive increasing the depth of anaesthesia three different fusimotor effects could be observed: 1. A static effect; the static discharge of the primary endings was strongly increased; the response to phasic stretch was decreased or remained unaltered. 2. A dynamic effect; the dynamic sensitivity of the primary endings was powerfully increased while the rate of discharge under static conditions was only slightly augmented. 3. A depressant effect; the static discharge and the dynamic sensitivity of primary endings were decreased. Repeated stimulation elicited successive static and dynamic effects. No specific regions within the MRF could be related to a particular effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235241
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    Etude fonctionnelle du contrôle de l'activité des fibres fusimotrices dynamiques et statiques par les formations réticulées mésencéphalique, pontique et bulbaire chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 325-345 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Gamma motor control ; Reticular formations ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. During a progressive increase of Fluothane (Halothane) anaesthesia, repetitive stimulation of the mesencephalic retioular formation (MRF) produces several fusimotor effects — static, dynamic or depressant — on primary endings of soleus muscle spindles (Vedel et Mouillac-Baudevin 1969). 2. Transection of the brain immediately rostral to the site of stimulation may increase the dynamic effect but does not alter the static or the depressant effects. 3. A section of the rubrospinal tract does not modify the fusimotor effects elicited by stimulation of the MRF. 4. Transections of the spinal cord have shown that the pathways responsible for the transmission of these effects are mainly situated in the ipsilateral ventral and ventrolateral funiculi which contain the efferent fibers from the pontine reticular formation (PRF), from the bulbar reticular formation (BRF) and from the vestibular nucleus. 5. Contra and ipsilateral PRF stimulation produces the static fusimotor effect; contralateral stimulation from a small anterior region produces the dynamic effect. 6. Stimulation of the lateral part of the ipsilateral BRF elicits the dynamic effect while stimulation of the medial part elicits the static effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235242
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    Die asynchrone und lokal umschriebene Reizwirkung von Mittelfrequenz-Dauerströmen im Hypothalamus der Katze (1969)
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    Details
    ISSN: 1432-1106
    Keywords: Emotional behaviour ; Hypothalamus ; Electricalstimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. In order to compare the selective value of repetitive cathodal pulses of 8 c.p.s. and of continuous sine-wave alternating currents of 5000 c.p.s. (middle frequency current) when applied to brain tissue, explorations were made in the region of the hypothalamus that had yielded defence and/or flight reactions in earlier experiments. The region was explored by stimulating each point in turn with both current forms. At the same time measurement was made of the impedance of the brain tissue, and the effects produced by altering the time of rise of the middle frequency current on threshold of responses were also studied. The experiments were carried out on unanaesthetized, freely moving cats. 2. Both stimulation types produced affective (“emotional”) responses. The patterns elicited by low frequency cathodal pulse stimulation were often associated with stimulus-bound phasic muscle activity, i.e., flapping of ears, and twitching of whiskers, or, rotation of the head. Such extraneous motor effects were rarely obtained when continuous middle frequency currents were applied, and were tonic in character when present. 3. Mapping of reactive points revealed that the area producing defence or flight following middle frequency stimulation is smaller in size than the field delimited by means of repetitive cathodal pulse stimulation. These results strongly suggest that spread of current can be reduced by using middle frequency current stimulation. This apparently local (and hence highly selective) action is paralleled by a lower impedance of the brain tissue to the rapidly changing polarity of this current. 4. The hissing (and/or growling) associated with the defence pattern showed adaptation to suddenly rising middle frequency currents of 30 secs duration. An increase in threshold of hissing occurred when the time of rise of the current was prolonged. Flight, in contrast, was obtained at the same critical intensity regardless of the time of rise of current. 5. The nature of the stimulatory action of middle frequency current (examined in the peripheral nerve by Wyss) and the advantages presented by this new method of brain stimulation are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238329
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    The lateral cervical nucleus in the cat III. An electron microscopical study after transection of spinal afferents (1969)
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    Details
    ISSN: 1432-1106
    Keywords: Lateral cervical nucleus ; Spinal lesions ; Ultrastructural investigation ; Degenerating boutons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of terminal degeneration within the lateral cervical nucleus (LCN) after transection of its spinal afferent fibers 2 days–2 years earlier is described. The degeneration after 2 days was of both the neurofilamentous and dense type. The highest number of degenerating terminals, about 15%, was found after 4–5 days. Then most of the degenerating boutons were of the dense type. The degenerating terminals had synaptic contact with cell bodies and dendrites of LCN-neurons. Removal of the degenerating boutons seemed to be effected by a phagocytic cell present in increased number compared to the normal LCN. In cases with long survival times an increase in the number of astroglial filaments was observed. In an animal where the spinal afferents to the LCN had been cut 2 years earlier a decrease in medium size of the neurons was observed. The amount of dendritic spines was also considerably smaller than normally.
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    URL: http://dx.doi.org/10.1007/BF00236106
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    Inhibition in the medial geniculate body of the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    Details
    ISSN: 1432-1106
    Keywords: Medial geniculate body ; Inhibition ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Inhibitory activity in the cat medial geniculate body (MG) was examined by stimulating electrically and acoustically the input and output of the MG. 2. A longer and more profound depression of excitability occurs following a click-evoked potential in the MG than in the inferior colliculus (IC) in both anesthetized and unanesthetized states. Recovery is cyclic in the barbiturate MG preparation. 3. Electrical stimulation of the brachium of the inferior colliculus (BIG) evokes a field potential in the MG consisting of clearly distinguishable presynaptic and postsynaptic components. The presynaptic component recovers rapidly, while the postsynaptic component requires 100–200 msec for full recovery. This depression of excitability is localized within the MG since cortical ablation does not alter its occurrence. 4. Stimulation of the BIC mimics the effects of click stimulation on single units. Excitatory, inhibitory and reverberatory responses are evoked by the BIC shock. Suppression of single unit activity correlates with the depression of excitability following a BIC-evoked field response. 5. Cortical stimulation can evoke antidromic and trans-synaptic unit responses in the MG, as well as causing a variety of inhibitory effects and reverberation. In view of the fact that cortical ablation does not impair the recording of these responses to afferent stimuli, it is suggested that the cortical-evoked responses are at least partly mediated by antidromic conduction to MG. 6. Evidence is presented that inhibitory effects of both afferent and cortical stimulation are due to active inhibition of MG unit activity. Speculations are made as to the mechanisms producing inhibition and reverberation in the MG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236108
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    Electronmicroscopic observations on the structure of the pontine nuclei and the mode of termination of the corticopontine fibres an experimental study in the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 95-110 
    Details
    ISSN: 1432-1106
    Keywords: Electron microscopy ; Pontine nuclei ; Experimental neuroanatomy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electron microscopical changes occurring in the pontine nuclei following unilateral lesions of the primary sensorimotor cortex have been studied in 7 cats with a survival time from 2–23 days. A description is also given of the fine structure of the pontine regions in receipt of the fibres. These regions are shown in Fig. 1. The study shows that the boutons are practically only in synaptic contact with dendrites. The bouton density on these is only 16%. The boutons are of the en passage and terminal type, with the latter as the most common (Figs. 4a-e). The synaptic vesicles are rounded or elongated. The formaldehyde fixed material had 17.8% boutons with vesicles of the elongated type; the material fixed with a mixture of formaldehyde and glutaraldehyde had only 11.5% of such boutons. The degenerating boutons show the dark type of reaction and the majority of the corticopontine fibres are of the type shown in Figs. 4d and 4e. Astrocytes and microglial cells participate in the removal of degenerating boutons and terminal fibres. Degenerating boutons are present even at the 23 day stage and some have apparently only started to degenerate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235436
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    Eine faktorenanalyse von schwellen subcorticaler reizantworten (1969)
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    Details
    ISSN: 1432-1106
    Keywords: Evoked potential thresholds ; Factor analysis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zur Beschreibung von Korrelationen zwischen zahlreichen elektrophysiologischen Daten aus verschiedenen Hirngebieten wurde eine Faktorenanalyse nach der Hauptachsenmethode gerechnet. Ausgangsmaterial dieser Analyse waren Schwellen subcortical ausgelöster und abgeleiteter Antwortpotentiale auf Einzelreize. Das resultierende Faktorenmuster ermöglicht ein quantitatives Konzept der Schwellendetermination subcorticaler Reizantworten und zugleich ein Modell von Funktionsbeziehungen zwischen einigen Hirnstrukturen. Die Reizungen und Ableitungen erfolgten bei 35 encéphale isolé-Katzen mit Hilfe bipolarer Elektroden in folgenden Arealen: Amygdala, Hippocampus, Septum, N. dorsomedialis Thalami, Hypothalamus posterior und Formatio reticularis mesencephali. Es wurden 435 Korrelationskoeffizienten zwischen den Schwellen von 30 subcorticalen Verbindungen gebildet und zum Zwecke einer Datenreduktion durch eine Matrix von 5 Faktoren reproduziert. 1. Jeder Faktor repräsentierte hohe Schwellenkorrelationen zwischen den efferenten Projektionen jeweils eines Kerngebietes. Demnach nimmt im allgemeinen die Aktivität des Reizortes den größten Einfluß auf die Schwelle eines Antwortpotentials. Diese Hypothese ist durch pharmakologische Untersuchungen belegt worden [27] 2. Kovariationen von Reizantworten mit identischen Ableiteorten ergaben sich ausnahmslos, wenn die Latenzzeiten mehr als 11 msec betrugen. 3. Zusätzlich zeigte die Faktorenmatrix Schwellenkorrelationen zwischen: a) den hypothalamischen Efferenzen und mehreren hippokampalen Afferenzen langer Latenz (positive Korrelationen) b) retikulo-limbischen Verbindungen und „primären” Efferenzen von Amygdala und Hippocampus (positive Korrelationen) c) Antwortpotentialen, die durch Reizung der Formatio reticularis, und solchen, die durch Reizung des N. Amygdalae ausgelöst waren (negative Korrelationen) d) den Efferenzen des N. dorsomedialis Thalami und limbischen Projektionen langer Latenz zur mesencephalen Formatio reticularis (positive Korrelationen) Die Interpretation dieser Zusammenhänge bestätigt und erweitert einige bekannte Modelle von Beziehungen zwischen subcorticalen Kerngebieten. Abschließend wird mit Rücksicht auf die Linearität der mathematischen Methode die Anwendbarkeit der Faktorenanalyse auf Schwellen von Reizantworten diskutiert.
    Notes: Summary In 35 cats (encéphale isolé) evoked responses were elicited and recorded with bipolar electrodes from the amygdala, hippocampus, septum, dorsomedial thalamic nucleus, posterior hypothalamus, and mesencephalic reticular formation. Correlations between the thresholds of responses in different areas following stimulation of other areas were described by a factor analysis according to the principal axis method. 435 coefficients of correlation were calculated and reproduced by a matrix of 5 factors for the purpose of data reduction. Each factor represented high threshold correlations between the efferent projections of one region, which suggests that the activity of the stimulated site exerts a major influence on the evoked potential threshold. This is supported by pharmacological studies [27, 49]. Covariations of responses recorded in the same nucleus were always found, if the latencies exceeded 11 msec. The factor matrix indicated threshold correlations between: the efferent projections of the hypothalamus and several long latency afferent projections to the hippocampus (positive correlations); reticulo-limbic connections and “primary” efferent connections of the amygdala and hippocampus (positive correlations); evoked potentials following reticular and amygdaloid stimulation (negative correlations); the efferent projections of the dorsomedial thalamic nucleus and long latency limbic projections to the mesencephalic reticular formation (positive correlations). The interpretation of these relationships confirms and extends some well known models of relations between subcortical regions. The applicability of factor analysis to evoked potential thresholds is discussed with regard to the linearity of the mathematical method.
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    URL: http://dx.doi.org/10.1007/BF00234927
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    Interaction of defence and flight reactions produced by simultaneous stimulation at two points in the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 130-149 
    Details
    ISSN: 1432-1106
    Keywords: Emotional Behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The results presented in the present paper are an extension of preceding work devoted to exploration of the hypothalamic defence and flight fields using coaxial electrodes with small cathode. In 33 cats simultaneous stimulation was applied to two points which upon single stimulation had yielded defence, flight, or defence and flight respectively. Results were compared with those produced at either point alone. In 2 cats combined stimulation of a defence and a flight point was carried out with a stuffed cat present. 2. The latencies and rates of the vocal effects associated with defence (growling and hissing), and the latencies of flight (jump from the table) were measured. 3. Simultaneous stimulation of two points which had yielded defence, or of two points which had yielded flight resulted in facilitation (spatial summation) of the effects evoked: a more complete defence response associated with decrease of the latencies and increase in the rates of the vocal effects; decrease of flight latencies and increase of flight impetuosity. 4. Simultaneous stimulation of a defence point which had yielded growling at lower threshold than hissing, and of a point which had yielded flight resulted in facilitation of hissing. Growling and flight were often suppressed; when they occurred, latencies were lengthened and growling rates were increased somewhat. 5. Stimulation of a defence point with a dummy present produces striking (fending off). Simultaneous stimulation of a flight point resulted in facilitation of both hissing and striking. 6. It is concluded that the complex patterns obtained when defence is combined with flight are the result of facilitatory and inhibitory interaction between the elements of the individual patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234535
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    Räumliche summation und hemmungsvorgänge im receptiven feldzentrum von retina-neuronen der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    Details
    ISSN: 1432-1106
    Keywords: Retinal Ganglion Cells ; Spatial Summation ; Center Inhibition ; Dynamic Organisation of Receptive Fields ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. An retinalen Ganglienzellen der Katze wurde die räumliche Summation im receptiven Feldzentrum (KFZ) bei Dunkeladaptation und Helladaptation durch mittelpunktzentrierte Lichtreize verschiedener Flächengrößen untersucht. Als Kriterium dienten die Entladungsraten der ersten 200 und 500 msec nach Licht-an oder Licht-aus. Das Summationsverhalten wurde sowohl für Einzelneurone als auch gruppenstatistisch für die beiden Neuronen-Systeme B (on-Zentrum) und D (off-Zentrum) untersucht. 2. Die räumliche Summation ist auf den inneren Bereich des RFZ beschränkt: bei on-Zentrum-Neuronen steigt die Entladungsrate nur bis zu Reizflächen, die etwa 1/5 der Fläche des RFZ belichten, bei off-Zentrum-Neuronen bis zu Reizflachen von ca. 1/10 des RFZ. Bei Variation der Reizfläche zwischen 20 und 100% der Fläche des RFZ bleibt das Entladungsniveau konstant (asymptotischer Verlauf der Summationskurve). 3. Die Begrenzung der räumlichen Summation auf einen kleinen Bereich des RFZ beweist eine bereits im Feldzentrum wirksame Hemmung. Diese Zentrum-Inhibition begrenzt die Erregungssummation im RFZ bei zunehmender Flächengröße des Lichtreizes. 4. On- und off-Zentrum-Neurone unterscheiden sich in beiden Adaptationszuständen in der Höhe des Entladungsniveaus. Die Entladungsraten der on-Zentrum-Neurone nach Licht-an übertreffen um ein Mehrfaches die Entladungsraten der off-Zentrum-Neurone nach Licht-aus. Die Unterschiede sind gruppenstatistisch hoch signifikant. Die interneuronale Variabilität der Entladungsraten ist bei den onZentrum Neuronen erheblich geringer als bei den off-Zentrum-Neuronen. 5. Dunkel -und Helladaptation führt zu signifikantem Unterschied der Entladungsraten: bei Helladaptation liegt die Impulsrate beider Neuronentypen höher als bei Dunkeladaptation und der Summationsbereich ist um 5–10% größer. 6. Für die mathematische Beschreibung der Summationsverläufe ist die Hyperbel besser geeignet als die logarithmische und Potenzfunktion. Logarithmus- und Potenzfunktionen beschreiben den konstanten asymptotischen Teil der Summationskurven ungenügend und eigenen sich nur für den Kurventeil im innersten Summationsbereich. Die Bedeutung der Befunde für eine dynamische Interpretation der visuellen Feldorganisation und mögliche Beziehungen zur lateralen Umfeldhemmung werden diskutiert.
    Notes: Summary 1. Spatial summation of suprathreshold light stimuli within receptive field centers (RFZ) of retinal ganglion cells was investigated during dark and light adaptation in cats. The mean discharge rates for 200 and 500 msec following light on or off were the computed response criteria. The summation effects were analyzed for single neurones and statistically for grouped neuron populations of the two neuronal subsystems B (on-center-neurones) and D (off-center-neurones). 2. Spatial summation is restricted to a small part of the RFZ. On-centerneurones increase their on-discharge rates with increasing spot sizes, only if the stimulus illuminates less than 1/5 of the RFZ. The summating area of the off-centerneurones is smaller (about 1/10 of the RFZ). 3. The limitation of spatial summation to a small part of the RFZ indicates the existance of inhibition within the RFZ. This center-inhibition sets a constant limit for excitation summation in the RFZ. 4. The mean neuronal response rates for the 2 subsystems show significant differences: The on-discharges of the on-center-neurones exceed the off-discharges of the off-center-neurones by a factor of 3–5. These highly significant differences occur at both adaptation levels and are not due to different spontaneous activity. Interneuronal response variability of the off-center-neurones was twice as large as that of the on-center-neurones. 5. Change from dark to light adaptation had only a small but significant influence on summation properties. The poststimulus discharge rates were higher during light adaptation and the summating area was slightly larger (about 5–10%). 6. A comparative curve fitting procedure for three suitable mathematical functions revealed that the hyperbola describes the neuronal summation curves better than a logarithmic or power function. The latter do not fit the constant asymptotic part of the curve. The significance of the results for a dynamic interpretation of the organisation of visual receptive fields is discussed.
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    URL: http://dx.doi.org/10.1007/BF00234924
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    Räumliche summation im receptiven feldzentrum von neuronen des geniculatum laterale der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 53-65 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate body ; Spatial summation ; Off-center-characteristics ; Geniculate transfer ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die räumliche Summation im receptiven Feldzentrum von Neuronen des Corpus geniculatum laterale (CG-L) wird beschrieben und mit entsprechenden Untersuchungen an retinalen Ganglienzellen verglichen. Neben größerer interneuronaler Variabilität ergeben sich ausgeprägtere Unterschiede der Summationseigenschaften der on-und off-Zentrum-Neurone. Der effektive Summationsbereich von etwa 1/5 der Fläche des RFZ ist in Retina und CGL etwa gleich. 2. Die on-Zentrum-Neurone des CGL zeigen in beiden Adaptationszuständen einen ähnlichen Summationsverlauf wie in der Retina. Das Entladungsnieau ist im CGL jedoch erheblich geringer und nicht durch Unterschiede in der Spontanaktivität zu erklären. 3. Die Mehrzahl der off-Zentrum-Neurone des CGL zeigt bei DA inverse Summationsverläufe wie in der Retina: durchgehende Verminderung der Entladungsrate der off-Antworten bei Vergrößerung der Reizfläche im RFZ. Eine kleine Gruppe zeigt einen parabelförmigen Summationsverlauf mit Entladungszunahme bis zu Reizflächen von 10–30% der Fläche des RFZ und darauffolgender Entladungsminderung. Bei Helladaptation zeigen fast alle off-Zentrum-Neurone diesen Parabelverlauf. Das durchschnittliche Entladungsniveau ist von dem retinaler offZentrum-Neurone nicht signifikant verschieden. 4. Die interneuronale Variabilität der Summationsvorgänge im RFZ von CGLNeuronen ist gegenüber den retinalen Ganglienzellen deutlich größer. Dies gilt insbesondere für die off-Zentrum-Neurone. Das Summationsverhalten von CGLNeuronen läßt sich daher nicht wie in der Retina durch einen Funktionstyp beschreiben. 5. Die Befunde sprechen für eine Transformation des retinalen Eingangs der off-Zentrum-Neurone im CGL, während die on-Zentrum-Neurone außer der bekannten Frequenzuntersetzung keine wesentliche Umformung erkennen lassen.
    Notes: Summary 1. Spatial summation in the receptive field center of neurones of the lateral geniculate body (CGL) is limited by inhibition to a small part of field center. Variations of stimulus size are only effective if the stimulus is smaller than about 1/5 of the area of receptive field center. Thus, the active summating area of the field center in the CGL corresponds to that of the retina. Geniculate neurones, however, show less homogeneous responses and the summation properties of the two neuronal subsystems (on-center-and off-center-cells), show greater differences than in the retina. 2. The form of summation curves for the on-center-neurones of the CGL is similar to those of the retina at both adaptation levels. However, the average responses rates in the CGL are considerably lower. This is not due to differences of spontaneous activity. 3. The summation characteristics of off-responses of off-center-neurones of the CGL are quite different from those in the retina. In dark adaptation the majority of CGL neurones respond with decreasing discharge rates to increasing spot-sizes within the field center. A small number show an initial increase of discharge rates up to stimulus sizes of about 1/10 of the receptive field center before a decrease occurs. This parabolic summation type is typical for most off-center-neurones in light adaptation. The mean discharge levels are the same as those of the retinal offcenter-neurones. 4. The higher interneuronal variability of summation curves especially of the off-center-neurones of the CGL indicates a more complex determination of the discharge properties of CGL neurones. This functional differentiation of single neurones is congruent with the more complex structural and synaptic organisation in CGL. 5. With respect to spatial summation, the results indicate a transformation of the retinal input of the off-center-neurones at the geniculate level, whereas the oncenter-neurones are nearly unchanged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234925
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    Langfristige Verträglichkeitsprüfung mit Benperidol an der Katze (1969)
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    Details
    ISSN: 1432-2072
    Keywords: Benperidolum ; Cat ; Extrapyramidal Side Effect ; EEG ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Daily doses of 1–10 mg Benperidol were given perorally to cats during 26 months. The general behaviour and the EEG were unchanged during the treatment, in particular no signs of dyskinesia were observed. After discontinuation of the administration, the behaviour and the EEG of the animals stayed normal. Thus no lasting and irreversible side effects could be observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403690
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  • 87
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    Effects of LSD on the spontaneous and evoked activity of retinal and geniculate ganglion cells (1969)
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    Details
    ISSN: 1432-2072
    Keywords: LSD ; Retina ; LGN ; Single Unit Activity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of LSD 25 (i. v. injection) on the spontaneous and evoked activity of the visual system was investigated in cats. 50 γ/kg did not change significantly the ERG and the visual cortical evoked potential. The spontaneous discharge rate of 14 out of 21 retinal ganglion cells showed an increase which reached its maximum within 20–30 min and which could still be present 1 hour following the injection. One third of the retinal units showed a slight depression of their spontaneous dischaRge rate with about the same time course. Single units of the LGN showed about the same behaviour. The response to light stimulation was slightly increased in some units and light induced inhibition was slightly shortened. The possible mechanism of the LSD-effect on retinal ganglion cell activity is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403713
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  • 88
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    Responses of neurones in cat's abducens nuclei to horizontal angular acceleration (1969)
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    Details
    ISSN: 1432-2013
    Keywords: Labyrinthine Stimulation ; Types of Abducens Neurones ; Frequency Analysis ; Cat ; Labyrinthreizung ; Abducensneurone ; Frequenzanalyse ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single cell activity was recorded extracellularly from neurones in cat's abducens nuclei in unanesthetized, decerebrate preparations. Two types of neurones were found. i) The motoneurones (type IIA) increased their firing linearly or exponentially to contralateral constant angular accelerations and decreased firing to ipsilateral rotation. The increased frequency was maintained at a constant level without any sign of adaptation. This constant level of maximum frequency was proportional to the logarithm of the acceleration applied. No significant differences of the frequency responses of tonic and silent motoneurones were found. The conduction velocities of the axons of spontaneously firing type IIA cells were slower than in silent neurones. Electrical stimulation of the contralateral VIIIth nerve led to activation of the type IIA cells; stimulation of the ipsilateral nerve resulted in inhibition of both spontaneous discharge and antidromic invasion of the motoneurones. ii) The type IA units increased their firing rate to ipsilateral rotation and ceased to discharge in response to contralateral rotation. They never were excited antidromically by stimulation of the VIth nerve. However, they were excited by stimulation of the ipsilateral VIIIth nerve. Their possible functional role in the vestibulo-ocular system was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587754
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  • 89
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    Die Rolle „spezifischer” und unspezifischer Afferenzen für den Antrieb der Atmung, untersucht durch Reizung und Blockade von Afferenzen an der decerebrierten Katze (1969)
    Springer
    Pflügers Archiv 312 (1969), S. 189-205 
    Details
    ISSN: 1432-2013
    Keywords: Cat ; Decerebration ; Afferents to Respiratory Centers ; Medulla Oblongata ; Reticular Formation ; Katze ; Decerebrierung ; Afferenzen zu Atemzentren ; Medulla oblongata ; Formatio reticularis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 11 intercolliculär decerebrierten Katzen wurde geziegt, daß Kälteblockade eines eng umschriebenen Feldes auf der ventralen Oberfläche der Medulla oblongata, wie früher für anaesthesierte Tiere beschrieben, zu Atemstillstand führt, wenn die kontralaterale Stelle auf der Medulla oblongata, die Sinusnerven und die Vagi ausgeschaltet sind. Zu Atemstillstand kam es auch, wenn statt der Kälteblockade 2% Novocain durch lokale Superfusion bei gleichzeitiger Gegenspülung der Umgebung mit künstlichem Liquor angewandt wurde, oder wenn ein mit 1% Novocain getränkter Tupfer lokal aufgelegt wurde. Außerdem führte Kälteblockade zu Atemstillstand, wenn durch kontinuierliche auch während der Kälteblockade anhaltende elektrische Reizung eines N. femoralis oder hinterer Lumbalwurzeln an decerebrierten Katzen oder des Hypothalamus an einer anaesthesierten Katze Steigerungen der Ventilation ausgelöst worden waren. Elektrische Reizung eines Sinusnerven führte zu Atemsteigerungen. Bei Sinusnervenreizung während eines durch Kälteblockade ausgelösten Atemstillstands kam es zu rhythmischer Atmung. Aus diesen Untersuchungen wird geschlossen, daß mit der Ausschaltung der beschriebenen Felder auf der ventralen Oberfläche der Medulla oblongata am sonst desafferentierten Tier die Gesamtheit der für die zentrale CO2-Empfindlichkeit verantwortlichen Strukturen erfaßt ist, daß nach Ausschaltung der zentralen und der peripheren Chemosensibilität eine unspezifische Aktivierung der Atmungszentren unwirksam ist und daß die Atmungszentren zur Ausbildung einer rhythmischen Atmung von spezifischen Antrieben abhängig sind.
    Notes: Summary It was shown in 11 decerebrated cats, that cooling of a small and well defined area on the ventral surface of the medulla will cause respiratory arrest if the contralateral area of the medulla, the vagi and sinus nerves are eliminated. This confirms earlier observations obtained in anesthetized cats. Apnea was also produced by local superfusion of 2% procain with simultaneous flushing of the immediate surrounding area with mock spinal fluid. Local application of a small sponge soaked with 1% procain had the same effect. Electrical stimulation of femoral nerves or posterior roots which results in hyperventilation on the decerebrated cat failed to show any effect during periods of cold blockade. There was no respiratory response to direct stimulation of the hypothalamus in an anesthetized cat during cooling. Electrical stimulation of one sinus nerve caused an increase of ventilation. Sinus nerve stimulation during apnea induced by cold blockade resulted in rhythmical respiration. It is concluded from these experiments: Blocking of the area under discussion on the ventral surface of the medulla, inhibits all structures responsible for the central CO2-sensitivity in the deafferentiated animal. There was no response to non-specific stimuli of the respiratory center after elimination of central and peripheral chemosensitivity. The respiratory centers apparently depend on specific stimuli to support rhythmical respiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586928
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  • 90
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    Defence, attack, and flight elicited by electrical stimulation of the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    Details
    ISSN: 1432-1106
    Keywords: Emotional behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Affective behaviour patterns produced by electrical stimulation of the hypothalamus were studied in unanaesthetized, freely-moving cats. Bipolar stimulation with coaxial electrodes and small cathode was used to elicit defence, attack or flight. The development of these responses was studied by varying stimulation strength. In some experiments a stuffed animal was introduced in order to study the reactions of the cat to changes in the environment during stimulation. 2. The following responses were evoked at threshold intensity: (i) growling reaction; (ii) hissing reaction; (iii) two types of flight — type a preceded by hastily looking to and fro as if in search of an exit, type b preceded by inspection of surroundings, in most cases associated with sniffing. 3. Increasing stimulation 1.5 times threshold often yielded combined patterns. At points yielding the growling reaction a defence response in which growls alternated with hisses was obtained. The points yielding flight type a sometimes yielded hissing followed by flight. Increasing stimulation at hissing points yielded either a defence reaction or the combined effect hissing-flight. 4. The growling reactions were obtained from the tuber region. The hissing responses were obtained from points above the tuber. The flight reactions, type a, were produced from the intermediate zone extending from the level of the preoptic area to the mamillary bodies and type b from the caudo-lateral hypothalamus. 5. The reactions of the cats to a dummy during stimulation varied depending on the type of response which had been evoked in the absence of the dummy. The defence reaction was converted into threatening and striking of the dummy, the combined effects into threatening, striking or biting, culminating in sudden flight. The dummy was ignored during stimulation of points yielding flight type a, but examined by sniffing during stimulation of points yielding flight type b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234534
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  • 91
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    Evidence for mediated transport of chloride in cat cerebral cortex in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex in vitro ; Chloride transport ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The kinetics of the uptake of chloride by slices of cat cerebral cortex incubated in vitro have been studied for a wide range of concentrations of chloride and potassium in the incubation media. 1. In studies with 36Cl at a constant concentration of external K+, the rate of entry of chloride into slices of cat cerebral cortex (after equilibration with the fluid of the extracellular space) followed Michaelis-Menten kinetics with Vmax=7.7 μmoles/g/min and Km=245 mM. The kinetic data so described differ significantly from a curve describing simple diffusion (P 〈 0.02). 2. A clear dependence on concentration of K+ in the incubation medium was demonstrated. When external chloride was held constant at 6.8 mM and concentrations of potassium were varied over a range of 27–100 mM, the apparent rate of entry of chloride followed Michaelis-Menten kinetics with Vmax=0.191 μmoles/ g/min and Km=30.3 mM. 3. Under similar equilibrium conditions, the rate of influx of chloride was not statistically different from the rate of efflux, and the value for extracellular space (355 μl/g) derived by extrapolation from efflux data was of an identical order of magnitude to the value (352 μl/g) obtained from influx data. These values are essentially identical to those previously determined for chloride space of cat cerebral cortex in vivo (Bourke, Greenberg and Tower 1965). 4. The total, membrane-delimited content of chloride in cerebral cortex, as defined in these studies in vitro, was a function of the concentration of K+ in the incubation medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234250
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  • 92
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    Studies of the development and subsequent reduction of swelling of mammalian cerebral cortex under isosmotic conditions in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex in vitro ; Edema ; Fluid compartmentation ; Chloride transport ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ionic parameters of incubation media which foster both the development and subsequent reduction of swelling of slices of cerebral cortex under isosmotic conditions of incubation in vitro are described. A linear relationship between increasing chloride concentrations in incubation media and progressive swelling of tissue slices (under conditions of constant temperature and K+ concentrations and isotonicity of incubation media) is demonstrated. Subsequent reduction of chloride concentration in incubation media together with reciprocal replacement by isethionate is associated with significant and characteristic reduction in the volume of tissue swelling when all other conditions of incubation, including isotonicity of the media, are kept constant. The ionic composition of the fluid of swelling under different conditions of incubation is derived together with the ionic composition and expected transmembrane potentials of the neuronal compartment of cerebral cortex in vitro. Mechanisms involved in the development and subsequent reduction of swelling of cerebral cortex in vitro are discussed, and proposals for possible clinical applications are suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234251
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  • 93
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    Verbesserung der Resorption von Helveticosid und Helveticosol durch Substitution der Hydroxylwasserstoffe an der Digitoxose (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    Details
    ISSN: 1432-1912
    Keywords: Strophanthidine Derivatives ; Toxicity ; Absorption ; Guinea-Pig ; Cat ; Strophanthidinderivate ; Toxicität ; Resorption ; Meerschweinchen ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde die Wirksamkeit verschiedener Ester und Äther von Helveticosid und Helveticosol bei i.v. und intraduodenaler Zufuhr an Katzen und Meerschweinchen geprüft. 1. Bei i.v. Dauerinfusion waren Helveticosol und seine Derivate bei Meerschweinchen etwa doppelt so wirksam wie die analogen Helveticosidverbindungen. Bei der Katze bestand kein Unterschied. Die Monomethyläther Cymarin und Cymarol waren gleich oder sogar stärker wirksam, alle übrigen Derivate deutlich schwächer als die Ausgangssubstanzen. 2. Die tödlichen Dosen bei intraduodenaler Injektion lagen beim Meerschweinchen für einige Substanzen in gleicher Größenordnung oder niedriger als die Titer bei i.v. Infusion. Diese hohe enterale Wirksamkeit kann bei Helveticosid und seinen Derivaten durch eine Reduktion zu dem wirksameren Helveticosol, bei Estern außerdem durch eine Hydrolyse zu wirksameren Glykosiden vorgetäuscht werden. 3. Bei intraduodenaler Infusion an Katzen waren alle geprüften Ester und Äther wirksamer als Helveticosid und Helveticosol. Die aus dem Verhältnis der toxischen Dosen bei i.v. und intraduodenaler Infusion berechnete enterale Wirksamkeit lag zwischen 20 und 50%. 4. Unterschiede in der Dauer der intraduodenalen Infusion bei Katzen lassen sich berücksichtigen, wenn man von der theoretischen Annahme einer exponentiellen und vollständigen Resorption ausgeht und die Halbwertszeit für die Resorption berechnet. Die minimale Resorptionsgeschwindigkeit lag bei einigen Derivaten in gleicher Größenordnung wie bei Digoxin und Digitoxin. Es wird auf den Unterschied zwischen der auf Grund der pharmakologischen Wirkung bestimmten relativen enteralen Wirksamkeit und der Resorptionsquote hingewiesen. Letztere ist für die Verläßlichkeit der therapeutischen Wirkung eines Glykosids bei oraler Gabe maßgebend.
    Notes: Summary The efficacy of several esters and ethers of Helveticosid and Helveticosol was assayed by intravenous and intraduodenal administration to cats and guinea-pigs. 1. In guinea-pigs, Helveticosol and its derivatives were approximately twice as active on intravenous infusion as the analogous derivatives of Helveticosid; in cats there was no significant difference. The monomethylethers Cymarin and Cymarol were equally or slightly more potent, all other derivatives were weaker than the original compound. 2. In guinea-pigs the lethal doses of some compounds on intraduodenal injection were equal to or even lower than those on intravenous infusion. This may partly be accounted for by a reduction of Helveticosid and its derivatives to the more potent Helveticosol analogues, partly by a hydrolysis of the esters, yielding compounds of higher activity. 3. On intraduodenal infusion in cats, all the investigated esters and ethers were more active than Helveticosid and Helveticosol. The relative enteral activity calculated from the ratio of the toxic doses on intravenous and intraduodenal infusion varied between 20 and 50%. 4. Due to a delayed absorption from the gastrointestinal tract, the toxic dose falls with a reduced speed of intraduodenal infusion. Assuming an exponential and complete absorption, the half time of absorption was calculated. For some of the compounds investigated, the speed of absorption was comparable to that of Digoxin and Digitoxin. The difference between the relative enteral activities determined by comparing equiactive doses on enteral and parenteral administration and the percentages of the glycosides which are absorbed from the gastrointestinal tract is pointed out. The latter is of prime importance for obtaining reproducible effects after enteral administration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00536819
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  • 94
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    Electronic Resource
    Morphologische Untersuchungen an der Glandula bulbourethralis der Katze (1969)
    Springer
    Cell & tissue research 101 (1969), S. 607-620 
    Details
    ISSN: 1432-0878
    Keywords: Glandula bulbourethralis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Parenchym der Glandula bulbourethralis der Katze besteht aus weitlumigen, gebuchteten intraglandulären Gängen, in welche kurze, englumige, zumeist unverzweigte Tubuli einmünden. Der Drüse fehlt eine äußere Organkapsel, so daß ihre peripheren Tubuli stellenweise direkt zwischen den Fasern des quergestreiften M. bulboglandularis liegen. Die Drüsentubuli und die Buchten der intraglandulären Gänge sind mit einem einschichtigen Zylinderepithel ausgekleidet, auf den Gangfalten ist das Epithel abschnittsweise mehrreihig, Die sezernierende Epitheloberfläche ist durch die Ausbildung von interzellulären Sekretkapillaren vergrößert. Breite Zwischenzellspalten (Durchmesser etwa 1,5μ), in welche schlanke interdigitierende Cytoplasmafortsätze hineinragen, erstrecken sich von der Basalmembran bis kurz unter das Tubulusbzw. Ganglumen. Die lumenseitigen Zellgrenzen tragen einige stummelförmige Mikrovilli und besitzen zerklüftete Außenkonturen, die durch glykogenreiche Cytoplasmaprojektionen bedingt sind. Alle Epithelzellen sind reich an Mitochondrien. Die supranuklearen Abschnitte der meisten Gang- und Tubuluszellen enthalten Sekretgranula, welche im Elektronenmikroskop unterschiedliche optische Dichten aufweisen können. Die Granula enthalten ein PAS-positives, neuraminsäurehaltiges epitheliales Muzin, das in einzelnen Sekretkörnchen auch eine histochemische Reaktion auf Sulfatgruppen gibt. Alle Epithelzellen reagieren sehr stark auf unspezifische Esterase und stark auf β-D-Glucuronidase, β-D-Glactosidase sowie die Enzyme des Citronensäurezyklus, der Glykolyse und der Atmungskette (NAD-ICDH, SDH, ALD, LDH, ADH, GDH, NADH-T-Red, Cyt-Ox).
    Notes: Summary The bulbourethral glands of sexually mature male cats are studied with the light and electron microscope. The parenchyma consists of spacious, sinus-like intraglandular ducts and short, narrow, mostly unbranched tubular endpieces. The gland has no complete connective tissue capsule, consequently some of the peripheral tubules are situated directly in between the fibers of the surrounding bulboglandularis muscle. The endpieces and the sinus of the intraglandular ducts are lined by a simple columnar epithelium, whereas the folds of the ducts are generally covered by a low pseudostratified epithelium. The secretory surface of the cells is increased by intercellular canaliculi which communicate with the gland lumen. These canaliculi are identified on the light microscopic level by their strong 5′-nucleotidase activity. Furthermore widened intercellular spaces (approximately 1,5 μ in diameter) filled with slender, interdigitating cytoplasmic processes extend from the basal lamina to the apical junctional complexes. The luminal cell pole exhibits some short microvilli and forms irregularly shaped, glycogen containing protrusions. Within the cytoplasm of the gland cells numerous spherical mitochondria, some dense bodies, a typical Golgi apparatus, free ribosomes and a poorly developed endoplasmic reticulum are to be observed. Secretory granules which can be grouped into three types on the basis of their electron density occur in the supranuclear regions of most of the cells. According to histochemical tests all granules contain a periodate reactive sialomucin and some of them also sulfate groups. The glandular parenchyma is site of an exceptionally strong unspecific esterase activity and is rich in β-D-glucuronidase, β-D-glactosidase, aldolase, α-glycerophosphate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase and cytochrome oxydase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335273
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  • 95
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    Mode of activation of hippocampal pyramidal cells by excitatory synapses on dendrites (1966)
    Springer
    Experimental brain research 2 (1966), S. 247-260 
    Details
    ISSN: 1432-1106
    Keywords: Synaptic excitation ; Hippocampus ; Pyramidal cells ; Dendritic activation ; Cat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following selective activation of four afferent paths that terminate exclusively on dendrites, only a small proportion of pyramidal cells in the hippocampal fields CA1 and CA3 discharged impulses. Following a single afferent volley, an EPSP was never observed even in cells synaptically excited. On tetanic stimulation (about 10/sec), a large EPSP developed, but this was not a prerequisite for an action potential. Studies of the extracellular field potentials corresponding to the EPSP and the population spike potential, indicated that the EPSP was generated across the dendritic membrane and that the spike was initiated in the neighbouring part of the dendritic tree, propagating from there along the thicker dendrites towards the soma. This conduction had an average velocity of 0.4m/sec, and, presumably, a relatively low safety factor. In certain cases, the intrasomatic electrode recorded small all-or-nothing spikes which presumably were generated in the dendritic tree. These small spikes (D-spikes) invaded the soma only if assisted by some additional depolarization, for example by frequency potentiation of excitatory synapses. The results indicate two functional types of pyramidal dendrites, the conducting and the synaptic type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236716
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  • 96
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    The inhibitory interneurones within the cerebellar cortex (1966)
    Springer
    Experimental brain research 1 (1966), S. 1-16 
    Details
    ISSN: 1432-1106
    Keywords: Inhibitory interneurones ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Extracellular microelectrode recording has been employed to study the responses of three types of interneurones in the cat cerebellar cortex: basket cells, superficial stellate cells and Golgi cells. The large unitary spike potentials of single cells were sharply localized and presumably were generated by impulse discharges from the cell somata. The characteristics of their responses described below sharply distinguished them from Purkinje cells. 2. The parallel fibre volleys generated by surface stimulation of a folium evoked brief repetitive discharges that were graded in respect of frequency and number. Maximum responses had as many as 10 impulses at an initial frequency of 500/sec. 3. At brief test intervals there was facilitation of the response to a second parallel fibre volley; at about 50 msec it passed over to depression for over 500 msec. 4. Stimulation deep in the cerebellum in the region of the fastigial nucleus (juxta-fastigial, J.F.) evoked by synaptic action a single or double discharge, presumably by the mossy fibre-granule cell-parallel fibre path, but climbing fibre stimulation from the inferior olive also usually had a weak excitatory action evoking never more than one impulse. 5. J.F. stimulation also had an inhibitory action on the repetitive discharge evoked by a parallel fibre volley. Possibly this is due to the inhibitory action of impulses in Purkinje cell axon collaterals. 6. There was a slow (7–30/sec) and rather irregular background discharge from all interneurones. The inhibitory actions of parallel fibre and J.F. stimulation silenced this discharge for some hundreds of milliseconds, probably by Golgi cell inhibition of a background mossy fibre input into granule cells. 7. All these various features were displayed by cells at depths from 180 to 500 μ; hence it was concluded that superficial stellate, basket and Golgi cells have similar properties, discrimination being possible only by depth, the respective depth ranges being superficial to 250μ, 250μ to 400μ, and deeper than 400μ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235206
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    Parallel fibre stimulation and the responses induced thereby in the Purkinje cells of the cerebellum (1966)
    Springer
    Experimental brain research 1 (1966), S. 17-39 
    Details
    ISSN: 1432-1106
    Keywords: Parallel fibres ; Purkinje cells ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. When electrical stimuli were applied to the surface of a cerebellar folium by a local electrode (LOC), there was a propagated potential wave along the folium with a triphasic (positive-negative-positive) configuration. 2. Investigations by microelectrode recording established that this wave is produced by impulses propagating for at least 3 mm and at about 0.3 m/sec along a narrow superficial band or “beam” of parallel fibres. As expected from this interpretation, there was an absolutely refractory period of less than 1 msec and impulse annihilation by collision. 3. Complications occurred from the potential wave forms resulting from the excitation of mossy fibres by spreading of the applied LOC stimulus. These complications have been eliminated by chronically deafferenting the cerebellum. 4. When recording within the beam of excited parallel fibres there was a slow negative wave of about 20 msec duration, and deep and lateral thereto, there was a slow positive wave of approximately the same time course. 5. These potential fields were expressed in serial profile plots and in potential contour diagrams and shown to be explicable by the excitatory and inhibitory synaptic action on Purkinje cells: excitatory depolarizing synapses of parallel fibre impulses on the dendrites; and hyperpolarizing inhibitory synapses of stellate and basket cells respectively on the dendrites and somata. The active excitatory synapses would be strictly on the parallel fibre beam and the inhibitory concentrated deep and lateral thereto, which is in conformity with the axonal distributions of those basket and stellate cells that would be excited by the parallel fibre beam. 6. Complex problems were involved in interpretation of slow potentials produced by a second LOC stimulus at brief stimulus intervals and up to 50 msec: there was a potentiation of the slow negative wave, and often depression of the positive wave deep and lateral to the excited beam of parallel fibres. 7. Often the LOC stimulus evoked impulse discharge from the Purkinje cells, these discharges being inhibited by a preceding LOC stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235207
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    Electronic Resource
    Electronic Resource
    Spontane postsynaptische potentiale von nervenzellen des motorischen cortex der katze (1966)
    Springer
    Experimental brain research 1 (1966), S. 48-64 
    Details
    ISSN: 1432-1106
    Keywords: Spontaneous post-synaptic potentials (EPSPs, IPSPs) ; Motor cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Im motorischen Cortex von ausgewachsenen Katzen (mittlere Nembutalnarkose) wurden spontane postsynaptische Potentiale (PSP) mit intrazellulären Mikroelektroden untersucht. Die spontanen EPSP wurden mit ausgelösten EPSP nach schwachen Reizen in spezifischen (VL) und unspezifischen (CM) Thalamuskernen verglichen. 2. Spontane EPSP treten entweder einzeln oder gruppiert auf. spontane IPSP sind seltener und machen nur 3–10% aller spontanen PSP aus. Die kleinsten EPSP haben eine Amplitude von 150–200 μV, daneben kommen kleinere, flache Schwankungen des Membranpotentials vor. Die mittlere Amplitude von spontanen EPSP liegt bei 0.7 mV. Amplitudenhistogramme spontaner EPSP unterscheiden sich nicht wesentlich von solchen, die durch schwache CM- oder VL-Reize ausgelöst sind. 3. Die Anstiegssteilheit von spontanen EPSP liegt zwischen 2 und 15 msec. Es besteht keine konstante Beziehung zwischen Amplitude und Anstiegssteilheit. Der Potentialabfall ist annähernd exponentiell, die Zeitkonstante liegt zwischen 8 und 12 msec und ist damit etwas länger als die passive Neuronzeitkonstante (8.5±2.2 msec nach Creutzfeldt u. Mitarb., 1964b). Es bestehen keine konstanten Unterschiede der Zeitverläufe von spontanen, durch VL- oder CM-Reiz ausgelösten EPSP-Einheiten. 4. Die Intervallhistogramme von spontanen EPSP sind verschieden je nach dem, ob alle Intervalle oder nur Perioden mit sporadischer, nicht-gruppierter Aktivität ausgezählt werden. Nicht gruppierte EPSP haben längere mittlere Intervalle (70–80 msec). 5. Nach überschwelligen Thalamusreizserien ist sowohl die spontane als auch die reizinduzierte PSP-aktivität vermindert. Es kann jedoch nicht entschieden werden, inwieweit corticale und inwieweit thalamische Mechanismen für diese post-tetanische Depression verantwortlich sind. 6. Während reversibler Deafferentierung des Cortex durch K+-depolarisation afferenter Fasern und im chronisch isolierten Cortex finden sich keine spontanen PSP mehr, obwohl EPSP und IPSP am isolierten Cortex durch epicorticale Reize noch ausgelöst werden können. 7. Aus den Befunden wird geschlossen, daß die beobachteten PSP durch afferente und collaterale Faseraktivität ausgelöst sind. Für echte „Miniaturpotentiale” entsprechend Beobachtungen an Muskelendplatten findet sich kein Anhalt. Insofern repräsentiert das „synaptische Rauschen” corticaler Zellen die konvergierende Afferenz dieser Zellen und kann nicht als echtes „spontanes Rauschen” angesehen werden.
    Notes: Summary Spontaneous post-synaptic potentials (PSP's) of neurones of the motor cortex are analysed (intracellular recording, Nembutal anesthesia, cats). Distinct EPSP's either appear grouped or more sporadically distributed. Spontaneous EPSP's only represent about 3–10% of all spontaneous PSP's. The mean amplitude of EPSP's is about 0.7 mV. The smallest EPSP's have an amplitude of 150–200 μV, smaller slow fluctuations of the membrane potential (MP) are seen occasionally. Amplitude histograms of spontaneous EPSP's are similar to those of evoked EPSP units following weak thalamic stimulation. — The rising time of spontaneous EPSP's varies between 2 and 15 msec. and is not correlated with the peak amplitude. The decay is almost exponential, the time constant is between 8 and 12msec., thus being slightly higher than the neurone time constant of cortical pyramidal cells (8.5±2.2 msec. Creutzfeldt et al., 1964b). No consistant differences in time course and amplitude of “EPSP units” after VL and CM thalamic stimulation and of spontaneous EPSP's was found. Cortical and thalamic components of post-tetanic depression of spontaneous and evoked PSP activity cannot be distinguished. Interval histograms are different whether all EPSP's during sporadic and grouped activity or whether only sporadically appearing EPSP's are counted. Non-grouped EPSP's show longer mean intervals (between 70 and 80 msec.). — During reversible deafferentation with K+-depolarization of afferent fibers and in the chronically isolated cortex no spontaneous EPSP's or IPSP's are found eventhough membrane fluctuations of cells in the latter preparation may sometimes be difficult to distinguish from real EPSP's. In the chronically isolated cortex, EPSP's and IPSP's can still be elicited by epicortical stimulation. — From these findings it is concluded that the observed spontaneous PSP's represent “unit” EPSP's and IPSP's due to afferent and collateral fiber activity and that no true miniature potentials due to spontaneous liberation of transmitter substance can be recorded. Thus, the “synaptic noise” of cortical neurones represents convergent activity on these cells and consequently cannot be considered as true “spontaneous noise”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235209
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