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  • 1
    Electronic Resource
    Electronic Resource
    Effects of orally administered interferon-α on the pathogenesis of feline leukaemia virus-induced erythroid aplasia (1995)
    Springer
    Comparative clinical pathology 5 (1995), S. 79-83 
    Details
    ISSN: 1433-2981
    Keywords: Cat ; Feline leukaemia virus ; Interferon-α
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The use of orally administered interferon-α as a treatment for retroviral disease was evaluated in the experimental model of feline leukaemia virus (FeLV)-induced erythroid aplasia. Progressive anaemia, FeLV viraemia, and leukopenia developed in cats inoculated with the Kawakami-Theilen isolate of feline leukaemia virus (FeLV-KT). A treatment regimen with orally administered recombinant interferon-α or natural interferon-α as employed in this study had no significant effects on viraemia, course of disease, or differential leucocyte counts. The results of this study did not reveal any beneficial effects of human interferon-α administered by the oral route for treatment of cats with experimentally induced FeLV infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00638923
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of decalcification on bone mineral content and bending strength of feline femur (1995)
    Springer
    Calcified tissue international 56 (1995), S. 78-82 
    Details
    ISSN: 1432-0827
    Keywords: Bone mineral content (BMC) ; Cat ; Decalcification ; Ethylene diaminetetra acetic acid (EDTA) ; Femur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The relationships between bone mineral content (BMC), bone calcium, and bone strength were studied in fractionally demineralized feline femurs. In 44 pairs of cat femurs, the right bones were decalcified in ethylene diaminetetra acetic acid (EDTA) to 20%, 40%, 60%, 80%, and 100% of the mineral content of the intact left bone (=control). The bones were then loaded to failure, and maximum strength values were recorded. The data were then used to calculate the percentage strength of the right relative to the left femurs. A correlation coefficient (r) of 0.970 was found between the percentage decalcification and percentage bending strength. A direct relationship (r=0.876) was also observed between the total calcium extracted and total loss in BMC. The EDTA solutions were spot checked for protein content to determine if the organic matrices had been altered by demineralization. Protein was never detected. Nor did the demineralized tissues display histologic evidence of gross microscopic damage. This study has shown that in cat femurs, 20% decalcification led to about 35% loss in bending strength, and 60% decalcification caused 75% loss in strength. These values are significant as they highlight the importance of calcium to the strength of osteopenic bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298748
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  • 3
    Electronic Resource
    Electronic Resource
    Different patterns of fore-hindlimb coordination during overground locomotion in cats with ventral and lateral spinal lesions (1995)
    Springer
    Experimental brain research 104 (1995), S. 70-80 
    Details
    ISSN: 1432-1106
    Keywords: Locomotion ; Spinal lesions ; Interlimb coordination ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of large, low thoracic (T10–T11), partial spinal lesions involving the ventral quadrants of the spinal cord and, to a different extent, the dorsolateral funiculi, on fore-hindlimb coordination was examined in cats walking overground at moderate speeds (40–100 cm/s). Three different forms of impairment of fore-hindlimb coordination depending on the extent of the lesions, were observed. Lesions sparing the dorsolateral or the ventral funiculus on one side preserved the equality of the fore- and hindlimb locomotor rhythms but changed the coupling between the movements of both girdles as compared to intact animals. Larger lesions in which, in addition to the ventral quadrants of the spinal cord, also major parts of the dorsolateral funiculi were destroyed elicited episodes of rhythm oscillations in both girdles, which appeared at the background of a small difference in these rhythms. Lesions destroying almost the whole spinal cord induced a permanent difference (about 200 ms) in the step cycle duration of the fore- and the hindlimbs. However, even in these animals some remnant form of fore-hindlimb coordination was found. The results suggest that dorsolateral funiculi play a major role in preserving the equality of rhythms in the foreand the hindlimbs, while lesions of the ventral quadrants change the coupling between limbs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229856
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of neonatal splitting of the optic chiasm on the development of feline visual callosal connections (1995)
    Springer
    Experimental brain research 104 (1995), S. 275-286 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Vision ; Cortex ; Plasticity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract During normal postnatal development, there is an overproduction and subsequent partial elimination of the callosal projections of cortical areas 17 and 18 in the cat. In the present study, we investigated how neonatal splitting of the optic chiasm affects this process. Our results indicate that neonatal splitting of the optic chiasm 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. It does not, however, cause a significant change in the number of callosally projecting neurons in the infragranular layers. These data suggest that in addition to other factors previously described, the level or spatial distribution of correlated binocular input to visual cortical neurons may influence the stabilization/elimination of immature callosal connections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242013
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  • 5
    Electronic Resource
    Electronic Resource
    Dopaminergic control of transmission from group II muscle afferents to spinal neurones in the cat and guinea-pig (1995)
    Springer
    Experimental brain research 105 (1995), S. 39-47 
    Details
    ISSN: 1432-1106
    Keywords: Dopamine ; Group II muscle afferents ; Spinal cord ; Cat ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of dopamine and its agonists on transmission from muscle afferents to spinal neurones were investigated in the cat and guinea-pig spinal cord, by measuring the drug effects on the amplitude of monosynaptic field potentials evoked by electrical stimulation of group I and group II muscle afferents. Local iontophoretic application of dopamine, the dopamine D1/D5 agonist SKF-38393 and the D2/D3/D4 agonist quinpirole all depressed the group II field potentials evoked at the base of the dorsal horn. Group II field potentials in the intermediate zone were depressed by dopamine to a similar degree as the dorsal horn field potentials, whereas the dopamine agonists were without effect upon them. The intermediate zone field potentials evoked by group I muscle afferents were not depressed by any of the drugs. The dopamine-evoked depression of the group II-evoked field potentials in the dorsal horn in the guinea-pig spinal cord was reduced by the simultaneous application of haloperidol. The results demonstrate that dopamine receptors mediate the depression of transmission from group II muscle afferents to interneurones in the dorsal horn, but not to neurones in the intermediate zone of the spinal cord.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242180
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  • 6
    Electronic Resource
    Electronic Resource
    Transmission characteristics for the 1:1 linkage between slowly adapting type II fibers and their cuneate target neurons in cat (1995)
    Springer
    Experimental brain research 105 (1995), S. 67-75 
    Details
    ISSN: 1432-1106
    Keywords: Slowly adapting type II ; Cuneate neuron ; Synaptic transmission ; Tactile afferent fiber ; Somatosensory system ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Transmission from single, identified, slowly adapting type II (SAII) tactile fibers to their target neurons in the cuneate nucleus was examined in anesthetized cats. Simultaneous recordings were made from cuneate neurons and from fine, intact fascicles of the superficial radial nerve in which it was possible to identify and monitor the activity of each group II fiber. Selective activation of individual SAII fibers was achieved by means of skin stimulation with fine probes, in conjunction with extensive forelimb denervation. Responses were studied for seven SAII-driven cuneate neurons. For three there was unequivocal monitoring of the identified SAII input fiber. However, in six of the seven there was evidence that just one SAII fiber provided suprathreshold input to the cuneate neuron, and neither temporal nor spatial summation was required for reliable transmission. Cuneate impulse rates, in response to SAII inputs lasting 1 s, were less than 250 impulses per second, even though the SAII impulse rates could be 500 s-1. Responses to individual SAII impulses consisted of a burst of 2–3 impulses at low SAII input rates, but burst responses disappeared at high SAII rates. In all three SAII-cuneate pairs studied, the transmission security (the percentage of SAII impulses that evoked cuneate spike output) exceeded 80% in response to static skin displacement and in response to certain frequencies of skin vibration, in particular, at 100–200 Hz, exceeded 98% when the SAII fiber responded near the 1∶1 level (one impulse per vibration cycle). Transmission characteristics for the SAII-cuneate linkage resulted in the cuneate neuron showing tight phaselocking of responses to high-frequency (〉100 Hz) vibrotactile stimuli and higher impulse rates than its SAII input (up to input rates of ∼50 impulses s-1). Security of transmission across the SAII-cuneate synapse is similar to that demonstrated previously for tactile fibers of the SAI and Pacinian corpuscle (PC)-related classes, which suggests that there is no marked differential specialization in transmission characteristics for dorsal column nuclei neurons that receive input from different tactile fiber classes. Furthermore, it means that the reported failure of individual SAII fiber inputs to generate conscious sensation in man following intraneural microstimulation is not related to transmission failure at the first central relay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242183
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  • 7
    Electronic Resource
    Electronic Resource
    Relationship of simultaneously recorded cerebellar nuclear neuron discharge to the acquisition of a complex, operantly conditioned forelimb movement in cats (1995)
    Springer
    Experimental brain research 105 (1995), S. 325-330 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Motor learning ; Reaching ; Cerebellar nuclei ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study was designed to examine the changes in the modulation of small populations of cerebellar neurons during the acquisition of a complex, operantly conditioned forelimb task in cats. The experiments are based on the general postulate that, during the learning of a complex motor behavior, the cerebellum is important for generating a coordinated movement that meets the task's objectives, and that, as the cerebellum participates in this process, it acts to reinforce the effective motor pattern once it has been established. This specific study examines whether the changes in the modulation of cerebellar nuclear neurons during the learning of this task are consistent with this view. Cats were required to learn to move the manipulandum through a novel pattern of 2–3 consecutive straight grooves connected end to end in different spatial configurations, e.g., the letter L, an inverted L, and the letter C. Throughout the acquisition process, 6–12 single units were recorded simultaneously in the cerebellar nuclei, and the kinematics of the movement were evaluated using an Optotrak system. Cells were recorded from the two interposed nuclei and the dentate nucleus in these initial studies. Trials were sorted off-line based on the level of skill at which the required movement was performed. This was assessed using several objective criteria such as movement times, kinematic characteristics, and smoothness (number of peaks in the velocity profile). Event-related histograms then were constructed from each group of sorted trials. Changes in modulation related to a specific event were measured in successive histograms for each neuron. One of the most consistent findings across the cells in all nuclei was that the magnitude of the task-related modulation reached a peak at the time the task was first performed reasonably well and then progressively decreased (but did not disappear) as the task became well practiced. Both the initial increase and the subsequent decrease in response amplitude were significant statistically. The implications of these observations are discussed in the context of the role the cerebellum may play in the acquisition of complex motor tasks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240970
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  • 8
    Electronic Resource
    Electronic Resource
    Express saccades in cat: effects of task and target modality (1995)
    Springer
    Experimental brain research 103 (1995), S. 209-217 
    Details
    ISSN: 1432-1106
    Keywords: Express saccade ; Reaction time ; Attention ; Fixation ; Orienting response ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Saccadic eye movements to visual, auditory, and bimodal targets were measured in four adult cats. Bimodal targets were visual and auditory stimuli presented simultaneously at the same location. Three behavioral tasks were used: a fixation task and two saccadic tracking tasks (gap and overlap task). In the fixation task, a sensory stimulus was presented at a randomly selected location, and the saccade to fixate that stimulus was measured. In the gap and overlap tasks, a second target (hereafter called the saccade target) was presented after the cat had fixated the first target. In the gap task, the fixation target was switched off before the saccade target was turned on; in the overlap task, the saccade target was presented before the fixation target was switched off. All tasks required the cats to redirect their gaze toward the target (within a specified degree of accuracy) within 500 ms of target onset, and in all tasks target positions were varied randomly over five possible locations along the horizontal meridian within the cat's oculomotor range. In the gap task, a significantly greater proportion of saccadic reaction times (SRTs) were less than 125 ms, and mean SRTs were significantly shorter than in the fixation task. With visual targets, saccade latencies were significantly shorter in the gap task than in the overlap task, while, with bimodal targets, saccade latencies were similar in the gap and overlap tasks. On the fixation task, SRTs to auditory targets were longer than those to either visual or bimodal targets, but on the gap task, SRTs to auditory targets were shorter than those to visual or bimodal targets. Thus, SRTs reflected an interaction between target modality and task. Because target locations were unpredictable, these results demonstrate that cats, as well as primates, can produce very short latency goal-directed saccades.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231707
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  • 9
    Electronic Resource
    Electronic Resource
    Cross-correlation of augmenting expiratory neurons of the Bötzinger complex in the cat (1995)
    Springer
    Experimental brain research 103 (1995), S. 251-255 
    Details
    ISSN: 1432-1106
    Keywords: Respiratory neurophysiology ; Cross-correlation ; Bötzinger complex ; Expiratory neurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ipsilateral and contralateral pairs of augmenting expiratory neurons were recorded simultaneously from the Bötzinger complex using glass-coated tungsten microelectrodes in pentobarbitone-anaesthetized cats. The neurons were identified both by firing pattern and by antidromic activation from the contralateral site of the dorsal respiratory group. Cross-correlation histograms of the extracellularly recorded action potentials were calculated in order to detect short time-scale synchronizations of firing indicative of synaptic connections between the neurons. The cross-correlation histograms for 40 ipsilateral pairs of neurons less than 1 mm apart showed eight (20%) narrow troughs (mean half-amplitude width ±SD, 1.1±0.37 ms) at short latencies (mean latency±SD, 1.0±0.35 ms) suggestive of monosynaptic inhibition. These included two cross-correlation histograms which showed troughs on both sides of time zero, indicating a mutual inhibition. For another four pairs of neurons (10%), a central broad peak suggestive of common activation due to either excitation or release from inhibition was evident. Contralateral pairs of expiratory neurons of the Bötzinger complex were examined in a similar manner. The cross-correlation histograms for 43 pairs of neurons showed five (12%) narrow troughs (mean half-amplitude width±SD, 1.2±0.67 ms) at short latencies (mean latency±SD, 2.7±1.47 ms) suggestive of monosynaptic inhibition. These included one cross-correlation histogram which showed troughs (one not statistically significant) on both sides of time zero, indicating a mutual inhibition. For another two pairs of neurons (4.6%) a central, broad peak suggestive of common activation due to either excitation or release from inhibition was evident. We conclude that inhibitory interconnections exist between augmenting expiratory neurons of the Bötzinger complex ipsilaterally and contralaterally. These connections may synchronize the expiratory burst of activity within this population and assist in the patterning of the burst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231711
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  • 10
    Electronic Resource
    Electronic Resource
    Binaural noise stimulation of auditory callosal fibers of the cat: responses to interaural time delays (1995)
    Springer
    Experimental brain research 104 (1995), S. 30-40 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Sound localization ; Interaural time delays ; Midline fusion ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The corpus callosum, the principal neocortical commissure, allows for the interhemispheric transfer of lateralized information between the hemispheres. The aim of the present experiment was to study callosal transfer of auditory information in the cat, with particular reference to its contribution to sound localization. The corpus callosum was approached under direct visual control, and axonic responses were recorded under light anesthesia using glass micro-pipettes. Results showed that auditory information is transmitted in the posterior portion of the callosum. Diotic presentations, in which interaural time delay was manipulated, indicated that, for a large number of fibers, the largest excitatory or inhibitory interactions were obtained at null interaural time delay, a condition which supports the notion of a callosal contribution to auditory midline fusion. However, an important number of callosal fibers was also found to be excited maximally at specific, non-zero interaural time delays, suggesting that they preferred sounds situated at spatial locations other than the midline. The results are discussed in relation to those obtained electrophysiologically for the visual and somesthesic modalities and in terms of results obtained in human and animal behavioral experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229853
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  • 11
    Electronic Resource
    Electronic Resource
    Brainstem modulation of signal transmission through the cat dorsal lateral geniculate nucleus (1995)
    Springer
    Experimental brain research 103 (1995), S. 372-384 
    Details
    ISSN: 1432-1106
    Keywords: Contrast gain ; Lateral geniculate nucleus ; Neuromodulation ; Retinogeniculate transmission Lagged and nonlagged cells ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied changes in retinogeniculate transmission that occur during variation of modulatory brainstem input and during variation of stimulus contrast. Responses of single cells in the dorsal lateral geniculate nucleus (dLGN) to a stationary flashing light spot of varying contrast were measured with and without electrical stimulation of the peribrachial region (PBR) of the brain-stem. PBR stimulation increased the contrast gain (slope of response versus contrast curve) and the dynamic response range (range between spontaneous activity and maximal firing). Lagged and nonlagged X-cells reached the midpoint of the dynamic response range at lower contrasts during PBR stimulation than in the controls. No comparable change was seen for Y-cells. Only minor changes of threshold contrast were seen. The characteristics of the retinogeniculate transmission were directly studied by comparing the response of dLGN cells with their retinal input (slow potentials, S-potentials). With increasing contrast there was a marked increase in the transfer ratio (proportion of impulses in the input that generates action potentials in the dLGN cell). The transfer ratio seemed to be primarily determined by the firing rate of the retinal input. The transfer ratio increased with increasing input rates from low values near threshold to values that could approach 1 at high-input firing rates. PBR stimulation increased the transfer ratio, particularly at moderate input firing rates. The increased transfer ratio, caused by increasing input firing rates, enhanced the response versus contrast characteristics through an increase in contrast gain and dynamic response range. The modulatory input from the PBR further enhanced these characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241496
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  • 12
    Electronic Resource
    Electronic Resource
    The auditory pathway in cat corpus callosum (1995)
    Springer
    Experimental brain research 104 (1995), S. 534-540 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Auditory pathway ; Primary auditory field ; Tonotopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The cortical auditory fields of the two hemispheres are interconnected via the corpus callosum. We have investigated the topographical arrangement of auditory callosal axons in the cat. Following circumscribed biocytin injections in the primary (AI), secondary (AII), anterior (AAF) and posterior (PAF) auditory fields, labelled axons have been found in the posterior two-thirds of the corpus callosum. Callosal axons labelled by small individual cortical injections did not form a tight bundle at the callosal midsagittal plane but spread over as much as one-third of the corpus callosum. Axons originating from different auditory fields were roughly topographically ordered, reflecting to some extent the rostro-caudal position of the field of origin. Axons from AAF crossed on average more rostrally than axons from AI; the latter crossed more rostrally than axons from PAF and AIL Callosal axons originating in a discrete part of the cortex travelled first in a relatively tight bundle to the telo-diencephalic junction and then dispersed progressively. In conclusion, the cat corpus callosum does not contain a sector reserved for auditory axons, nor a strictly topographically ordered auditory pathway. This observation is of relevance to neuropsychological and neuropathological observations in man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231988
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  • 13
    Electronic Resource
    Electronic Resource
    Depression of transmission from group II muscle afferents by electrical stimulation of the cuneiform nucleus in the cat (1995)
    Springer
    Experimental brain research 105 (1995), S. 25-38 
    Details
    ISSN: 1432-1106
    Keywords: Cuneiform nucleus ; Synaptic transmission ; Spindle afferents ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of short trains of electrical stimuli applied within the cuneiform nucleus and the subcuneiform region were examined on transmission from group I and group II muscle afferents to first-order spinal neurons. Variations in the effectiveness of transmission from these afferents were assessed from changes in the sizes of the monosynaptic component of extracellular field potentials evoked following stimulation of muscle nerves. Field potentials evoked from group II muscle afferents in the dorsal horn of the midlumbar and sacral segments and in the intermediate zone of the midlumbar segments were reduced when the test stimuli applied to peripheral nerves were preceded by conditioning stimulation of the cuneiform nucleus or the subcuneiform region. The depression occurred at conditioning-testing intervals of 20–400 ms, being maximal at intervals of 32–72 ms for dorsal horn potentials and 40–100 ms for intermediate zone potentials. At the shortest intervals, both group II and group I field potentials in the intermediate zone were depressed. Conditioning stimulation of the cuneiform nucleus depressed group II field potentials nearly as effectively as conditioning stimulation of the coerulear or raphe nuclei. We propose that the nonselective depression of transmission from group I and II afferents at short intervals is due to the activation of reticulospinal pathways by cells or fibers stimulated within the cuneiform area. We also propose that the selective depression of transmission from group II afferents at long intervals is mediated at least partly by monoaminergic pathways, in view of the similarity of the effects of conditioning stimulation of the cuneiform nucleus and of the brainstem monoaminergic nuclei and by directly applied monoamines (Bras et al. 1990). In addition, it might be caused by primary afferent depolarization mediated by non-monoaminergic fibers (Riddell et al. 1992).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242179
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  • 14
    Electronic Resource
    Electronic Resource
    Distribution of vestibulospinal synaptic input to cat triceps surae motoneurons (1995)
    Springer
    Experimental brain research 107 (1995), S. 1-8 
    Details
    ISSN: 1432-1106
    Keywords: Deiters' nucleus ; Vestibulospinal system ; Motoneurons ; Synaptic input ; Synaptic currents ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We applied supramaximal, repetitive stimulation to the lateral vestibular nucleus (Deiters' nucleus, DN) at 200 Hz to evoke steady-state synaptic potentials in ipsilateral triceps surae motoneurons of the cat. The effective synaptic currents underlying these potentials were measured using a modified voltage-clamp technique. The steady-state effective synaptic currents evoked by activating DN were generally small and depolarizing (mean±SD 2.5±2.6 nA). DN stimulation generated hyperpolarizing synaptic currents in 2 of the 34 triceps motoneurons studied. The effective synaptic currents from DN tended to be larger in putative type F motoneurons than in putative type S cells (type F mean 3.0±3.1 nA; type S mean 1.8±1.0 nA). There was a statistically significant difference between the inputs to putative type FF and putative type S motoneurons (mean difference 2.8 nA, t=2.87, P〈0.01). The synaptic input from DN to medial gastrocnemius motoneurons had approximately the same mean amplitude as that from homonymous la afferent fibers. However, the distribution of DN input with respect to putative motor unit type was the opposite of that previously reported for Ia afferent input. Thus, the synaptic input from DN might act to compress the range of recruitment thresholds within the motoneuron pool and thereby increase the gain of its input-output function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228010
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  • 15
    Electronic Resource
    Electronic Resource
    Non-length-tuned cells in layers II/III and IV of the visual cortex: the effect of blockade of layer VI on responses to stimuli of different lengths (1995)
    Springer
    Experimental brain research 104 (1995), S. 12-20 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Layer VI to layer IV ; Non-length-tuned cells ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have previously shown, using a local inactivation technique, that layer VI provides a facilitatory input to the majority of hypercomplex cells located in layer IV above, and hence to layers II/III, which in many cases enhances length selectivity. However, many cells in these layers are not tuned for stimulus length, being equally responsive to long and short stimuli. Thus it is important to know whether layer VI can influence the responses of these cells. We have now used a similar paradigm of iontophoretic application of GABA to examine the effect of blockade of layer VI on the length tuning profiles of these cells in layers II–IV. During the blockade of layer VI, the most common effect, seen in 41% of the cells, was inhibition of visual responses, (i.e. commensurate with loss of a facilitatory input). An increase in response magnitude was found in 21% of the population, and responses were unaffected in 36% of cells tested. This suggests that the predominant influence of local regions of layer VI on this cell type, located in layers II/III and IV, is facilitatory, with a smaller proportion of cells receiving an inhibitory input. Such effects were seen even with the shortest lengths tested, suggesting once more that elements of layer VI are responsive to stimuli much shorter than was previously accepted. Thus these data suggest that layer VI plays a role in the generation of the response dynamics of non-length-tuned cells in overlying layers II/III and IV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229851
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  • 16
    Electronic Resource
    Electronic Resource
    On-line compensation of gaze shifts perturbed by micro-stimulation of the superior colliculus in the cat with unrestrained head (1995)
    Springer
    Experimental brain research 106 (1995), S. 196-204 
    Details
    ISSN: 1432-1106
    Keywords: Gaze shifts ; Dynamic feedback ; Superior colliculus ; Microstimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prior studies have led to the gaze feedback hypothesis, which states that quick orienting movements of the visual axis (gaze shifts) are controlled by a feedback system. We have previously provided evidence for this hypothesis by extending the original study of Mays and Sparks (1980) to the cat with unrestrained head (Pélisson et al. 1989). We showed that cats compensated for a stimulation-induced perturbation of initial gaze position by generating, in the dark, an accurate gaze shift towards the remembered location of a flashed target. In the present study, we investigate goal-directed gaze shifts perturbed “in flight” by a brief stimulation of the superior colliculus. The microstimulation parameters were tuned such that significant perturbations were induced without halting the movement. The ambient light was turned off at the onset of the gaze shift, suppressing any visual feedback. We observed that, following stimulation offset, the gaze shift showed temporal and spatial changes in its trajectory to compensate for the transient perturbation. Such compensations, which occurred “on-line” before gaze shift termination, involved both eye and head movements and had dynamic characteristics resembling those of unperturbed saccadic gaze shifts. These on-line compensations maintained gaze accuracy when the stimulation was applied during the early phase of large and medium (about 60 and 40°) movements. These results are compatible with the notion of a gaze feedback loop providing a dynamic gaze error signal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241115
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  • 17
    Electronic Resource
    Electronic Resource
    Analysis of potentials induced in red nucleus neurones from the somaesthetic pathway stimulated at the bulbar level (1995)
    Springer
    Experimental brain research 106 (1995), S. 377-390 
    Details
    ISSN: 1432-1106
    Keywords: Motor control ; Somaesthesia ; Magnocellular red nucleus ; Intracellular recording ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A somaesthetic pathway to the magnocellular red nucleus (RNm) via relays other than corticoor cerebello-rubral relays was previously found to exist in the cat. At the brainstem level, the ascending spinorubral fibres follow the medial lemniscus (LM). The present paper aims at describing in detail and evaluating the quantitative importance of the short-latency responses in RNm cells after microstimulation performed in the LM through a monopolar electrode. The RNm cells, tested intracellularly in cats anaesthetized with α-choralose and placed in a stereotaxic device, were identified by their antidromic activation to stimulation of the rubrospinal tract in the cervical cord. It was established that single-shock stimulation below 100 μA current delivered to the LM induced short-latency postsynaptic potentials (PSPs) in 87% of all the rubrospinal cells tested. The responses were indeed due to activation of LM fibres, as demonstrated by different tests: the location of the electrode tip in the LM was verified by recording, with the same electrode, the potentials evoked by stimulating the dorsal columns of the cord. The site was later confirmed histologically. The absence of stimulus spread from the LM to the underlying pyramidal tract was systematically checked by simultaneously recording the responses evoked in RNm cells and in the motor cortex. Monosynaptic excitatory responses (EPSPs) were evoked in RNm cells with a minimum stimulating current of less than 20 μA in the LM and a mean threshold of 42 μA. Disynaptic inhibitory potentials (IPSPs) were evoked in 23% of these cells with single-pulse stimulation. These latter responses showed a temporal facilitation with short trains of three pulses, which indicated that they were transmitted through inhibitory interneurones. Recordings were also performed from presumed LM fibre terminals running inside the RNm. The results therefore confirm the existence of strong lemniscal projections to RNm and demonstrate that they transmit both excitatory and inhibitory messages to rubrospinal cells. As the somaesthetic pathway to the RNm was previously found to come from the spinal cord, where it is located in the ventral portion, the present results also confirm that the LM is composed of fibres originating not only from neurones in the dorsal column nuclei, but also from cells placed at the segmental levels of the cord. The presumed sensorimotor function of this ascending pathway is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231061
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  • 18
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    Electronic Resource
    Functional relation between corticonuclear input and movements evoked on microstimulation in cerebellar nucleus interpositus anterior in the cat (1995)
    Springer
    Experimental brain research 106 (1995), S. 365-376 
    Details
    ISSN: 1432-1106
    Keywords: Climbing fibres ; Rubrospinal tract ; Motor control ; Motor learning ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The functional relation between receptive fields of climbing fibres projecting to the C1, C3 and Y zones and forelimb movements controlled by nucleus interpositus anterior via the rubrospinal tract were studied in cats decerebrated at the pre-collicular level. Microelectrode tracks were made through the caudal half of nucleus interpositus anterior. This part of the nucleus receives its cerebellar cortical projection from the forelimb areas of these three sagittal zones. The C3 zone has been demonstrated to consist of smaller functional units called microzones. Natural stimulation of the forelimb skin evoked positive field potentials in the nucleus. These potentials have previously been shown to be generated by climbing fibre-activated Purkinje cells and were mapped at each nuclear site, to establish the climbing fibre receptive fields of the afferent microzones. The forelimb movement evoked by microstimulation at the same site was then studied. The movements usually involved more than one limb segment. Shoulder retraction and elbow flexion were frequently evoked, whereas elbow extension was rare and shoulder protraction never observed. In total, movements at the shoulder and/or elbow occurred for 96% of the interpositus sites. At the wrist, flexion and extension movements caused by muscles with radial, central or ulnar insertions on the paw were all relatively common. Pure supination and pronation movements were also observed. Movements of the digits consisted mainly of dorsal flexion of central or ulnar digits. A comparison of climbing fibre receptive fields and associated movements for a total of 110 nuclear sites indicated a general specificity of the input-output relationship of this cerebellar control system. Several findings suggested that the movement evoked from a particular site would act to withdraw the area of the skin corresponding to the climbing fibre receptive field of the afferent microzones. For example, sites with receptive fields on the dorsum of the paw were frequently associated with palmar flexion at the wrist, whereas sites with receptive fields on the ventral side of the paw and forearm were associated with dorsiflexion at the wrist. Correspondingly, receptive fields on the lateral side of the forearm and paw were often associated with flexion at the elbow, whereas sites with receptive fields on the radial side of the forearm were associated with elbow extension. The proximal movements that were frequently observed also for distal receptive fields may serve to produce a general shortening of the limb to enhance efficiency of the withdrawal. It has previously been suggested that the cerebellar control of forelimb movements via the rubrospinal tract has a modular organisation. Each module would consist of a cell group in the nucleus interpositus anterior and its afferent microzones in the C1, C3 and Y zones, characterised by a homogenous set of climbing fibre receptive fields. The results of the present study support this organisational principle, and suggest that the efferent action of a module is to withdraw the receptive field from an external stimulus. Possible functional interpretations of the action of this system during explorative and reaching movements are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231060
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  • 19
    Electronic Resource
    Electronic Resource
    Stimulation of the group I extensor afferents prolongs the stance phase in walking cats (1995)
    Springer
    Experimental brain research 103 (1995), S. 20-30 
    Details
    ISSN: 1432-1106
    Keywords: Ib afferent ; Locomotion ; Walking ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Group I afferents in nerves innervating the lateral gastrocnemius-soleus (LG-Sol), plantaris (P1), and vastus lateralis/intermedius (VL/VI) muscles were stimulated during walking in decerebrate cats. The stimulus trains were triggered at a fixed delay following the onset of bursts in the medial gastrocnemius muscle. Stimulation of all three nerves with long stimulus trains (〉600 ms) prolonged the extensor bursts and delayed the onset of flexor burst activity. LG-Sol nerve stimulation had the strongest effect; often delaying the onset of flexor burst activity until the stimulus train was ended. By contrast, flexor bursts were usually initiated before the end of the stimulus train to the P1 and VL/VI nerves. The minimum stimulus strength required to increase the cycle period was between 1.3×threshold and 1.6×threshold for all three nerves. Simultaneous stimulation of the P1 and VL/VI nerves produced a larger effect on the cycle period than stimulation of either nerve alone. The spatial summation of inputs from knee and ankle muscles suggests that the excitatory action of the group I afferents during the stance phase is distributed to all leg extensor muscles. Stimulation of the group I afferents in extensor nerves generally produced an increase in the amplitude of the heteronymous extensor EMG towards the end of the stance phase. This increase in amplitude occurred even though there were only weak monosynaptic connections between the stimulated afferents and the motoneurones that innervated these heteronymous muscles. This suggests that the excitation was produced via oligosynaptic projections onto the extensor motoneuronal pool. Stimulation with 300 ms trains during the early part of flexion resulted in abrupt termination of the swing phase and reinitiation of the stance phase of the step cycle. The swing phase resumed coincidently with the stimulus offset. Usually, stimulation of two extensor nerves at group I strengths was required to elicit this effect. We were unable to establish the relative contributions of input from the group 1a and group 1b afferents to prolonging the stance phase. However, we consider it likely that group Ib afferents contribute significantly, since their activation has been shown to prolong extensor burst activity in reduced spinal preparations. Thus, our results add support to the hypothesis that unloading of the hindlimb during late stance is a necessary condition for the initiation of the swing phase in walking animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241961
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  • 20
    Electronic Resource
    Electronic Resource
    Effects of eye position on auditory localization and neural representation of space in superior colliculus of cats (1995)
    Springer
    Experimental brain research 104 (1995), S. 402-408 
    Details
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Sensory integration ; Auditory localization ; Eye movement ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The maps of visual and auditory space within the superior colliculus are in approximate register both with each other and with the underlying motor maps associated with orienting responses. The fact that eyes and ears can move independently poses a problem for the sensorimotor organization of these two modalities. By monitoring eye and pinna positions in alert, head-fixed cats, we showed that the accuracy of saccadic eye movements to auditory targets was little affected by eye eccentricity (range ±15 deg) at the onset of the sound. A possible neural basis for this behavioral compensation was suggested by recordings from superior colliculus neurons. The preferred sound directions of some neurons in the deep layers of this midbrain nucleus exhibited a shift with the direction of gaze, while in others the response throughout the auditory receptive field was either increased or decreased, suggesting that changes in eye position alter the gain of the auditory response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231975
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  • 21
    Electronic Resource
    Electronic Resource
    Effect of reversible dorsal cold block on the persistence of inhibition generated by spinal reflexes (1995)
    Springer
    Experimental brain research 107 (1995), S. 205-214 
    Details
    ISSN: 1432-1106
    Keywords: Motoneuron ; Stretch reflex ; Cutaneous ; Contralateral ; Spinal ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of bilateral focal cooling of dorsolateral thoracic spinal cord on segmental reflex pathways to the triceps surae muscles were assessed in decerebrate cats from the reflex forces produced by single shocks or trains of electrical stimuli applied to the ipsilateral caudal cutaneous sural and the contralateral tibial nerves. The validity of the dorsal cold block technique as a substitute for acute surgical dorsal hemisection was established by showing that focal cooling reliably reproduced the stretch-induced “clasp knife” inhibition of triceps surae reflexive force seen following dorsal hemisection. Under control (warm) conditions, the inhibitory components of electrically evoked ipsilateral sural and contralateral tibial reflexes faded rapidly during sustained trains, with a resultant production of large-amplitude reflex force as measured from either the entire triceps surae or from the medial gastrocnemius muscle alone. Dorsal cold block greatly reduced the amplitude of reflexive force evoked by sustained electrical stimulation of either nerve. Indeed, the cold block completely reversed the sign of train-evoked reflexes to a net inhibition of reflex force output in one-half of the sural and one-half of the contralateral tibial stimulation experiments. Peak transient forces evoked by single shocks to the sural or contralateral tibial nerves were also sometimes reduced, but this result was more variable than for prolonged nerve stimulation. The persistence of activity in segmental inhibitory pathways during dorsal cold block, as indicated by instances of reflex sign reversal, suggests that descending bulbospinal pathways traversing the dorsolateral funiculi may be responsible for “fading” of segmental inhibitory reflex components in decerebrate cats with intact spinal cords during sustained afferent input. The possibility that the enhanced magnitude and duration of segmental inhibition during cold block will increase the likelihood of disruption of the size principle for motoneuron recruitment is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230042
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  • 22
    Electronic Resource
    Electronic Resource
    Differences in the temporal dynamics of the visual ON and OFF pathways (1995)
    Springer
    Experimental brain research 104 (1995), S. 171-176 
    Details
    ISSN: 1432-1106
    Keywords: Visual channels ; Lateral geniculate nucleus ; Visual cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The temporal structure of spike trains recorded from optic fibers and single units of the lateral geniculate nucleus (LGN) and primary visual cortex of the cat was studied with a novel method of inter-spike interval analysis. ON type relay cells of the LGN exhibited a multimodal interval distribution preferring a distinct interval (fundamental interval) and its multiples during the sustained light response, whereas most OFF cells showed a broad, unimodal distribution. The general pattern of the interval distribution was relatively independent of stimulus size and contrast and the degree of light adaptation. Simultaneously recorded S-potentials originating from the retinal input generally produced only a single peak at the fundamental interval length. Therefore, the multimodal interval distribution of LGN cells seems to be a result of intra-geniculate inhibition. Cortical cells also showed a weak tendency to fire with spike intervals similar to LGN cells. Therefore, the regular firing pattern observed at peripheral stages of the visual pathway can persist at higher levels and might promote the occurrence of oscillatory activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229868
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  • 23
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    Electronic Resource
    The effects of baclofen on the stretch reflex parameters of the cat (1995)
    Springer
    Experimental brain research 104 (1995), S. 287-296 
    Details
    ISSN: 1432-1106
    Keywords: Baclofen ; Stretch reflex ; Muscle stiffness ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Experiments were done in cats decerebrated at the precollicular postmammillary level to determine how a tonic increase of presynaptic inhibition of the intraspinal terminals of muscle spindle afferents changes the mechanical properties of the soleus stretch reflex (s.r.). Baclofen, a specific GABAB receptor agonist, was injected i.v. (1–2 mg/kg) so as to induce a tonic increase in presynaptic inhibition. The effects of baclofen on the stiffness and threshold of the s.r. were determined, respectively, from plots of stiffness vs background force and force vs length (length-tension plot). Baclofen, at these doses, had no effect on the excitation-contraction coupling properties of muscle or on the intrinsic stiffness-force relation. Changes of the soleus background force, required to obtain the stiffness vs force plots, were produced by stimulation of the contralateral common peroneal nerve or the posterior tibial nerve and occasionally by electrical stimulation in the area of the red nucleus. The stiffness of the s.r. as a function of the background force level was determined by stretching the muscle with a square pulse of 1–2 mm amplitude and 200–300 ms duration. The stiffness at each force level was calculated by dividing the change in force by the change in length, at a point where the force trace had stabilized. The length-tension relation of the s.r. was determined by stretching the muscle 12–17 mm at a constant rate of 1–2 mm/s. At all force levels, baclofen produced a significant decrease (40% or more) in the s.r. stiffness, within 10–15 min of injection as determined from the stiffness-force plots. The length-tension plots revealed that the decrease of s.r. stiffness was always accompanied by an increase in the s.r. threshold (typically 2–3 mm). It is suggested, therefore, that the s.r. threshold is not an independent variable, depending on the membrane potential of the α- motoneurons, and additionally on the level of presynaptic inhibition of the muscle spindle afferent terminals. The present results also imply that it may be possible for the CNS to adaptively modify the s.r. stiffness via presynaptic inhibition of the intraspinal terminals of muscle afferents. However, any such change of s.r. stiffness will be accompanied by a change in the s.r. threshold.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242014
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  • 24
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    Electronic Resource
    Effects of eye position on saccadic eye movements and on the neuronal responses to auditory and visual stimuli in cat superior colliculus (1995)
    Springer
    Experimental brain research 103 (1995), S. 227-242 
    Details
    ISSN: 1432-1106
    Keywords: Vision ; Audition ; Superior colliculus ; Saccade ; Multisensory convergence ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Many neurons in the deeper layers of the superior colliculus (SC) respond to multiple sensory inputs — visual, auditory, and somatic — as well as provide signals essential for saccadic eye movements to targets in different modalities. When the eyes and pinnae are in primary position, the neural map of auditory space is in rough topographic alignment with the map of visual space, and if the auditory map is based solely on head-pinna coordinates, any changes in eye position in the orbit will cause misalignment of the maps. We investigated the effects of eye position on the response of sound-sensitive neurons in the SC of cats because previous work on cats and on monkeys had suggested the possibility of species differences in the representation of auditory signals in the SC. We also investigated the effects of eye position on the accuracy of saccades to auditory, visual, and bimodal stimuli. All studies were conducted in alert, trained cats with the head restrained in a fixed position. Neuronal and behavioral responses were studied during periods when the eyes were steadily directed to different positions relative to the position of the sound. Cats showed partial compensation for eye position in making saccades, regardless of the modality of the target, and they showed similar patterns of error in saccades to auditory and visual targets. These behavioral data are consistent with coding the location of visual and auditory targets in the same coordinate system. In the vast majority of intermediate-layer neurons, eye position significantly affected the number of spikes evoked by sound stimuli. For most of these neurons, changes in eye position produced significant shifts in the speaker location producing maximal response. In some neurons, eye position significantly facilitated the magnitude of neuronal response evoked by sounds from a variety of speaker locations. Because few pinna movements could be detected, it is unlikely that these changes in neuronal response could be due to changes in the position of the pinnae. Our results indicate that the deep layers of the SC contain an eye-centered representation of sound location. Because eye position did not affect the percentage of neurons exhibiting multimodal integration, visual and auditory maps appear to remain integrated in the SC even when the eyes are directed eccentrically. Examination of the effects of eye position on neuronal responses to visual stimuli revealed that a substantial minority of neurons showed quantitative changes in the magnitude of response to visual stimuli when the retinal locus of stimulation was held constant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231709
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  • 25
    Electronic Resource
    Electronic Resource
    Encoding of jaw movements by central trigeminal neurons with cutaneous receptive fields (1995)
    Springer
    Experimental brain research 104 (1995), S. 363-375 
    Details
    ISSN: 1432-1106
    Keywords: Cutaneous ; Jaw movements ; Vi ; Kinesthesia ; Trigeminothalamic ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neurons with orofacial cutaneous receptive fields that responded to jaw movements were recorded in the trigeminal subnucleus interpolaris of the cat. Movement-related neuronal activity was identified by imposing passive ramp and hold stretches of the jaw at four different rates. Thirty-nine neurons with hair (26), skin (9), or convergent (4) receptive fields were studied. Thalamic projection neurons were identified by antidromic stimulation of the ventroposteromedial nucleus of the thalamus. The receptive fields of movement-related hair units included multiple hairs located mainly around the angle of the jaw and chin. The receptive fields of movement-related skin units were smaller than those of hair units and they were located primarily around the angle of the mouth. The convergent units had more than one receptive field that usually included hair or skin. All of the hair units were activated both during opening and closing jaw movements. They typically responded with short bursts of action potentials. Four units with skin receptive fields exhibited similar responses. The five skin units that did not show bursting activity included two that were active during both opening and closing of the jaw, two that were active only during opening, and one that was tonically active during maintained open position. All of the convergent units showed biphasic responses, and three responded with bursts. The maximum discharge rate, the mean discharge rate (mean bursting rate for units with bursting responses), and the total number of spikes per movement were measured. Statistical analysis was performed on these variables to assess functional properties of each unit. The results were used to classify units as velocity, speed, direction, or transient motion detectors. Thirty-three percent of the neurons were trigeminothalamic neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231972
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  • 26
    Electronic Resource
    Electronic Resource
    Latency variability of responses to visual stimuli in cells of the cat's lateral geniculate nucleus (1995)
    Springer
    Experimental brain research 105 (1995), S. 7-17 
    Details
    ISSN: 1432-1106
    Keywords: Lagged cells ; Nonlagged cells ; Visual system ; Thalamus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We constructed average histograms from responses evoked by flashing stimuli and noted previously described variations in the shape of the response profile, particularly with respect to sharpness of the peak. To express this variable, we measured the half-rise latency, which is the latency from stimulus onset required to reach half the maximum response. A short half-rise latency, which is characteristic of nonlagged cells, is associated with a brisk response and sharp peak; a long half-rise latency, characteristic of lagged cells, is associated with a sluggish response and broad peak. Nonlagged cells were readily seen; we attempted to identify cells with long latencies as lagged, but we were unable to do so unambiguously due to failure to observe lagged properties other than latency. We thus refer to these latter cells as having “lagged-like” responses to indicate that we are not certain whether these are indeed lagged cells. In addition to the histograms, we analyzed the individual response trials that were summed to create each histogram, and we used spike density analysis to estimate the initial response latency to the flashing spot for each trial. We found that lagged-like responses were associated with more variability in initial response latency than were nonlagged responses. We then employed an alignment procedure to eliminate latency variation from individual trials; that is, responses during individual trials were shifted in time as needed so that each had a latency equal to the average latency of all trials. We used these “aligned” trials to create a second, “aligned” response histogram for each cell. The alignment procedure had little effect on nonlagged responses, because these were already well aligned due to consistent response latencies amongst trials. For lagged-like responses, however, the alignment made a dramatic difference. The aligned histograms looked very much like those for nonlagged responses: the responses appeared brisk, with a sharply rising peak that was fairly high in amplitude. We thus conclude that the slow build up to a relatively low peak of firing of the lagged-like response histogram is not an accurate reflection of responses on single trials. Instead, the sluggishness of lagged-like responses inferred from average response histograms results from temporal smearing due to latency variability amongst trials. We thus conclude that there is relatively little difference in briskness between nonlagged and lagged-like responses to single stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242177
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  • 27
    Electronic Resource
    Electronic Resource
    Integration in trigeminal premotor interneurones in the cat (1995)
    Springer
    Experimental brain research 104 (1995), S. 449-461 
    Details
    ISSN: 1432-1106
    Keywords: Premotor interneurones ; Subnucleus oralis-γ ; Trigeminal motor nucleus ; Spike-triggered averaging ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A population of last-order interneurones within the rostrodorsal part of the oral nucleus of the spinal trigeminal tract (NVspo-γ) has been investigated in 21 chloralose anaesthetised cats. The neurones were identified by their antidromic (AD) response to microstimulation (median current 9 μA, range 3–39 μA) of the ipsior the contralateral masseteric subnucleus of the trigeminal motor nucleus. Fifty-one of 113 interneurones tested were discharged from the ipsilateral and eight from the contralateral motor nucleus. The average conduction time was 0.50 ms from the ipsilateral and 0.74 ms from the contralateral motoneurone pool. Conduction velocities of the axons ranged from 2.0 to 14.0 ms. The pattern of primary afferent input onto the selected neurones was analysed by graded electrical stimulation of dissected trigeminal nerves. Low-threshold afferents innervating the intraoral mucosa including the tongue and the perioral skin of the lower lip were the most effective inputs, as judged from both the frequency of occurrence and from the latencies of the evoked spike discharges. Ninety-six percent of the neurones responded to stimulation of the inferior alveolar nerve (Alv inf) and 83% responded to stimulation of the lingual nerve (Ling). The median threshold strength required to evoke the Alv inf and the Ling responses was 1.7 T (range 1.0–3.6 T) and 1.3 T (range 1.0–5.0 T), respectively. The median latency to spike discharges evoked by the Alv inf was 2.0 ms (range 1.3–4.8 ms) and to the Ling it was 2.5 ms (range 1.4–7.0 ms). Action potentials elicited by stimulation of the masseteric and digastric nerves were observed in 40% and 10% of the neurones, respectively. These responses, which had median latencies of more than 8 ms (range 4.7–16.0 ms), were only seen at stimulation intensities above 2 T (range 2.5–25 T). An input from the maxillary whisker nerve was seen in only one case. Postspike averages of the extracellular field potentials within the trigeminal motoneurone subnuclei evoked by interneuronal spikes were made in a subsample of 51 NVspo-γ neurones activated by iontophoresis of L-glutamic acid. Excitatory synaptic effects within the masseteric subnucleus were observed in eight cases. An inhibitory effect was seen in one case. One specific neurone gave an excitatory extracellular field potential within the digastric motoneurone subnucleus. This interneurone was AD activated from the digastric, but not from the masseteric subnucleus. The physiological properties of the NVspo-γ-mass interneurones are discussed in relation to their suggested roles in the phase-dependent control of the trigeminal motoneurones during oro-facial masticatory behaviours.
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    URL: http://dx.doi.org/10.1007/BF00231979
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  • 28
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    Electronic Resource
    An in vivo electrophysiological investigation of group Ia afferent fibres and ventral horn terminations in the cat spinal cord (1995)
    Springer
    Experimental brain research 106 (1995), S. 403-417 
    Details
    ISSN: 1432-1106
    Keywords: Spinal Ia terminations ; Myelinated fibres ; Action potentials ; Primary afferent depolarization ; Transmitter release ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An extracellular microstimulation technique has been used to investigate and compare the properties of group I primary afferent myelinated fibres in the dorsal column and group Ia unmyelinated terminations in the lumbar spinal cord of cats anaesthetised with pentobarbitone sodium. Fibres were distinguished from terminations on the basis of location, anodic blocking factor and sensitivity to GABAA mimetics. The recovery curves of threshold following an orthodromic impulse provided an estimate of both action potential duration and rate of repolarization. The action potentials of group Ia terminations were of briefer duration (by a factor of approximately 2) with more rapid rates of repolarization (factor of approximately 3) than those of the myelinated fibres. The prolongation of termination but not fibre action potentials by microelectrophoretic tetraethylammonium and 4-aminopyridine indicated the presence of voltage-activated potassium channels in the termination membrane. Differences in the effects on Ia termination action potentials of depolarizations (reductions in threshold) associated with a preceding action potential, synaptically released GABA, microelectrophoretic piperidine-4-sulphonic acid or dl-homocysteic acid suggest that an increase in termination membrane conductance is the major factor in the reduction of transmitter release during the activation of presynaptic GABAA receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231063
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  • 29
    Electronic Resource
    Electronic Resource
    Evidence for high-velocity smooth pursuit in the trained cat (1995)
    Springer
    Experimental brain research 106 (1995), S. 509-512 
    Details
    ISSN: 1432-1106
    Keywords: Eye movement ; Smooth pursuit ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It is generally accepted that in cats smooth pursuit velocity of the eye never exceeds a few degrees per second. This is in contrast with observations in primates, where smooth pursuit velocity can reach values as high as 100°/s. Cats were trained to fixate and pursue spots of light appearing on a translucent screen. Spots were moved in the horizontal and vertical planes at different constant velocities up to 80°/s. Eye position was recorded with the sclerai search coil technique. Naive cats did not pursue moving targets with high efficiency. Smooth eye movement velocity saturated at 5°/s. After a few days of training, smooth-pursuit eye velocity increased with target velocity and saturated at 25°/s on average. However, velocities twice as high have been observed frequently. When the target was unexpectedly extinguished, smooth eye movement velocity dropped to values close to 0°/s in approximately 350 ms. After a short training period (usually 5 times the same target presentation), the eye continued to move smoothly until the target reappeared. These data suggest that smooth pursuit eye movements of the cat are qualitatively similar to those of primates, but reach lower velocities and are more variable in their characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231076
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  • 30
    Electronic Resource
    Electronic Resource
    Ozone exposure suppresses epithelium-dependent relaxation in feline airway (1995)
    Springer
    Lung 173 (1995), S. 47-56 
    Details
    ISSN: 1432-1750
    Keywords: Airway hyperresponsiveness ; Ozone ; Airway epithelial cell ; Bronchiole ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the effect of exposure to ozone on the epithelium-dependent relaxation (EpDR) of bronchioles evoked by electrical field stimulation (EFS) in a feline model with hyperresponsive airways induced by exposure to ozone. Airway responsiveness was assessed by measuring the increases in total pulmonary resistance (RL) produced by aerosolized acetylcholine (ACh) in vivo. Airway responsiveness was also measured in vitro in dissected bronchiolar ring preparations. Exposure to ozone (3 ppm, 2 h) significantly increased the airway responsiveness in vivo. The concentration of ACh required increasing R L to 200% of the baseline value, decreased from 1.97 mg/ml (GSEM 1.94) to 0.12 mg/ml (GSEM 1.77, p 〈 0.01) after exposure to ozone. EFS evoked atropine-, guanethidine-, and tetrodotoxin-resistant relaxations in the control bronchiolar rings precontracted by 5-hydroxytryptamine. Such relaxation was significantly suppressed by the mechanical denudation of epithelium, confirming that it was epithelium dependent. The amplitude of EpDR was significantly suppressed in the animals exposed to ozone. These results suggest that EpDR is present in cats, and that its inhibition may contribute to the development of airway hyperresponsiveness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167600
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  • 31
    Electronic Resource
    Electronic Resource
    Interactions of the subthalamic nucleus and the subpallidal area in oro-facial dyskinesia: role of GABA and glutamate (1995)
    Springer
    Psychopharmacology 119 (1995), S. 20-26 
    Details
    ISSN: 1432-2072
    Keywords: Oro-facial dyskinesia ; Subthalamic nucleus ; Globus pallidus ; GABA ; Glutamate ; Behaviour ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have shown that lowering the GABAergic activity in the sub-pallidal area (SP) in the cat results in the display of oro-facial dyskinesia (OFD). There exists an intense, mutual anatomical connection between the SP and the subthalamic nucleus and the adjoining lateral hypothalamic area (STH). The present study investigated whether the STH is also involved in OFD. Once this turned out to be true (see below), it was investigated whether the SP-specific OFD is funneled via the STH, or vice versa. Bilateral injections of low doses (50–250 ng) of picrotoxin, a non-competitive GABA antagonist, into the STH were found to elicit OFD. This effect which was quantified in terms of numbers of tongue protrusions, was dose-dependent: a bell-shaped dose-response was found (50–500 ng). The OFD elicited by the most effective dose of picrotoxin (250 ng) was significantly antagonized by muscimol, a specific GABAA agonist, in a dose (50 ng) which itself was ineffective, indicating GABA specificity. In addition, it was found that OFD elicited by local injections of picrotoxin (250 ng) into the STH was significantly attenuated by SP injections of the broad spectrum glutamate antagonist kynurenic acid in a dose (1000 ng) which itself was ineffective, but not by muscimol (100 ng), indicating that the STH-elicited OFD needs an intact and functioning glutaminergic, but not GABAergic, transmission process in the SP for its expression. Finally, it was found that OFD elicited by picrotoxin injections (500 ng) into the SP was significantly attenuated by muscimol injections (50 ng) into the STH, indicating that the SP-elicited OFD needs an intact and functioning GABAergic transmission process in the STH for its expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246049
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  • 32
    Electronic Resource
    Electronic Resource
    Horseradish peroxidase in axons of the dorsal funiculi of the cat: distribution after an injection of the enzyme into the dorsal column nuclei (1995)
    Springer
    Cell & tissue research 283 (1995), S. 67-73 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Node of Ranvier ; Axon ; Horseradish peroxidase (HRP) ; Retrograde axonal transport ; Electron microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Horseradish peroxidase (HRP) was injected into the left dorsal column nuclei of adult cats. Large dorsal funiculi axons of the C3, C5, C8 and L7 segments were searched for HRP-activity after 12, 24, 36 and 48 h using light and electron microscopy. Accumulations of intra-axonal HRP-positive bodies occurred at nodes of Ranvier in the C3–C8 segments at 12, 24 and 36 h and in the L7 segments at 24, 36, and 48 h. The accumulations of HRP in three spatio-temporally different consecutive patterns, noted earlier at nodes of Ranvier in the peripheral nervous system (PNS) portion of feline alpha motor axons for more than 70 h after an intramuscular injection of the enzyme, were not observed in the present material. We suggest that the differences in the modes in which large PNS and CNS axons interact with retrogradely transported HRP are due to differences in the organization of the respective nodal regions. We also emphasize that endocytosis via axon terminals in the CNS normally represents uptake of material from an extracellular space which is controlled and protected by the blood-brain barrier. This is in contrast to endocytosis via axon terminals in a muscle, which represents uptake of material from an extracellular space openly exposed to influx of different substances from the blood stream.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050513
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  • 33
    Electronic Resource
    Electronic Resource
    A monoclonal anticarbohydrate antibody detecting superfast myosin in the masseter muscle (1995)
    Springer
    Cell & tissue research 283 (1995), S. 85-92 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Masseter muscle ; Limb muscles ; Superfast fibres ; Myosin heavy chains ; Glycosylation ; Galactose ; ATPase ; Cat ; Dog ; Macaca fascicularis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Superfast-contracting muscle fibres (II M) were identified by ATPase staining and after incubation with an antiserum raised against myosin type II M and with an antibody raised against the Galα1–3Galβ1–4GlcNAc structure. II M fibres were present in masseter muscles from cat, dog and Macaca fascicularis but not in limb muscles from the same animals and not in masseter muscles from rat, pig, cow or man. Electrophoresis and staining of blots from myosin preparations showed that the anticarbohydrate antibody detected myosin heavy chains from cat masseter but not myosin heavy chains from cat biceps. The α-galactose specific lectin Griffonia simplicifolia isolectin B4 (GS I B4) did not stain muscle fibres or myosin heavy chains. Therefore, the epitope on myosin heavy chains defined by the anticarbohydrate antibody is presumably not Galα1–3Galβ1–4GlcNAc although the antibody staining was strongly inhibited after absorption by 10 mM of this trisaccharide. Antibody staining of the muscle fibres was totally inhibited by adding 10 mM p-nitrophenyl β-D-glucuronide to the incubation medium. The results thus imply that an anticarbohydrate antibody distinctively detects a carbohydrate epitope specific for myosin in superfast contracting muscle fibres from jaw-closing muscles and confirm that this epitope is not present in other muscle fibre types. This appears to be the first report on differentiated glycosylation among myosin isoforms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050515
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  • 34
    Electronic Resource
    Electronic Resource
    A new combination of methods for the localization, identification, and three-dimensional reconstruction of the sensory endings of articular afferents characterized by electrophysiology (1995)
    Springer
    Cell & tissue research 281 (1995), S. 283-294 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Articular afferents ; Corpuscular endings ; Free nerve endings ; Morpho-functional examination ; Three-dimensional reconstruction ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A combination of methods is described to identify and reconstruct corpuscular and non-corpuscular sensory endings of group II and group III nerve fibers following functional examination by electrophysiology. Afferent units activated by electrical stimulation of the medial articular nerve of the cat’s knee were analyzed by single fiber recordings and characterized by their responsiveness to mechanical stimuli. The receptive fields of the units were closely demarcated by fine needles when the responses elicited by insertion of the needles were being recorded. After fixation, the tissue around the demarcated field was dissected and histologically processed. Series of semithin sections were cut from the embedded tissue blocks containing the receptive fields. Corpuscular endings of group II fibers and peripheral myelinated group III nerve fibers, presumably corresponding to the characterized units, were identified by light microscopy of semithin sections and localized within the demarcated area. Non-corpuscular endings were identified by electron microscopy of ultrathin sections cut in alternation with, or after re-embedding of, semithin sections. Morphometric analysis of ultrathin section series allowed the measurement of parameters such as the mean axon diameter and the organelle content of the sensory endings. The methods described are appropriate for collecting data that correlate the structural and functional characteristics of sensory endings in deep tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050425
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  • 35
    Electronic Resource
    Electronic Resource
    Association of immune cells with neuroepithelial bodies in the lungs of neonatal dogs, cats and hamsters (1995)
    Springer
    Cell & tissue research 282 (1995), S. 519-522 
    Details
    ISSN: 1432-0878
    Keywords: Lungs ; Chemoreceptors ; Mast cells ; Eosinophils ; Neutrophils ; Newborns ; Dog ; Cat ; Golden hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A close topographical association between neuroepithelial bodies and immune cells is occasionally observed in the lungs of various neonatal mammalian species. The immune cells concerned are mast cells and neutrophil or eosinophil granulocytes. In the lungs of newborn puppies having undergone left lung autotransplantation, mast cells are particularly numerous in the airway mucosa of both right and left lungs and their association with neuroepithelial bodies is highly significant. Several of the substances known to be synthesized by the neuroepithelial bodies have a chemoattractive effect on immune cells. Thus, our observations indicate that intrapulmonary neuroepithelial bodies contribute to the local immune response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318884
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  • 36
    Electronic Resource
    Electronic Resource
    Association of immune cells with neuroepithelial bodies in the lungs of neonatal dogs, cats and hamsters (1995)
    Springer
    Cell & tissue research 282 (1995), S. 519-522 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Lungs ; Chemoreceptors ; Mast cells ; Eosinophils ; Neutrophils ; Newborns ; Dog ; Cat ; Golden hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A close topographical association between neuroepithelial bodies and immune cells is occasionally observed in the lungs of various neonatal mammalian species. The immune cells concerned are mast cells and neutrophil or eosinophil granulocytes. In the lungs of newborn puppies having undergone left lung autotransplantation, mast cells are particularly numerous in the airway mucosa of both right and left lungs and their association with neuroepithelial bodies is highly significant. Several of the substances known to be synthesized by the neuroepithelial bodies have a chemoattractive effect on immune cells. Thus, our observations indicate that intrapulmonary neuroepithelial bodies contribute to the local immune response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050503
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  • 37
    Electronic Resource
    Electronic Resource
    A new combination of methods for the localization, identification, and three-dimensional reconstruction of the sensory endings of articular afferents characterized by electrophysiology (1995)
    Springer
    Cell & tissue research 281 (1995), S. 283-294 
    Details
    ISSN: 1432-0878
    Keywords: Articular afferents ; Corpuscular endings ; Free nerve endings ; Morpho-functional examination ; Three-dimensional reconstruction ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A combination of methods is described to identify and reconstruct corpuscular and non-corpuscular sensory endings of group II and group III nerve fibers following functional examination by electrophysiology. Afferent units activated by electrical stimulation of the medial articular nerve of the cat's knee were analyzed by single fiber recordings and characterized by their responsiveness to mechanical stimuli. The receptive fields of the units were closely demarcated by fine needles when the responses elicited by insertion of the needles were being recorded. After fixation, the tissue around the demarcated field was dissected and histologically processed. Series of semithin sections were cut from the embedded tissue blocks containing the receptive fields. Corpuscular endings of group II fibers and peripheral myelinated group III nerve fibers, presumably corresponding to the characterized units, were identified by light microscopy of semithin sections and localized within the demarcated area. Non-corpuscular endings were identified by electron microscopy of ultrathin sections cut in alternation with, or after re-embedding of, semithin sections. Morphometric analysis of ultrathin section series allowed the measurement of parameters such as the mean axon diameter and the organelle content of the sensory endings. The methods described are appropriate for collecting data that correlate the structural and functional characteristics of sensory endings in deep tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00583397
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  • 38
    Electronic Resource
    Electronic Resource
    Intraretinal analysis of electroretinogram with K+ microelectrodes during acute intraocular pressure elevation (1995)
    Springer
    Documenta ophthalmologica 91 (1995), S. 129-139 
    Details
    ISSN: 1573-2622
    Keywords: Cat ; C-wave ; Electroretinogram ; Intraocular pressure ; Potassium ion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the effects of acute intraocular pressure elevation on the intraretinal electroretinogram in the cat dark-adapted eye. Perfusion pressure of the eye (mean arterial pressure minus intraocular pressure) was regulated within the range of 25–75 mm Hg by increasing the intraocular pressure, which was adjusted by changing the height of the reservoir of balanced salt solution perfused into the eye through a needle placed in the anterior chamber. The vitreal electroretinogram, transepithelial c-wave, slow PIII and light-evoked decrease in extracellular K+ concentration were recorded during intraocular pressure elevation in the darkadapted retina. The c-wave increased in amplitude between 40 and 75 mm Hg of perfusion pressure and decreased below 40 mm Hg in some cases. These changes were unrelated to the standing potential. The transepithelial c-wave, slow PIII and light-evoked decrease in extracellular K+ concentration were larger in the range of perfusion pressure examined. These suggest that some factor induces electroretinographic changes that are not readily explained by hypoxia or pH changes alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01203692
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  • 39
    Electronic Resource
    Electronic Resource
    Serotonin-containing projections to the mesencephalic trigeminal nucleus of the cat (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 241 (1995), S. 136-142 
    Details
    ISSN: 0003-276X
    Keywords: Mesencephalic trigeminal nucleus ; Serotonin ; WGA-HRP ; Retrograde tracing ; Immunocytochemistry ; Cat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: It is well known that the mesencephalic trigeminal nucleus (MTN) neurons transmit somatosensory information from proprioceptors in the oral-facial region. Several mechanisms of sensory transduction in these specialized receptors have been proposed, but the neurotransmitters which are responsible for mediating proprioceptive information are still unknown. The current study concentrates on the distribution of one putative neurotransmitter system, serotonin (SER), in the cat MTN. A second objective was to clarify the location and sources of serotoninergic projections on the MTN neurons.Methods: To determine whether SER was localized in the MTN, the peroxidase-antiperoxidase (PAP) immunocytochemical technique was applied at light and electron microscopic levels in colchicine-treated animals. The origin of SER-containing fibers in the MTN was studied using a doublelabeling method combining retrograde transport with wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) and SER immunocytochemistry.Results: There were no SER-containing neurons in the MTN. The cell bodies of immunonegative MTN neurons were closely surrounded by fine SER-positive fibers and terminals. The labeled fibers were in most cases very thin and sometimes varicose. Ultrastructurally, direct synaptic contacts between SER-containing terminals and perikarya of MTN neurons of all sizes could be seen. The majority of SER-labeled structures were synaptic terminals in which the immunoreactive material was located within the small round clear as well as the small granular vesicles (diameter 50-80 nm) and a few large dense-cored vesicles (up to 150 nm). Retrograde tracing demonstrated that most of cells in the nuclei raphe dorsalis, pontis and magnus were WGA-HRP-labeled.Conclusions: These results indicated that MTN neurons received serotoninergic projections from the raphe nuclei of the brainstem. In light of these morphological data, it is concluded that the MTN of the cat is under the influence of SER-containing axons and this serotoninergic input may modulate MTN neuronal activity at the first synaptic relay. © 1995 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092410118
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  • 40
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of tyrosine hydroxylase and gamma-aminobutyric acid in the mesencephalic trigeminal nucleus of the cat: A light and electron microscopic study (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 242 (1995), S. 123-131 
    Details
    ISSN: 0003-276X
    Keywords: Mesencephalic trigeminal nucleus ; Catecholamines ; Tyrosine hydroxylase ; Gamma-Aminobutyric acid ; Immunocytochemistry ; Cat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Recent studies conducted on the rat have demonstrated that the mesencephalic trigeminal nucleus (MTN) neurons, involved in the proprioceptive transmission, contain some neuroactive substances, including classical and amino acid neurotransmitters. In addition, there is evidence that serotonin could not act as a neurotransmitter at the first synaptic relay in the cat MTN. In the present study, we aimed to examine two other possible neurotransmitter systems, i.e., catecholamines and gamma-aminobutyric acid (GABA), and the relationships between GABA-immunoreactive (IR) neurons and tyrosine hydroxylase (TH)-IR axonal varicosities in the MTN of the cat.Methods: To ensure the localization of immunoreactive structures, the experiments were carried out at the light and electron microscopic level using single immunostaining for TH and GABA alone. The correlation between GABA-IR cell bodies and TH-IR fibers was investigated by means of double-labeling immunogold and peroxidase technique for GABA and TH.Results: Light microscopically, a few GABA-IR neurons were observed in the cat MTN. These small-size, labeled cells, most likely interneurons, were apposed to unstained large mesencephalic trigeminal cells. Most of the large nonreactive MTN neurons were closely surrounded by fine TH-IR varicose or nonvaricose fibers and dot-like structures, presumably nerve terminals. Under the electron microscope, TH-IR fibers were not seen in synaptic contact and only rarely appeared to be in close proximity to neuronal profiles of small GABAergic cells, which contained gold particles.Conclusions: Taken together with earlier studies from other laboratories, the present findings suggest that GABAergic system might play an indirect role in the proprioceptive information processing in the cat MTN by interactions of GABA-immunoreactive neurons with the systems that control the transmission of selected sensory information. In contrast, the presence of TH-IR fibers in direct apposition to the majority of MTN neurons provide further evidence that presumed GABAergic interneurons have extensive interactions with catecholamine varicosities and raise the possibility that catecholamines could modify the transmission on these neurons. © 1995 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092420116
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  • 41
    Electronic Resource
    Electronic Resource
    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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  • 42
    Electronic Resource
    Electronic Resource
    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.
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    URL: http://dx.doi.org/10.1007/BF00522492
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  • 43
    Electronic Resource
    Electronic Resource
    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.
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    URL: http://dx.doi.org/10.1007/BF00521281
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  • 44
    Electronic Resource
    Electronic Resource
    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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  • 45
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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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    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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  • 47
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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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  • 48
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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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  • 49
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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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  • 50
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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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  • 52
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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.
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    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.
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    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.
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    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.
    Type of Medium: Electronic Resource
    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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    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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  • 62
    Electronic Resource
    Electronic Resource
    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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    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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    Electronic Resource
    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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    Electronic Resource
    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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    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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    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.
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    URL: http://dx.doi.org/10.1007/BF00536819
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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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    Effects from the sensorimotor cortex on the spinal cord in cats with transected pyramids (1967)
    Springer
    Experimental brain research 3 (1967), S. 117-134 
    Details
    ISSN: 1432-1106
    Keywords: Supraspinal effects ; Extrapyramidal pathways ; Spinal activity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of stimulation of the sensorimotor cortex on activity of the lumbosacral cord were studied in pyramidotomized cats. The following actions initiated by corticofugal volleys were found: 1. postsynaptic effects on motoneurones, mainly excitatory in flexor motoneurones and inhibitory or excitatory in extensor motoneurones, 2. facilitation of spinal reflexes to motoneurones at an interneuronal level, 3. depolarization of presynaptic terminals of group Ib and cutaneous fibres. The latencies of the earliest cortical effects on motoneurones as indicated by modification of monosynaptic reflexes or PSPs were 9–12 msec. Experiments with lesions of different spinal tracts suggest that the effects on motoneurones are mediated mainly by pathways in the ventral part of the lateral funiculus (probably reticulospinal), the facilitation of reflex transmission by pathways in the dorsal part of the lateral funiculus (probably rubrospinal) and primary afferent depolarization by both the former and the latter pathways. The strongest cortical effects were evoked by stimulation of an area around the postcruciate dimple.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233257
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    A rubro-olivary pathway I. identification of a descending system for control of the dynamic sensitivity of muscle spindles (1967)
    Springer
    Experimental brain research 3 (1967), S. 372-381 
    Details
    ISSN: 1432-1106
    Keywords: Red nucleus ; Inferior olive ; Muscle spindles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In cats anesthetized with halothane the influence of central stimulation upon the dynamic sensitivity of muscle spindles in the flexor digitorum longus muscle was studied. One mesencephalic and one medullary region were found which caused an increase in dynamic spindle sensitivity when stimulated electrically. Histological identification of stimulating points showed these regions to be the caudal pole of the red nucleus and the inferior olivary nucleus respectively. Lesions in the olive decreased rubral effects on the spindles, indicating that the red nucleus and the olive are parts of the same system descending to dynamic fusimotor neurones. Further evidence for this point are given in a following paper (APPELBERG 1967).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237562
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    A Rubro-Olivary pathway II. Simultaneous action on dynamic Fusimotor neurones and the activity of the posterior lobe of the cerebellar cortex (1967)
    Springer
    Experimental brain research 3 (1967), S. 382-390 
    Details
    ISSN: 1432-1106
    Keywords: Red nucleus ; Inferior olive ; Cerebellum ; Muscle spindles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the preceding paper (Appelberg and Molander 1967) the caudal part of the red nucleus and parts of the inferior olivary nucleus were shown to cause increased dynamic sensitivity of muscle spindles when stimulated repetitively. The results to be presented will show that single shock electrical stimulation in the caudal part of the red nucleus evoked a field potential in the inferior olivary nucleus. This response seemed to be monosynaptically evoked and was observed only in parts of the olive where repetitive stimulation caused increased dynamic sensitivity of muscle spindles. Stimulation in the red nucleus as well as single shock stimulation in the actual part of the inferior olive also caused a potential in the vermis of the posterior cerebellar lobe. In conditioning — test experiments with the two stimuli the conditioning shock was seen to cause alternating periods of decreased and increased responsiveness in the pathway concerned. The same type of interaction was seen between two responses caused by double shock stimulation in the red nucleus. It is concluded that information from the caudal part of the red nucleus reaches dynamic fusimotor neurones in the spinal cord via a relay in the inferior olivary nucleus; an additional relay in the pathway is also predicted. The cerebellum seems to receive information about ongoing activity in the pathway but mesencephalic stimulation was seen to cause spindle effects also in decerebellated animals.
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    URL: http://dx.doi.org/10.1007/BF00237563
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    Presynaptic inhibition of the monosynaptic reflex following the stimulation of nerves to extensor muscles of the ankle (1967)
    Springer
    Experimental brain research 4 (1967), S. 34-42 
    Details
    ISSN: 1432-1106
    Keywords: Monosynaptic reflex ; Presynaptic inhibition ; Extensor nerve ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Electrical stimulation of extensor nerves of the ankle has been used to investigate the presynaptic inhibition in a synergic monosynaptic reflex arc. 2. Depression of monosynaptic reflex response as well as increase in excitability of Ia afferent terminals in the MG (medial gastrocnemius) reflex arc is found following the conditioning stimulation of LGS (lateral gastrocnemius-soleus) nerve at Group I strength. 3. Excitability increase of the Ia terminals of the LGS nerve is also found following the conditioning stimulation of either a group of fibres of the same nerve or the MG nerve. 4. Conditioning by Group I afferent volleys from either the LGS or the PBST (posterior biceps-semitendinosus) muscles produces comparable changes in excitability of the Ia terminals from MG muscle. 5. The hypothesis is advanced that the depression of the monosynaptic reflex discharge during repetitive stimulation is mainly caused by the depolarization of the Ia afferent terminals, i.e. by presynaptic inhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235215
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    Spontaneous diabetes in dogs and cats (1967)
    Springer
    Diabetologia 3 (1967), S. 249-265 
    Details
    ISSN: 1432-0428
    Keywords: Spontaneous Diabetes ; Dog ; Cat ; Diabetes in dogs and cats ; Pancreas ; Islets of Langerhans ; B cells ; Insulitis ; Hyalin ; Capillaries ; Kidney ; Retina ; Microaneurysms ; Pituitary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les auteurs présentent une étude histopathologique de 30 chiens et de 5 chats spontanément diabétiques. — Les îlots de Langerhans et les cellules B étaient fortement diminués en nombre chez la grande majorité des chiens. Les cellules B étaient souvent dégranulées et hydropiques. Chez les chiens dont le diabète avait évolué pendant longtemps, les îlots étaient très rares et les cellules B absentes. — Chez les 5 chats spontanément diabétiques par contre, les îlots et les cellules B étaient nombreuses. Les cellules B étaient dégranulées et hydropiques chez 4 chats. Chez 1 des chats, les cellules B paraissaient normales. De nombreux îlots présentaient des dépôts de substance hyaline dans le stroma. Chez un chat, il existait une infiltration lymphocytaire très dense dans un îlot. — Ni chez les chiens, ni chez les chats, il n'a été vu de lésions glomérulaires identiques à celles de glomérulosclérose diabétique humaine. Les lésions les plus fréquentes consistaient en un épaississement des axes membraneux des touffes glomérulaires et une hypertrophie de la paroi des artérioles afférentes.— Dans les rétines des chiens diabétiques il existait une acellularité focale ou généralisée de la paroi des capillaires. Un petit nombre de microanévrysmes ont été trouvés chez 3 chiens diabétiques. L'incidence plus faible des lésions de rétinopathie vasculaire, comparativement aux diabétiques humains, s'explique probablement par la durée de vie plus courte du chien et du chat. Il est possible aussi que les capillaires rétiniens de ces animaux soient moins susceptibles de développer des lésions dégénératives. — Un degré marqué de stéatose hépatique a été observé chez beaucoup de chiens et de chats. Les surrénales étaient souvent hypertrophiées et contenaient des adénomes, mais ces lésions ne paraissent pas différentes de celles que l'on peut trouver chez des chiens et des chats non diabétiques de même âge. L'hypophyse a été prélevée chez 7 chiens. Dans 2 cas, elle contenait un adénome. Une étude cytologique plus complète des hypophyses sera publiée ultérieurement.
    Abstract: Zusammenfassung Die Autoren berichten über die Ergebnisse von Untersuchungen an 30 spontan-diabetischen Hunden und 5 spontan-diabetischen Katzen. Bei der großen Mehrzahl der diabetischen Hunde war die Zahl der Langerhansschen Inseln und der B-Zellen stark herabgesetzt. Die B-Zellen waren oft degranuliert und hydropisch. Bei Hunden mit schon lang anhaltender Krankheit waren die Inseln nur noch vereinzelt und B-Zellen überhaupt nicht mehr nachweisbar. — Im Gegensatz zu diesen Ergebnissen fanden sich bei allen 5 Katzen zahlreiche Inseln und B-Zellen. Bei 4 dieser Katzen jedoch waren die B-Zellen, wie bei den Hunden, degranuliert und hydropisch entartet. Bei einer Katze war das Aussehen der B-Zellen normal. Im Stroma der Inseln von 2 Katzen konnten starke Hyalinablagerungen nachgewiesen werden. In einem Falle zeigten die Inseln eine starke lymphocytäre Infiltration. — Weder bei den Hunden noch bei den Katzen waren typische Läsionen der Glomeruli, wie sie bei der Glomerulosklerose des menschlichen Diabetes auftreten, nachweisbar. Die häufigsten Veränderungen bestanden aus einer mehr oder weniger ausgeprägten Verdickung des mesangialen Teils der Kapillaren der Glomeruli und aus einer Hypertrophie der Wand der zuführenden Arteriolen. Bei einigen Hunden und Katzen bestanden auf chronische Pyelonephritis zurückführende Narben. — In der Retina der diabetischen Hunde waren zellenlose und funktionslose Kapillaren vorhanden, und degenerierte Pericyten (“ghostcells”) waren häufiger als bei normalen Hunden. In drei Hunden wurden einige Mikroaneurismen beobachtet. Daß diese für die Retinopathie des Diabetes typischen Läsionen beim Hund verhältnismäßig selten auftreten könnte mit der kürzeren Lebensdauer der Krankheit bei diesen Tieren zusammenhängen. Es ist jedoch nicht ausgeschlossen, daß die Retina von Hunden und Katzen weniger zu degenerativen Veränderungen neigt. — In der Leber vieler Hunde und Katzen wurde eine schwere Steatose beobachtet. In vier Hunden zeigte sich beginnende Lebercirrhose. In diabetischen Hunden und Katzen waren die Nebennieren oft hypertrophisch und enthielten Adenome, die allerdings auch bei nichtdiabetischen alternden Hunden beobachtet wurden. In 2 von 7 Hypophysen diabetischer Hunde fanden sich Adenome, über deren cytologische Untersuchung in einer späteren Veröffentlichung berichtet wird.
    Notes: Summary A histological study of 30 spontaneously diabetic dogs and 5 spontaneously diabetic cats is presented. — The islets of Langerhans and the B cells were strongly reduced in number in a large majority of the diabetic dogs. The B cells were often degranulated and hydropic. In cases of longer duration, the islets were scarce and B cells could no longer be found. — In contrast to the findings in diabetic dogs, all five cats showed numerous islets and B cells. However in 4 cats, the B cells showed complete degranulation and hydropic changes, as in the dogs. In one cat, the B cells had a normal appearance. Extensive hyalin deposits were found in the stroma of the islets in 2 cats. In one cat, an islet showed a dense lymphocytic infiltration. — No lesions identical to human diabetic glomerulosclerosis were found in any of the dogs or cats. The changes most frequently observed were a variable degree of thickening of the mesangial stalk of the glomerular capillaries, and an hypertrophy of the wall of the afferent arteriole. Scars resulting from chronic pyelonephritis, were found in a few dogs and cats. — Acellular, non-functional capillaries, with degeneration of pericytes (“ghost-cells”) were found in larger numbers in the retinas of the diabetic dogs than in non-diabetic control dogs. A very few microaneurysms could be found in 3 dogs. The lower incidence of the most typical lesions of diabetic retinopathy in dogs, as compared with the human diabetic, is probably related to the shorter duration of the disease in these animals. However, a lower susceptibility of the retina of dogs and cats to develop degenerative changes cannot be excluded. — A severe steatosis was observed in the liver of many dogs and cats. In 4 dogs, the liver showed early cirrhosis. In diabetic dogs and cats, the adrenal cortex often showed hypertrophy and contained adenomas; however, these changes have also been reported in non-diabetic aging dogs. An adenoma was found in 2 of the 7 pituitaries obtained from diabetic dogs; the cytological aspect of these adenomas and of the pituitaries will be reported in a later publication.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01222202
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    Responses evoked in the cerebellar cortex by stimulating mossy fibre pathways to the cerebellum (1967)
    Springer
    Experimental brain research 3 (1967), S. 95-110 
    Details
    ISSN: 1432-1106
    Keywords: Mossy fibre pathways ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Field potentials in the vermal cerebellar cortex generated by a mossy fibre volley along reticulo-, cuneo- and spino-cerebellar tracts were recorded with microelectrodes and analysed by the same procedures as was done for the mossy fibre responses in the cortex by juxta-fastigial (J.F.) and trans-folial (T.F.) stimulations in the previous paper (Eccles, Sasaki and Strata 1967a). li 3. All these results corroborate the analyses and the interpretations of the field potentials in the cerebellar cortex produced by T.F.- and J.F.-evoked mossy fibre volleys in the previous paper. 4. There have not been found electrophysiologically significant differences, as Szentágothai (1964) has suggested, between the modes of mossy fibre terminations of the reticulo-cerebellar and the spino-cerebellar systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233255
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    Neuronale reaktionen im tectum opticum der katze auf bewegte und stationäre lichtreize (1967)
    Springer
    Experimental brain research 3 (1967), S. 353-367 
    Details
    ISSN: 1432-1106
    Keywords: Tectum opticum ; Movement detecting neurons ; Directional sensitive neurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden 80 Einheiten des Tectum opticum der Katze abgeleitet und ihre Reaktionen auf stationäre und bewegte optische Reize geprüft. Neben den Neuronen, die in ihrer Reaktionsweise retinalen Einheiten vergleichbar waren, fanden sich überwiegend (89%) Neurone, die auf bewegte optische Reize reagierten. Unter den letzteren zeigte die Mehrheit (70%) richtungsspezifisches Verhalten. Bei einigen Neuronen war in einem beschränkten Bereich von 1–7.5∘/sec die Reaktion gesetzmäßig abhängig von der Winkelgeschwindigkeit des Bewegungsreizes (Potenzfunktion mit dem Exponenten 0.67). Die rezeptiven Felder waren meist rund mit einem durchschnittlichen Durchmesser von 8.1∘ (3–22∘). 68% der Einheiten reagierten nicht auf diffusen Lichtreiz. Die Reaktionen auf nicht bewegte Punktlichtreize waren rasch adaptierend und inkonstant in ihrer Art und Stärke. In kurzen Abständen mehrfach wiederholte Bewegungsreize bewirkten bei einem Teil der Bewegungsneurone rasche Adaptation. Zwei kurz aufeinander folgende Punktlichtreize ergaben eine Reaktion, die niedriger als die Summe der Erregungen der jeweils einzeln gegebenen Lichtreize war, wenn die zeitliche Folge der beiden Reize der Vorzugsrichtung des Neurons entgegengesetzt war. Bei Reizfolgen entsprechend der Vorzugsrichtung entsprach die Gesamtreaktion der Summe der Einzelreizantworten. Dies läßt vermuten, daß die Richtungsspezifität durch unilaterale Hemmung bedingt ist.
    Notes: Summary Recordings were made from 80 single units in cat's Tectum opticum during visual stimulation with moving and stationary optic stimuli. The majority of units (89%) showed movement specific reactions, the rest behaved functionally similar to retinal or geniculate neurons. 70% of the movement specific units showed directional selective reactions. The receptive fields, as determined with stationary and moving stimuli were mostly circular with an average diameter of 8.1° (range 3–22°). Stimuli passing through the periphery of the field led to less pronounced reactions than those going through the center. In 10 out of 30 units, the relation between discharge rate and angular velocity in a restricted range from 1°–7.5°/sec could be approximated by a power function with an exponent of 0.67. Above 10°/sec irregular and unsystematic alterations of reactivity were observed. 68% of the tectal units recorded did not respond to diffuse light stimuli. The reactions to localized intermittent stationary light stimuli were mostly off (42%) or on-off-responses (19%) and were characterized by fast adaptation, change of reaction type during successive intermittent stimulation and by the absence of an antagonistic field-structure. Stimulation of adjacent points in a temporal sequence corresponding to movement opposite to the most sensitive direction of a directional specific neuron led to a reaction which was below the sum of the reaction of the two stimuli given alone. At a temporal sequence of the two stimuli such as to simulate the most sensitive direction, the resulting reaction corresponded to the sum of the reactions of both stimuli given alone. This suggests a mechanism of unilateral inhibition to be responsible for directional selectivity.
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    URL: http://dx.doi.org/10.1007/BF00237560
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    Über die Bildung von H-3-Dopa aus H-3-Tyrosin und die Bestimmung der Dopa-Neubildungsrate in der Nebenniere des Huhnes und der Katze unter in vivo-Bedingungen (1967)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 257 (1967), S. 391-408 
    Details
    ISSN: 1432-1912
    Keywords: Dopa formation ; Tyrosine hydroxylase ; Dopa decarboxylase ; Adrenal gland ; Cat ; Dopa-Bildung ; Tyrosin-Hydroxylase ; Dopa-Decarboxylase ; Nebenniere ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nach Injektion von H-3-Tyrosin wurde die Bildung von H-3-Dopa in verschiedenen Organen (Nebenniere, Hirnstamm, Herz, Leber, Niere, Milz, Pankreas und Blut) des Huhnes und der Katze gemessen. Die Isolierung von H-3-Dopa wurde wie folgt durchgeführt: 1. Die säurelösliche Fraktion wurde durch Papierhochspannungselektrophorese im Pyridin-Eisessig-Puffer vorgetrennt. 2. Die Tyrosin-Dopa-Bande wurde eluiert und papierchromatographisch aufgetrennt. 3. Die Dopa-Bande wurde erneut eluiert und Dopa wurde als Borat-Komplex durch Papierhochspannungselektrophorese in einem Borat-Puffer charakterisiert. Nach Hemmung der Dopa-Decarboxylase mit NSD-1034 [N-Methyl-N-(3-hydroxybenzyl)hydrazin-dihydrogenphosphat] betrug der Anteil des H-3-Dopa an der Gesamtaktivität der säurelöslichen Fraktion der Nebenniere beim Huhn 4% und bei der Katze 5%. Unter diesen Bedingungen konnte H-3-Dopa in allen anderen untersuchten Organen nicht nachgewiesen werden. Ohne NSD-1034 fand sich auch in der Nebenniere kein H-3-Dopa. Bei Versuchen an Katzen wurde die H-3-Dopa-Konzentration im venösen Blut der Nebenniere gemessen. In einigen Blutproben betrug die H-3-Dopa-Aktivität bis zu 3% der Gesamtaktivität. Nahezu die gesamte von der Nebenniere gebildete Menge an H-3-Dopa wurde an das venöse Blut abgegeben. Nur 5% des neugebildeten Dopa waren am Ende des Versuches in der Nebenniere nachweisbar. Das zeigt, daß Dopa von der Nebenniere nicht gespeichert wird. Im Blut anderer Organe fand sich hingegen kein Dopa. Die Dopa-Konzentration der Nebenniere betrug nach Blockierung der Dopa-Decarboxylase ca. 1 μg/g Naßgewebe und war ohne Hemmung 〈0,2 μg/g. Die Dopa-Neubildungsrate der Nebenniere wurde abgeschätzt aus dem H-3-Dopa-Gehalt der Nebenniere sowie aus dem zeitlichen Verlauf der H-3-Dopa-Aktivität und der spezifischen Aktivität des freien H-3-Tyrosins. Bei der Katze werden von einer einzelnen Nebenniere etwa $$\frac{{0,02{{\mu}}g}}{{\min /kg}}$$ Dopa gebildet $$\left( { = \frac{{1,2{{m\mu Mol}}}}{{\min /1{{gNebenniere}}}}} \right)$$ .
    Notes: Summary After injection of H-3-tyrosine the synthesis of H-3-dopa was measured in various organs (adrenal glands, brain stem, heart, liver, kidney, spleen, pancreas and blood) of fowl and cat. The isolation of H-3-dopa was carried out in the following way: 1. The acid soluble fraction was fractionated by high voltage paper electrophoresis in a pyridine-acetic acid-buffer. 2. The tyrosine-dopa-spot was eluated and descending paper chromatography was carried out. This system separated tyrosine from dopa. 3. The dopa-spot was eluated again, and dopa was characterized by its complex with boric acid in paper high voltage electrophoresis in a boric acid-sodium hydroxide-buffer. After inhibition of the dopa decarboxylase by NSD-1034 [N-methyl-N-(3-hydroxybenzyl)hydrazine dihydrogen phosphate] H-3-dopa represented in adrenal glands of domestic fowl 4% and in those of cats 5% of the total radioactivity. Under these conditions in all the other organs investigated H-3-dopa could not be detected. Without NSD-1034 H-3-dopa was undetectable in the adrenals, too. In experiments with cats the H-3-dopa concentration in the venous blood of the adrenals was measured. In some samples H-3-dopa represented up to 3% of the total radioactivity. Nearly the total amount of H-3-dopa formed in the adrenals was secreted into the venous blood, and only 5% of the total amount were detected in the gland at the end of the experiments. This demonstrates that dopa cannot be stored by the adrenals. We failed to detect H-3-dopa in blood from any other organ. The concentration of dopa in the adrenals was about 1 μg/g wet weight after inhibition of dopa decarboxylase and without inhibition it was 〈0.2 μg/g wet weight. The dopa synthesis rate in adrenals was calculated from the H-3-dopa activity in the gland and in the venous blood and from the specific activity of its precursor H-3-tyrosine. One adrenal of the cat synthetized 0.02 μg dopa/min·kg body weight (=1.2 mμMol/min·1 g adrenal).
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