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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 265-268 
    ISSN: 1432-1106
    Schlagwort(e): Vestibular nerve ; Spontaneous activities ; Development ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The spontaneous activity of primary vestibular neurons was studied during postnatal development in the cat. Activities were categorized as regular, intermediate and irregular on the basis of the coefficient of variation. At birth, few regularly firing units were found while the percentage of intermediate and irregular units was high. During development, the percentage of units meeting the criterion of regularity increased steadily with age. At the same time the number of intermediate and irregular units decreased. The average resting rate of all categories of unit showed an increase in firing from birth up to the adult stage, i. e., around the second postnatal month. The mean firing rate of regularly firing units was always higher than the two other categories throughout all the stages of development. These results were compared with similar work performed in the rat.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 215-233 
    ISSN: 1432-1106
    Schlagwort(e): Spinal Ia terminals ; Primary afferent depolarization ; GABA ; Bicuculline ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The unmyelinated terminal regions of extensor muscle Ia afferent fibres were stimulated electrically near lumbar motoneurones in anaesthetised cats using 300 μs pulses of less than 1 μA passed through the central NaCl barrel of seven barrel micropipettes. Such terminations were identified by anodal blocking factors of less than four and the latency of the antidromic impulse recorded in the appropriate peripheral muscle nerve. Although the effects of microelectrophoretically administered GABA were occasionally complex, the most consistent finding was a reduction in termination threshold followed by an increase. Both this reduction in threshold by GABA, and that produced by tetanic stimulation of low threshold flexor afferents (PAD) were diminished by microelectrophoretic bicuculline methochloride. This GABA antagonist alone elevated the threshold of some terminations but did not reduce the depolarizing action of either potassium or L-glutamate. Furthermore, since reductions in threshold by GABA, but not by either potassium or L-glutamate, were associated with a decrease in PAD, GABA appears to increase terminal membrane conductance. Since neither GABA nor bicuculline methochloride influenced the threshold or afferent depolarization of non-terminal regions of Ia fibres, these results are consistent with the function of GABA as a depolarizing transmitter at gabergic axoaxonic synapses upon the terminals of Ia afferent fibres synapsing with motoneurones.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 234-242 
    ISSN: 1432-1106
    Schlagwort(e): Ventral lateral geniculate nucleus ; Dorsal lateral geniculate nucleus ; Superior colliculus ; Cat ; Efferent projections
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cells in the cat superior colliculus which project to the ventral and dorsal lateral geniculate nuclei (VLG and DLG) have been labeled by retro-grade transport of horseradish peroxidase (HRP). We studied the depth, area, and morphology of each labeled neuron quantitatively. Our measurements show that the projection neurons to both VLG and DLG vary in laminar position, size, and morphology. Labeled cells projecting to both nuclei were concentrated within the superficial gray layer, but were also scattered through the optic layer and, after DLG injections, in the intermediate gray layer as well. Labeled cells in both groups varied greatly in size, ranging from 49–344 μm2 cross-sectional area (mean 143 μm2) for the VLG group and from 31–398 μm2 (mean 165 μm2) for the DLG group. The labeled cells also varied in morphology after both VLG and DLG injections. The majority had a granule or vertical fusiform morphology. There were fewer with a stellate morphology and almost none with a horizontal morphology. At least three types of superior colliculus cells thus appear to project to the ventral and dorsal lateral geniculate nuclei. These cell types likely give rise to distinct functional channels to these nuclei.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-1106
    Schlagwort(e): Dorsal column nuclei ; Inferior olive ; Upper cervical projections ; Spino-olivary paths ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Spino-olivary projections from segments C1 and C2 were examined in 17 cats using autoradiographic methods and in nine cats using the method of retrograde horseradish peroxidase (HRP) transport. Injections of 3H-leucine at the junction of the C1–C2 segments produced anterograde terminal labelling in two regions of the contralateral inferior olive, one in the rostromedial half of the dorsal accessory olive (DAO), the other in the caudal half of the medial accessory olive (MAO). Projections to the rostromedial DAO were best demonstrated when tracer labelled the ventromedial part of the dorsal horn, while projections to the caudal MAO were strongly labelled by injections in both the lateral and medial parts of the intermediate grey matter. Injections of HRP into the region of the inferior olive led to retrograde marking of cells in both regions of the contralateral spinal cord implicated by autoradiographic studies to have spino-olivary projections. Dense groupings of small rounded or fusiform cells were labelled contralaterally on the medial aspect of the dorsal horn in C1 and C2, while medium-sized multipolar cells were more sparsely distributed throughout intermediate laminae of C1-C5. Olivary projections from dorsal column nuclei were also examined and compared to those of spinoolivary projections. Injections of 3H-leucine into n. gracilis and cuneatus led to terminal labelling in three olivary regions, including the rostral DAO, the caudo-lateral DAO and the caudal MAO. Projections from the DCN to the rostral DAO and the caudal MAO overlapped with regions of projection from upper cervical segments although the territories occupied by DCN and upper cervical projections were not identical. Amino acid injections which were confined to n. cuneatus gave rise to terminal labelling in only the rostromedial DAO.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 48 (1982), S. 1-12 
    ISSN: 1432-1106
    Schlagwort(e): Cerebellar nuclei ; Superior colliculus ; Horseradish peroxidase ; Autoradiography ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary After injections of horseradish peroxidase (HRP) into various parts of the superior colliculus (SC) in 14 cats, retrogradely labeled neurons were found in parts of all deep cerebellar nuclei. The present study demonstrated that there are three main origins of the cerebellotectal projections in regard to the locations of the cell bodies: (1) the caudal half approximately of the fastigial nucleus (NM) including the subnucleus medialis parvocellularis (SMP), (2) the ventral and lateral parts of the posterior interpositus nucleus (NIP), and (3) the ventral part of the dentate nucleus (NL) including the subnucleus lateralis parvocellularis (SLP). The pathways and terminations of these projections have also been shown autoradiographically. Thus, fibers from NM crossed within the cerebellum and terminated in the intermediate and deep gray layers of the bilateral SC. Fibers from NIP and NL passed within the superior cerebellar peduncle, which crossed in the tegmentum (“decussation” of the peduncle) and ended in the two layers of the contralateral SC. In addition, some cerebellofugal fibers were found to terminate in the nuclei interstitialis of Cajal and Darkschewitsch, as well as in parts of pretectum and thalamus. The tecto-ponto- (and olivo-) cerebellotectal loop (cf. Kawamura 1980) has been established morphologically and it is briefly commented on in correlation with the propagation of the teleceptive (optic and acoustic) impulses.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 163 (1982), S. 487-500 
    ISSN: 1432-0568
    Schlagwort(e): Monocular and binocular visual cortex ; Cat ; Cytoarchitectonic ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aim of this study was to determine the differences between the monocular and binocular segments of the visual cortex in three cats by means of stereological procedures. The cytoarchitectonic images of both segments are described. The thickness of layers in both segments are slightly different. The following results have been obtained. 1. The nerve and glial cell densities are significantly smaller in the monocular segment than in the binocular one. 2. The mean projection area of the neurons is significantly (p〈0.1%) larger in the monocular segment than in the binocular one. Consequently, the mean perikaryon volume in the monocular segment amounts to about one and a half of that in the binocular segment. 3. A two-way variance analysis of neuronal densities and perikaryon sizes shows a significant difference (p〈0.1%) between both segments. 4. The perikaryon volume fraction of the monocular segment is slightly larger than that of the binocular one. 5. The perikaryon size distributions of both segments are different. The shape of the size distributions within the layers vary in both segments. The results are in accordance with the Y-X-W-classification of nerve cells in the visual system. Semi-automatic sterological procedures are capable of detecting distinct functional areas in the brain which are difficult to distinguish visually.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 48 (1982), S. 137-143 
    ISSN: 1432-1106
    Schlagwort(e): GABA uptake ; Radioautography ; Ultrastructure ; Oculomotor nucleus ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The uptake of tritiated γ-aminobutyric acid (3H-GABA) in the oculomotor nucleus of the cat was studied, using light and electron microscopic examination of radioautograms after intracerebral in vivo administration of the amino-acid. A glial uptake by oligodendrocytes was seen together with a neuronal uptake of the tracer in a certain type of axon terminals found in synaptic contact with both dendrites and soma, some of them exhibiting all the ultrastructural features of motoneurons. Previous neurochemical, electrophysiological and immunocytochemical studies indicate that GABA might well be the inhibitory neurotransmitter in the vestibuloocular reflex arc. The present results show that a morphological substrate exists for the presumed postsynaptic GABAergic inhibition of ocular motoneurons, at least in the oculomotor nucleus of the cat.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 48 (1982), S. 199-208 
    ISSN: 1432-1106
    Schlagwort(e): Thiamine ; Vitamin B1 ; Cat ; Amnesia ; Brain lesions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Behavioral and neuroanatomical consequences of a thiamine-deficient diet, combined with the application of a thiamine-antagonist (pyrithiamine) were investigated in the cat. Eight cats (the experimental group) were subjected to a vitamine-B1-poor diet until they developed neurological symptoms (epileptic attacks, ataxia, gait disturbances), while 24 cats were fed normally and served as control group. Immediately following the appearance of neurological signs, a high dose of thiamine was given to the cats of the experimental group; they were then allowed to recover for ten days. Thereafter the performance in learning an alternation task in a T-maze was tested and compared with that of the control group. Behaviorally, the cats of the experimental group manifested drastically retarded acquisition rates in the learning task compared to the cats of the control group. Neuroanatomically, damage was found in the brains of each of the cats in the experimental group; this damage consisted mainly of enlarged ventricles, hemorrhages, neuronal loss and gliosis. Those regions most consistently affected were the periaqueductal gray, the inferior colliculi and the mamillary nuclei. The thalamic mediodorsal nucleus was affected to a minor degree in three cats only. Four cats manifested damage in the hippocampal formation. No damage was found in the cerebellum. Most of the damaged neuroanatomical loci resemble those found in patients with a Wernicke-Korsakoff syndrome.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 48 (1982), S. 401-408 
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Striate cortex ; Ocular dominance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We recorded from single cells in the cat's visual cortex to quantitatively evaluate (1) the reliability of subjective assessments of ocular dominance (101 cells) and (2) the stability of ocular dominance over time (25 cells). We found that the correlation between subjective and objective measures of this variable was poorer than expected, and was worst for cells with low overall response strengths. This result appears to reflect variability in the subjective assessment procedure. For the second part of the study, we recorded from single cortical cells of 5-week-old kittens, and made repeated objective measurements of ocular dominance over time. Twenty-four of the twenty-five cells examined were quite stable in ocular dominance for periods so long as 8 h. One unit was encountered which showed substantial progressive shifts in ocular dominance over time.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 368-376 
    ISSN: 1432-1106
    Schlagwort(e): Saccade-related activity ; Retinotopic organization ; Visual cortex ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single unit activity of 842 cells has been recorded in cat visual cortex and analyzed with respect to vestibular induced, and spontaneous saccadic eye movements performed in the dark. This study has been done in awake, chronically implanted cats, subsequently placed in “acute” conditions to achieve the precise retinotopic mapping of the cortical areas previously investigated. In areas 17 and 18, respectively, 27% and 24% of the cells tested were influenced by horizontal saccadic eye movements in the dark (E. M. cells). In the Clare-Bishop area, the proportion of E. M. cells was 12%, while only 2% of such cells were found in areas 19 and 21. The distribution of E.M. cells in areas 17 and 18 with respect to retinotopy showed that E.M. cells were more numerous in the cortical zones devoted to the representation of the area centralis (38% in area 17, 27% in area 18) than in the zones subserving the periphery of the visual field (17% and 12%, respectively). Two of the characteristics of E. M. cell activations appear dependant on the retinotopic organization. First, a larger number of E.M. cells presenting an asymmetry in their responses to horizontal saccadic eye movements in opposite directions (directional E.M. cells) were encountered in the cortical representation of the peripheral visual field. 53% of E. M. cells recorded in area 17 and 71% in area 18 were directional in the cortex corresponding to the peripheral visual field. This percentage was of 23% and 25% respectively in the cortex devoted to area centralis. Second, E.M. cells were found to have a latency from the onset of the saccade systematically larger than 100 ms (i.e, they discharged at, or after the end of the eye movement) if they were located in the cortical representation of the area centralis, while E.M. cells related to the peripheral visual field displayed a wider range of latencies (0–240 ms). Results obtained in Clare Bishop area, although limited to the representation of the peripheral visual field, were quantitatively and qualitatively similar to those observed in the homologous retinotopic zones of areas 17 and 18. It is concluded that an extra-retinal input related to oculomotor activity is sent to the cat visual cortex and is organized, at least in areas 17 and 18, with respect to the retinotopic representation of the visual field. These data support the hypothesis of a functional duality between central and peripheral vision and are discussed in the context of visual-oculomotor integration.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 438-447 
    ISSN: 1432-1106
    Schlagwort(e): Deiters' neurons ; Locomotion ; Perturbation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of mechanical stimulation (tap) on single unit activity of Deiter's neurons were analysed in walking cats decerebrated at the premammillary level. Deiters' neurons projecting to the ipsilateral cervical, but not to the lumbosacral, spinal cord (C-Deiters' neurons) were identified by antidromic activation, cerebellar stimulation, and localization of the neurons. During each unperturbed cycle of quadrupedal locomotion, most C-Deiters' neurons showed two frequency modulation peaks in their impulse discharges: one (A peak) in the late swing (E1) or the early stance (E2) phase, the other (B peak) in the late stance (E3) or the early swing (F) phase, of the ipsilateral forelimb. The A peak started to rise shortly before the ipsilateral forelimb was placed. When mechanical perturbation was applied during locomotion to the paw dorsum of the left forelimb (LF) in its stance phase, the ongoing LF stance phase shortened and the simultaneous swing phase of the right forelimb (RF) shortened. Accordingly, in the RF, extensor activity in the swing phase to place down the limb occurred earlier than in unperturbed step cycles. The same LF tap induced a marked enhancement of impulse discharges in C-Deiters' neurons on the right side (with a magnitude of 20–100 imp/s, and the shortest latency of 25 ms). This enhancement was more pronounced than that induced when the perturbation was applied to the LF during its swing phase. The latency manifested a close time relation to the RF extensor activity supporting the postulate that the increased C-Deiters' activity in the RF swing phase contributes to the earlier onset of RF extensor activity which plays an important role in maintaining alternating footfalls after perturbation.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 448-453 
    ISSN: 1432-1106
    Schlagwort(e): Eye-head coordination ; Vestibular nystagmus ; Visuo-motor system ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The activity of neck muscles was recorded in the alert, head-fixed cat together with the horizontal and vertical components of eye movements. Electromyographic activity of obliquus capitis cranialis and caudalis, and longissimus capitis, is closely related to horizontal eye position in the orbit both during spontaneous eye movements and vestibular nystagmus. The activity of splenius also shows this relationship but the coupling is less tight, probably because of the postural function of this muscle.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 462-466 
    ISSN: 1432-1106
    Schlagwort(e): β-Endorphin ; Periaqueductal gray ; Cat ; Arcuate nucleus ; Naloxone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electrical activation of the ipsilateral arcuate region of the hypothalamus produced an inhibitory influence upon three separate subpopulations of cells encountered in the ventrolateral PAG. Quiescent PAG cells were classified by their response pattern to sural nerve stimulation: Type A cells displayed only a short latency discharge; whereas, Type B cells exhibited a triphasic response pattern. Arcuate nucleus stimulation dramatically reduced the evoked discharge of both A and B cell types. Type C cells represented spontaneously active PAG neurons which were less affected by arcuate nucleus activation. Systemic naloxone (5 mg/kg) reduced the degree of inhibition of only Type B neurons. Naloxone was ineffective in attenuating arcuate inhibition of Type A and C neurons. Type B neurons may represent a class of cells which are more involved in nociceptive systems and therefore are susceptible to modulation by endogenous opiate peptides.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 451-455 
    ISSN: 1432-1106
    Schlagwort(e): Vestibular input ; Visual cortex ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study examines the possibility of a vestibular input to the visual cortex using chronically implanted cats subjected to horizontal sinusoïdal rotation in the dark. In areas 17 and 18 the activity of respectively 14% and 11% of units was modified by vestibular stimulation. Both non-specific and specific influences were observed. Specific influences (42% in area 17 and 33% in area 18) were similar to the types of responses recorded in the vestibular nuclei, and were encountered more frequently within the cortex subserving the peripheral visual field. Our results could provide a neurophysiological basis for some psychophysiological observations concerning visuo-vestibular interactions.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 47 (1982), S. 79-94 
    ISSN: 1432-1106
    Schlagwort(e): Horseradish peroxidase ; Cat ; Limbic system ; Hippocampal formation ; Mamillary bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The afferent projections to, and the interconnections between, four structures of the socalled limbic system were investigated in the cat. The retrograde horseradish peroxidase (HRP) technique was used to trace the origins of fibers projecting to each of these four loci. Particular emphasis was laid on tracing cortical afferents of these regions. Four injections were performed in the dorsal and two in the ventral subicular regions; six were centered within the mamillary nuclei, four within the anterior thalamic nuclei, and three within the cingulate gyrus. For each region, a number of projections were found which had apparently not been described before, at least not for the cat: For injections into the subicular regions, a hitherto unknown number of cortical afferents was detected, including labeled cells in the prefrontal and premotor fields and from large areas within the posterior parietal, temporal and occipital cortex (i.e., sensory and sensory integration cortex); numerous neurons were labeled in the anterior nuclear group of the thalamus. Injections of HRP into the mamillary nuclei revealed, aside from a strong projection from the subicular regions, frontocortical and cingulate projections to the mamillary nuclei; the mamillary nuclei also received subcortical projections from the septum, the diagonal band of Broca and from the periaqueductal gray. Following injections into the anterior thalamic nuclei, labeled cells were found in the prefrontal cortex, and to a lesser extent in lateral parts of the cortical hemisphere; subcortically, the mamillary nuclei received connections from hypothalamic areas, the periaqueductal gray, the diagonal band of Broca and the claustrum. Cingulate injections labeled cells in temporal and parietal cortical areas, in the subicular region, and also in the periaqueductal gray. Our findings reveal that each of the four injected areas receives a large number of afferents from divergent regions of the brain; of these, a considerable number is shared by each of the four injection loci. Furthermore, the present results reveal that the subiculum, the mamillary bodies, and the anterior thalamus are more strongly interconnected than previously assumed.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 47 (1982), S. 209-222 
    ISSN: 1432-1106
    Schlagwort(e): Developmental plasticity ; Visual cortex ; Attention ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In five, dark-reared, 4-week-old kittens the posterior two thirds of the corpus callosum were split, and a lesion comprising the intralaminar nuclei was made of the left medial thalamic complex. In addition, the right eye was closed by suture. Postoperatively, the kittens showed abnormal orienting responses, neglecting visual stimuli presented in the hemifield contralateral to the side of the lesion. Sudden changes in light, sound, or somatosensory stimulation elicited orienting responses that all tended toward the side of the lesion. These massive symptoms faded within a few weeks but the kittens continued to neglect visual stimuli in the hemifield contralateral to the lesion when a second stimulus was presented simultaneously in the other hemifield. Electrophysiologic analysis of the visual cortex, performed after the end of the critical period, revealed marked interhemispheric differences. In the visual cortex of the normal hemisphere most neurons were monocular and responded exclusively to stimulation of the open eye, but otherwise had normal receptive field properties. In the visual cortex of the hemisphere containing the thalamic lesion, the majority of the neurons remained binocular. In addition, the selectivity for stimulus orientation and the vigor of responses to optimally aligned stimuli were subnormal on this side. Thus, the same retinal signals, which in the control hemisphere suppressed the pathways from the deprived eye and supported the development of normal receptive fields, failed to do either in the hemisphere containing the thalamic lesion. Apparently, experience-dependent changes in the visual cortex require both retinal stimulation and the functioning of diencephalic structures which modulate cortical excitability and control selective attention.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 133-143 
    ISSN: 1432-1106
    Schlagwort(e): Cutaneous reflexes ; Supraspinal control ; Motoneurons ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We examined the characteristics of postsynaptic potentials (PSPs) produced in antidromically-identified medial gastrocnemius (MG) α-motoneurons by electrical stimulation of low threshold (〈 3×T) distal limb cutaneous afferents in the sural (SUR) nerve in adult cats anesthetized with α-chloralose, together with the effects on SUR PSPs of supraspinal conditioning stimulation of the contralateral red nucleus (RN) and pyramidal tract (PT). In the majority of MG motoneurons, SUR afferents with electrical thresholds 〈 1.5×T produced early excitatory synaptic potentials (EPSPs) with minimum central latency of about 2.0 ms, suggesting activation of a trisynaptic segmental pathway with two interposed interneurons. Such early EPSPs were often detectable with stimuli 〈 1.2×T, as determined by recording the compound action potential in the sciatic nerve and from the first appearance of the N1 wave of the cord dorsum potential. Inhibitory synaptic potentials (IPSPs) were regularly produced by SUR volleys of only slightly greater strength (often as low as 1.3×T) and these had minimum central latencies of about 3.0 ms (about 1.0 ms longer than the earliest EPSPs), suggesting a three interneuron central pathway. Repetitive stimulation of RN and PT regularly produced facilitation of both EPSP and IPSP components in the SUR response, suggesting that these supraspinal systems directly or indirectly excite some of the same interneurons that convey the SUR effects to MG motoneurons. When using very low strength SUR stimuli, PT conditioning produced relatively pure facilitation of the SUR EPSPs but with larger SUR volleys, PT clearly facilitated both EPSPs and IPSPs. RN conditioning produced more parallel facilitation of SUR EPSPs and IPSPs. Supraspinal control of the polysynaptic pathway producing SUR EPSPs is of particular interest because of earlier evidence that this pathway is differentially distributed to motoneurons of fast twitch versus slow twitch MG motor units.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 115-125 
    ISSN: 1432-1106
    Schlagwort(e): Voluntary movement ; Cat ; Triphasic ; EMG ; Antagonist
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electromyographic (EMG) activity associated with rapid voluntary limb movements exhibits a characteristic “three burst pattern”. The first burst is in the agonist muscle (AG1), the second is in the antagonist (ANT) and the third is again in the agonist (AG2). The present study was undertaken to determine whether ANT and AG2 reflect preprogrammed commands or responses to stretch consequent upon limb displacement. To answer this question EMG activity of agonist and antagonist muscles was examined in cats performing a tracking task. To dissociate centrally programmed muscular events from their intended mechanical consequences, isometric and anisometric conditions were presented in either a predictable or unpredictable sequence. A torque motor was used to control limb trajectory and to impose passive angular displacements. Whereas AG1 was present under both isometric and anisometric conditions, ANT and AG2 required limb displacement and were time locked to movement parameters. ANT occurred within 15 ms following the onset of acceleration. Its magnitude varied linearly with this parameter and inversely with AG1. Passive displacements stretching the antagonist elicited responses with similar latencies and greatest magnitude for a given acceleration. AG2 was only present in underdamped movements with terminal oscillations and typically occurred when the position reached its peak and the velocity recrossed zero. Its magnitude was a function of both limb deceleration and of intended force. The data indicate that both ANT and AG2 represent responses to muscles stretch whose amplitudes are modulated by descending commands. Reciprocal mechanisms operating at a spinal level could account for the reduction of the antagonist response as a function of intended force. The increased sensitivity of late stretch responses in the agonist with higher intended forces is compatible with motoneuron facilitation by tonic descending commands. It is proposed that the stretch evoked responses function to dampen terminal oscillations which ensue from rapid displacement of the mass of the limb against elastic forces of muscle and soft tissue.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 269-280 
    ISSN: 1432-1106
    Schlagwort(e): Vestibular nuclear neurons ; Canal-neck interaction ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The convergence and interaction of horizontal semicircular canal and neck proprioceptive inputs were studied in neurons of the caudal two thirds of the vestibular nuclear complex. Extracellular neuron activity was recorded under muscle relaxation and slight anesthesia in chronically prepared cats. The following stimulations were applied: horizontal rotations of (a) the whole body (labyrinth stimulation), (b) the trunk vs. the stationary head (neck stimulation), and (c) the head vs. the stationary trunk (combined labyrinth and neck stimulation). Of 152 neurons investigated, 83 (55%) showed convergence of the two inputs. In about half of these neurons, the neck input was very weak and hardly affected the labyrinthine response during head rotation. Judged from the response pattern, several of these neurons presumably were related to vestibulo-oculomotor function (i.e., vestibular nystagmus). In the other half (i.e., 27% of all neurons), sensitivity of the two inputs was similar. Both labyrinthine and neck responses contained a dynamic (“velocity”) component; neck responses of more than half of these neurons had, in addition, a static (“position”) component. The dynamic components were either “antagonistic” or “synergistic” as to their convergence during head rotation. When applying this combined stimulation, the dynamic components summed linearly, yielding subtraction in case of antagonistic convergence and addition in case of synergistic convergence. In contrast, the static components of the neck responses remained largely unchanged during head rotation. However, the static head-to-trunk deflection determined the tonic discharge level in such neurons and thus facilitated or disfacilitated the dynamic responses to superimposed labyrinth stimulation. We suggest that the two patterns of labyrinthine-neck interaction observed in vestibular nuclear neurons, i.e., subtraction and addition, may be involved in the postural control of the trunk and head, respectively. In contrast, interference of the neck input with vestibule-oculomotor function appears to be almost negligible in the intact cat.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 151-154 
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Oblique effect ; Visual evoked potentials ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An oblique effect was observed in the amplitude of the VEP recorded from area 17 of the cat. The ratio of the responses to oblique gratings compared with responses to horizontal and vertical gratings averaged 0.77. Orientation dependence was strongest at low spatial frequencies, unlike the effect found in primates.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 47 (1982), S. 28-32 
    ISSN: 1432-1106
    Schlagwort(e): Cortico-striatal projections ; Cat ; Visual cortex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Direct projections from visual areas 17, 18, 19, and lateral suprasylvian visual area (LS) to the striatum were searched for in 12 adult cats using the autoradiographic technique to detect neuronal pathways. Striatal labels were found only after injections in areas 19 and LS. Projections homolateral to the injection sites were observed from both areas to the head and body of the caudate nucleus and to the putamen. Contralateral projections were found from both areas 19 and LS: however, area 19 did not project to the contralateral putamen. The extent of contralateral projections was smaller and they were confined within the same regions as the homolateral ones. Silver grains were often arranged in cluster-like patches, which were more evident ipsilaterally, in the head of the caudate nucleus and after injections in area LS. The present data support the view of a not strictly topographical segregation of striatal projections from the cat visual cortex.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 59-70 
    ISSN: 1432-1106
    Schlagwort(e): Thalamocortical connection ; Cat ; Suprasylvian sulcus area ; Horseradish peroxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The thalamic projections to the cortical area surrounding the anterior (ASs) and middle (MSs) suprasylvian sulci in the cat were studied using horseradish peroxidase histochemistry. The medial MSs area (medial wall of the MSs) receives thalamic afferents from the pulvinar-lateralis posterior (Pul-LP) complex, posterior nucleus (Pn) and medial interlaminar nucleus (MIN) and C laminae of the dorsal lateral geniculate nucleus (GLd). Groups of labeled cells in the Pul-LP complex are arranged to form four different neuronal bands oriented dorsoventrally. The four neuronal bands are located, laterally to medially, in the lateral and medial parts of Pul and in the lateral and central parts of LP. The ventral ends of the first (in the lateral Pul) and the third (in the lateral LP) bands extend to MIN and Pn, respectively. The locations of the four bands in the Pul-LP complex appear to correspond to the terminal fields of afferents from four different regions (retina, pretectum, visual cortex and superior colliculus) related to visual function. The anterior part of the lateral MSs area (lateral wall of the MSs) receives thalamic fibers from the lateral and intermediate divisions of the posterior nuclear group (POl and POi), while its posterior part receives fibers from the dorsal and medial parts of LP and POi. Both walls of the ASs receive fibers from the ventrolateral part of LP as well as from the anterior part of POl and the POl-POm border. In addition, the ASs-MSs area receives fibers from the central lateral nucleus (CL) It is of interest to correlate the locations of cells projecting to the ASs-MSs area with the pathways terminating in thalamic regions. It is clear that, from the hodological point of view, the ASs-MSs area is functionally segregated, which is in agreement with previous studies we have made of corticocortical connections.
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  • 23
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Development ; Plasticity ; Central core ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fifteen dark-reared, 4- to 5-week-old kittens were stimulated monocularly with patterned light while they were anesthetized and paralyzed. Six of these kittens were exposed to the light stimuli only, in four kittens the light stimuli were paired with electric stimulation of the mesencephalic reticular formation and in five kittens with electric activation of the medial thalamic nuclei. Throughout the conditioning period, the ocular dominance of neurons in the visual cortex was determined from evoked potentials that were elicited either with electric stimulation of the optic nerves or with phase reversing gratings of variable spatial frequencies. In two kittens, ocular dominance changes were assessed after the end of the conditioning period by analyzing single unit receptive fields. Monocular stimulation with patterned light induced a marked shift of ocular dominance toward the stimulated eye, when the light stimulus was paired with electric activation of either the mesencephalic reticular formation or of the medial thalamus. Moreover, a substantial fraction of cells acquired mature receptive fields. No such changes occurred with light or electric stimulation alone. It is concluded that central core projections which modulate cortical excitability gate experience-dependent modifications of connections in the kitten visual cortex.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 47 (1982), S. 234-238 
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Connections ; Auto-radiography ; Superior colliculus ; Intralaminar nuclei ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Contralateral corticofugal projections were investigated following multiple injections of a mixture of tritiated leucine and proline into the lateral, postlateral, suprasylvian and ectosylvian gyri of adult cats. Transported label was found in several Contralateral subcortical regions. These included the claustrum, caudate-putamen, thalamic intralaminar nuclei, pretectum, and the superior and inferior colliculi. These results show that the crossed corticofugal projections are common in the cat and are more extensive than has been previously reported.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 48 (1982), S. 177-184 
    ISSN: 1432-1106
    Schlagwort(e): Motor unit types ; Twitch and tetanic tensions ; Potentiation ; Peroneus tertius muscle ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Motor units of the cat peroneus tertius muscle were systematically analyzed using the criteria established by Burke et al. (1973). On the basis of their speed of contraction and resistance to fatigue, 121 (97%) of 125 motor units examined in ten adult cats could be classified as belonging to one of four types: fast-fatiguable (FF), fast-resistant (FR), fast-intermediate (FI), and slow-resistant (S). Peroneus tertius was found to contain 30% FF motor units, 9% FI units, 39% FR units, and 22% S units. Contraction times of fast motor units (FF, FR, and FI) ranged from 15 to 27 ms and those of S units from 26 to 42 ms. The mean tetanic tensions were 37 g for FF units, 29 g for FI units, 7.5 g for FR units, and 1.1 g for S units. Fast motor units displayed considerable post-tetanic potentiation of twitch tension. Under similar conditions of stimulation, FF units appeared able to potentiate more and faster than FR units.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 48 (1982), S. 245-255 
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Cat ; Orientation columns ; Perpendicular penetrations ; Orientation shift
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary On the postlateral gyrus of the cat striate cortex the cells' preferred orientation was measured as a function of cortical depth in penetrations as parallel as possible to the radial fibre bundles. According to the penetration angle and in agreement with the current model of orientation columns, there was a low orientation drift in layers 2–4. At the transition between layers 4 and 5 an orientation shift of 45–90 deg was found in most penetrations. The orientation differences between adjacent recording sites in lower layers was normally low too, but clearly higher than in upper layers. The results are discussed in terms of more independent orientation mechanisms in upper and lower layers.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 285-294 
    ISSN: 1432-1106
    Schlagwort(e): Velocity sensitivity ; Upper cut-off velocity ; Temporal summation ; Cat ; Visual cortex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To understand why some cells in the visual cortex respond to high stimulus velocities while others fail to do so, a sample of 71 of such cells were examined for their responses to stationary presented stimuli as well as to moving edges or slits of different widths. When presented with stationary stimuli it was found that cells which respond best to slowly moving stimuli generally have tonic discharges, long time to peak latencies and often long minimal durations of stimulation. In contrast, cells which respond preferentially to fast stimuli have phasic discharges, short latencies and short critical durations of stimulation when presented with stationary flashed slits. In the latter type of cells the responses to very fast stimulus movement were abolished selectively when contrast and width of the stimulus were not optimal. A few cells exhitited a velocity-response (VR) curve with a central dip indicating good responsiveness to either slow or fast movement but little to medium velocities. These cells responded both phasically and tonically to stationary slits and the latency of the tonic and phasic responses corresponded well to the latency of the responses at low and high velocities, respectively. It is suggested that the ability of phasic cells to respond to high velocities is linked to their limited need for temporal summation.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 45 (1982), S. 333-348 
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Inferior olive afferents ; Mesencephalon ; Superior colliculus ; Autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Descending projections from the mesencephalon and superior colliculus to the inferior olive were analyzed by an autoradiographic tracing method. Injections of tritium-labelled leucine were placed in regions which had previously been identified as sources of afferents to the olive. These were located adjacent to the central gray and extended from the rostral red nucleus to the posterior thalamus. Additional injections were made in the superior colliculus. Other injections were placed in the basal ganglia and thalamus. Injections restricted to one side of the central mesencephalon resulted in predominantly ipsilateral labelling of the olive. After injections in the caudo-medial parafascicular and subparafascicular nuclei and rostral nucleus of Darkschewitsch, deposits of grains were observed in the rostral pole of the medial accessory olive and adjacent ventral lamella of the principal olive. The medial accessory olive contained grains into its middle third. More caudal injections which involved the interstitial nucleus of Cajal as well as the nucleus of Darkschewitsch and rostral red nucleus resulted in the dense labelling of the entire principal olive (except the dorsal cap), the entire medial acessory olive (except subnucleus β and the caudo-medial pole) and the caudo-dorsal accessory olive. Injections centered in the caudal magnocellular red nucleus and extending into the rostral parvocellular division labelled the dorsal lamella of the principal olive almost exclusively. When only the caudal part of the red nucleus was involved in the injection, the olive was entirely clear of grains. Minor contralateral distributions were observed in the dorsomedial cell column, the medial tip of the dorsal lamella and in the caudal medial accessory olive. The deep layers of the superior colliculus were found to project strongly to the contralateral medial accessory olive immediately beside subnucleus β and weakly to the same area ipsilaterally. Four pathways were identified as contributing fibers to the olivary projections. These were the medial longitudinal fasciculus, the medial tegmental tract, the central tegmental tract and tectospinal or tectobulbar fibers. The rubrospinal tract did not contribute projections to the olive. Injections in the caudate nucleus, entopeduncular nucleus and ventral anterior and ventral lateral thalamic nuclei, did not result in any labeling in the olive.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 46 (1982), S. 12-23 
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Medullary nuclei ; Dorsolateral spinal afferents ; Orthograde degeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The course and termination of afferents in the spinal dorsolateral fascicle to some medullary sensory nuclei were studied by tracing degeneration following lesions of spinal white matter. The main conclusions depend on successive degeneration experiments; other points were studied with single-stage lesions. The dorsal column nuclei were particu-larly studied; terminations in these nuclei following dorsolateral lesions followed a clear-cut pattern, with fibres arising from segments below T 6 terminating in the gracile nucleus and those with more rostral origin solely in the cuneate nucleus. In both nuclei, the major terminations were in their rostral third with most fibres traversing deep caudal regions where some termination also occurred. Some fibres ended contralaterally. These restricted regions of termination contrasted with the wide-spread terminations seen after lesions of the dorsal column. A region at the cuneate rostral pole, adjacent to but clearly separable from nucleus z, receives a dense projection from both caudal and rostral spinal levels, the former fibres terminating in the dorsal part of the region, the latter extending more ventrally. We treat this as a separate subnucleus. The afferents to the dorsal column nuclei (together with those terminating in the other nuclei studied) were confined to the extreme dorsolateral white matter. Our observations confirm the established view that only afferents arising from caudal segments (below at least T 4–5) terminate in nucleus z, and that afferents terminating in group x arise from all levels (at least between C 5 and L 5): also that neither receives any afferents through the dorsal columns. Dorsolateral fibres arising from segments above at least T 6 terminate in a clear-cut area at the lateral border of the external cuneate nucleus. Heavy terminal degeneration was also seen in the lateral cervical nucleus of afferents arising from both above and below T4–5
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 321 (1982), S. 44-47 
    ISSN: 1432-1912
    Schlagwort(e): Vagal reflex bradycardia ; Carotid sinus nerve stimulation ; Depressor nerve stimulation ; Clonidine ; Yohlmbine ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Vagal reflex bradycardia was induced in anaesthetized cats with high level spinal axotomy by electrical stimulation of either the carotid sinus nerves or a depressor nerve. In both preparations reflex bradycardia increased with the rate of stimulation. Injection of 1 μg/kg clonidine into a lateral cerebral ventricle augmented reflex bradycardia in response to carotid sinus nerve stimulation while the same dose of clonidine was ineffective when given intravenously. The antagonistic effect of intracerebroventricular yohimbine (50 μg/kg) indicated that the effect of clonidine was due to its α1agonistic action. In contrast to carotid nerve stimulation the reflex bradycardia in response to depressor nerve stimulation was affected neither by intracerebroventricular injection of clonidine (2 μg/kg) nor by yohimbine (100 μg/kg). It is concluded that in the cat, the function of the central parts of the baroreceptor reflex which originate from the carotid sinus area is augmented by stimulation of α1adrenoceptors while the function of those parts originating from the aortic area is not.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 321 (1982), S. 282-286 
    ISSN: 1432-1912
    Schlagwort(e): Release of endogenous histamine ; Hypothalamus ; Cat ; Freely moving rabbit ; Electrical stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The hypothalamus of anaesthetized cats and conscious, freely moving rabbits was superfused with CSF through double-walled, push-pull cannulae and the release of endogenous histamine was determined in the superfusates by a radioenzymatic assay. In the posterior hypothalamic area of the anaesthetized cat, the rate of release of endogenous histamine varied rhythmically; phases of high rate of release appeared at 60 min cycles. The release of histamine was increased by electrical stimulation of the superfused area, as well as by hypothalamic superfusion with potassium-rich CSF. In the conscious rabbit, the anterior hypothalamic area and the posterior hypothalamic nucleus were superfused simultaneously. In both regions, the resting release of histamine varied rhythmically at approximately 70 min cycles. Phases of high or low-rate of release in the anterior hypothalamic area coincided with the corresponding phases in the posterior hypothalamic nucleus. The rhythmic release of endogenous histamine in the hypothalamus, as well as the ability of depolarizing stimuli to enhance the release of the amine support the idea that histamine acts as a neurotransmitter in the central nervous system.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 394 (1982), S. 156-160 
    ISSN: 1432-2013
    Schlagwort(e): Spinal sympathetic nucleus ; Antidromic field potential analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The spinal sympathetic preganglionic nuclei were mapped using antidromic field potential analysis during electrical stimulation of L2 and L3 white rami. The spinal sympathetic nuclei were localized respectively in L2 and L3 segments of the lumbar cord as a narrow strip along craniocaudal axis of the spinal cord. The caudal and of each preganglionic sympathetic nucleus was localized caudally to the corresponding dorsal root entry (DRE). The cranial end of the nucleus in different experiments was localized at different levels along the corresponding DRE or cranial to the corresponding DRE. We suggest that neurones which send axons to a single white ramus form an anatomically separate sympathetic preganglionic nucleus in the lumbar spinal cord within one segment.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 395 (1982), S. 99-107 
    ISSN: 1432-2013
    Schlagwort(e): Dorsal spino-cerebellar tract ; Signal transmission from Ia afferents ; Sinusoidal muscle stretch ; Quantitative analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A defined class of cells within the nucleus dorsalis (Clarke's column) receives excitatory input from Ia afferents of mainly one muscle. Action potentials were recorded from axons of these cells (DSCT neurons) which are excited by Ia afferents of the gastrocnemius muscles. We investigated the response to sinusoidal muscle stretch over a wide range of amplitudes (10 μm–4 mm) and frequencies (0.1–130 Hz) in the deefferented preparation. The dynamic stretch was superimposed on a moderate static muscle stretch to ensure that the muscle was not slack during the phase of release. The response up to 10 Hz was displayed as PST histograms (cycle histograms) and a sinewave of stretch frequency was fitted to the PST histograms to define amplitude and phase of a response sinewave. At a constant frequency of about 3Hz, the relation between stretch amplitude and response amplitude could well be described by decelerating intensity functions: the hyperbolic or tanh log function and a modified power function (exponent 0.48±0.12). The phase lead of the response sinewave increased with increasing stretch amplitudes of up to 0.5 mm and then decreased. At constant stretch amplitudes of 0.5–2.0 mm the frequency response was investigated. In relation to stretch frequencies between 0.1 and 1 Hz an increase in the response amplitude of 4.4dB was observed and an increase for 13dB/decade between 3 and 10 Hz. At 0.1 Hz the phase of the response sinewave was 48° in advance and increased to a maximum lead of 89° at 6–8Hz. Above 10Hz the positions of the responding action potentials with respect to the stretch cycle were used to define a phase, which was in advance up to 60 Hz but decreased and changed to a phase lag at higher frequencies. If in PST histograms no periods of silence occurred during the phase of stretch release, the mean discharge rate was found to be independent of the sinusoidal stretching. If the pauses were present the mean rate increased with increasing stretch frequencies or amplitudes.
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  • 34
    ISSN: 1432-2013
    Schlagwort(e): Cat ; Carbon monoxide ; Chemoreceptor mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Carbon monoxide (CO) slugs (10–100 ml) injected into the inspired air of 6 hypoxic, anaesthetized cats reduced carotid body chemoreceptor discharge. The inhibition was invariably associated with a sharprise in $$P_{a, O_2 }$$ which was continuously recorded by a fast responding intravascular electrode. This suggests that CO in solution in the blood leaving the lungs displaces O2 from blood after it has left the exchange region and that the displaced O2 raises the $$P_{a, O_2 }$$ and inhibits chemoreceptor discharge. Our results provide no support for the idea that a haemoglobin-like pigment is involved in the mechanism of arterial chemoreceptor excitation.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 222 (1982), S. 695-698 
    ISSN: 1432-0878
    Schlagwort(e): Pineal gland ; Ultrastructure ; Dense-core vesicles ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Dense-core vesicles, 90–200 nm in diameter, were found in pinealocytes of the cat. They were present both in perikarya and cell processes.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 224 (1982), S. 247-267 
    ISSN: 1432-0878
    Schlagwort(e): Serotonin ; Brainstem ; Immunohistochemistry ; Rat ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphological characteristics and distribution of the somata of serotonin-containing neurons in the brainstem of rats and cats were studied by use of the peroxidase-anti peroxidase (PAP) immunohistochemical method employing highly specific antibodies to serotonin. Antibodies were raised in rabbits against an antigen prepared by coupling serotonin to bovine thyroglobulin and using formaldehyde as the coupling reagent. The distribution pattern of serotonin neurons observed in the present material is essentially in agreement with that described by other investigators who used the Falck-Hillarp method. In addition, this immunohistochemical technique revealed serotonin-containing perikarya in the following regions: 1) the periaqueductal gray, especially lateral to the nucleus raphe dorsalis, 2) the nucleus interpeduncularis, 3) the nucleus parabrachialis ventralis and dorsalis, 4) the field of the lemniscus lateralis, and 5) the reticular formation of the pons and medulla oblongata. The described immunohistochemical procedure makes it possible to study central serotonin neurons in detail without pharmacological pretreatment. The wide distribution of serotonin neurons demonstrated in this study should be considered when interpreting experiments dealing with the serotonin system.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 225 (1982), S. 437-442 
    ISSN: 1432-0878
    Schlagwort(e): Lateral geniculate nucleus ; Cortical deafferentation ; Free postsynaptic sites ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Following chronic decortication, free postsynaptic sites were found in the lateral geniculate nucleus of adult cat. Quantitative electron-microscopic analysis of the free postsynaptic sites revealed that they were not identical with the original, vacant postsynaptic sites, but were newly assembled formations. The ability of both relay cells and local interneurons of the adult lateral geniculate nucleus to assemble and/or maintain postsynaptic sites indicates that these nerve cells may be involved in the formation of new synapses.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 226 (1982), S. 1-12 
    ISSN: 1432-0878
    Schlagwort(e): Serotonin-immunoreactive nerve fibers ; Cerebellum ; Cat ; Rat ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localization of serotonin (5-HT)-immunoreactive nerve fibers in the cerebellum of the rat and cat was investigated by means of the peroxidase-anti-peroxidase (PAP) method using highly specific antibodies to 5-HT. Serotonin-containing nerve fibers were distributed throughout the entire cerebellum including the deep cerebellar nuclei, while 5-HT-positive neuronal somata were not detected in the cerebellum of either species. A different pattern of 5-HT innervation was found among the three layers of the cerebellar cortex. There were also interspecific differences in the pattern of distribution of 5-HT. In the rat, the pool of 5-HT nerve fibers mainly consisted of tangential elements, which were predominant in the molecular layer, while in the cat only a few 5-HT fibers were found in the molecular layer of the cerebellar cortex; dense networks of 5-HT nerve fibers were present in the granular layer. Some differences are evident in the pattern of distribution of 5-HT fibers in cerebellar regions classified on an anatomical and functional basis.
    Materialart: Digitale Medien
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  • 39
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Vasoactive intestinal polypeptide ; Brain-gut peptide ; Pyloric antrum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunoreactivity to VIP by endocrine-like cells in the feline pyloric mucosa was examined by using three kinds of region-specific anti-porcine VIP sera. VIP-immunoreactive endocrine-like cells were detected clearly with all of the VIP antisera used. They were located mainly around the neck of the pyloric glands. Some of these endocrine-like cells showed dilution-dependent immunoreactivity against VIP antisera. The immunostaining intensity of VIP-immunoreactive endocrine-like cells showing dilution-independence could not be distinguished from those of nerve elements. The present results suggest that the immunoreactivity with properties very similar to those of authentic VIP may be present in the endocrine-like cells of the feline pyloric glands.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    ISSN: 1432-1912
    Schlagwort(e): Intestinal Absorption ; Cardiac Glycosides ; Blood of Portal Vein ; Intestinal Lymph ; Cat ; Intestinale Resorption ; Herzglykoside ; Portalvenenblut ; Darmlymphe ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    ISSN: 1432-0568
    Schlagwort(e): Arterial supply ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    ISSN: 1432-0568
    Schlagwort(e): Postnatal development ; Fixation ; Neuroglia ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
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  • 43
    ISSN: 1432-1106
    Schlagwort(e): Lateral cervical nucleus ; Midbrain lesions ; Nauta method ; Ultrastructural investigation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    ISSN: 1432-1106
    Schlagwort(e): Reticular formation ; Convergence ; Inhibition ; Cat ; Chloralose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    ISSN: 1432-1106
    Schlagwort(e): Cutaneous receptive fields ; Spinal cord ; Cat ; Pain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    ISSN: 1432-1106
    Schlagwort(e): Corpus callosum ; EEG synchronization ; Homolateral sensory evoked potentials ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    ISSN: 1432-1106
    Schlagwort(e): Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    ISSN: 1432-1106
    Schlagwort(e): Pyramidal tract ; Fusimotor Neurons ; Forelimb ; Extensor ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 9 (1969), S. 307-324 
    ISSN: 1432-1106
    Schlagwort(e): Muscle spindle ; Gamma motor control ; Mesencephalic reticular formation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
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  • 50
    ISSN: 1432-1106
    Schlagwort(e): Muscle spindle ; Gamma motor control ; Reticular formations ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    ISSN: 1432-1106
    Schlagwort(e): Emotional behaviour ; Hypothalamus ; Electricalstimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    ISSN: 1432-1106
    Schlagwort(e): Lateral cervical nucleus ; Spinal lesions ; Ultrastructural investigation ; Degenerating boutons ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    ISSN: 1432-1106
    Schlagwort(e): Medial geniculate body ; Inhibition ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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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  • 54
    ISSN: 1432-1106
    Schlagwort(e): Electron microscopy ; Pontine nuclei ; Experimental neuroanatomy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    ISSN: 1432-1106
    Schlagwort(e): Evoked potential thresholds ; Factor analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
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  • 56
    ISSN: 1432-1106
    Schlagwort(e): Emotional Behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    ISSN: 1432-1106
    Schlagwort(e): Retinal Ganglion Cells ; Spatial Summation ; Center Inhibition ; Dynamic Organisation of Receptive Fields ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 8 (1969), S. 53-65 
    ISSN: 1432-1106
    Schlagwort(e): Lateral geniculate body ; Spatial summation ; Off-center-characteristics ; Geniculate transfer ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    ISSN: 1432-2072
    Schlagwort(e): Benperidolum ; Cat ; Extrapyramidal Side Effect ; EEG ; Toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    ISSN: 1432-2072
    Schlagwort(e): LSD ; Retina ; LGN ; Single Unit Activity ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    ISSN: 1432-2013
    Schlagwort(e): Labyrinthine Stimulation ; Types of Abducens Neurones ; Frequency Analysis ; Cat ; Labyrinthreizung ; Abducensneurone ; Frequenzanalyse ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 62
    ISSN: 1432-2013
    Schlagwort(e): Cat ; Decerebration ; Afferents to Respiratory Centers ; Medulla Oblongata ; Reticular Formation ; Katze ; Decerebrierung ; Afferenzen zu Atemzentren ; Medulla oblongata ; Formatio reticularis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    ISSN: 1432-1106
    Schlagwort(e): Emotional behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex in vitro ; Chloride transport ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex in vitro ; Edema ; Fluid compartmentation ; Chloride transport ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    ISSN: 1432-1912
    Schlagwort(e): Strophanthidine Derivatives ; Toxicity ; Absorption ; Guinea-Pig ; Cat ; Strophanthidinderivate ; Toxicität ; Resorption ; Meerschweinchen ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 101 (1969), S. 607-620 
    ISSN: 1432-0878
    Schlagwort(e): Glandula bulbourethralis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: 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).
    Notizen: 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.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 127 (1968), S. 221-231 
    ISSN: 1432-0568
    Schlagwort(e): Marginal glia ; Superficial nerve cells ; Brain stem ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An Paraffinschnitten durch perfusionsfixierte Gehirne von erwachsenen Katzen werden in der Glia marginalis des Hirnstamms unterschiedlich gebaute Bezirke beschrieben. Es wird gezeigt, daß über dem Nucleus paragigantocellularis und über dem Ncl. “z” swischen den Fasern der Glia marginalis Nervenzellen liegen. Über dem erstgenannten Kern stellen diese Zellen möglicherweise das morphologische Substrat der chemosensiblen Felder dar, die durch die physiologischen Untersuchungen von Loeschcke, Mitchell u.a. bekannt geworden sind.
    Notizen: Summary In the marginal glia covering the brain stem of the cat, regional differences are described in paraffin sections of brains which had been fixed by perfusion of Bouin's fluid. It is shown that between the glia fibres covering the nucleus paragigantocellularis and the nucleus “z” there are nerve cells. It is suggested that in the region of the nucleus paragiganto-cellularis these cells are the morphological substrate of a chemosensible zone described in physiological experiments by Loeschcke, Mitchell and others.
    Materialart: Digitale Medien
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 127 (1968), S. 138-144 
    ISSN: 1432-0568
    Schlagwort(e): Capillary density ; Postnatal development ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An Paraffinschnitten durch das Corpus callosum perfusionsfixierter Gehirne von 19 Katzen im Alter von einem Tag bis zu 2 1/2 Jahren wurde das Capillarvolumen bestimmt. Es beträgt bei der neugeborenen Katze 0,81 Vol.-%. In der 2. Lebenswoche beginnt eine Zunahme, die in der 5. Woche ein Maximum von 2,92 Vol.-% erreicht. Im Verlauf der 6. Woche setzt eine zunächst rasche, von der 7. Woche an aber nur noch langsam verlaufende Abnahme ein, bis bei einem Lebensalter von etwa 1 Jahr ein für das erwachsene Tier charakteristischer Wert um 1,5 Vol.-% erreicht wird. Die Abnahme des Capillarvolumens hängt mit der Markscheidenbildung und der dadurch bedingten Zunahme des Fasermaterials zusammen.
    Notizen: Summary Postnatal changes of capillary density have been determined in paraffin sections through the corpus callosum of 19 cats. At birth the capillary density amounts to 0.81 vol.-%. In the 2nd week of postnatal life it begins to increase and reaches a maximum of 2.92 vol.-% in the 5th week. From the 6th week onwards there is an initially steep and later on less pronounced decrease until at an age of about 1 year a value of about 1.5 vol.-% is reached, which is maintained in adult life. — The decrease in the percentage of capillary volume seen after the 5th week is caused by the rapid increase in fibrous material due to myelination.
    Materialart: Digitale Medien
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  • 70
    ISSN: 1432-0533
    Schlagwort(e): Alumina Cream ; Intracerebral Injection ; Pathology of Growing Brain ; Myelination ; Demyelination ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zum Studium der Reaktion des jugendlichen und erwachsenen Gehirnes auf einen chronischen Reiz wurden bei Katzen verschiedenen Lebensalters intracerebrale Injektionen von Aluminiumhydroxyd vorgenommen. Die Tiere wurden nach Überlebenszeiten von 7 Tagen, 40 Tagen und 3 Monaten durch Perfusion mit Bouinscher Lösung getötet. Die histologische Untersuchung der Gehirne ergab eine Reihe von Unterschieden, je nachdem ob die Injektion vor oder nach der Markscheidenbildung erfolgt war. Besonders auffällig war der Befund, daß in der noch unmyelinisierten weißen Substanz jugendlicher Tiere kein Hirnödem und keine Gliose auftritt. Obgleich durch fluorescenzmikroskopische Untersuchungen gezeigt werden konnte, daß das Aluminium von der Injektionsstelle aus weit in das umgebende Hirngewebe eindringt und dort über lange Zeit festgehalten wird, werden bei den jungen Tieren die Markscheiden später bis in die unmittelbare Umgebung des Herdes normal angelegt. Bei erwachsenen Tieren kam es dagegen in der Nachbarschaft des Herdes stets zu einem starkem Ödem der weißen Substanz, zum Zerfall der Markscheiden und zu einer ausgebreiteten Gliose. Weitere Unterschiede in der Reaktionsweise des Gehirnes jugendlicher und erwachsener Tiere, die den Cortex und insbesondere die marginale Gliafaserschicht betreffen, werden im einzelnen beschrieben und diskutiert.
    Notizen: Summary In order to compare the reaction to chronic irritation of young and adult brain intracerebral injections of alumina cream were made in cats of various ages. The animals were killed by perfusion with Bouin's fluid after a survival time of 7 days, 40 days, and 3 months. Histological investigation revealed gross differences in the reaction according to whether the intracerebral injections had been made before or after myelination. Particularly striking was the finding that in the non-myelinated white matter of young animals there was no edema and no subsequent gliosis. Although alumina, as evidenced by fluorescence microscopy after staining with Morin, spreads into the tissue surrounding the focus, subsequent myelination appeared to be normal even in regions close to the site of injection. In contrast, injection into the brains of adult animals was followed by edema, widespread demyelination and gliosis of the white matter near the site of injection. Further differences between young and adult animals were found in the reaction of the grey matter and particularly of the marginal glia.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 5 (1968), S. 326-340 
    ISSN: 1432-1106
    Schlagwort(e): Subcellular fractionation ; Parallel fiber axons ; Cerebellum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fractionation of the cat cerebellum has revealed that the parallel fibers of the cerebellar cortex break into two types of fragments which can be recognized in thin sections and in suspensions of negatively stained material. Fragmented material correlates well with electron micrographs of parallel fibers in situ. Parallel fiber axons and their bulbous presynaptic expansions sediment mainly into two subfractions. One unique layer consists of the intersynaptic tubular pieces of parallel fiber axons. Another layer is enriched in the synaptic portions which make contact with Purkinje spines. The possible contaminants of these fractions are discussed. These fractions may permit analysis of the chemical organization of conducting vis à vis synaptic membranes from a known anatomical source. This material was presented as a preliminary report at the Sixth Annual Meeting of the American Society for Cell Biology, November 1966, and is contained in J. Cell. Biol. 31, 52A, 1966.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 6 (1968), S. 234-246 
    ISSN: 1432-1106
    Schlagwort(e): Tactile discrimination ; Dorsal column-medial lemniscus ; Spino-cervico-thalamic tract ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The role of two spinal sensory pathways, the dorsal column (DC) pathway and the spino-cervico-thalamic tract (SCTT), involved in tactile discrimination was studied. Pour lesion groups of cats (DC lesion, SCTT lesion, combined DC and SCTT lesion, and sham-operated) were tested to discriminate various degrees of roughness. Animals with either the SCTT or the combined lesions performed at around 50–60% level under all the conditions tested. On the other hand, those with the DC lesion and sham-operations generally attained 80–100% level of performance. A difference between the DC group and sham-operated group was found in their rate of learning and ability for finer discrimination. These results are interpreted as an indication that a duplicity in transmission of tactile sensation exists, the DC pathway being more specific than the SCTT.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 5 (1968), S. 55-60 
    ISSN: 1432-1106
    Schlagwort(e): EEG frequency ; Regional cortical blood flow ; Isotope measurements ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The EEG frequency content in cats, anaesthetized by Nembutal and artificially ventilated, was altered by means of injections of either additional Nembutal or of Metrazol. The EEG in cerveau isolé preparations was also changed in the same way. The regional cortical blood flow was determined by means of the 85Krypton technique. A high correlation was found between the frequency content of the EEG, measured by means of manual frequency analysis, and the regional cortical blood flow. The cortical blood flow increased when the mean frequency increased, and vice versa. A similar correlation was found when the EEG mean frequency was changed by means of sensory stimulation.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 5 (1968), S. 61-71 
    ISSN: 1432-1106
    Schlagwort(e): EEG frequency ; Regional cortical blood flow ; Isotope measurements ; Effects of hypoxia ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The relationship between cortical blood flow and the frequency content of the EEG was studied in a circumscribed area of the exposed cerebral cortex in cats under nitrous oxide-oxygen anaesthesia. Autoregulation of the cortical blood flow was also tested during step-changes of the arterial blood pressure. Observations were made before and after an episode of severe hypoxia. 2. An episode of systemic hypoxia disrupted the normal high correlation between cortical blood flow and EEG frequency content. In the post-hypoxic period cortical flows of up to about three times normal values were recorded together with brain swelling and a slow wave EEG. The hyperemia and swelling subsided during 1–2 h after the hypoxic episode, and were accompanied by partial or complete recovery of the EEG. In the post-hypoxic period a defective autoregulation of the cortical blood flow to changes in the systemic blood pressure was demonstrated. 3. The cerebral post-hypoxic state with hyperaemia, brain swelling, EEG depression, and loss of autoregulation of blood flow, is probably caused by an accumulation of anaerobic metabolites which lead to cerebral tissue acidosis.
    Materialart: Digitale Medien
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  • 75
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex ; Thalamus ; Cat ; Nauta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The corticothalamic projections from the gyrus proreus and the medial wall of the rostral hemisphere have been studied in the cat with the silver method of Nauta. The gyrus proreus projects upon the following nuclei (for abbreviations, see list on page 133), ipsilateral R, VA, VM, VL, MD, Pc, CL, CM, Pf, VPM, VPMpc. VPI and to the contralateral principal nucleus of the trigeminal nerve. The medial wall of the rostral hemisphere projects bilaterally upon R, VA, VM, VL, MD, Pc, CL, CM, Pf, VPM, VPMpc, VPI, VPL, the dorsal column nuclei and the principal nucleus of the trigeminal nerve. The ipsilateral thalamic projection is more abundant than the contralateral. The latter appears to increase in amount as the lesion is placed successively more ventrally on the medial wall of the rostral hemisphere. Some degenerating fibers cross in the corpus callosum and descend in the contralateral internal capsule but the majority cross in the dorsal part of the anterior commissure and reach the medial aspect of the anterior limb of the contralateral internal capsule. A somatotopical organization of the medial wall of the rostral hemisphere has been demonstrated. The rostrocaudal part projects upon the ipsilateral VPL lateralis (VPLl) and nucleus cuneatus and the contralateral nucleus gracilis and VPL medialis (VPLm). The caudal part of this cortical area sends fibers bilaterally to VPM, VPMpc, and the principal nucleus of the trigeminal nerve. The intermediate part, which also includes agranular cortex on the medial wall, projects upon ispsilateral VPLm and nucleus gracilis and upon contralateral VPLl and nucleus cuneatus. — The fibers to the ventro-basal complex, dorsal column nuclei and the principal nucleus of the trigeminal nerve are rather thick. The corticofugal fibers to the other thalamic nuclei are quite thin. — The findings are discussed in light of relevant anatomical and physiological observations in the literature and special emphasis has been laid on reported observations on the “supplementary motor” area.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 5 (1968), S. 153-172 
    ISSN: 1432-1106
    Schlagwort(e): SII ; Thalamus ; Cat ; Somatotopical localization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The corticothalamic projection from the anterior ectosylvian gyrus in the cat has been studied with the silver impregnation method of Nauta. The second somatosensory cortical area (SII) projects upon the ipsilateral nucleus ventralis posterolateralis (VPL), nucleus ventralis posteromedialis (VPM), the posterior thalamic region (PO) and to a slight extent upon the reticular nucleus of the thalamus (R), the centrum medianum (CM), the parvocellular part of VPM (VPMpc) and the nucleus ventralis posterior inferior (VPI). A somatotopical arrangement in the projection upon the ventro-basal (VB) complex has been demonstrated and a topical arrangement in the corticothalamic fibers from SII to PO is also evident. The transitional area between SII and the second auditory cortex sends fibers mainly to the entire magnocellular part of the medial geniculate body (MGmc) and to a lesser degree to the principal division of this nucleus (MGp). The corticofugal fibers from SII follow various and rather complicated circuitous routes before they end in the different thalamic nuclei. The experimental findings are discussed in the light of recent anatomical and physiological observations. It is shown that zones B and C of SII which have been shown by Carreras and Andersson (1963) to possess a large number of place and modality specific neurons project upon the VB-complex. On the other hand, zone A which contains a majority of place and modality unspecific neurons sends its fibers exclusively to PO. Finally the problem of thalamocortical projections to SII is briefly discussed.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 5 (1968), S. 210-234 
    ISSN: 1432-1106
    Schlagwort(e): Sensorimotor cortex ; Pontine nuclei ; Somatotopical localization ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Small lesions (in some cases bilateral) were made in the cerebral primary sensorimotor region in altogether 21 adult cats and the ensuing degeneration in the pontine nuclei was studied with the silver impregnation methods of Nauta and Glees. Using thermocoagulation it was possible to obtain lesions restricted entirely to particular cortical regions (for example the “hindlimb region” in the posterior sigmoid gyrus). The main results are as follows: 1. All parts of the primary sensorimotor region send fibres to the pontine nuclei. The projections from the posterior part of the posterior sigmoid gyrus and the posterior part of the coronal gyrus are relatively scanty. 2. The cortical “motor” area (the anterior sigmoid gyrus and the anterior part of the coronal gyrus) and the “sensory” area (the posterior sigmoid gyrus and the posterior part of the coronal gyrus) do not project to identical pontine regions, although both projections are organized in principally the same way. 3. The “motor” and “sensory” areas both project in a somatotopical manner onto two longitudinally oriented sharply delimited columns. In both projections one column is located medial and one lateral to the longitudinal fibre bundles of the corticospinal and corticobulbar tracts. Within the medial columns the “hindlimb” is represented ventrally with “face” most dorsally, within the lateral columns the “hindlimb” is located most caudally, with “forelimb” and “face” successively more rostrally. 4. The present results are in agreement with physiological observations on the cerebrocerebellar relations, but show that the pontine projection from the primary sensorimotor cortex is organized in a more complex manner than hitherto assumed.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 4 (1968), S. 321-329 
    ISSN: 1432-1106
    Schlagwort(e): Temperature ; Interval histograms ; Optic nerve ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung In 13 Katzen wurde die Aktivität von 128 Einzelfasern des N. opticus bei Temperaturen zwischen 27 und 39° C abgeleitet und direkt einer Intervallanalyse zugeführt. Die Durchschnittsfrequenz sank mit abnehmender Temperatur von 56/sec bei 39–37° C auf 21/sec unter 29° C. Bei Temperaturen über 35° C wurden nur unimodale oder zweigipfelige Verteilungen mit gehäuften Mehrfachentladungen gefunden. Unter 35° C traten multimodale Intervallhistogramme und Übergangstypen auf, bei denen einer Verteilung mehrere Gipfel aufgesetzt erschienen. Unter 29° C wurden nur mehrgipfelige Verteilungen beobachtet. In der phasischen Reaktion der Neurone wurden mit der Temperaturabnahme Latenzen länger und Hemmungen stärker. Unter 30° C konnte der Reaktionstyp des Neurons oft nicht mehr erkannt werden. Das vermehrte Auftreten multimodaler Verteilungen bei niedrigen Temperaturen ließe sich durch Verminderung von Interaktionen in der Retina erklären. Die Anregung zu dieser Untersuchung wurde von Herrn Professor Dr. Hans Bornschein gegeben.
    Notizen: Summary The activity of 128 single fibers of the optic nerve was recorded in 13 cats at temperatures between 27 and 39° C. Nonsequential interval histograms were computed on line. Decreasing temperature diminished the mean frequency of the fiber activity from 56/sec at 37–39° C to 21/sec below 29° C. Above 35° C the histograms were unimodal or bimodal, the first peak caused by repetitive discharges. Below 35° C multimodal histograms appeared; in some distributions several peaks were superimposed. At temperatures below 29° C only multimodal distributions were obtained. The phasic response of the neurons to light showed an increase of latency and of inhibition according to the decrease of temperature. Often the type of the response of the neuron could not be recognized below 30° C. During hypothermia interactions in the retina may be reduced and this may explain why multimodal distributions occur more frequently.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 299 (1968), S. 261-284 
    ISSN: 1432-2013
    Schlagwort(e): Cat ; Electrophysiology ; Single Units ; Bulbar Trigeminal Nuclei ; Katze ; Elektrophysiologie ; Einzelneurone ; Bulbäre Trigeminuskerne
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Funktionelle Eigenschaften der excitatorischen Verbindungen von Cortex, Thalamus und Peripherie zu 438 Neuronen der bulbären Trigeminuskerne wurden untersucht. Es konnten Beziehungen zwischen den Latenzzeiten der Antworten auf ipsilaterale, periphere Einzelreize, contralaterale thalamische Einzel- und Serienreize (N. ventralis posteromedialis) und contralaterale corticale Einzel- und Serienreize (somatosensorisches Projektionsgebiet S I, S II) nachgewiesen werden. 2. Für die Gesamtheit der Neurone wurde mit zunehmender Latenzzeit der Entladung auf periphere Reize eine Zunahme der prozentualen Ansprechbarkeit und der Latenzzeit der Antwort auf zentrale Reize beobachtet. 3. Die Neurone, deren periphere, thalamische und corticale Antworten Reizfrequenzen von 50 Hz und mehr folgten, hatten im Mittel kürzere periphere Latenzzeiten als Neurone, die Reizfrequenzen von 50 Hz nicht folgten. 4. Bulbäre Neurone, die mit thalamischen Reizen antidrom erregt wurden (lemniscale Neurone), unterschieden sich im Mittel von den übrigen Neuronen durch kürzere Latenzzeiten für periphere und zentrale Reize. 5. Es wurden lemniscale Neurone beobachtet, die mit corticalen Reizen monosynaptisch erregt werden konnten. 6. Neurone mit kleinen peripheren rezeptiven Feldern hatten im Mittel kürzere Latenzzeiten auf periphere Reize als Neurone mit großen rezeptiven Feldern. 7. Die periphere Reizantwort von Neuronen konnte durch vorausgehende thalamische und corticale Reize gehemmt werden. Im Mittel wurde die Hemmung bei Neuronen mit Latenzzeiten auf periphere Reize häufiger beobachtet. 8. Mögliche Bahnen, die an der Übertragung thalamo-bulbärer Effekte beteiligt sind, wurden diskutiert und schematisch dargestellt. Die Ergebnisse wurden mit statistischen Methoden geprüft.
    Notizen: Summary 1. Functional properties of excitatory connections from cortex, thalamus and periphery to a total of 438 trigeminal bulbar neurons of the cat have been investigated extracellularly. For the sample considered, correlations between latency of response to ipsilateral electrical single stimuli, contralateral electrical thalamic single and serial stimuli (N. ventralis posteromedialis) and also contralateral electrical cortical single and serial stimuli (somatosensory areas S I, S II) were established. 2. With increasing peripheral latency of response, the percentage of neurons responding to central stimulation increased as well. 3. Neurons following thalamic, cortical or peripheral stimulation frequencies of 50 cps or more showed in the average shorter latencies of response compared with neurons that could not be driven with 50 cps stimulation. 4. Bulbar neurons antidromically invaded by stimulation of the thalamus showed shorter latencies to peripheral, thalamic and cortical stimuli compared with other neurons. 5. Lemniscal neurons that could be activated monosynaptically by cortical stimulation have been observed. 6. Neurons with a small peripheral receptive field had in the average a shorter latency to peripheral stimuli than neurons with a large receptive field. 7. Responses to peripheral stimuli could be inhibited by preceding thalamic and cortical stimuli. 8. Possible pathways that are involved in transmission of thalamo-bulbar effects have been discussed and schematically represented. 9. All results have been examined by means of statistical methods.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 303 (1968), S. 173-180 
    ISSN: 1432-2013
    Schlagwort(e): Hippocampus ; Corpus geniculatum laterale ; Katze ; Mikroelektrophorese ; Acetylcholin ; Hippocampus ; Lateral Geniculate Body ; Cat ; Microelectrophoresis ; Acetylcholine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary 1. Hippocampal and lateral geniculate neurones in anaesthetized cats (Chloralose-Urethane) were examined with multibarrelled microelectrodes, testing their responsiveness to microelectrophoretic application of acetylcholine and photic stimulation. 2. In the ventral hippocampus and in the lateral geniculate body 60% of all neurones responded to acetylcholine. 3. Hippocampal neurones were activated with relatively short delay, often less than 1 sec. By contrast, lateral geniculate neurones responded with a latency period of 2–12 sec. The recovery time after acetylcholine-microelectrophoresis was found to be 10–20 sec in both regions. 4. The response of hippocampal and lateral geniculate neurones to photic stimulation was enhanced by local application of acetylcholine; even during phenobarbital depression the photic responses were restored by acetylcholinemicroelectrophoresis.
    Notizen: Zusammenfassung 1. Neurone im Gebiet des Hippocampus und des Corpus geniculatum laterale der mit Chloralose-Urethan narkotisierten Katze wurden mit mehrkanüligen Mikroelektroden auf ihre Ansprechbarkeit auf mikroelektrophoretisch appliziertes Acetylcholin und auf optische Reizung untersucht. 2. Im ventralen Hippocampus und im Corpus geniculatum laterale wurden 60% aller untersuchten Neurone durch Acetylcholin aktiviert. 3. Die Neurone des Hippocampus wurden nach relative kurzer Latenz, oft weniger als 1 sec, aktiviert. Neurone des Corpus geniculatum laterale dagegen zeigten eine Latenz von 2–12 sec. Die Zeit nach der Mikroelektrophorese bis zur Wiedererreichung der normalen Aktivität betrug 10–20 sec für beide Gebiete. 4. Die Acetylcholin-Mikroelektrophorese verstärkte die Reizantwort der Neurone des Hippocampus und des Corpus geniculatum laterale auf visuelle Reizung. Die nach Phenobarbital abgeschwächte Antwort auf visuelle Reizung wurde durch Acetylcholin-Mikroelektrophorese wieder verstärkt.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    European archives of psychiatry and clinical neuroscience 211 (1968), S. 43-62 
    ISSN: 1433-8491
    Schlagwort(e): Neuronal activity ; EEG-cortex ; Hypoglycemia ; Cat ; Neuronale Aktivität ; EEG-Cortex ; Hypoglykämie ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. An Katzen wurden EEG-Veränderungen durch Hypoglykämie hervorgerufen und mit den Aktivitätsveränderungen corticaler Neurone verglichen, wie sie sich bei intracellulären und „quasi-intracellulären“ Ableitungen darstellen. Es zeigte sich, daß pathologische EEG-Veränderungen erst bei niedrigen Blutzuckerwerten (zwischen 30 und 25 mg-%) auftreten und daß es erst bei Werten unter 10–15 mg-% zur elektrischen Stille kommt. 2. Während des flachen, desynchronisierten EEG des wachen Hirns vor Hypoglykämie lassen sich keine Beziehungen zwischen den kleinen EEG- und statistisch verteilten Zellpotentialen nachweisen. — Während der regelmäßigen 8–10/sec- Spindelgruppen, die bei tiefer Hypoglykämie häufig zu beobachten sind, findet sich eine enge Korrelation zwischen den einzelnen Oberflächen-negativen Spindelwellen und Zelldepolarisationen, die meist unterschwellig sind. 3. Bei den langsamen Wellen der δ-Frequenz finden sich ähnliche, aber weniger enge Korrelationen für die flachen, „monomorphen“ δ-Wellen. Andere Formen von langsamen Potentialkomplexen des Cortiocogramms, die im Tintenschreiber als „polymorphe“ δ-Wellen imponieren können, zeigen etwas andere, aber für den einzelnen Wellenkomplex jeweils konstante Beziehungen zur Zellaktivität. 4. Die steilen Wellen wurden unterteilt in primär positive und in primär negative bi- (oder auch tri-)phasische Potentiale. Die primäre Phase der primär-positiven steilen Potentiale ist im Durchschnitt kürzer (unter 20–40 msec) als die negative Phase der primär-negativen Phase (über 100 msec). Die meist überschwellige Zelldepolarisation, die in der Regel zu einer kurzen Gruppenentladung führt, fällt mit der primären Phase, also entweder der positiven oder der negativen zusammen. Die Phasenkoppelung, d. h. die „Synchronisation“ mit dem EEG-Potential, ist jedoch im Fall der primär-positiven Phase enger und die Dauer der Depolarisation kürzer als im Fall der primär-negativen steilen Potentiale. Diese Befunde werden als Hinweis auf eine stärkere Synchronisation der Aktivität der corticalen Nervenzellpopulation im Fall der primär-positiven steilen Potentiale gewertet. 5. Die verschieden engen Phasenkoppelungen und die je nach Steilheit der Wellen wechselnden Phasenbeziehungen zwischen Zellaktivierung und oberflächennegativen resp. -positiven Potentialen werden an Hand eines einfachen Modells der Elektrogenese von EEG-Potentialen erklärt, das den Synchronisationsgrad cortico-petaler und cortico-fugaler Faseraktivität sowie die Summation postsynaptischer Potentiale corticaler Neurone berücksichtigt.
    Notizen: Summary 1. The EEG, recorded monopolarly from the pial surface, was investigated during insuline induced hypoglycemia in acute cats and compared with the activity of cortical cells recorded with intra or “quasi-intracellular” electrodes. 2. Pathological changes of the EEG were observed only when the blood glucose fell below 25–30 mg-%. Electrical silence was observed at blood glucose levels below 15–10 mg-%. 3. The essentially flat, “desynchronized” EEG of the awake animal before hypoglycemia did not show any relation between the small, irregular fast EEG- potentials and the statistically distributed cellular potentials. —During the regular 8–10/sec spindles (Fig. 3) a close correlation was found between the single surface- negative spindle waves and the mostly subthreshold compound cellular EPSP's. 4. Slow waves of δ-frequency showed similar but less close correlations, if the waves were of regular appearance comparable to “monomorphic” δ-waves (Fig.4A). Other forms of slow complex potentials (Fig.4B and C), which correspond to “polymorphic” δ-waves in an EEG-record (e.g. Fig.4C and Fig.2d) may show different relations between cellular and EEG-activity which were, however, consistent for each type of complex wave. 5. Sharp waves were divided into primary positive and primary negative bi- (or tri-)phasic potentials. The primary positive phase was always shorter (below 20–40 msec) than the primary negative phase (above 100 msec). The mostly suprathreshold cellular depolarization, which may lead to a short burst of discharge, coincided with the primary, i.e. either the primary positive or the primary negative phase (Fig. 7 shows records from the same cell and different EEG-phenomena). The phase coupling, i.e. the “synchronization” with the EEG-potential, is closer in the primary positive than the primary negative waves, and the duration of the cellular depolarization is also shorter in the former case (compare Fig.7B I–III with 7B IV). This can be interpreted as stronger synchronization of cellular activity during the short primary positive waves. 6. A causal relation between cortical neuronal activity and EEG-potentials is assumed. Differences in the closeness of phase coupling and the changing phase relation between cellular and EEG-activity according to the form and steepness of cortical EEG-potentials are explained by a simple model of electrogenesis of EEG-potentials, which takes in account the degree of synchronization of corticopetal and cortico-fugal fibre activity as well as the summation of postsynaptic potentials of cortical neurones.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    European archives of psychiatry and clinical neuroscience 211 (1968), S. 155-169 
    ISSN: 1433-8491
    Schlagwort(e): Sleep EEG ; Experimental Epilepsy ; Cat ; Schlaf-EEG ; Experimentelle Epilepsie ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Frage der Wacho- der Schlaf-Aktivierung der fokalen Epilepsien wird bei 20 epileptischen Katzen im chronischen Experiment untersucht (Kopeloff-Methode). Die Narben wurden im Nucleus amygdaloideus (Pars basolateralis), Hippocampus dorsalis, Formatio reticularis mesencephali, Isocortex gesetzt. Bei einer Untersuchungsdauer der einzelnen Tiere zwischen 3 und 60 Tagen, wurden insgesamt 442 Std in Polygraphie (EEG, EMG, Augenbewegungen) abgeleitet. Die Tiere zeigten innerhalb der ersten 7 Tage Krampfpotentiale im EEG und die meisten ab der 2. Woche Krampfanfälle. Bei Katzen mit subcorticalen Narben war keine Veränderung der Dauer, der Verteilung und der Organisation der einzelnen Schlafstadien nachweisbar. Die im Ruhe-EEG vorhandenen Paroxysmen wurden während des langsamen Schlafes nicht aktiviert und fokalisiert. Im paradoxen Schlaf waren die Krampfpotentiale völlig desaktiviert, es traten einzelne Spindeln auf. Die Tiere mit Narben im Isocortex zeigten im langsamen Schlaf seltene Paroxysmen. Während der häufigeren kurzen Phasen des paradoxen Schlafes war eine Fokalisierung der Spitzen im Bereich der Läsion nachweisbar, jedoch, keine Aktivierung. Bei allen Tieren war die ausgeprägteste Aktivierung der Krampfbereitschft stets in dem von uns als „Wach mit motorischer Inaktivität“ bezeichnete Phase zu bemerken. Daher wird angenommen, daß dieser Zustand bei der Katze mit dem Einschlafstadium des Menschen vergleichbar ist.
    Notizen: Summary The activation of focal epileptic activities during wakefulness, slow and REM sleep was studied in chronic experiments in 20 epileptic cats (Kopeloff's method). The lesions were produced in the nucleus amygdaloideus (pars basolateralis), hippocampus dorsalis, formatio reticularis mesencephali and in the isocortex. Each animal was observed from between 3 to 60 days and a total of 442 hours of polygraphy (E.E.G., E.M.G, Eye movements) were recorded. Within the first 7 days all animals showed E.E.G paroxysms and most of them showed seizures from the beginning of the second week. In those cats with subcortical lesions there was no change detected in the duration, distribution and organisation of the different sleep phases. The paroxysmal E.E.G activity seen in the wakeful animal were not activated or focalised during slow-wave sleep; in REM sleep the paroxysms disappeared completely, only a few spindles were seen. Animals with lesions in the isocortex rarely showed paroxysms during the slow wave sleep. However, during REM sleep a clear focalisation was seen, although there was no additional activation in the area of the lesion. In all animals the most significant of the paroxysms was seen during a state which we should like to describe as; “Awake without any motor activity”. It is assumed that this state corresponds to the state of falling asleep in man.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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