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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 179 (1988), S. 55-71 
    ISSN: 1432-0568
    Keywords: Human embryo ; Human brain ; Amygdaloid body ; Diencephalon ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twenty-six embryos (6–11 mm) of stage 15 (approximately 33 days) were studied in detail and graphic reconstructions of three of them were prepared. Characteristic features of this stage include closed lens vesicles, presence of nasal pits, and retinal pigment. The neuromeric pattern is still visible. Each cerebral hemisphere is limited by the torus hemisphericus internally and by the di-telencephalic sulcus externally. The medial (diencephalic) eminence of the basal nuclei (previously misinterpreted by others as the lateral) had appeared in stage 14, and the lateral eminence, which is telencephalic, is now distinguishable. The amygdaloid body in stages 14 and 15 is derived from the medial eminence. The hippocampal thickening is identifiable in the dorsomedial part of the cerebral hemisphere. Medial and basal forebrain bundles are developing. The olfactory eminence is visible. Future olfactory bulb and tubercle possess an intermediate layer. The wall of the diencephalon presents five longitudinal zones: epithalamus, dorsal thalamus, ventral thalamus, subthalamus, and hypothalamus. The primordium of the epiphysis cerebri is beginning in the more advanced embryos. The sulcus limitans ends rostrally at the midbrain (M1) and is not continuous with the hypothalamic sulcus. Hence the alar/basal distinction does not arise in the forebrain. In the roof of the midbrain (M2) the mesencephalic evagination already noticed at stage 14 is characteristic. It is suggested that it may function as a temporary circumventricular organ. The precursors of some new tracts are identifiable: habenulo-interpeduncular, medial tectobulbar, and mamillotegmental fibres. Commissures include the supramamillary, that of the superior colliculi, and (in some embryos) the first fibres of the posterior commissure. Nuclei include the habenular, mamillary, and probably subthalamic. The cerebellum, the beginning of which was already noted at stages 13 and 14, consists of (1) a rostral part that arises from the alar plate of the isthmic segment and will form the superior medullary velum and part of the corpus cerebelli; and (2) a caudal part that develops from rhombomere 1. The involvement of the isthmic segment, first elucidated with stage 14, has not been observed in previous reports. All cranial nerves except the olfactory and optic are present in the more advanced embryos.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Taurine ; Immunocytochemistry ; Quantification ; Electron microscopy ; Cerebellum ; Purkinje cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrathin sections of plastic-embedded rat cerebella were incubated with an antiserum against conjugated taurine and subsequently treated with a secondary antibody coupled to colloidal gold. The density of gold particles in various cellular profiles was calculated with the assistance of a computer. In the cerebellar cortex the highest density was found in the somata, dendrites, and dendritic spines of the Purkinje cells, supporting parallel light-microscopical observations in postembedding stained semithin sections from the same tissue blocks. The remaining profiles could be divided into three groups according to their immunolabelling intensity, in descending order: 1) somata and processes of granule and Golgi cells; 2) somata and processes of stellate, basket, and glial cells, and 3) mossy fiber terminals. In a representative experiment, the structures in the first and second groups showed gold particle densities in the range of 19–25%, and 4–11%, respectively, of that in the Purkinje cell somata (values corrected for background) whereas the particle density in the mossy fiber terminals was not significantly above background level. In the cerebellar nuclei, taurine-like immunoreactivity was concentrated in terminals that typically established symmetric or intermediate type contacts with weakly labelled dendrites and cell bodies. These terminals, which shared the ultrastructural features of Purkinje cell terminals, showed an average gold particle density that was about 60% higher than that of the Purkinje somata. For specificity control, ultrathin sections containing a series of different amino acid conjugates were incubated in the same drops of sera as the tissue sections. The highly selective labelling of the taurine conjugate indicated that the distribution of gold particles in the tissue was not confounded by crossreactivity with GABA, glutamate or other common amino acids but adequately reflected the distribution of fixed taurine. For additional control of specificity, the taurine antiserum was applied to the soluble fraction of a rat brain extract separated by thin layer chromatography. In this system the taurine antiserum stained a single spot that comigrated with free taurine. The present results suggest that all cell types and processes in the rat cerebellum (with the exception of the mossy fiber terminals) contain taurine. However, the concentration of taurine appears to vary considerably among the different cell types and may also differ between different parts of the same neuron.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 75 (1988), S. 474-480 
    ISSN: 1432-0533
    Keywords: Lhermitte-Duclos disease ; Cerebellum ; Hamartoma ; Purkinje cell ; Immuno-histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immunocytochemical studies were carried out on two previously reported autopsy cases of Lhermitte-Duclos disease. The unaffected cerebellar cortex adjacent to the lesions served as control. The findings supported the view, previously expressed by one of the authors, of a heterogeneous neuronal structure of the lesion, consisting of at least two cell types. No further light was thrown on the predominant medium-sized cells, believed to represent hypertrophic internal granular neurons. On the other hand the large cells shared a number of features with Purkinje cells. In particular they were recognized by the pan-T-cell antibody anti-Leu-4, were surrounded by axosomatic synapses visualized by the antisynaptic vesicle glycoprotein antibody SV2, and contained both nonphosphorylated and phosphorylated neurofilament epitopes. It is suggested that these cells represent dysplastic Purkinje cells. The lesion therefore appears to be a complex hamartoma rather than a simple hypertrophy of the internal granular neurons.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 72 (1988), S. 450-456 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Inferior olive ; Interposito-olivary pathway ; Brachium conjunctivum ; GABA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Climbing fibres were activated by peripheral nerve stimulation at ‘high’ frequencies (〉3 Hz) for 15–25 s and then at 0.9 Hz for about 1 min. The high frequency activation induced a post-conditioning inhibition, lasting up to about 1 min, of climbing fibre responses recorded from the cerebellar surface. 2. Electrolytic lesions were made in the superior cerebellar peduncle (brachium conjunctivum). After the lesion, the post-conditioning inhibition was completely eliminated. 3. Injections of the GABA-receptor blocker bicuculline methiodide into the inferior olive reversibly blocked the post-conditioning inhibition. 4. The results support the hypothesis proposed by Andersson and Hesslow (1987a), that post-conditioning inhibition is mediated by a GABA-ergic interposito-olivary pathway.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Basilar pontine nuclei ; Dorsal column nuclei ; Cerebellum ; Convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous studies in the rat have demonstrated that corresponding peripheral tactile and somatosensory cortical inputs converge within the granule cell layer of various cerebellar lobules and further that descending corticopontine projections from the forelimb sensory cortex (FLSCx) partially overlap with the projection zones of ascending basilar pontine afferents from nucleus cuneatus (NC). The present study employed anatomical and electrophysiological procedures to determine whether cortical and dorsal column nuclear afferent projections converge on pontine neurons that, in turn, provide mossy fiber input to the granule cell layer of the paramedian lobule (PML), i. e., that portion of the rodent cerebellum shown to receive forelimb peripheral inputs. The combination of the orthograde and retrograde axonal transport of horseradish peroxidase (HRP) conjugated to wheat germ agglutinin (WGA) was used light microscopically to demonstrate that orthogradely labeled projections from injections of the FLSCx and NC converged with ponto-paramedian projection neurons that were retrogradely labeled from injections of the PML. These studies were also repeated in conjunction with ablations of either the FLSCx or NC which resulted in the ultrastructural identification of degenerating, as well as WGA-HRP labeled axonal boutons of these pontine afferent projections thus confirming that such projections actually formed synaptic contacts with the retrogradely labeled pontoparamedian projection neurons. Single unit recording analyses of neurons in the ventromedial region of the basilar pons following combined electrical stimulation of various regions of the sensorimotor cortex and the contralateral body surface indicated that approximately 40% of all cells recorded responded to electrical stimulation of corresponding regions of the cortex and periphery, particularly the FLSCx and the forepaw. Natural cutaneous stimuli applied to the forepaw that also elicited responses in these same groups of basilar pontine neurons and were associated with relatively small receptive fields. Taken together, these observations indicate that the previously observed convergence of peripheral and somatosensory cortical inputs within the granule cell layer of the cerebellar cortex may be at least partially organized at the level of the basilar pons.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 73 (1988), S. 167-180 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Movement control ; Timing ; Movement execution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a previous study (Ivry and Keele, in press), cerebellar patients were found to be impaired on both a motor and a perceptual task which required accurate timing. This report presents case study analyses of seven patients with focal lesions in the cerebellum. The lesions were predominantly in the lateral, hemispheric regions for four of the patients. For the remaining three patients, the lesions were centered near the medial zone of the cerebellum. The clinical evaluation of the patients also was in agreement with the different lesion foci: lateral lesions primarily impaired fine motor coordination, especially apparent in movements with the distal extremities and medial lesions primarily disturbed balance and gait. All of the patients were found to have increased variability in performing rhythmic tapping when tapping with an effector (finger or foot) ipsilateral to the lesion in comparison to their performance with a contralateral effector. Separable estimates of a central timekeeper component and an implementation component were derived from the total variability scores following a model developed by Wing and Kristofferson (1973). This analysis indicated that the poor performance of patients with lateral lesions can be attributed to a deficit in the central timing process. In contrast, patients with medial lesions are able to accurately determine when to make a response, but are unable to implement the response at the desired time. A similar dissociation between the lateral and medial regions has been observed on a time perception task in patients with cerebellar atrophy. It is concluded that the lateral regions of the cerebellum are critical for the accurate functioning of an internal timing system.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 70 (1988), S. 477-484 
    ISSN: 1432-1106
    Keywords: Transplantation ; Cerebellum ; Migration ; Purkinje cells ; Granule cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebellar primordia of different ages (embryonic days of 14 to 20) were transplanted into cerebella of normal syngeneic adult rats (Fischer 344). After 1–12 months (mostly 5–6 months), the host brains were examined by light and electron microscopy. In about 80% of our successful experiments, grafted Purkinje and/or granule cells migrated into the host molecular layer. Some granule cells migrated down along host Bergmann glia, reminiscent of their normal developmental migration route. Other granule cells migrated along astroglial processes that ensheathed capillary walls. Some grafted Purkinje cells were also located ectopically in the host molecular layer. They were identified as graft origins autoradiographically. This migration seemed to be encouraged under conditions where the subjacent host Purkinje cells had been lost. Where the grafted Purkinje cells were located on top of the host molecular layer, their primary dendrites faced vertically downwards into the host molecular layer. However, the position of the apical poles of migrated Purkinje cell bodies in the deeper aspect of the molecular layer varied considerably, suggesting that the orientation of the Purkinje cell dendrites is probably determined by the availability of afferent fibers. Thus, the present study has demonstrated that Purkinje and granule cells can migrate from embryonic cerebellar grafts into the molecular layer of the normal, adult host rat cerebellum.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 72 (1988), S. 417-424 
    ISSN: 1432-1106
    Keywords: 3H-corticosterone ; In vivo autoradiography ; Tree shrew brain ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present investigation deals with in vivo binding of 3H-corticosterone in the brains of tree shrews as visualized by autoradiography. Tree shrews were injected with 3H-corticosterone and brain sections were mounted on slides which were subsequently exposed on tritium sensitive film. The relative labeling of 20 different brain structures was determined densitometrically. The indusium griseum, which demonstrated the highest binding for corticosterone of all brain regions in the autoradiograms, was taken as reference and defined as 100% relative labeling (RL). As in other species, the hippocampal subdivisions of the tree shrew retained high amounts of the steroid (60 to 80% RL). In other parts of the limbic system, medium labeling intensities were observed with approximately 40% RL in the lateral septum. The amygdala was less intensely labeled revealing around 30% RL in the basal accessory, the cortical, central, and the lateral nuclei. Autoradiographic grey values in the ventral striatum and pallidum were comparable to those in the amygdala, but in the islands of Callejae they were approximately as high as in the lateral septum (44% RL). In contrast to previous reports dealing with other species, the tree shrew cerebellum also demonstrated a high binding capacity for corticosterone. The RL was nearly 60% in the cerebellar granular layer. This finding may indicate that the cerebellum also plays a role in mediating the effects of corticosterone in the central nervous system.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1106
    Keywords: Taurine ; GABA ; Colocalization ; Cerebellum ; Purkinje cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distributions of taurine-like and GABA-like immunoreactivities in the rat cerebellum were compared by analysis of consecutive semithin and ultrathin sections, postembedding labeled with the peroxidase-antiperoxidase technique or with an indirect immunogold procedure, respectively. Taurine-like immunoreactivity was selectively enriched in Purkinje cell bodies, dendrites and spines, and boutons in the cerebellar nuclei exhibiting ultrastructural features typical of Purkinje cell terminals. The stellate and basket cell bodies and terminals were very weakly labeled. A computer assisted quantitative assessment of the net immunogold labeling revealed that the mean gold particle density in the Purkinje cell terminals was about 70% higher than that in the Purkinje cell dendrites, and about 14 times higher than that in the stellate/basket cell terminals in the molecular layer. Stellate, basket and Purkinje cell terminals emerged as intensely immunoreactive in adjacent sections processed with an antiserum against conjugated GABA. These findings indicate, contrary to recent electrophysiological data, that GABA is a more likely transmitter candidate than taurine in the stellate cells. The apparent colocalization of GABA and taurine in the terminals of Purkinje cells raises the possibility that these terminals are capable of releasing two different inhibitory amino acids.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1433-0350
    Keywords: Malignant astrocytoma ; Glioblastoma ; Cerebellum ; Children ; Cytofluorometric DNA analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The case of a 1-year-old girl with primary malignant astrocytoma of the cerebellum is presented with special reference to ultramicroscopic study and cytofluorometric DNA analysis. The routine light microscopic study was not pathognomonic because of the immaturity of the composing cells. The glial fibrillary microfilaments characteristic of astroglial cells were confirmed by means of electron microscopy. Cytofluorometrically, the DNA histogram of this case revealed a prominent peak in the 4C region, with considerable dispersion to the 8C region, indicating the polyploidic and heterogeneic pattern of malignant tumors.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 237 (1988), S. 135-138 
    ISSN: 1433-8491
    Keywords: Force control ; Motor disorders ; Hemiparesis ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A method for the continuous registration of rapid isometric force changes was investigated in 24 healthy control persons, 10 hemiparetic patients and 10 cerebellar patients. Though the selection of both patient groups involved comparable deficits with respect to the number of force changes attained, the analysis of the underlying force-velocity patterns revealed considerable differences in the performance of hemiparetic and cerebellar patients. Hemiparetic patients showed gross deficits in both the force increasing and decreasing phases. In contrast to this, most cerebellar patients were able to release force as fast as normal controls, while marked slowness was only found for the force increasing phases.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-0878
    Keywords: Cerebellum ; Energy metabolism ; Neurons ; Glial cells ; Purkinje cells ; Rat, Sprague-Dawley
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Recent reports have revealed that certain neurons do not survive in vitro in the presence of glucose, which is the primary substrate and exclusive source of energy in the brain. But these neurons can survive in the presence of low-molecular-weight agents such as pyruvate, which are supplied by glial cells (Selak et al. 1984). To test whether this result also holds true in vivo, we investigated the distribution of hexokinase, lipoic dehydrogenase, β-hydroxybutyrate dehydrogenase, and glucose-6-phosphate dehydrogenase activities in the developing rat cerebellum. Hexokinase activity was relatively higher in glial cells than in neurons. After postnatal day 8, the activity of hexokinase could hardly be detected in Purkinje cells, whereas it was highest in Bergmann glial cells. Purkinje cells were the only type of neuron with high levels of lipoic dehydrogenase at all ages tested. β-Hydroxybutylate dehydrogenase activity was also high in Purkinje cells, especially in those from young rats. Relatively high glucose-6-phosphate dehydrogenase activity was demonstrated in basket and stellate cells from adult brain. Thus, it appears that, in vivo, certain neurons utilize relatively little glucose, and it is indeed possible that glial cells may supply some substance(s) other than glucose, for example pyruvate, as the primary source of energy.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 145 (1988), S. 141-144 
    ISSN: 1615-6102
    Keywords: Tubulin binding domain ; C-terminal region ; Microtubule-associated proteins ; Tau factors ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 10 (1988), S. 129-151 
    ISSN: 0741-0581
    Keywords: Synapse ; Junction ; Spine ; Synapsin I ; Cerebellum ; Neurotransmission ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Application of rapid freezing, freeze substitution fixation, and freeze fracture techniques to the study of synaptic junctions in the mammalian central nervous system has revealed new aspects of synaptic structure that are consistent with and partially explicate advances in synaptic biochemistry and physiology. In the axoplasm adjacent to the presynaptic active zone, synaptic vesicles are linked to large spectrin-like filamentous proteins by shorter proteins that resemble synapsin I in morphology. This mesh of presynaptic filamentous proteins serves to concentrate synaptic vesicles in the vicinity of the active zone. The affinity with which the vesicles are bound by the mesh is probably modulated by the extent of phosphorylation at specific sites on the constituent filamentous proteins, and changes in the binding affinity result in changes in transmitter release.The structural organization of the postsynaptic density in Purkinje cell dendritic spines consists of very fine strands with adherent, heterogeneous globular proteins. Some of these globular proteins probably correspond to protein kinases and their substrates. The postsynaptic density, positioned at the site of the maximal depolarization caused by synaptic currents, apparently serves as a supporting framework for a variety of proteins, which respond to and transduce postsynaptic depolarization.At least two classes of filamentous protein fill the cytoplasm of spines with a complex mesh, which presumably contributes to maintenance of the spine shape. Membrane bound cisterns are a ubiquitous feature of Purkinje cell dendritic spines. Studies of rapidly frozen tissue with electron probe microanalysis and elemental imaging reveal that these cisterns take up and sequester calcium, which is derived from the extracellular space, and which probably enters the spine as part of the synaptic current.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 10 (1988), S. 229-246 
    ISSN: 0741-0581
    Keywords: Cerebellum ; Cerebral cortex ; Dorsal column nuclei ; Cerebellar nuclei ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Ultrastructural studies are described that have identified in the basilar pontine nuclei (BPN), the synaptic boutons formed by the corticopontine, cerebellopontine, tectopontine, and dorsal column nucleipontine afferent projection systems. In addition, immunocytochemical studies visualized neuronal somata, dendrites, and synaptic boutons that contain immunoreactivity for GABA or the synthesizing enzyme glutamic acid decarboxylase (GAD).Based upon differences in the mode of degeneration and postsynaptic locus of degenerative synaptic boutons in the BPN, it is suggested that two types of cortical neurons and three classes of deep cerebellar nuclear cells project to the BPN. For similar reasons, it appears that two types of neurons in the dorsal column nuclei project to the BPN while only one type of afferent synaptic bouton takes origin from the superior colliculus. Furthermore it appears that the population of BPN neurons projecting to the paramedian lobule receives convergent inputs from the cutaneous periphery and the corresponding region of sensorimotor cortex. Studies employing GAD immunohistochemistry indicate that GABA-ergic neurons and axon terminals are present in the BPN and thus support the suggestion that a local inhibitory interneuron is present within the BPN. Taken together these observations suggest that basilar pontine neurons might play a more active role in the integration of various types of information destined for the cerebellar cortex than has previously been recognized.
    Additional Material: 5 Ill.
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  • 16
    ISSN: 1432-0568
    Keywords: Synaptology ; Cerebellum ; Quantitative analysis ; Autoradiography ; Electron microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a previous study observations in semithin sections of E-PTA-stained cerebellar cortex of the cat revealed differences in size of synaptic grids between the molecular and granular layer (Van der Want et al. 1984). In addition, synaptic size differences were observed between superficial and deep levels in the molecular layer. The present study was an attempt to analyze synapses in ultrathin sections of the cerebellar cortex with special emphasis on size differences of distinct types of synapses at different levels in the molecular layer. Climbing fibers were identified by means of anterograde transport of 3H-leucine injected in the inferior olive and parallel fibers were identified on account of fine structural criteria. Synaptic profiles were measured semi-automatically in the neuropil of the cerebellar cortex at the supra-Purkinje level and the subpial level. Measurements of the trace- and chordlength were obtained from random sections. The frequency distribution of the true diameters of the synapses was reconstructed with a discrete “unfolding”-procedure. The overall diameter at the superficial level was 390.2±1.5 nm, at the deep level 406.6±1.5 nin. Climbing fibers exhibited mean values of 431.9±4.7 and 461.3±4.1 nm at these levels and parallel fiber terminals mean values of 370.7±2.9 and 395.8±3.0 nm. The frequency distributions showed remarkable and statistically significant differences compared with the overall distributions observed at the superficial and the deep levels respectively. The frequency distributions of synaptic diameters at the superficial and deep levels also differ significantly. The results suggest that synapses are characterized by a specific size which might be related to the region of termination or might be determined by the afferent neuron. This is in agreement with earlier observations in E-PTA treated material.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 172 (1985), S. 227-238 
    ISSN: 1432-0568
    Keywords: Cerebral cortex ; Pontine nuclei ; Cerebellum ; HRP-WGA ; Anterograde transport ; Retrograde transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To reveal the organization and relative magnitude of connections from various parts of the cerebral cortex to the cerebellar paramedian lobule via the pontine nuclei, horseradish peroxidase conjugated to wheat germ agglutinin was injected in the paramedian lobule in conjunction with injection of the same tracer in various parts of the cerebral cortex in 14 cats. Termination areas of cortical fibres (anterogradely labelled) and pontine neurons projecting to the paramedian lobule (retrogradely labelled) were carefully plotted in serial sections through the pons. On the average 89% of all labelled cells were found in the pontine nuclei contralateral to the cerebellar injection, 11% in the ipsilateral pontine nuclei. The highest degree of overlap between anterograde and retrograde labelling was found after injections in the posterior sigmoid gyrus (SmI), while less overlap was found after injections of the anterior sigmoid gyrus (MsI). Injections of the second somatosensory area (SmII) and the parietal association cortex (areas 5 and 7) gave moderate degrees of overlap. Very little or no overlap was found after injections of the premotor cortex (area 6), the visual areas 17, 18 and 19 and the auditory cortex (AI and AII). It is concluded that a major cortical input to the paramedian lobule arises in the posterior sigmoid gyrus (SmI), but that additional contributions arise in the anterior sigmoid gyrus (MsI), the parietal areas 5 and 7 and the second somatosensory cortex (SmII). Among the latter regions probably the parietal areas contribute most. Overlap between terminal regions of cortical fibres and cells projecting to the paramedian lobule takes place at numerous discrete sites at virtually all rostrocaudal levels of the pons. Cerebrocortical afferents via the pontine nuclei to the intermediate zone of the posterior lobe are organized according to the same principles as described previously for cortical afferents to the hemispheral parts of the posterior lobe (crus I and II).
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 65 (1985), S. 270-280 
    ISSN: 1432-0533
    Keywords: Motor neurons ; Spinal ganglia ; Thalamus ; Optic nerves ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It is not widely recognized that the pathology of Werdnig-Hoffman disease (WHD) may include cells other than the lower motor neuron. In the early infantile (acute) forms of this degenerative disease, neuropathologic involvement may extend well beyond the lower motor neuron territory to include neurons in spinal sensory ganglion and thalamus. The present report describes the neuropathologic findings of four patients with early infantile degenerative motor neuron disease, compares them to other reported patients, and discusses the relationship of these patients to those with classic WHD. We found involvement of thalamic and primary sensory neurons, although mild, to be a common finding in classic WHD. We suggest that early infantile forms of degenerative lower motor neuron disease which show prominent involvement of thalamic, primary sensory, and other neurons are but one end of the spectrum of WHD.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 67 (1985), S. 167-169 
    ISSN: 1432-0533
    Keywords: Hirano body ; Purkinje cell ; Alzheimer's disease ; Cerebellum ; Senile plaque
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cylindrical forms of Hirano bodies were observed in the perikaryon of a Purkinje cell in a case of Alzheimer's disease. Scattered, typical senile plaques were also seen in the cerebellar cortex.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 67 (1985), S. 254-264 
    ISSN: 1432-0533
    Keywords: Capillary ; Cerebellum ; Endothelial cell ; Hemangioblastoma ; Morphometry ; Pericyte ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron microscopy and computerized morphometric techniques were employed to examine pericyte ultrastructure and to assess quantitatively their relationship to endothelial cells in five cases of cerebellar capillary hemangioblastoma. A total of 97 cross-sectioned capillary profiles were studied. Pericyte coverage of capillary ranged from 30.2% to 97.3% with a mean value of 68.7%, which is higher as compared with the available data from the cerebral cortex, skeletal and cardiac muscle, and pulmonary capillaries. The higher pericyte coverage of capillary suggests that pericyte is an active component of cerebellar capillary hemangioblastoma and may have a close functional relationship to endothelial cells. Pericytes contained bundles of parallel microfilaments along the adluminal side and in the terminal processes, and exhibited an intimate “peg-and-socket” relationship with endothelial cells, suggesting a contractile function of pericytes and their possible role in regulating capillary lumina and focal blood flow. The finding of abundant micropinocytic vesicles along the abluminal side of the cytoplasmic membrane indicates an active metabolic exchange between pericytes and the interstitium. It is possible that in cerebellar hemangioblastoma pericytes may act as a mechanical and metabolic monitor barrier for endothelial cells.
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  • 21
    ISSN: 1432-0568
    Keywords: Cerebellum ; Amygdala ; Parabrachial nucleus ; Locus coeruleus ; Fluorescent latex microspheres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After injections in the cat of Rhodamine labelled latex microspheres in the amygdala and of Fast Blue in the cerebellum neurons labelled with one of these tracers as well as some double labelled neurons were found in the parabrachial nucleus, the nucleus locus coeruleus and some adjacent nuclei (the nucleus subcoeruleus and the pontine tegmental reticular formation). All double labelled cells were located on the ipsilateral side. A few double labelled neurons were also found bilaterally in the dorsal raphe nucleus. It therefore appears that a certain number of cerebellar projecting neurons in these brain stem nuclei by means of divergent axon collaterals also project to the amygdala. The location of the double labelled cells found in this study suggests that at least some of the neurons are catecholaminergic. The findings are related to previous reports on the distribution of catecholaminergic neurons and on the amygdaloid and cerebellar projections from this part of the brain stem, and the possible involvement of these connections in cerebellar non-somatic responses are discussed. Some comments are made concerning the use of fluorescent latex microspheres for double labelling studies in combination with another fluorescent tracer.
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  • 22
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    Anatomy and embryology 171 (1985), S. 325-338 
    ISSN: 1432-0568
    Keywords: Immunohistochemistry ; Transmitter localization ; 5-Hydroxytryptamine ; Serotonin ; Development ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present study we have used the indirect antibody peroxidase anti-peroxidase technique to analyze the development of serotonin in the cerebellum of pouch young opossums ranging in age from birth (postnatal day (PD) 1) — to PD 47. The pathways by which serotoninergic axons enter the cerebellum appear to change during development. Between PD 1 and PD 11 varicose serotoninergic fibers course though the continuity between the tectum and the dorsal medial aspect of the cerebellar plate and distribute primarily to the intermediate zone. By PD 11 serotoninergic fibers enter the cerebellum via a connecting band between the cerebellum and the dorsal lateral aspect of the rostral medulla. Fibers entering the cerebellum via this later route course around the lateral recess of the fourth ventricle and initially distribute to ventral and lateral areas of the cerebellum. At later developmental ages (PD 14–PD 47) serotoninergic fibers are present in: 1) the cellular zone of migration between the Purkinje cell layer and deep nuclei; 2) the Pukinje cell layer; 3) the internal granule cell layer; and 4) the deep cerebellar nuclei. The external granule cell and the molecular layers rarely contain serotoninergic fibers. The present study has shown that serotonin is present in the cerebellar anlage on PD 1 (within 13 days of conception). This is prior to the arrival of other major afferent systems (King et al. 1982; Bishop et al. 1983; Martin et al. 1983; Morgan et al. 1983). Further, serotoninergic axons reach the cerebellum via different routes at different stages of development. The presence of serotonin in the intermediate zone early in development supports the hypothesis that it may influence neuronal migration and differentiation (Lander and Krebs 1976). Axons containing serotonin and arriving later in development may function in synaptic transmission, a role proposed for this indoleamine in the adult (Strahlendorf et al. 1979).
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  • 23
    ISSN: 1432-0533
    Keywords: Neoplasms ; Cerebellar diseases ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sera from patients with paraneoplastic cerebellar degeneration have been shown to contain high titers of antibody to human Purkinje cells. It is not known, however, whether these sera react with cerebellar material from species other than man. The present study was conducted to determine whether cerebellar tissue of nonhuman species could be used to screen human sera for anticerebellar antibodies and whether similarities in cerebellar antigens between nonhuman and human material might permit attempts to transmit cerebellar degeneration to experimental animals by passive transfer of patient sera. Sections of human, monkey, pig, sheep, cat, rabbit, and rat cerebellar tissue were overlaid with serial dilutions of positive sera from patients with cancer and with paraneoplastic cerebellar degeneration and were stained using indirect immunofluorescence methods. All sera stained specific Purkinje cells when reacted with monkey, pig, and rabbit cerebellar sections, but not all sera stained sheep, cat, or rat tissue. Immunofluorescent labeling of animal cerebellar tissue was less bright than that obtained with human cerebellar sections, and anticerebellar antibody titers were invariably lower when assayed with nonhuman than with human material. Although human anticerebellar antibodies react with cerebellar tissue from other animal species, patient-to-patient variation in staining is sufficiently great that not all patient sera might be suitable for passive transfer experiments, and that attempts to identify anticerebellar antibodies by reacting patient sera with nonhuman cerebellar tissue could be negative where these antibodies are in fact present and could be demonstrated using human material.
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  • 24
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    Acta neuropathologica 67 (1985), S. 67-74 
    ISSN: 1432-0533
    Keywords: Mouse ; Phenytoin ; Cerebellum ; Purkinje cell ; Axoplasmic flow ; Endoplasmic reticulum ; Presynaptic area ; Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An animal model of central distal axonopathy following chronic administration of phenytoin is described. Male C57/BL6J mice received diphenylhydantoin (DPH) in the daily diet (liquid diet ‘Stardit’, supplemented with vitamins) over a period of 8 weeks. Control and experimental animals were pair-fed. Twelve mice of both groups were perfused via the left ventricle with glutaraldehyde. Representative samples of the cerebral cortex (area 3), cerebellum (vermis and deep cerebellar nuclei), thalamus, hypothalamus, and liver were embedded in araldite. Semithin sections and electron microscopy of the cerebellar vermis revealed marked dystrophic changes in the Purkinje cell axons. The presynaptic segments of Purkinje cell axons in the deep cerebellar nuclei showed massive enlargement and swelling due to accumulation of spherical particles and tubular structures in the axoplasm. These structures represent a proliferation of the smooth endoplasmic reticulum. Identical changes were found in hepatocytes of treated animals. Because phenytoin induces hepatic microsomal enzymes, we suggest that phenytoin-related Purkinje cell damage may be produced by an induction of Purkinje cell microsomes with proliferation of the smooth endoplasmic reticulum which causes a swelling and enlargement of presynaptic segments of Purkinje cell axons in deep cerebellar nuclei. Chronic phenytoin administration to mice is a new model of phenytoin-induced encephalopathy and of distal axonopathy of cerebellar neurons.
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  • 25
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    Acta neuropathologica 66 (1985), S. 98-104 
    ISSN: 1432-0533
    Keywords: Brain ; Cerebellum ; Infancy ; Rhabdomyosarcoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tumors of the central nervous system (CNS) composed of pure mesenchymal derivatives with both embryonal and mature striated muscle cells devoid of neuroblastic elements should be considered rhabdomyosarcomas. Some 13 cases have been reported, and here we study four additional cases in infancy under 3 years of age which represent 0.82% of 483 intracranial tumors studied by us at the Children's Hospital in the last 12 years. Two cases were localized in the temporal lobes, and two were in the cerebellar vermis. All of them were typical embryonal rhabdomyosarcomas at various stages of differentiation including undifferentiated mesenchymal cells, embryonal cells, and rhabdomyoblasts. Tumor cells achieved a higher degree of differentiation in the cerebellum, as shown by readily detectable immature muscle fibers which were consistently absent in tumors involving the brain. Myoglobin [peroxidase-antiper-oxidase (PAP) techniquel was positive throughout in rhabdomyoblasts and in immature muscle cells, whereas glial fibrillary acidic protein was negative in all four tumors. In spite of the well differentiated appearance of the cerebellar tumors, their behavior was highly malignant with extensive infiltration of brainstem leptomeninges in one case, and all patients survived for only a short time after surgery. These tumors may be observed in the midline structures of the posterior fossa and in the brain, but we suspect their true incidence might be higher if immunohistochemical techniques were applied.
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  • 26
    ISSN: 1432-1106
    Keywords: Outbred rodent strains ; Anatomical abnormalities ; Primary fissure ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A significant variation in the incidence of alterations in the cellular organization along the primary fissure of the cerebellum is observed in outbred Sprague-Dawley rats obtained from Hilltop Animal Labs (89.9%) and Charles River Canada (34.1%). In this abnormality, there are areas in the depths of the primary fissure which lack pial cells, exhibit fusion of the apposing molecular layers, and contain ectopic granule cells, often with an associated disorganization of the cortical laminae. The extent and incidence of the abnormality can vary between individuals and litters, but the general incidence rate for a given breeder appears to be consistent over extended breeding cycles. This finding has serious implications for the use of outbred animals from different breeders when collecting data during the course of an experiment and when comparing and replicating data from different laboratories.
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  • 27
    ISSN: 1432-1106
    Keywords: Basilar pontine nuclei ; Cerebellum ; Pontocerebellar system ; GAD ; GABA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immunocytochemical procedures employing the unlabeled antibody enzyme (PAP) method were used to visualize those neuronal elements in the basilar pontine nuclei (BPN) and nucleus reticularis tegmenti pontis (NRTP) of the rat which contain glutamic acid decarboxylase (GAD), a key enzyme involved in the synthesis of the neurotransmitter gamma-aminobutyric acid (GABA). Neuronal somata, axons, and axon terminals in the BPN and NRTP exhibited GAD-immunoreactivity. Both thick and thin varieties of labeled axons and terminals were distributed in varying densities throughout the BPN and NRTP. The greatest accumulation of labeled terminals was noted in the ventrolateral and lateral border regions of the BPN while a slightly less dense aggregation was observed along the ventral, ventromedial and midline regions of the pontine gray. Labeled fibers and terminals were also observed in the dorsal and ventral peduncular regions as well as central portions of the lateral, ventral, and medial pontine areas. Axonal and terminal labeling was present throughout the NRTP but no focal increases in density similar to those in the BPN were apparent. No obvious GAD-labeled fiber bundles could be observed to enter the BPN or NRTP. However, small fascicles of labeled axons were seen to course ventrally around the dorsolateral aspect of the cerebral peduncle to reach lateral pontine areas while other labeled axons descended through clefts in the mid-portion of the cerebral peduncle or passed through the medial lemniscus and around the medial portion of the cerebral peduncle to enter the pontine gray. The number of GAD-positive neuronal somata in the BPN and NRTP is quite sparse in comparison to that of neighboring brainstem regions such as the ventral nucleus of the lateral lemniscus and the pontine reticular formation. The majority of labeled neuronal somata were less than 20 μm in diameter although some, particularly in NRTP, were as large as 28 μm. A variety of morphologies was represented in the population of labeled somata ranging from spheroidal to spindle-shaped or polygonal. GAD labeled somata were distributed throughout the BPN and NRTP but were most numerous in the rostral medial pontine region and the lateral, ventral, and medial border areas of the BPN, adjacent to the fibers of the brachium pontis. From these observations it is proposed that the population of GAD positive cells in the BPN and NRTP gives rise to at least a portion of the labeled axon terminals while other GABA-ergic neurons extrinsic to the pontine gray serve as a source of the remainder of the labeled axons and terminals.
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  • 28
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    Experimental brain research 57 (1985), S. 279-285 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Development ; Methylazoxymethanol ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Methylazoxymethanol (MAM), a powerful antimitotic, has been extensively used to affect rodent CNS development. Here we show that MAM causes different effects on mouse cerebellum depending on the age of the injected pup. Sublethal doses were determined for each age. A single injection at birth permanently reduces the number of cells. In addition, the cytoarchitecture was greatly perturbed: Purkinje cells retained an immature aspect and were dispersed through the cerebellar cortex. A single dose of MAM injected into 5 day old mice also affected the number of cells but, at the level of light microscopy, the cytoarchitecture of the cerebellar cortex appeared not to be altered. Purkinje cells, however, showed some immaturity and degenerated around the 22nd postnatal day. This modulation of MAM effect appears to provide a good model for studying cerebellar ontogeny and neuronal plasticity.
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  • 29
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    Experimental brain research 61 (1985), S. 73-86 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Climbing fiber responses ; Olivocerebellar projection ; Somatotopic organization ; Receptive fields
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine grain organization of the climbing fiber (CF) representation for the intermediate cortex of lobules III, IV, and Va was examined. Data were obtained from cats anesthetized with sodium pentobarbital. Through extracellular recording techniques, CF responses were identified in 814 Purkinje cells; 74% were elicited by mechanical stimulation of various body surfaces. Of the CF responses elicited by stimulation, 60% involved the ipsilateral hindlimb, 36% represented parts of the forelimb, and only 4% represented areas of the face, tail, or abdomen. Hindlimb representation predominated in lobules III and IV, and forelimb representation was mainly confined to lobule Va. No distinct parasagittal zones that involved all three lobules were identified. In general, the organization for most sublobules could be best described as a mixture of patches of forelimb or hindlimb representations. Within the patches there was considerable diversity of receptive field types, particularly for the extremities. The receptive fields involving the distal phalanges were generally smaller than those for the proximal areas, but a range in field sizes was evident for both distal and proximal regions. More than half of either the forelimb or the hindlimb representation was limited to the distal paw areas; the two middle toes received the most frequent representation. Representations of the proximal limb areas were generally centered around either the wrist or the heel, or around the elbow or knee, but many of these receptive fields also extended to the phalanges. The multiple representation of various areas of forelimb and hindlimb throughout the rostral intermediate cortex was consistent with the type of organization that had been identified in other regions of the anterior lobe, although each cortical area contained a unique proportional CF representation of various body areas.
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  • 30
    ISSN: 1432-1106
    Keywords: Cerebellum ; Inferior olive ; Climbing fibres ; WGA-HRP ; Sagittal zones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The climbing fibres to the x and lateral c1 zones of the anterior lobe of the cerebellum arise as branches of common stem olivary axons. Anatomical studies have shown that the c1 zone receives its climbing fibres from the dorsal accessory olive (DAO). It has, therefore, been assumed that the x-zone also receives its climbing fibres from this olivary subnucleus. The present study demonstrates that both the x-zone and the lateral part of the c1 zone in fact receive their climbing fibre input from the middle portion of the medial accessory olive (MAO) (approximate antero-postero-levels P10-13). Electrophysiological techniques were used to define the extent of these cerebellar zones and small volumes (15–50 nl) of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) were pressure injected into the defined zone. These small pressure injections resulted in injection sites with minimal spread to adjacent zones. The sensitive tetramethylbenzidine (TMB) reaction was used to visualize both the injection site and retrogradely labelled cells in the inferior olive. This combination of electrophysiological and neuroanatomical techniques gave extremely reproducible results. The results suggest that the zone previously named lateral c1 would be better designated cx.
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  • 31
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    Experimental brain research 61 (1985), S. 186-193 
    ISSN: 1432-1106
    Keywords: Plasma membrane ; Intramembrane particles ; Cerebellum ; Purkinje cells ; Dendritic spines ; Trophic factors ; Axonal transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Destruction of the inferior olivary nucleus in the rat by thermocoagulation results in the degeneration of climbing fibers in the cerebellar cortex. Under these conditions the plasma membrane of Purkinje cells was selectively affected at the level of the spines on large dendrites (LD spines), the postsynaptic targets for climbing fibers. The number of small (〈 10 nm) non-junctional intramembrane particles (IMP) was significantly decreased in E-faces during the first 3 days following the lesion (47% of control IMP values). Later, the number of IMPs progressively recovered to reach 67% of the control IMP values 1 month following the lesion. IMP numbers in the P-face and in the postsynaptic junctional aggregates of the E-face were unaffected by destruction of climbing fibers. Following injection of colchicine into the inferior olivary nucleus, a treatment that inhibits axonal transport in climbing fibers, a selective decrease in IMP numbers on the E-faces of LD spines was also found. The maximal decrease was found during the first 10 days after injection (48% of control values), and then the number of IMPs gradually increased to reach control values by 90 days post-injection. In the case of colchicine treatment also, the reduction in the number of IMPs affected selectively a class of non-junctional small IMPs, less than 10 nm in diameter. These data show that there is a similar selective modification in the membrane structure of Purkinje cells, not only following destruction of climbing fibers by thermocoagulation, but also following inhibition of axonal flow in climbing fibers by colchicine injection. The results are consistent with the hypothesis that Purkinje cell membrane structure is modulated by the presence of a trophic factor(s) associated with climbing fibers.
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  • 32
    ISSN: 1432-1106
    Keywords: Auditory cortices ; Paraflocculus ; Cerebellum ; Corticocerebellar pathways
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study investigated afferent projections to the cerebellum, in particular those from the auditory cerebral cortex. The parafloccular lobule of the rat cerebellum is shown to be a primary target for the auditory cortical information with the midvermal region being a receiving area from the inferior colliculus. The method of anterograde transport of tritiated amino acids was employed to determine projections of the auditory cortex to the pons. Autoradiography showed that the site of termination of efferents from the auditory cortex corresponds to the location of neurons that project to the paraflocculus. Histogram analysis of neuronal activity in halothane anesthetized rats was employed to determine the response characteristics of neurons in paraflocculus and midvermis following cortical and tectal electrical stimulation. In addition, unit recordings of parafloccular neurons in immobilized, locally anesthetized animals demonstrated general characteristics of the responses of these neurons to auditory field stimulation. Electrical stimulation of the auditory cortex evoked mixed, excitatory-inhibitory and pure inhibitory mossy fiber responses in 33% of neurons in the paraflocculus, with no responses evident in the midvermis. Following inferior collicular stimulation, 12.6% of the neurons in the midvermis elicited a response. Recordings from parafloccular neurons in unanesthetized, immobilized rats showed evidence for excitatory and inhibitory mossy fiber responses, following auditory field stimulation. This spectrum of basic studies establishes the existence of a pathway in which the paraflocculus is revealed as an integrating target for cortical auditory information.
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  • 33
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    Experimental brain research 57 (1985), S. 456-463 
    ISSN: 1432-1106
    Keywords: Purkinje cell ; Climbing fibres ; Inferior olive ; Cerebellum ; Anaesthesia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous experiments performed in rats under barbiturate anaesthesia have shown a remarkable increase of simple spike firing rate in cerebellar Purkinje cells following inferior olive lesion or inactivation. The increase is due, at least in part, to the withdrawal of the tonic background activity of corticocerebellar interneurones, which have GABA as a chemical transmitter. Since barbiturates potentiate GABAergic inhibition, it is possible that the effect is due to the presence of this type of anaesthesia. In absence of general anaesthesia, we have compared the simple spike firing rate of the Purkinje cells in rats with intact inferior olive and 3–5 days after inferior olive lesion by 3-acetylpyridine. In the latter condition, the firing rate is significantly higher. In other rats, under urethane anaesthesia, which is not known to interfere with GABAergic transmission, the inferior olive has been reversibly inactivated by applying a cooling probe to the ventral surface of the medulla. Following cooling of the inferior olive on one side, a remarkable increase of simple spike activity, parallel to the disappearance of complex spike activity, has been observed in the Purkinje cells of the contralateral side. These results show that the presence of the simple spike firing increase, which follows the removal of the climbing fibre activity, does not depend on an anaesthetic which potentiates GABAergic transmission, although its amplitude is affected by the same anaesthetic. They suggest, therefore, that the tonic inhibition exerted by the olivocerebellar pathway on the Purkinje cells operates also in physiological conditions. By analysing the pattern of discharge of the Purkinje cell simple spikes in intact rats and following suppression of inferior olive activity, we have seen that, in the latter condition, the highest firing rate is accompanied by a higher degree of regularity. This change of pattern does not depend significantly on the removal of an irregularity induced by the complex spikes, but it is mainly the consequence of the firing rate increase.
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  • 34
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    Experimental brain research 60 (1985), S. 127-135 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Fastigial nucleus ; Muscular stimulation ; Unitary activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In lightly barbiturized cats, the discharges of neurons in the cerebellar fastigial nucleus (CBM) were recorded while single muscles in ipsilateral forelimb were activated by direct stimulation. The aim was a) to verify whether CBM cells could selectively detect the activity of afferent fibers from a muscle or a joint and b) to compare the various response characteristics of the rostral and the caudal division of the nucleus, which are known to control a different muscular periphery. Six muscles were routinely tested, two axial, two proximal and two distal ones. A good percentage of neurons in both partitions of the nucleus responded to the muscles tested (53% and 48% in the rostral and caudal part, respectively). In the rostral part of CBM a large proportion of cells (78% of those responsive) were influenced by one or more muscles having either the same function (the extensors or flexors) or acting on the same joint. Many such neurons showed a marked capability to respond to activation of distal muscles and a prevalence of inhibitory responses mainly on contraction of extensor and axial muscles. In the caudal division of the nucleus, 47% of the responsive cells displayed a stereotyped discharge pattern (excitatory or inhibitory) in response to activation of any tested muscle. In contrast to the rostral CBM the incidence of responses to proximal and distal muscles was about equal in the caudal CBM and a majority of neurons had excitatory responses to flexor muscle contraction. The latencies of the excitatory effects ranged from 8 to 53 ms in rostral and 9 up to 69 ms in caudal CBM. Inhibitory responses were seen at latencies between 9–78 ms in rostral and 9–80 ms in the caudal parts of the nucleus, the distribution in the latter being bimodal. The high specificity of the responses observed in rostral CBM to the activation of ipsilateral forelimb muscles is consistent with the suggestion that the nuclear output influences the same peripheral area. The conspicuous number of neurons with inhibitory responses detected on contractions of axial and extensor muscles could possibly be due to an inhibitory feedback from the peripheral muscles to the rostral CBM division. With regards to the caudal part of the nucleus, which is known to facilitate contralateral extensor muscles, the excitatory effects seen on ipsilateral flexor muscle activation could support a mechanism of postural balance.
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  • 35
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    Experimental brain research 60 (1985), S. 114-126 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Lobule HVI ; Corticonu-clear projection ; Precerebellar nuclei ; Horseradish peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the connections of cerebellar cortical lobule HVI in the rabbit. We have studied the anterograde and retrograde transport of wheatgerm-agglutinated horseradish peroxidase (WGA-HRP) following its injection into HVI to reveal efferent and afferent connections. All of the cases showed strong anterograde transport to the anterior interpositus nucleus (AIP) — indicating that this is the major efferent target of HVI. Retrogradely labelled cells were found in the inferior olivary, spinal trigeminal, lateral reticular, inferior vestibular and pontine nuclei. Within the olive, the medial part of the rostral dorsal accessory olive (DAO) and the adjacent medial part of the principal olive (PO) were consistently labelled in all cases. This area is known to receive somatosensory information from the face and neck. There was no projection to the hemispheral part of lobule VI from visual parts of the olive within the dorsal cap and medial parts of the medial accessory olive. Likely sources of visual and auditory information to HVI are the dorsolateral basilar pontine nuclei and nucleus reticularis tegmenti pontis, which were densely labelled in all cases. These anatomical findings are consistent whith the suggestion that, during NMR conditioning, information related to the periorbital shock unconditional stimulus (US) may be provided by climbing fibres to HVI and light and white noise conditional stimulus (CS) information may be supplied by pontine mossy fibres.
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  • 36
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    Experimental brain research 60 (1985), S. 87-98 
    ISSN: 1432-1106
    Keywords: Nictitating membrane response ; Classical conditioning ; Cerebellum ; Interpositus nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The classically conditioned nictitating membrane response (NMR) of the rabbit, a simple form of associative motor learning, is crucially dependent upon the cerebellum. Discrete unilateral lesions of the cerebellar nuclei were made in 20 rabbits. Lesions of the anterior interpositus nucleus (IA) abolished NMR conditioning to light and white noise stimuli on the side of the lesion without affecting unconditional responses. Lesions of the posterior interpositus nucleus, fastigial and dentate nuclei were without effect upon NMR conditioning.
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  • 37
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    Neuroradiology 27 (1985), S. 390-398 
    ISSN: 1432-1920
    Keywords: Cerebellum ; anatomy ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The salient features of the normal CT anatomy of the various lobules of the cerebellar hemispheres and vermis are described. The subdivisions of the vermis were found to be most constant. The surface appearance of the hemisphere lobules was also relatively constant; however, at CT these fissures are imaged at depth and this constancy is not reflected in CT images because folia cross the depths of the major sulci from one lobule to the other in a highly variable manner. The flocculus has been confused with the anterior angle of the cereellum, and the cerebellar tonsils with the biventral lobule.
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  • 38
    ISSN: 1432-0878
    Keywords: Thyroidectomy ; Cerebellum ; Coated pit ; Mossy fiber terminal ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence that thyroid hormones have on the development of the cerebellar cortex is well known. Their absence in adults leads to important functional changes probably related to abnormalities in nerve terminal activity, although no morphological alterations have hitherto been described. Using ultrastructural morphometric methods, we have studied the effects of thyroidectomy on the cerebellar cortex mossy fiber terminals of adult rats with different survival periods. No significant changes in the volume and surface area of these terminals were found. The numbers of synaptic vesicles in groups 7, 15 and 30 days after thyroidectomy were significantly greater than in controls. A significant increase in coated pit formation was found when thyroidectomized groups were compared with controls. This increase is due to the lack of thyroxin since it can be counteracted by thyroxin administration. Whether this increased coated pit formation is a membrane retrieval mechanism or is related to the uptake of extracellular molecules remains to be determined.
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  • 39
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    Cell & tissue research 242 (1985), S. 649-656 
    ISSN: 1432-0878
    Keywords: Degeneration ; Brain lesions ; Cerebellum ; Sensory projections ; Visual system ; Octopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A modification of the Fink-Heimer silver stain (Method II) is shown to be an excellent stain of degenerating axons and terminals in the Octopus CNS. At temperatures around 23° C the time for optimum degeneration (as seen in the light microscope) is between 1–3 days after lesioning, although some degeneration persists as late as 8 days post lesion. The degeneration is usually discrete and prominent against a pale, clear background and this method, used with caution and in conjunction with other stains and tracing techniques should prove valuable in tracing connections in the cephalopod CNS. The technique has been validated on pathways in the visual system already described; but new evidence is presented of projections to a visuo-motor centre, the peduncle lobe. This supports earlier evidence that these swift, agile invertebrates have a region of their brain organised like a cerebellum and that, to regulate motor programs, this utilises a range of information of the kind used by vertebrates.
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  • 40
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    Experimental brain research 2 (1966), S. 18-34 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Parallel fibres ; Basket cells ; Purkinje cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Stimulation through concentric electrodes on the surface of a wide cerebellar folium was employed to set up a parallel fibre volley or beam. Serial recording of the field potential was made over a range of depths along microelectrode tracks arranged in a transverse plane across the folium in order to discover the action on Purkinje cells, both those that were on-beam for the parallel fibre volley and those at various distances off-beam. A juxta-fastigial electrode was carefully placed so that an applied stimulus could excite the axons of Purkinje cells distributed across the folium under investigation, the antidromic propagation of impulses thus obtained being utilized to test the effect of parallel fibre volleys upon Purkinje cells. 2. The observations were in accord with the two actions that a parallel fibre volley would be expected to exert on Purkinje cells: a direct excitatory action by the synapses made by parallel fibres with the spines of the Purkinje cell dendrites; an inhibitory action mediated by the stellate and basket cells that themselves are directly excited by the parallel fibre volley. 3. The excitatory synaptic action would result in the two types of responses that were restricted to the narrow zone and superficial location of the parallel fibre volley: active sinks formed by this excitatory synaptic action on the superficial dendrites of Purkinje cells would account for the observed depth profile of extra-cellular slow potentials, a superficial negative wave reversing to a deeper positive wave formed by passive sources on deeper dendrites; superficial synaptic excitation would also account for the facilitation of the propagation of antidromic impulses into the superficial dendrites. 4. The inhibitory synaptic action would result in the two types of responses that were widely dispersed transversely and in depth, far beyond the traject of the parallel fibre volley: a slow positive potential wave with a maximum at a depth usually of 300–400 μ; an inhibitory action on the antidromic invasion of Purkinje cells. The transverse profiles of these two presumed indices of inhibitory action on Purkinje cells apparently revealed that a basket cell may give inhibitory synapses up to 1000 μ laterally from the location of its soma and dendrites. 5. A description is given of the variants in the transverse profiles of the deeper positive waves and of inhibitory actions of a parallel fibre volley that presumably are mediated by basket cells and also by the superficial stellate cells. These physiological findings are correlated with the histologically determined distribution of synapses from a basket cell onto Purkinje cells.
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  • 41
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    Experimental brain research 1 (1966), S. 1-16 
    ISSN: 1432-1106
    Keywords: Inhibitory interneurones ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Extracellular microelectrode recording has been employed to study the responses of three types of interneurones in the cat cerebellar cortex: basket cells, superficial stellate cells and Golgi cells. The large unitary spike potentials of single cells were sharply localized and presumably were generated by impulse discharges from the cell somata. The characteristics of their responses described below sharply distinguished them from Purkinje cells. 2. The parallel fibre volleys generated by surface stimulation of a folium evoked brief repetitive discharges that were graded in respect of frequency and number. Maximum responses had as many as 10 impulses at an initial frequency of 500/sec. 3. At brief test intervals there was facilitation of the response to a second parallel fibre volley; at about 50 msec it passed over to depression for over 500 msec. 4. Stimulation deep in the cerebellum in the region of the fastigial nucleus (juxta-fastigial, J.F.) evoked by synaptic action a single or double discharge, presumably by the mossy fibre-granule cell-parallel fibre path, but climbing fibre stimulation from the inferior olive also usually had a weak excitatory action evoking never more than one impulse. 5. J.F. stimulation also had an inhibitory action on the repetitive discharge evoked by a parallel fibre volley. Possibly this is due to the inhibitory action of impulses in Purkinje cell axon collaterals. 6. There was a slow (7–30/sec) and rather irregular background discharge from all interneurones. The inhibitory actions of parallel fibre and J.F. stimulation silenced this discharge for some hundreds of milliseconds, probably by Golgi cell inhibition of a background mossy fibre input into granule cells. 7. All these various features were displayed by cells at depths from 180 to 500 μ; hence it was concluded that superficial stellate, basket and Golgi cells have similar properties, discrimination being possible only by depth, the respective depth ranges being superficial to 250μ, 250μ to 400μ, and deeper than 400μ.
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  • 42
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    Experimental brain research 1 (1966), S. 17-39 
    ISSN: 1432-1106
    Keywords: Parallel fibres ; Purkinje cells ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. When electrical stimuli were applied to the surface of a cerebellar folium by a local electrode (LOC), there was a propagated potential wave along the folium with a triphasic (positive-negative-positive) configuration. 2. Investigations by microelectrode recording established that this wave is produced by impulses propagating for at least 3 mm and at about 0.3 m/sec along a narrow superficial band or “beam” of parallel fibres. As expected from this interpretation, there was an absolutely refractory period of less than 1 msec and impulse annihilation by collision. 3. Complications occurred from the potential wave forms resulting from the excitation of mossy fibres by spreading of the applied LOC stimulus. These complications have been eliminated by chronically deafferenting the cerebellum. 4. When recording within the beam of excited parallel fibres there was a slow negative wave of about 20 msec duration, and deep and lateral thereto, there was a slow positive wave of approximately the same time course. 5. These potential fields were expressed in serial profile plots and in potential contour diagrams and shown to be explicable by the excitatory and inhibitory synaptic action on Purkinje cells: excitatory depolarizing synapses of parallel fibre impulses on the dendrites; and hyperpolarizing inhibitory synapses of stellate and basket cells respectively on the dendrites and somata. The active excitatory synapses would be strictly on the parallel fibre beam and the inhibitory concentrated deep and lateral thereto, which is in conformity with the axonal distributions of those basket and stellate cells that would be excited by the parallel fibre beam. 6. Complex problems were involved in interpretation of slow potentials produced by a second LOC stimulus at brief stimulus intervals and up to 50 msec: there was a potentiation of the slow negative wave, and often depression of the positive wave deep and lateral to the excited beam of parallel fibres. 7. Often the LOC stimulus evoked impulse discharge from the Purkinje cells, these discharges being inhibited by a preceding LOC stimulus.
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  • 43
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    Experimental brain research 1 (1966), S. 65-81 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Cerebellar synaptology ; Climbing fibers ; synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An attempt is made to identify, under the electron microscope, the climbing fibers of the cerebellum (in the cat) and their synaptic contacts with Purkinje cells and other cortical neurons. — Two kinds of axonal profiles, having synaptic contacts with primary and secondary dendrites of Purkinje neurons, can be recognized: One being terminal fibers densely packed with neurofilaments, having mainly contacts “de passage” with the dendrite surface, with small accumulations of synaptic vesicles at the presynaptic side of the contact. The others are rather knob-shaped contacts filled with synaptic vesicles and poor in neurofilaments. In chronically isolated folia, in which only local neurons and their processes have survived, all filamentous profiles have disappeared while vesicular ones are not appreciably reduced in number. It is inferred from this, that the neurofilamentous profiles correspond to climbing fibers, whereas the vesicular ones could be the endings of outer stellate axons, recurrent Purkinje axon collaterals, or ascending basket axon collaterals. — Similar two kinds of axon-terminal profiles are found in synaptic contact with Golgi and basket cell bodies. As in chronically isolated folia only the vesicular profiles survive, it is inferred that the climbing fiber has axo-somatic terminals on Golgi cells and basket cells as well. Previous information of this kind, gained with the light microscope and with degeneration studies, is thus substantiated with the aid of the electron microscope. The vesicular presynaptic profiles on Golgi and basket neurons are in the first case certainly and in the second with high probability endings of recurrent Purkinje axon collaterals. — The few axosomatic synapses found on outer stellate neurons may also be terminals of climbing fibers, but degeneration evidence for this is not conclusive. — The observations are summarized and evaluated from the functional point of view in a diagram, with consideration to recent physiological information on the function of climbing fibers.
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  • 44
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    Experimental brain research 1 (1966), S. 82-101 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Mossy fibre input ; olgi cell inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The glomerulus in the cerebellar granular layer is composed of the three elements; the mossy fibre terminal, the granule cell dendrites and the Golgi cell axons. The afferent input to the cerebellar cortex through the glomerulus, the mossy fibre-granule cell relay (M.G.R.), and its inhibitory control by the Golgi cells were studied by recording, a) extracellular field potentials in the granular and molecular layers, b) unitary spikes of granule cells, and c) intracellular postsynaptic potentials in Purkinje cells. 2. Mossy fibres were activated by juxta-fastigial, transfolial, lateral cuneate nucleus and radial nerve stimulation. Stimulation of an adjacent folium (transfolial stimulation) could excite branches of mossy fibres under the stimulating electrode which supply other branches also to the folium under the recording electrode. This technique was utilized to distinguish the response due to mossy fibre activation from those due to the climbing fibre and Purkinje cell axons. 3. These stimulations resulted in, through the M.G.R., a powerful activation of granule cells whose axons (parallel fibres) excited in turn the Purkinje cells and the inhibitory interneurones, including the Golgi cells, in the molecular layer. 4. Field potentials and unitary spikes due to granule cell activity elicited by the stimulation of mossy fibres were markedly depressed for hundreds of milliseconds after the direct stimulation of parallel fibres (LOC stimulation). The postsynaptic potential in Purkinje cells evoked by mossy fibre activation was also depressed by the conditioning LOC stimulation in the same manner. The “spontaneous” background activities recorded from granule cells as unitary spikes and from Purkinje cells as inhibitory synaptic noise were silenced for hundreds of milliseconds after the LOC stimulation. 5. These depressions indicate that the parallel fibre activation evokes an inhibitory action upon M.G.R. On anatomical grounds this inhibition can be mediated only by the Golgi cell, and it is postulated that the inhibitory action is postsynaptic upon the dendrites of granule cells. 6. It is concluded that the Golgi cell inhibition regulates the mossy fibre input to the cerebellar cortex at the M.G.R. by a form of negative feed-back.
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  • 45
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    Experimental brain research 1 (1966), S. 161-183 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Purkinje cells ; Intracellular recording ; Postsynaptic potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Intracellular recording from Purkinje cells has been employed in investigating the excitatory and inhibitory synaptic action that is exerted on these cells by the mossy fibre input into the cerebellum. 2. These synaptic actions are evoked not directly by the mossy fibres, but probably always through granule cells and their axons, the parallel fibres. The intracellular records conform with the anatomical evidence that the parallel fibres directly exert a powerful synaptic excitatory action on Purkinje cells, and that the inhibitory pathway occurs via an inhibitory interneurone — a basket cell or a stellate cell. Direct stimulation of parallel fibres gives intracellular potentials closely resembling those produced by deep stimulation of mossy fibres. 3. As would be expected, direct stimulation of parallel fibres produces an EPSP with a latency 1 to 2 msec briefer than the IPSP. The IPSP has a duration usually in excess of 100 msec. The EPSP appears to be briefer, though its superposition on the IPSP greatly reduces its apparent duration. Neutralization of the IPSP by appropriate membrane polarization or by intracellular chloride injection reveals an EPSP duration of up to 50 msec. 4. The IPSP is typically affected by polarizing currents; reduced and even inverted by hyperpolarizing currents, and increased by depolarizing currents. The IPSP is converted to a depolarizing response by excess of intracellular chloride. It must therefore be generated by an increased ionic permeability of the inhibitory subsynaptic membrane, chloride ions being importantly concerned. 5. Often small irregular IPSPs can be observed occurring spontaneously, and they react to polarizing currents and to chloride injections in a manner identical to the evoked IPSPs. It is concluded that they are generated by the spontaneous discharges of basket cells. 6. A brief account is given of various spontaneous rhythmic responses of impaled Purkinje cells, and of the effect of synaptic inhibitory action upon them. 7. There is a general discussion of these findings in relation to the various neural pathways and neural mechanisms that have been postulated in the light of the preceding investigations.
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  • 46
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    Experimental brain research 1 (1966), S. 306-319 
    ISSN: 1432-1106
    Keywords: Lateral reticular nucleus ; Reticulocerebellar tract ; Spinoreticular tract ; Cerebellum ; Flexor reflex afferents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mass discharges were recorded from the dissected left restiform body in unanaesthetized, decerebrate, and decerebellate cats. The spinal cord was severed in the thoracic or cervical region sparing only the left ventral quadrant. In this preparation the discharges were shown to relate largely or exclusively to activity in the reticulocerebellar tract originating from the lateral reticular nucleus. The ascending spinal tract was identified with the bilateral ventral flexor reflex tract (bVFRT) of Lundberg and Oscarsson (1962). The reticulocerebellar tract was activated from the flexor reflex afferents and nerve volleys from each of the four limbs were equally effective. It is concluded that the lateral reticular nucleus is not responsible for the somatotopically organized projection of cutaneous afferents, as assumed before. The bVFRT is strongly influenced from the cerebellar cortex and the organization of the closed loop formed between the cortex and the spinal cord is discussed.
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  • 47
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    Experimental brain research 1 (1966), S. 320-328 
    ISSN: 1432-1106
    Keywords: Lateral reticular nucleus ; Reticulocerebellar tract ; Spinoreticular tract ; Cerebellum ; Flexor reflex afferents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The experiments were done on unanaesthetized, decerebrate, and decerebellate cats. Recording was made from axons originating in the lateral reticular nucleus on stimulation of various nerves, cutaneous receptors, and certain descending tracts. Excitatory and inhibitory effects were evoked from the flexor reflex afferents of receptive fields which included most of the body surface. It is concluded that the lateral reticular nucleus with respect to its afferent inflow is similar to the non-cerebellar nuclei of the reticular formation. The possibility that the reticulocerebellar tract is important in determining the background excitation of cortical neurones is discussed. The effects evoked by stimulation of descending tracts were consistent with the disclosure that the bilateral ventral flexor reflex tract is the afferent path to the lateral reticular nucleus.
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  • 48
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    Experimental brain research 1 (1966), S. 329-337 
    ISSN: 1432-1106
    Keywords: Inferior olive ; Olivocerebellar tract ; Spinoolivary tract ; Cerebellum ; Flexor reflex afferents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The discharges were recorded from the dissected right restiform body in unanaesthetized, decerebrate, and decerebellate cats. The spinal cord was severed in the thoracic and/or cervical region sparing only the left ventral quadrant. The discharges were shown to relate largely or exclusively to activity in the olivocerebellar tract. The olivocerebellar discharges were elicited by stimulation of the flexor reflex afferents. Large responses were evoked from the right hindlimb nerves and small responses from the left hindlimb nerves. The responses had a latency of about 20 msec. The spinoolivary tract is tentatively identified with the contralateral ventral flexor reflex tract of Lundberg and Oscarsson (1962).
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  • 49
    ISSN: 1432-1106
    Keywords: Cerebellum ; Nucleus interpositus anterior ; Red nucleus ; Somatotopy ; Degeneration study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Small lesions were done in various areas of the nucleus interpositus anterior (NIA) of the cerebellum, and the distribution of terminal degeneration was studied in the red nucleus with the methods of Nauta and Glees. The NIA projects to the contralateral red nucleus. Two principles of organization can be demonstrated in the projection: a caudorostral arrangement in the red nucleus corresponds to a mediolateral organization in the NIA and a mediolateral arrangement in the red nucleus corresponds to a caudorostral organization of the NIA. The latter distribution coincides with the somatotopical areas of the red nucleus defined by Pompeiano and Brodal (1957). Special attention has been paid to the questions of the subdivision of the cerebellar nuclei and of the course of the fibres issuing from the nuclei in the cerebellar hilus. The present findings on the projection of the NIA to the red nucleus have been correlated with recent anatomical and physiological data on the cerebellum and the red nucleus.
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