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  • 1965-1969  (21)
  • 1920-1924
  • 1900-1904
  • 1850-1859
  • 1968  (10)
  • 1966  (11)
  • Cerebellum  (20)
  • Purkinje cells
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 5 (1968), S. 326-340 
    ISSN: 1432-1106
    Keywords: Subcellular fractionation ; Parallel fiber axons ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: 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.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 6 (1968), S. 49-68 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Granule cell ; Necrosis ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Granule cell necrosis was produced in rats by thiophen injection. The earliest detectable change was the formation of blebs in the perinuclear cisternae. This was followed by precipitation of the nuclear chromatin and rupture of the cell membrane. Removal of the cell debris was accomplished by phagocytic cells in the walls of small blood vessels, hematogenous macrophages and astrocytes. Many of the mossy fiber endings and some of the Golgi II cells degenerated secondarily. The degenerated presynaptic contacts of the parallel fibers were replaced by processes of the Bergmann glia which completely surrounded the Purkinje cell spines. These spines retained their usual appearance including the usual thickening of the post synaptic membrane. Implications of these findings are discussed.
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  • 3
    ISSN: 1432-1106
    Keywords: Cerebellum ; Climbing fiber input ; Somatotopy of climbing fiber input
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Volleys in group I and II fibers of muscle nerves and group II fibers of cutaneous, joint and fascial nerves have evoked CF responses in the anterior lobe of the cerebellum. In the pars intermedia there is a fairly sharp somatotopic localization of the forelimb CF responses to the Vth lobule (Larsell) and the hindlimb to the IVth and IIIrd lobules. In the vermis there is much more admixture, with the hindlimb-evoked responses tending to dominate in the lateral vermis of the Vth lobule, and the forelimb more medially. In the IVth and IIIrd lobules forelimb responses were rare and were never large. In the medial vermis up to 1–1.7 mm from the midline there were no CF-evoked responses from the limb nerves. These distributions of CF-evoked responses are remarkably different from those reported by Oscarsson, and consideration is given to the factors responsible for this discrepancy. A more detailed examination was made of the CF-evoked responses from a large variety of hindlimb and forelimb nerves. Observations were made along many tracks usually arranged in a transverse plane, and it was found that between different recording sites along the same track or along adjacent tracks, there was a great deal of variation in the relative magnitudes of the CF-evoked responses from the different nerves. These distributions have an ill-defined patchy character so that at any focus there is opportunity for the most diverse kinds of piecemeal integration. These findings on the CF-input are considered in relationship to the mossy fiber input. It is pointed out that the pathways conveying CF-input to the cerebellum have a level of discriminative input adequate for the operation of fine control.
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  • 4
    ISSN: 1432-1106
    Keywords: Cerebellum ; Cerebrum ; Somatotopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stimulation of forelimb and hindlimb areas of the sensorimotor cortex in the cat evokes in the lobus anterior of the cerebellum an early response at latency of 3–3.5 msec due to the mossy fibre input (MF) and a later response at latency of 13–16 msec due to the climbing fibre (CF) input. In the pars intermedia these two types of responses are organized in a somatotopic manner: the hindlimb area projects in lobuli HIV and HIII whereas the forelimb area projects to lobulus HV. In the vermis a somatotopic arrangement is less clear. Both forelimb and hindlimb areas of the sensorimotor cortex project to lobuli III, IV and V: on a maintained somatotopy in a caudo-rostral direction there is a tendency for the hindlimb area of the sensorimotor cortex to be well represented in a longitudinal strip close to the paravermal sulcus. This arrangement in the vermis is evident for the CF pathways, but more difficult to demonstrate for the MF pathways. The forelimb area of the sensorimotor cortex projects to those areas of the lobus anterior impinged upon by the forelimb nerves through both the MF and CF systems and the same holds true for the hindlimb area and the hindlimb nerves.
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  • 5
    ISSN: 1432-1106
    Keywords: Cerebellum ; Evoked responses ; Mossy fibers ; Climbing fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses were evoked in the anterior lobe of the cerebellum by volleys in group I and II fibers of forelimb and hindlimb nerves — cutaneous, muscular, joint and fascial. These responses have been observed along microelectrode tracks that traverse the whole depth of the anterior lobe. These tracks have been identified in histological sections, and the recording sites along these tracks have been determined. It has been shown that there are many distinguishing features for the responses produced by the two types of afferent input to the cerebellum: climbing fibers and mossy fibers. The depth profiles are of particular importance in the differentiation of the CF and MF responses, and they correspond to those already determined for the exposed surface areas of the cerebellar cortex. As would be expected from the distribution of synapses by the CF fibers to the Purkinje cell dendrites, there is a maximum extracellular negativity deep in the molecular layer with sources superficial and deep thereto. In contrast, the mossy fiber input produces a powerful synaptic excitation in the granular layer, which is recorded there as a negative wave (N2). The mossy fiber input by sequential relay also produces a negative wave (N3) in the molecular layer. This wave is distinguished from the CF-evoked negative wave because it is not reversed in the fissura and the adjacent superficial molecular layer. An important distinguishing feature of the MF- and CF-evoked responses is that the latencies of the former are shorter by 6–12 msec for forelimb nerves and by 9–15 msec for hindlimb nerves. It is thus possible to measure the sizes of the MF and CF responses in the same traces. Another distinguishing feature is the failure of the CF responses with stimulus frequencies of 5–15/sec, whereas the MF-evoked potentials are well maintained above 15/sec. Also CF-evoked responses show much more size and latency variance than the MF-evoked responses, and often the facilitation of two or three volleys is required in order to evoke a stable CF response. By utilizing these various tests it is always possible to distinguish between the CF- and the MF-evoked responses recorded along the microelectrode tracks in the anterior lobe.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 5 (1968), S. 32-44 
    ISSN: 1432-1106
    Keywords: Gangliosides ; Hippocampus ; Cerebellum ; Synapses ; Neuronal membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of gangliosides in serial cryostat sections of area CA2 of the ox hippocampus cut parallel to the ventricular surface and of a cerebellar folium cut parallel to the pial surfaces have been determined utilizing a fluorimetric method for analysis of N-acetylneuraminic acid. Wide differences in the ganglioside content, even in adjacent sections, were found within the various laminae, particularly in the molecular layers of the hippocampus and cerebellum. The variations in ganglioside concentrations largely disappeared when sections were cut so as to include all the laminae in one section. Average ganglioside concentrations per unit of dry weight were highest in the granular cell and molecular layers of the cerebellum, but in the hippocampus the highest values were obtained just below the stratum granulare of the fascia dentata. The results indicate that gangliosides are not uniformly distributed throughout the neuron but are concentrated in regions densely supplied with synaptic endings on both cell bodies and dendrites.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 6 (1968), S. 247-264 
    ISSN: 1432-1106
    Keywords: Deiters neurones ; Disinhibition ; Cerebellum ; Cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following the stimulation of cerebellar cortex, a slow depolarization developed in the neurones which were impaled with microelectrodes in the dorsal portion of the nucleus of Deiters. Characteristically, it was produced bilaterally from a wide area of the culmen and, with double shock stimulation at brief intervals, showed a marked potentiation, often in association with a later depression. After repetitive stimulation of the cerebellar cortex the slow depolarization was prolonged for a period of many seconds. Even stimulation of the spinal cord caused similar depolarization. By intracellular injection of currents and ions, the depolarization was shown to be disinhibition, i. e., removal of background inhibition. Accordingly, it was confirmed that there was a steady production of IPSPs in dorsal Deiters neurones, which diminished during the phase of disinhibition. As the possible source of these background IPSPs, the Purkinje cell axons within the nucleus of Deiters were found to be discharging rhythmically at a rate of 20–90/sec, and in fact they were depressed very effectively after cerebellar stimulation. At the same time, volleys along Purkinje cell axons produced by a testing cerebellar stimulation also were diminished, indicating a depression in the excitability of Purkinje cells.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 5 (1968), S. 118-128 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Cerebellar synaptology ; Purkinje axon collaterals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Purkinje axon collaterals and their synaptic terminals can be identified on the basis of three criteria: (1) They are the only myelinated axons of local elements, hence any myelinated axon persisting in chronically isolated folium is a Purkinje axon or its collateral; (2) They are the only known transfolial axons, so that axons and synapses found in the state of secondary degeneration after lesions placed into neighbouring folia of the cerebellar cortex are Purkinje axon collaterals and synapses; (3) The peculiar axonal tubular systems described by Andres (1965) are specific for Purkinje axons and their synaptic endings, which offers an additional clue for their identification. Using these three criteria numerous synapses of Purkinje axon collateral endings have been identified on the large Golgi neurons, both cell bodies and principal dendrites, and on the bodies of basket neurons. No evidence of the termination of Purkinje axon collaterals on other Purkinje cells could be detected.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 4 (1968), S. 292-309 
    ISSN: 1432-1106
    Keywords: Red nucleus ; Cerebellum ; Disfacilitation ; Cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Large cells in the red nucleus of cats were impaled with glass microelectrodes. Under light Nembutal anesthesia it was found that stimulation of the cerebellar cortex produced hyperpolarization in their membrane. Unlike the inhibitory postsynaptic potentials, this hyperpolarization decreased when the membrane was depolarized by passage of currents through the microelectrode, and it increased during application of hyperpolarizing currents: Hence the hyperpolarization is presumed to be produced by removal of tonically impinging excitatory postsynaptic potentials, in the manner of “disfacilitation”. In accordance with the above view, spontaneously arising small EPSPs disappeared during the phase of the hyperpolarization. The source of tonic impingement of excitatory impulses onto the red nucleus was found in the interpositus nucleus. The cells in this nucleus were discharging impulses at frequencies of 50–100/sec which were suppressed after the cerebellar stimulation, presumably via Purkinje cell axons, a depression in the excitability of the interpositus neurones being revealed at the same time. Following the depression, the excitability and impulse discharges of the interpositus neurones were enhanced, and correspondingly there was a late depolarization in the red nucleus neurones. During stimulation of the inferior olive and even of the spinal cord, disfacilitation and late facilitation occurred similarly through the interpositus nucleus, though with longer latencies.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 4 (1968), S. 310-320 
    ISSN: 1432-1106
    Keywords: Deiters neurones ; Cerebellum ; Inhibitory zone ; Cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By recording intracellularly from Deiters neurones of cats, there was a survey of those cerebellar areas that, when stimulated, produced inhibitory postsynaptic potentials (IPSPs) monosynaptically in Deiters neurones. The monosynaptic inhibitory area expanded longitudinally mainly along the ipsilateral vermal cortex of the anterior lobe. The ipsilateral cortex of the posterior lobe was also effective in inhibiting Deiters neurones though less prominently than the anterior lobe. The inhibitory fibers could be stimulated in the white matter of the cerebellum, predominantly in the ipsilateral side at rostral regions of nuclei fastigii and interpositus. It was further shown that the monosynaptic inhibition from the anterior and posterior lobes occurs chiefly in the dorsal portion of Deiters nucleus. Since in both the cerebellum and Deiters nucleus the spatial pattern of distribution of the inhibitory fibers conforms to that of the corticovestibular fibers as histologically defined, the experimental findings are in accord with the hypothesis that the cerebellar Purkinje cells are inhibitory in nature.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    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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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    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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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    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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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    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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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    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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  • 16
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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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  • 17
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    Electronic Resource
    Springer
    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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  • 18
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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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  • 19
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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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  • 20
    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.
    Type of Medium: Electronic Resource
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 2 (1966), S. 330-349 
    ISSN: 1432-1106
    Keywords: Deiters neurones ; IPSP ; Monosynaptic ; Purkinje cells ; Inhibitory neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During stimulation of the anterior lobe of the cerebellum, postsynaptic potentials were recorded intracellularly from ipsilateral Deiters neurones of the cat. In the majority of examined cells, the inhibitory postsynapic potentials were induced with short latency; 1.06 msec on the average from lobule III or IV. The latency was longer (1.23 msec) when the lobule V was stimulated, while it was shorter (0.86 msec) from the juxtafastigial region. It follows that the IPSP was produced via a monosynaptic pathway at a conduction velocity of 15 to 20 m/sec. Recording of the extracellular field potentials and focal stimulation within and around Deiters' nucleus further indicated that the inhibitory impulses propagated out of the cerebellum along a remarkable bundle of fibres which terminated within Deiters' nucleus. These results are all explicable by assuming that the cerebellar Purkinje cells are inhibitory in nature and so produce IPSPs monosynaptically in Deiters neurones via the long corticofugal fibres. Monosynaptic EPSPs were also detected in some Deiters neurones. They are considered to be mediated by the other pathways formed of axon collaterals of the cerebellar afferents.
    Type of Medium: Electronic Resource
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