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  • Cat  (3)
  • Vestibulo-cerebellar input  (2)
  • Commissural inhibition  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Functional organization of the vestibular afferents to the cerebellar cortex of frog and cat (1969)
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    Details
    ISSN: 1432-1106
    Keywords: Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Field and unitary potentials evoked in the vestibulo-cerebellum of frog and cat following vestibular nerve stimulation were recorded with microelectrodes and correlated with their site of origin in the various layers of the cerebellar cortex. 2. In the frog, primary vestibular fibers project both as mossy and as climbing fibers onto the cerebellar auricular lobe. Secondary vestibulo-cerebellar fibers seem to end exclusively as mossy fibers in the auriculum. As a consequence of this dual projection, extra- and intracellular recordings from Purkinje cells in the auricular lobe show two kinds of responses to vestibular nerve stimulation: a) graded, repetitive firing mediated through mossy fiber-granule cell-parallel fiber pathways, and b) all-or-none burst responses caused by monosynaptic impingement of vestibular climbing fibers on Purkinje cells. 3. The field and unitary potentials evoked in the cat nodulus, flocculus and uvula following vestibular nerve stimulation are shown to be generated by mossy fibers exclusively. Considerable convergence of the two labyrinthine mossy fiber inputs to a given cerebellar area was found. 4. Interaction of contralateral and ipsilateral mossy fiber input at the level of the flocculus suggests that Golgi cell inhibition might operate not only as a simple inhibitory feedback loop, but also as a complex gating operator at the granule layer. 5. No short latency climbing fiber activation of Purkinje cells was observed following VIIIth nerve stimulation. Stimulation of the contralateral inferior olive evoked short latency climbing fiber EPSPs in Purkinje cells of the vestibulo-cerebellum. Suggestions are made as to the possible role of mossy and climbing fiber inputs to this area of the cerebellum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235450
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The inhibitory interneurones within the cerebellar cortex (1966)
    Springer
    Experimental brain research 1 (1966), S. 1-16 
    Details
    ISSN: 1432-1106
    Keywords: Inhibitory interneurones ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Extracellular microelectrode recording has been employed to study the responses of three types of interneurones in the cat cerebellar cortex: basket cells, superficial stellate cells and Golgi cells. The large unitary spike potentials of single cells were sharply localized and presumably were generated by impulse discharges from the cell somata. The characteristics of their responses described below sharply distinguished them from Purkinje cells. 2. The parallel fibre volleys generated by surface stimulation of a folium evoked brief repetitive discharges that were graded in respect of frequency and number. Maximum responses had as many as 10 impulses at an initial frequency of 500/sec. 3. At brief test intervals there was facilitation of the response to a second parallel fibre volley; at about 50 msec it passed over to depression for over 500 msec. 4. Stimulation deep in the cerebellum in the region of the fastigial nucleus (juxta-fastigial, J.F.) evoked by synaptic action a single or double discharge, presumably by the mossy fibre-granule cell-parallel fibre path, but climbing fibre stimulation from the inferior olive also usually had a weak excitatory action evoking never more than one impulse. 5. J.F. stimulation also had an inhibitory action on the repetitive discharge evoked by a parallel fibre volley. Possibly this is due to the inhibitory action of impulses in Purkinje cell axon collaterals. 6. There was a slow (7–30/sec) and rather irregular background discharge from all interneurones. The inhibitory actions of parallel fibre and J.F. stimulation silenced this discharge for some hundreds of milliseconds, probably by Golgi cell inhibition of a background mossy fibre input into granule cells. 7. All these various features were displayed by cells at depths from 180 to 500 μ; hence it was concluded that superficial stellate, basket and Golgi cells have similar properties, discrimination being possible only by depth, the respective depth ranges being superficial to 250μ, 250μ to 400μ, and deeper than 400μ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235206
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  • 3
    Electronic Resource
    Electronic Resource
    Parallel fibre stimulation and the responses induced thereby in the Purkinje cells of the cerebellum (1966)
    Springer
    Experimental brain research 1 (1966), S. 17-39 
    Details
    ISSN: 1432-1106
    Keywords: Parallel fibres ; Purkinje cells ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. When electrical stimuli were applied to the surface of a cerebellar folium by a local electrode (LOC), there was a propagated potential wave along the folium with a triphasic (positive-negative-positive) configuration. 2. Investigations by microelectrode recording established that this wave is produced by impulses propagating for at least 3 mm and at about 0.3 m/sec along a narrow superficial band or “beam” of parallel fibres. As expected from this interpretation, there was an absolutely refractory period of less than 1 msec and impulse annihilation by collision. 3. Complications occurred from the potential wave forms resulting from the excitation of mossy fibres by spreading of the applied LOC stimulus. These complications have been eliminated by chronically deafferenting the cerebellum. 4. When recording within the beam of excited parallel fibres there was a slow negative wave of about 20 msec duration, and deep and lateral thereto, there was a slow positive wave of approximately the same time course. 5. These potential fields were expressed in serial profile plots and in potential contour diagrams and shown to be explicable by the excitatory and inhibitory synaptic action on Purkinje cells: excitatory depolarizing synapses of parallel fibre impulses on the dendrites; and hyperpolarizing inhibitory synapses of stellate and basket cells respectively on the dendrites and somata. The active excitatory synapses would be strictly on the parallel fibre beam and the inhibitory concentrated deep and lateral thereto, which is in conformity with the axonal distributions of those basket and stellate cells that would be excited by the parallel fibre beam. 6. Complex problems were involved in interpretation of slow potentials produced by a second LOC stimulus at brief stimulus intervals and up to 50 msec: there was a potentiation of the slow negative wave, and often depression of the positive wave deep and lateral to the excited beam of parallel fibres. 7. Often the LOC stimulus evoked impulse discharge from the Purkinje cells, these discharges being inhibited by a preceding LOC stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235207
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  • 4
    Electronic Resource
    Electronic Resource
    Cerebellar Purkinje cell responses to physiological stimulation of the vestibular system in the frog (1971)
    Springer
    Experimental brain research 13 (1971), S. 408-431 
    Details
    ISSN: 1432-1106
    Keywords: Vestibulo-cerebellar input ; Purkinje cells ; Mossy fibers ; Climbing fiber ; Responses to rotation ; Frog cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electrical activity of single Purkinje cells was studied in the auricular lobe and in the vestibular cerebellum of Rana catesbeiana during horizontal angular acceleration. This form of physiological stimulation allowed the Purkinje cells to be categorized into four main classes, depending on the general properties of their responses. 1. Type I Purkinje cells responded to ipsilateral horizontal acceleration. Their discharge was blocked during contralateral rotation. Within this group, individual Purkinje cell responses to a protracted acceleration varied from purely phasic to purely tonic discharge. 2. Type II Purkinje cells were characterized by their activation following contralateral horizontal acceleration and by lack of response to the ipsilateral rotation. Both type I and II Purkinje cells were encountered mainly in the auricular lobe. 3. Type III, the most common form of Purkinje cell response, was activated by rotation in either ipsi- or contralateral direction. Their response, as that of type I, could vary from a purely phasic to a purely tonic discharge. The study of field potentials and unitary responses evoked by electrical stimulation of the vestibular nerve demonstrated that type III Purkinje cell response was evoked via a polysynaptic pathway different from that which activated Purkinje cells in the auricular lobe. 4. Type IV Purkinje cells were characterized by the reduction of spontaneous firing during acceleration in either ipsi- or contralateral directions. 5. A comparison of the responses evoked by type III Purkinje cells in the cerebellar cortex demonstrated that neighboring Purkinje cells may respond in different fashions to the same vestibular input. Furthermore, the tonic or phasic character of a given Purkinje cell was very similar for ipsi- and contralateral rotation, suggesting that the subtle differences between responses in neighboring Purkinje cells may be related to differences in their dynamic properties rather than differences in the types of afferents received. 6. Climbing fiber activation of Purkinje cells during horizontal rotation was clearly demonstrated in five cells. These responses are considerred to be mediated through the saccular or utricular systems rather than through the semi-circular canals. The conclusion is derived that the semi-circular canal input to the cerebellum is subserved mainly by mossy fiber input. 7. The possible functional meaning of the different types of Purkinje cell response is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234339
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  • 5
    Electronic Resource
    Electronic Resource
    Cerebellar modulatory action on the vestibulo-trochlear pathway in the cat (1972)
    Springer
    Experimental brain research 15 (1972), S. 364-385 
    Details
    ISSN: 1432-1106
    Keywords: Vestibulo-trochlear reflex ; Reverberation ; Floccular inhibition ; Commissural inhibition ; Cerebellar influence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Field and intracellular potentials were recorded at the level of the trochlear nucleus (TN) following stimulation of the ipsi- or contralateral vestibular nerve (Vi, Vc) or the cerebellar flocculus (Floc). Vi and Vc stimulation produced clear presynaptic field potentials in the TN as the vestibulo-trochlear volleys ascending from the vestibular nucleus reached the trochlear motoneurons (TMns). Paired Vi-Vi or Vc-Vc stimulation at different intervals demonstrated a clear depression of the second of the two presynaptic potentials in the TN. A similar finding was obtained intracellularly from TMns. These results indicate a marked reduction in the excitability of the vestibular neurons following the conditioning stimulus. This period of subnormality may last for as long as 40 msec. Electrical stimulation of Vi and Vc generated an IPSP and EPSP respectively in TMns. In most instances these synaptic potentials occurred in a repetitive fashion after a single stimulation to either nerve. This reverberatory-like tendency of the vestibulo-trochlear pathways was absent in decerebellate animals, implying a cerebellar modulatory mechanism on vestibulo-trochlear transmission. Floccular stimulation produced a strong monosynaptic depression of the field and intracellular potentials evoked in the TN by Vi activation. In chronic experiments where the vestibular nerve had been transected, Floc stimulation generated a disinhibition of TMns through its suppression of the ipsilateral inhibitory vestibular neurons which project to the TN. Contralateral Floc stimulation produced a clear disfacilitation of TMns by the inhibition of contralateral excitatory vestibular neurons. Direct evidence was obtained for commissural inhibition acting on both the inhibitory and excitatory vestibular neurons projecting to the TN. The functional implications of the interaction between ipsi- and contralateral vestibular nuclei and the cerebellum and vestibular nuclei are considered in the Discussion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234124
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