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  • 1965-1969  (7)
  • 1920-1924
  • 1880-1889
  • 1966  (7)
  • Purkinje cells  (4)
  • Squirrel monkey  (3)
  • 1
    Electronic Resource
    Electronic Resource
    The profiles of physiological events produced by a parallel fibre volley in the cerebellar cortex (1966)
    Springer
    Experimental brain research 2 (1966), S. 18-34 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234358
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  • 2
    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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  • 3
    Electronic Resource
    Electronic Resource
    Intracellularly recorded responses of the cerebellar Purkinje cells (1966)
    Springer
    Experimental brain research 1 (1966), S. 161-183 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236869
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  • 4
    Electronic Resource
    Electronic Resource
    Neurophysiological correlates of brightness discrimination in the lateral geniculate nucleus of the squirrel monkey (1966)
    Springer
    Experimental brain research 2 (1966), S. 1-17 
    Details
    ISSN: 1432-1106
    Keywords: Brightness discrimination ; Lateral geniculate ; Squirrel monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Incremental brightness thresholds (DI) were psychophysically determined at several background illumination intensities for three squirrel monkeys. Gross asymmetrical electrodes were then chronically implanted in the lateral geniculate nucleus of the same animals, and activity was recorded in stimulus conditions identical to behavioral testing. Overall activity, recorded through an integrating voltmeter, showed 1. a tendency to decrease as steady background illumination increased, and 2. an abrupt transient increase at both onset and offset to DI test flashes, directly proportional to test flash intensity. Background illumination, in proportion to its intensity, depressed response to a superimposed test flash. Test flashes below intensity DI at the various levels of background illumination produced no measurable response. The quantity DI was shown to be a function of the depressive or inhibitory effect of background illumination on the capacity of the system to respond to transient stimulation. A secondary determinant of DI appeared to be the amount of variability in ongoing neural activity upon which the DI flash is imposed. The author is indebted to the supervisor of her dissertation, Dr. L. R. Pinneo, for introducing her to the recording technique and for his help towards the completion of this work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234357
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  • 5
    Electronic Resource
    Electronic Resource
    Histochemical mapping of succinic dehydrogenase and cytochrome oxidase in the spinal cord, medulla oblongata and cerebellum of squirrel monkey (Saimiri sciureus) (1966)
    Springer
    Experimental brain research 2 (1966), S. 216-229 
    Details
    ISSN: 1432-1106
    Keywords: Squirrel monkey ; Brain stem-Histochemical mapping ; Succinic dehydrogenase ; Cytochrome oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of succinic dehydrogenase (SDA) and cytochrome oxidase (Cy. O) in serial sections of the cervical region of the spinal cord and the medulla oblongata, arranged caudo-cranially, has been described. The motor cranial nerve nuclei exhibit strong SDA and Cy. O activity in the neurons and neuropil. The nuclei gracilis, cuneatus, olivaris inferior, cochlearis and vestibularis likewise show strong enzyme activity. Nucleus intercalatus and nucleus tractus solitarius, however, show weak and moderate enzyme activity respectively. The lateral part of formatio reticularis myelencephali shows less SDA and Cy. O compared to the medial part, which shows some accumulation of these enzymes in the neuropil. The neuropil of the molecular layer of cerebellar cortex and the perikarya and dendrites of the Purkinje cells show strong SDA and Cy. O activity. The granular layer exhibits stronger SDA and Cy. O in the synaptic glomeruli. The cerebellar nuclei possess stronger enzyme activity in the neurons and dendritic branches, compared to mild activity in the neuropil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236714
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  • 6
    Electronic Resource
    Electronic Resource
    Histochemical mapping of succinic dehydrogenase and cytochrome oxidase in the pons and mesencephalon of squirrel monkey (Saimiri sciureus) (1966)
    Springer
    Experimental brain research 2 (1966), S. 230-246 
    Details
    ISSN: 1432-1106
    Keywords: Squirrel monkey ; Midbrain ; Histochemical mapping ; Succinic dehydrogenase ; Cytochrome oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of succinic dehydrogenase (SDA) and cytochrome oxidase (Cy. O) has been investigated in a series of sections through the pons and mesencephalon of the squirrel monkey brain. The localization of the two enzymes is very similar in the various regions and shows only slight differences. The epiphysis, however, shows moderately strong SDA and very mild Cy. O activity. Particularly strong SDA and Cy. O activity has been observed in the cell bodies of the various cranial nerve nuclei, nucleus colliculi inferioris, colliculi superioris, nuclei griseum pontis, reticularis tegmenti pontis, lemnisci lateralis pars dorsalis, geniculatum laterale and mediale, and pulvinaris. The enzyme content of the neurons and cell bodies is generally stronger compared to the neuropil which often occurs in smooth, loose, compact and reticulated forms. Any special relationship between the neurons and neuropil with regard to their enzyme content has, however, not been observed. The cranial nerves, and fibers of the brachium conjunctivum, corpus callosum, and fornix show very mild enzyme activity except those of the trapezoid complex which show moderate enzyme activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236715
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  • 7
    Electronic Resource
    Electronic Resource
    The origin of cerebellar-induced inhibition of Deiters neurones I. Monosynaptic initiation of the inhibitory postsynaptic potentials (1966)
    Springer
    Experimental brain research 2 (1966), S. 330-349 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00234779
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