Discharge patterns of Purkinje cells in cats anaesthetized with alpha‐chloralose.

Armstrong, David M.; Cogdell, B; Harvey, Richard J.

doi:10.1113/jphysiol.1979.sp012818

Cited by 13 publications

(8 citation statements)

References 40 publications

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“…Thus, changes in CS firing rates probably make little direct contribution to the final level of CS synchrony. Indeed, CS and SS firing rates are inversely related in many cases (de Montigny and Lamarre, 1973; Colin et al, 1980; Rawson and Tilokskulchai, 1981; Demer et al, 1985), and in the situation where CS firing rates are raised and SSs activity is decreased, the net result is an increase in nuclear firing rate (Armstrong et al, 1979; Andersson and Hesslow, 1987b), suggesting that changes in SS firing rates dominate those in CS firing rates.…”

Section: Discussionmentioning

confidence: 99%

Local Changes in the Excitability of the Cerebellar Cortex Produce Spatially Restricted Changes in Complex Spike Synchrony

Marshall¹,

Lang²

2009

J. Neurosci.

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Complex spike (CS) synchrony patterns are modulated by the release of GABA within the inferior olive (IO). The GABAergic projection to most of the IO arises from the cerebellar nuclei, which are themselves subject to strong inhibitory control by Purkinje cells in the overlying cortex. Moreover, the connections between the IO and cerebellum are precisely aligned, raising the possibility that each cortical region controls its own CS synchrony distribution. This possibility was tested using multielectrode recordings of CSs and simple spikes (SSs) in crus 2a of anesthetized rats. Picrotoxin or muscimol was applied to the cerebellar cortex at the borders of the recording array. These drugs induced significant changes in CS synchrony and in CS and SS firing rates and changes in post-CS pauses and modulation of SS activity. The level of CS synchrony was correlated with SS firing rate in control, and application of picrotoxin increased both. In contrast, muscimol decreased CS synchrony. Furthermore, when picrotoxin was applied only at the lateral edge of the array, changes in CS synchrony occurred sequentially across the recording array, with cells located in the lateral half of the array having earlier and larger changes in CS synchrony than cells in the medial half. The results indicate that a double-inhibitory feedback circuit from Purkinje cells to the IO provides a mechanism by which SS activity may regulate CS synchrony. Thus, CS synchrony may be a physiologically controlled parameter of cerebellar activity, with the cerebellum and IO comprising a series of self-updating circuits.

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Section: Discussionmentioning

confidence: 99%

Local Changes in the Excitability of the Cerebellar Cortex Produce Spatially Restricted Changes in Complex Spike Synchrony

Marshall¹,

Lang²

2009

J. Neurosci.

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“…Each discharge usually evokes a short burst of postsynaptic action potentials which can be recorded from the Purkinje cell soma as the so-called 'complex spike' or 'climbing fibre response'. This response is often followed by a highly variable pause in the single spike background activity (Armstrong, 1974;Armstrong, Cogdell & Harvey, 1979). The pause is assumed to be partly due to activation of inhibitory neurones by climbing fibre collaterals.…”

Section: Introductionmentioning

confidence: 99%

Prolonged depolarization elicited in Purkinje cell dendrites by climbing fibre impulses in the cat.

Ekerot¹,

Oscarsson²

1981

The Journal of Physiology

144

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1. Responses evoked in Purkinje cell dendrites by impulses in climbing fibres were studied by recording from the cat cerebellar cortex. Intra- and extracellular responses from dendrites of single Purkinje cells were recorded, as well as field responses from the intact cerebellar surface. The intracellular responses were presumably recorded from relatively proximal dendrites. The resting potential usually was 20-40 mV. The responses consisted of an initial spike-like component (amplitude 10-30 mV) followed by a plateau-like component (amplitude 2-12 mV) with a duration of about 100 ms. The duration of consecutive responses varied little. 3. The extracellular unitary responses were recorded from more distal dendrites. These responses were negative deflexions consisting of an initial component followed by a plateau-like component (amplitude 5-15 mV). The duration of consecutive responses varied widely from about 25 ms to more than 1 s. The negative deflexions are assumed to correspond to dendritic depolarizations. 4. The field responses recorded from the cerebellar surface consisted of a positivity followed by a negativity lasting several hundred milliseconds. The positivity signals the e.p.s.p.s generated by the climbing fibre synapses which do not extend to the most distal dendrites. The negativity presumably signals the plateau-like dendritic depolarizations which would involve also the most distal dendrites. 5. The nature and significance of the plateau-like depolarizations evoked by climbing fibre impulses in the purkinje cell dendrites are discussed.

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confidence: 99%

“…This striking response was tentatively identified as a disinhibitory phenomenon resulting from prolonged depression of the tonic background discharge in the P cells. Such depression is commonly observed following a cutaneous afferent volley in animals anaesthetized with c-chloralose (Freeman, 1968;Talbott, Towe & Kennedy, 1967;Armstrong, Cogdell & Harvey, 1979).In view of this difference between the response patterns of ip.n.s studied under different conditions of anaesthesia, together with other evidence that cerebellar cortical and deep nuclear activity is heavily influenced by type and depth of anaesthesia (e.g. Bloedel & Roberts, 1969;Gordon, Rubia & Strata, 1973; Eccles, Sabah & Taborikov6, 1974) it seems desirable that further studies should be made in the absence of anaesthetics.…”

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confidence: 99%

Responses of neurones in nucleus interpositus of the cerebellum to cutaneous nerve volleys in the awake cat.

Armstrong¹,

Rawson²

1979

The Journal of Physiology

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SUMMARY1. A method is described which permitted stable extracellular recordings to be made from 115 neurones in nucleus interpositus of the cerebellum in unanaesthetized free-to-move cats. At least 95 % of the neurones were cerebellar efferent cells since they were antidromically invaded following electrical stimulation of the brachium conjunctivum in the region of the contralateral red nucleus.2. In cats in a state of quiet wakefulness the majority of interpositus neurones were tonically active at rates ranging from 12 to 77 impulses/sec (over-all mean 34/sec). The remaining neurones were silent or discharged only a few impulses throughout observation periods of a few minutes.3. Cutaneous afferent volleys elicited by single shocks to the superficial radial nerves in the forearm at intensities too weak to evoke a flexion reflex or behavioural arousal produced changes in firing frequency in 62 % of eighty-one cells tested. Response patterns varied widely but in 86 % of the responding cells the earliest change was a short latency (6-20 ms) increase in discharge probability which from post-stimulus time histograms was found usually to average around one impulse per stimulus. In only four cells (8 %) the earliest response was a depression of the tonic firing. However, in many cells the initial acceleration was followed by a reduction in firing frequency which lasted between 10 and 85 ms.4. In 56 % of the responding cells a longer latency (25-80 ms) acceleration was present. Such accelerations varied widely in duration (from 55 to 550 ms) but most commonly lasted 100-200 ms. These responses were usually the most prominent feature in the response pattern: in the majority of neurones between two and five impulses were added per stimulus.5. Considering the whole time course of the responses, the net effect of nerve volleys was to produce an increase in nuclear cell output.6. These neurones which were influenced by nerve stimulation also discharged in response to taps to the forepaws.7. The responses to nerve stimulation are compared with those encountered in previous studies using cats anaesthetized with chloralose or barbiturates and with the responses ofPurkinje (P) Thach, 1968Thach, , 1970Mortimer, 1975) and cats (McElligott, 1976;Burton & Onoda, 1977) and these studies have revealed brisk tonic activity in stationary animals plus phasic alterations in the discharge of many units during conditioned movements of the limbs. Burton & Onoda (1977) have also presented evidence that activity patterns during forelimb movement in the cat are strongly influenced by input from rate sensitive movement detectors in the moving limb. This last is in good accord with the abundant evidence (see Bloedel, 1973; Oscarsson, 1973;Armstrong, 1974) that there are powerful inputs from deep (and cutaneous) receptors in the limbs to the 'intermediate' zone of the cerebellar cortex, the P cells of which project to and inhibit the ip. neurones (Voogd, 1964;Armstrong & Schild, 1978;Ito, Yoshida, Obata, Kawai & Udo, 1970).So far, studies in fr...

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Discharge patterns of Purkinje cells in cats anaesthetized with alpha‐chloralose.

Cited by 13 publications

References 40 publications

Local Changes in the Excitability of the Cerebellar Cortex Produce Spatially Restricted Changes in Complex Spike Synchrony

Local Changes in the Excitability of the Cerebellar Cortex Produce Spatially Restricted Changes in Complex Spike Synchrony

Prolonged depolarization elicited in Purkinje cell dendrites by climbing fibre impulses in the cat.

Responses of neurones in nucleus interpositus of the cerebellum to cutaneous nerve volleys in the awake cat.

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