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Excitatory Drive from Deep Cerebellar Neurons to the Superior Colliculus in the Rat: an Electrophysiological Mapping Study
Author(s) -
Max Westby G. W.,
Collinson Christine,
Dean Paul
Publication year - 1993
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1993.tb00924.x
Subject(s) - superior colliculus , neuroscience , tonic (physiology) , cerebellum , electrophysiology , pars reticulata , excitatory postsynaptic potential , nucleus , biology , anatomy , inhibitory postsynaptic potential , central nervous system , basal ganglia , globus pallidus
The cerebello‐tectal projection arising from the interpositus nucleus was investigated electrophysiologically to test the hypothesis that the deep cerebellar nuclei constitute a source of tonic excitation in the superior colliculus. A total of 117 spontaneously active collicular neurons were recorded during GABA microinjection into 26 interpositus sites, where tonic single‐cell deep cerebellar activity was also simultaneously recorded. GABA injection always led to suppression of interpositus activity, while in the colliculus a clear pattern of results emerged. 58% of superior colliculus cells showed no response to suppression of interpositus activity, 35% showed a frequency decrease and 7% showed a frequency increase. The majority of these responsive cells were found in a laterally located sheet of cells mainly restricted to the intermediate white layer, in close register with the known cells of origin of the predorsal bundle and completely overlapping the terminals of the nigrotectal pathway originating in dorsolateral substantia nigra pars reticulata. The implications of these results for cooperative theories of head movement control involving the superior colliculus, cerebellum and precerebellar nuclei are discussed.