Disinhibition as a basic process in the expression of striatal functions. II. The striato-nigral influence on thalamocortical cells of the ventromedial thalamic nucleus

doi:10.1016/0006-8993(85)90214-8

Brain Research

Volume 334, Issue 2, 20 May 1985, Pages 227-233

https://doi.org/10.1016/0006-8993(85)90214-8 Get rights and content

Abstract

Besides the nigro-collicular pathway, the nigro-thalamic projection to the ventromedial thalamic nucleus represents another efferent system of the basal ganglia through which striatum can influence motor centers. Since the striato-nigrothalamic circuit is composed of two successive GABAergic inhibitory links and the SNR is tonically active, we tested that by inhibiting nigrothalamic cells, the striatum may exert a facilitatory influence on VM-thalamocortical cells. We show that a transitory block of SNR (substantia nigra pars reticulata) firing (induced by either intranigral application of GABA or by stimulating the inhibitory striato-nigral pathway), causes a perfectly time-locked increase of activity in a large number of VM cells projecting to motor cortex. Moreover, the striatally evoked excitation of VM-thalamocortical cells requires the functional integrity of the GABAergic striato-nigral link. We conclude that the double inhibitory striato-nigrothalamic pathway acts on VM-thalamocortical cells through a disinhibitory mechanism. The functional implication of such a mechanism is discussed.

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Disinhibition as a basic process in the expression of striatal functions. II. The striato-nigral influence on thalamocortical cells of the ventromedial thalamic nucleus

Abstract

Brain Research

Brain Research

EEG clin. Neurophysiol.

Neuroscience

Brain Research

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Neurosci. Lett.

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Neuroscience

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