ELECTROENCEPHALOGRAM OF DECORTICATE MONKEYS

Abstract

The removal of all cerebral cortical tissue in monkeys (M. mulatto) is followed by the appearance of spontaneous electrical potentials from the subcortical nuclei which are characteristic for the individual nuclei. That of caudate and putamen is characterized by spontaneous bursts of high voltage 8-12/sec. rhythms superimposed upon a low-voltage background activity. The EEG from the thalamus is more rapid and regular than that of basal ganglia. It often, but not always, is synchronous with postcentral cortical EEGs when that part of the cortex has been left intact. No definite rhythm was obtained from hypothalamus. All 3 of these subcortical nuclei affect cortical EEGs. In particular, destruction of hypothalamus or of thalamus, if large, greatly diminishes or abolishes the medium rate rhythm obtained from cortex.