The Propagation of Cortical-After-Discharge Through Subcortical Structures

INTRODUCTION After-discharge arising from electrical stimulation of the cerebral cortex has been extensively studied, with particular emphasis on its cortical propagation and electrical characteristics. That it may implicate subcortical neuronal ganglia has been mentioned by a number of investigators, but careful studies of its subcortical propagation are rare. The present study was designed to investigate the spread of the discharge from different cortical areas to subcortical structures, particularly the basal ganglia. Our previous experiences with after-discharge have emphasized the necessity of using animals which have had no previous operations or experiments upon the nervous system, and which are not under the influence of drugs that might modify the direction and degree of propagation of the after-discharge. In a previous study of the phenomena, we found that in animals made epileptic by the application of aluminum oxide (alumina) cream to the cerebral cortex, or in which repeated epileptic attacks had been