THE CONTROL OF CLONIC RESPONSES OF THE CEREBRAL CORTEX

Abstract

In rhesus monkeys, under chloralose anesthesia, tonic-clonic cortical responses were elicited by rapid electric stimulation. Single shocks applied to appropriate cortical areas controlled the rate of the clonic discharges and prolonged the responses beyond their intrinsic duration. The following features of the driven clonic responses are described: alternation; termination of a series; influepce of frequency; pattern; specificity of the controlling connections. The controlling pathways are subcortical. Localized tonic-clonic responses may be coupled in distant areas; or else they may be independent. Afferent nerve impulses can control clonic discharges. The discussion deals with the similarity of the driven to the undriven clonic bursts, the controlling pathways, some properties of clonically active elements, the background cortical excitation, and the factors which determine the rate and end of a clonic selfsustained response.