CHARACTERISTICS OF AFTER-DISCHARGE FOLLOWING CORTICAL STIMULATION IN THE MONKEY

Abstract

Since the discovery of the excitability of the motor cortex by Fritsch and Hitzig in 1870,¹ much interest has been focused on the after-discharges which follow cortical stimulation and which closely resemble jacksonian seizures in man. The present paper is a report of a study of these tonic and clonic after-discharges following cortical stimulation in monkeys, both before and after cortical and subcortical ablations. METHOD Forty-seven monkeys—Macaca mulatta, the green monkey (Cercopithecus aethiops sabaeus) or the mangabey (Cercocebus torquatus atys)—were used. Most of the experiments were acute, but in some instances operation was performed under sterile precautions and lesions made which abolished after-discharge at the time. Such animals, when killed nine or ten weeks later, were examined for return of the after-discharge. The anesthetics used were dial, sodium amytal or ether. Dial was given in doses of 0.45 to 0.50 cc. per kilogram of body weight, half intramuscularly and