Epileptic Tendencies of the Normal Monkey

Abstract

The pattern of epileptic seizures in the macaque monkey originates in the pre-epileptic cortical patterning of the individual animal. Paroxysmal, generalized activity appeared in the resting electroencephalographic pattern of all normal monkeys. Its incidence was fairly steadfast for each single animal. No clinical seizures were ever seen in the normal animals, but bilateral, rapid, myoclonic twitches occurred in fingers, toes, and face musculature and were coincident with the hypersynchronous, "normal" paroxysmal activity. These twitches were potentiated by frontal ablation, by Metrazol administration, or when the animals were made epileptic. In the last instance, twitchings never occurred except during hyper-synchrony. Total paroxysmal activity either of the "normal" generalized type or of the focal epileptic was always increased by bilateral frontal ablation, but clinical seizures never resulted from this procedure alone. Chronic epileptic seizures produced by aluminum hydroxide applied to motor arm cortex always caused focal clinical seizures which later became generalized. These seizures occurred most frequently during fear or during drowsy periods and, when they appeared during an eeg recording, always followed a period of generalized hypersynchrony in which spontaneous muscle twitches of the myoclonic variety had been present.