Influences of cerebellar hemispherectomy on slow potentials in the motor cortex preceding self-paced hand movements in the monkey.

With chronically implanted electrodes, surface negative and deep positive, slowly increasing potentials were recorded in the forelimb area of the motor cortex prior to self-paced movements of the contralateral hand in monkeys. The slow premovement potentials were markedly reduced in size after ablation of the cerebellar hemisphere on the contralateral side to the motor cortex under recording. It was suggested that the cerebellar hemisphere (neocerebellum) participates in preparing the activity of the motor cortex prior to voluntary movements.