Bradykinesia following unilateral lesions restricted to the substantia nigra in the baboon

Abstract

Unilateral lesions were made in the substantia nigra of baboons which had been previously trained to carry out a visually guided pointing movement. During the early post-operative period, the animals were unable to perform the task with the contralateral forelimb because of the severity of the akinesia affecting it. After one or two weeks, the animals began to make the movement; at this time, there was a purely contralateral increase in the latency and particularly the duration of the movement, while its accuracy remained unchanged.