Cell activity in monkey caudate nucleus preceding saccadic eye movements.

Single cell activity was recorded in the monkey caudate nucleus. The monkey fixated a visual target, and, if the target jumped, followed it by making a saccade. A group of cells showed spike discharges before a contralateral saccade to the target. This activity was related to the saccade rather than the onset of the target, but was conditional in that it was unrelated to spontaneous saccades which were made without a particular target. Some caudate cells showed activity only when the saccade was made to a remembered position of a target. It is suggested that caudate cells contribute to the initiation of saccades in a selective manner by removing nigro-collicular tonic inhibition.