Distribution of responses to visual cues for movement in precentral cortex of awake primates

Unit recordings were made from areas 4 and 6 of monkeys after they were trained to align a cursor over a vertical target line on a video screen by control of a manipulandum with wrist flexion or extension movement. The appearance of the cursor and line on the screen was the visual cue for movement. Responses were observed 150 (±40) msec after cue presentation. The responses were found only in the forelimb area of precentral cortex, which was most immediately involved in the control of the task, and the majority of them were uncorrelated with either the specific details of the visual cue, or with the direction of the subsequent wrist movement.