Saccade-related activity in the primate prefrontal cortex and its role in working memory processes

Single neuron activity was recorded from the prefrontal cortex of monkeys performing saccadic eye movements. Thirty-four percent of recorded neurons changed their discharge rates in relation to saccadic eye movements. The great majority (78%) of these neurons exhibited only post-saccadic activity, and only 22% exhibited pre-saccadic activity. Most post-saccadic activity (92%) and almost all pre-saccadic activity (97%) were directionally selective. They have preferred directions towards the contralateral visual field. The majority of prefrontal neurons showed pre- or post-saccadic activity only in conjunction with task-related saccades. This context-dependency was characteristic of both pre- and post-saccadic activity of prefrontal neurons. These results indicate that prefrontal neurons participate in the control of purposive saccadic eye movements. Most saccade-related activity of prefrontal neurons was post-saccadic, and such post-saccadic activity may be important in terminating the processes leading to memory-guided responses. The pre-saccadic activity, although it is a small proportion of the total, could help initiate and guide saccadic eye movements.