Abstract
Neural systems employ predictive strategies to reduce behavioral response times. The supplementary eye fields (SEF) have been implicated in predictive oculomotor behavior based on remembered target motion from a previous trial. We asked whether SEF neurons could predict ongoing target motion, the trajectory of which was relevant for upcoming oculomotor behavior. To do this, we used an “ocular baseball task” previously employed to explore movement preparation activity (Kim and Heinen, 2001). The task involved having a monkey fixate and view an illuminated spot target that began to move on a screen in the peripheral visual field. If the trajectory of the spot crossed an illuminated “strike” zone that surrounded the fixation point, the monkey had to use a pursuit eye movement to follow it. If the target bypassed this zone, the monkey had to suppress pursuit and maintain fixation. Eye movements and single-unit activity in the SEF were recorded from two rhesus monkeys that performed the task. It was found that the monkeys could extract trajectory information from the approaching target as evidenced by short-latency ocular behavior. Some SEF neurons were recorded with activity related to pursuit movement preparation and suppression, as reported in the past. However, the activity of other neurons appeared to predict the trajectory of the target, but did not consistently predict the animal's behavior. The results suggest that the predictive role of the SEF is to provide high-level visual signals that can be used to guide oculomotor behavior.
Supported by: NIH(EY11720-05)