Prospective and retrospective representations of saccadic movements in primate prefrontal cortex.

Abstract

The dorso-lateral prefrontal cortex (dlPFC) contributes to flexible, goal-directed behaviors. However, a coherent picture of dlPFC function is lacking, as its activity is often studied only in relation to a few events within a fully learned behavioral task. Here we obtain a comprehensive description of dlPFC activity across different task epochs, saccade types, tasks, and learning stages. We consistently observe the strongest modulation of neural activity in relation to a retrospective representation of the most recent saccade. Prospective, planning-like activity is limited to task-related, delayed saccades directly eligible for a reward. The link between prospective and retrospective representations is highly structured, potentially reflecting a hard-wired feature of saccade responses. Only prospective representations are modulated by the recent behavioral history, but neither representation is modulated by day-to-day behavioral improvements. The dlPFC thus combines tightly linked flexible and rigid representations with a dominant contribution from retrospective signals maintaining the memory of past actions.