Evaluating self-generated decisions in frontal pole cortex of monkeys

The frontal pole cortex (FPC) expanded dramatically during human evolution, but its function remains uncertain in either monkeys or humans. Here we report the first study of single-cell activity in this area. On every trial, monkeys decided between two response targets based on a ’stay’ or ’shift’ cue. Feedback followed at a fixed delay. FPC cells encoded the monkeys’ decisions, not when they were made, but later, as feedback approached. This finding indicates a role for FPC in monitoring or evaluating decisions. A control task, which used delayed feedback, suggested that decision coding lasted until feedback only when the monkeys combined working memory with sensory cues to “self-generate” decisions, as opposed to when they simply followed trial-by-trial instructions. A role in monitoring or evaluating self-generated decisions could account for FPC’s expansion during human evolution.