Distinct Roles of the Prefrontal and Posterior Parietal Cortices in Response Inhibition

The dorsolateral prefrontal cortex and posterior parietal cortex have been implicated in the planning of movements and inhibition of inappropriate responses, though their precise roles in these functions are not known. To address this question, we trained monkeys to perform memory-guided saccade and anti-saccade tasks and compared neural responses in the same animals. A population of neurons with no motor responses was also activated by a stimulus appearing out of the receptive field and could therefore mediate vector inversion. These neurons were found almost exclusively in the prefrontal cortex. Prefrontal cortical activity better predicted the level of performance in the task. Representation of the saccade goal also peaked in the prefrontal cortex at a time that was predictive of reaction time. These results suggest that the prefrontal cortex is the primary site of vector inversion in the cerebral cortex and explain the importance of this area in response inhibition.