Separable neural mechanisms contribute to feedback processing in a rule-learning task.

To adjust performance appropriately to environmental demands, it is important to monitor ongoing action and process performance feedback for possible errors. In this study, we used fMRI to test whether medial prefrontal cortex (PFC)/anterior cingulate cortex (ACC) and dorsolateral (DL) PFC have different roles in feedback processing. Twenty adults completed a rule-switch task in which rules had to be inferred on the basis of positive and negative feedback and the rules could change unexpectedly. Negative feedback resulted in increased activation in medial PFC/ACC and DLPFC relative to positive feedback, but the regions were differentially active depending on the type of negative feedback. Whereas medial PFC/ACC was most active following unexpected feedback indicating that prior performance was no longer correct, DLPFC was most active following negative feedback that was informative for correct behavior on the next trial. The current findings show that inconsistent results about the role of prefrontal cortex regions in feedback processing are most likely associated with the informative value of the performance feedback. The results are consistent with the hypothesis that medial PFC/ACC is important for signaling expectation violation whereas DLPFC is important for goal-directed actions.