Medial prefrontal cortex and error potentials

William J. Gehring and Adrian R. Willoughby ("The medial frontal cortex and the rapid processing of monetary gains and losses," Reports, 22 March, p. 2279) report that a "medial-frontal negativity" (MFN), a negative-going deflection in the human event-related brain potential (ERP), was elicited by feedback stimuli indicating monetary gains or losses. The MFN was greater in amplitude following losses than following gains and was attributed to activity in medial frontal cortex. Previous studies have identified a similar negative deflection in the ERP that occurs following incorrect responses in speeded reaction time tasks (1, 2) and following feedback stimuli that indicate incorrect performance (3). Both of these response and feedback "error-related negativities" (ERNs) were thought to be produced in medial frontal cortex by a mechanism for error detection (1-3). As Gehring and Willoughby note, the MFN and the feedback-related ERN share identical scalp distributions and latencies, suggesting that they are the same phenomenon. Importantly, however, Gehring and Willoughby emphasize that the MFN/feedback ERN is sensitive to the "utilitarian" (gain or loss) value of feedback, rather than to the "performance" (correct or incorrect) value of feedback. In so doing, they dissociate that component from the response-related ERN and its associated function, error detection.