Multiple determinants of the medial frontal negativities related to error processing and feedback

Gehring, W. J., and Willoughby, A. R.
Department of Psychology, University of Michigan

The studies reported here address two related issues: how the various medial-frontal/anterior cingulate processes observed in electrophysiological and neuroimaging studies are related, and what the functional roles of these processes are in monitoring and regulating behavior. A variety of medial-frontal negativities are evident in diverse experimental paradigms (e.g., the ERN/Ne, the negativities elicited by error feedback and monetary losses, and the various N2s). One experiment employed time-frequency analysis (using continuous wavelet transforms) to determine whether these negativities arise from the same underlying pattern of brain activity. The response-locked ERN and the ERN-like activity elicited by monetary losses were each apparent as a burst of activity in the 4-7 Hz (theta) range. Variations in the scalp distribution of this theta activity suggest that the two phenomena are not identical, although there may be sources common to both. A second study explored the numerous ways in which a feedback stimulus can be "good or bad" and "expected or unexpected. Here, we examined the feedback-related negativities elicited by feedback stimuli signifying the rewards that were missed or penalties that were avoided because of a prior choice made by the subject. We observed several conditions in which feedback representing a favorable outcome elicited a feedback-related negativity as large as that elicited when the outcome was bad. Our results suggest that theories of medial-frontal function must accommodate the multiple neural sources of the scalp activity and the multiple ways in which a stimulus can deviate from contextually-determined expectancies.