Are all medial frontal negativities created equal? Toward a richer empirical basis for theories of action monitoring

Theories and empirical studies concerned with the action monitoring functions of the medial frontal cortex have generally assumed that numerous medial frontal negativities--such as the error-related negativity (ERN/Ne), N2, and the negativity elicited by error feedback and monetary losses--all reflect the activity of a common underlying neural generator. Several reports have asserted that the ERN and the feedback negativity both reflect the same underlying neural activity, and an influential model postulates that both components represent activity generated when the anterior cingulate cortex receives an error signal indicating that an event is “worse than expected.” In this paper, we use time-frequency analysis based on the continuous wavelet transform to test the proposal that the ERN and the feedback-related medial frontal negativity are equivalent. We find that the two components are not identical in their scalp distribution, indicating that a single, common source cannot be the only source generating the two components.