Neurofunctional characterization of early prefrontal processes contributing to interpersonal guilt.

Guilt is a social emotion that plays a central role in promoting prosocial behavior. Despite its relevance, it remains poorly understood. The present study aimed to fill this gap by verifying and characterizing a frontal negative fluctuation of the event-related brain potentials (ERP) emerging in conditions of interpersonal guilt. Paired participants would earn money if both performed correctly a dot estimation task (both right); otherwise, both would lose a similar amount (self wrong, partner wrong, and both wrong conditions). The reported feeling of guilt was noticeable in the self wrong condition, which yielded a frontal negativity between 300 and 500 ms after the onset of performance feedback. The amplitude of this fluctuation, however, did not correlate with the amount of guilt reported by the participants, whereas both these values did so with standard measures of empathy. Neither anxiety (trait or state) nor arousal (skin conductance response) seemed to relate to this negativity. A neural source (LORETA) analysis established its generators in the dorsal medial prefrontal cortex (mPFC), a region linked to guilt in fMRI studies but also, importantly, to empathy. The frontal negative fluctuation thus might reflect empathic processes contributing to achieve feelings of interpersonal guilt.