Source density analysis of scalp potentials during evaluated action. II. Lateral distributions.

An economical method of computing the source densities underlying human scalp-recorded event-related potentials (ERPs) is used to investigate the topography of "evaluation potentials" elicited when a subject assess the outcome of a goal-directed activity. No sign of a generative focus was observed in frontal locations; but lateral placements over temporal and parietal lobes revealed an inversion of polarity of the evaluation potential suggesting the involvement of those regions in its computation. Experiments using auditory feedback of outcome, instead of or together with visual, showed no qualitative dependence of the main phenomena on the modality of feedback.