Positive event-related potentials to real and dummy rule-learning feedback and to perceptuomotor feedback.

Amplitudes of 5 event-related potentials (ERPs) were recorded at 5 sites of 10 males to real (R-) and dummy (D-) feedback (FB) over two difficulty levels of a rule-learning task, with interspersed perceptuomotor (PM) task trials. Rule-learning R-FB for positive slow wave (PSW) and P3b was greater than for D-FB for both mean time-window and principal component factor score measures. FB effects varied by site for P2/P3a (mainly Fz-C4-Pz) and for a late PSW (LPSW; mainly C4-C3-Fz). A new ERP, P508, showed the greatest topographic differentiation, but no FB main effect. The following ERPs may reflect different sources: PSW versus P3b; P2/P3a versus LPSW; R-FB versus D-FB P2/P3a; R-FB versus D-FB LPSW; and P508 versus all others. LPSW was greater to simple than complex task difficulty; while the "P508" factor score trended towards being greater for complex than simple. ERP interpretation is in terms of stimulus recognition classification, comparative evaluation and development elaboration of mental models. Rule-learning D-FB exceeded PM accuracy R-FB for all ERPs but P2/P3a. Strongly implicated in these differences are preparatory acts in the former task as reflected by the PSW and LPSW.