Effects of value and reward magnitude on feedback negativity and P300.

Feedback negativity is a negative component of the event-related brain potential observed 250^300 ms after feedback stimuli. The present study investigated the eiects of value (correct or incorrect) and reward magnitude (no, small or large) on feedback negativity and P300.Feedback negativity was larger after incorrect feedback than after correct feedback, irrespective of reward magnitude. In contrast, P300 amplitude increased with reward magnitude, irrespective of value. The amplitude of feedback negativity was correlated with a trait score of negative aiect and not positive aiect, whereas P300 amplitude was correlated with positive aiect and not negative aiect. These results suggest that value and reward magnitude are processed separately in the brain. NeuroReport 16:407^ 411 � c 2005 Lippincott Williams & Wilkins.