The effect of accomplishment and failure on P300 potentials evoked by neutral stimuli

The effects of emotional slates of 'being successful' vs. 'being unsuccessf ul' were studied by measuring the P300 component of event-related potential s (ERPs). Nine subjects were instructed to reduce their P300 amplitude usin g feedback. Feedback was random but the relative probability of different s ignals created the situations of 'being successful' or 'being unsuccessful' . The probability of 'small' feedback was 0.7 in 'successful' and 0.15 in ' unsuccessful' trials. ERPs recorded without the feedback were used as a ref erence. Potentials, evoked by light stimuli in a standard 'odd-ball' proced ure, were recorded from Fz, Ct and Pt scalp sites. The amplitudes of P300 c omponents were reduced in 'unsuccessful' trials whereas in 'successful' tri als they did not differ significantly from responses recorded without the f eedback. There were no significant differences in peak latencies. These fin dings indicate that tonic emotional states affect the processing of neutral stimuli and that late components of ERPs can be useful indices in the anal ysis of these alterations. The results also indicate that the effects of po sitive and negative emotional states are not always reciprocal. Manipulated feedback is suggested as an useful model in the studies of emotions. Data can also facilitate the interpretation of the real feedback effects. (C) 19 99 Elsevier Science Ltd. All rights reserved.