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

The effects of emotional states of 'being successful' vs. 'being unsuccessful' were studied by measuring the P300 component of event-related potentials (ERPs). Nine subjects were instructed to reduce their P300 amplitude using feedback. Feedback was random but the relative probability of different signals 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 reference. Potentials, evoked by light stimuli in a standard 'odd-ball' procedure, were recorded from Fz, Cz and Pz scalp sites. The amplitudes of P300 components were reduced in 'unsuccessful' trials whereas in 'successful' trials they did not differ significantly from responses recorded without the feedback. There were no significant differences in peak latencies. These findings indicate that tonic emotional states affect the processing of neutral stimuli and that late components of ERPs can be useful indices in the analysis of these alterations. The results also indicate that the effects of positive 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.