Pre- and post-stimulus processes in affective task and event-related desynchronization (ERD): do they discriminate...

The present investigation was designed to study whether pre-stimulus (as measured by EEG power in the time interval before the stimulus presentation) and post-stimulus (as measured by event-related desynchronization (ERD)) processes of alpha components in two frequency bands (8-10 and 10-12 Hz) and their scalp distribution discriminate among anxiety coping styles in an affective task. We investigated this question by using a sample of 30 college students who were split into three groups consisting of 10 low-anxious (LA) and 10 high-anxious (HA) subjects, and 10 repressors (RE). In the present study, positive and negative emotions were operationalized by winning and losing certain amounts of money in gambling situation while measuring ERD to positive and negative feedback stimuli. The main findings of the prestimulus data analyses suggest that the prestimulus level of alpha power is sensitive to the anxiety coping styles. In terms of ERD effects, HA individuals were marked by relatively larger left-hemisphere activation compared to low-anxious subjects and repressors. Further, in contrast to LA and RE, the phenomena observed in our experiment of increased and extended ERD over time in HA in response to negative feedback stimulation implies that threatening information (loss of money) is more persistently activated in subjects with high anxiety. Although preliminary, the reported findings are of potential importance because they could lead to the development of a new psychophysiological measure of relevance to personality.