Temporal dynamics of the brain response to phobia-relevant and standard emotional visual stimuli in spider-phobic individuals

Abstract

Dense sensor event-related brain potentials were measured in participants with spider phobia and non-fearful controls exposed to spider and standard emotional (pleasant, unpleasant, neutral) pictures. Spider phobia participants showed enlarged P1 amplitudes for all picture contents than controls, suggesting increased vigilance in this group. Furthermore, spider phobia participants responded with significantly larger early posterior negativity (EPN) and late positive potential (LPP) during the encoding of phobia-relevant pictures, relative to non-fearful control participants. No group differences in the EPN and LPP were found for standard emotional materials indicating that these effects were specific to phobia-relevant material. However, within group comparisons of the spider phobia group revealed comparable EPN and LPP evoked by spider pictures and emotional (unpleasant and pleasant) picture contents. These results demonstrate a temporal shift in perceptual processing from unspecific vigilance (P1) to preferential responding (EPNand LPP) to phobia relevant materials in the spider phobia group. However, at the level of early stimulus processing, these effects of increased attention seem to be related to emotional relevance of the stimulus cues rather than reflecting a fear-specific response.