Brain dynamics in spider-phobic individuals exposed to phobia-relevant and other emotional stimuli.

Abstract

Dense sensor event-related brain potentials were measured in participants with spider phobia and nonfearful controls during viewing of phobia-relevant spider and standard emotional (pleasant, unpleasant, neutral) pictures. Irrespective of the picture content, spider phobia participants responded with larger P1 amplitudes than controls, suggesting increased vigilance in this group. Furthermore, spider phobia participants showed a significantly enlarged early posterior negativity (EPN) and late positive potential (LPP) during the encoding of phobia-relevant pictures compared to nonfearful controls. No group differences were observed for standard emotional materials indicating that these effects were specific to phobia-relevant material. Within group comparisons of the spider phobia group, though, revealed comparable EPN and LPP evoked by spider pictures and emotional (unpleasant and pleasant) picture contents. These results demonstrate a temporal unfolding in perceptual processing from unspecific vigilance (P1) to preferential responding (EPN and 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.

Neuro-behavioral pattern of sleep bruxism in wakefulness

“…N300 has been recognized as a component particularly sensitive to visual stimuli generated by emotional images (Rossignol et al, 2005). With regard to the latency of the N300, subjects with anxiety, fears or phobias showed faster reaction time than control group subjects in the experiments performed by Flykt and Caldara (2006) and Michalowski et al (2009). In our study, EG subjects, who also had higher levels of anxiety compared to CG subjects, showed faster reaction times (shorter latencies) in channels C3 and O2.…”

Modulation of the ERP repetition effects during exposure to phobia-relevant and other affective pictures in spider phobia

“…Moreover, phobic fear has been shown to modulate processes of stimulus perception and evaluation. For example, we recently reported (Michalowski et al, 2009) that spider phobia participants responded with overall larger P1 amplitudes than controls in a context in which phobia-relevant stimuli are likely to occur, an effect that suggests increased vigilance in this group. Moreover, in our study spider phobia participants exhibited a significantly enlarged early posterior negativity (EPN) during viewing of their feared material than controls.…”

Phobias Across the Lifespan

“…Circa-strike defense, characterized by strong autonomic arousal and escape behavior, is activated when the threat is imminent. In a recent experiment, we tested this model by measuring electrical brain responses during the presentation of spider pictures to individuals with spider phobia and control participants (Michalowski et al, 2009). The main results of this study together with a sketch of the model can be seen in Figure 1.…”