The two faces of avoidance: Time-frequency correlates of motivational disposition in blood phobia.

Contrary to other phobias, individuals with blood phobia do not show a clear-cut withdrawal disposition from the feared stimulus. The study of response inhibition provides insights into reduced action disposition in blood phobia. Twenty individuals with and 20 without blood phobia completed an emotional go/no-go task including phobia-related pictures, as well as phobia-unrelated unpleasant, neutral, and pleasant stimuli. Behavioral results did not indicate a phobia-specific reduced action disposition in the phobic group. Time-frequency decomposition of event-related EEG data showed a reduction of right prefrontal activity, as indexed by an increase in alpha power (200 ms), for no-go mutilation trials in the phobic group but not in controls. Moreover, theta power (300 ms) increased specifically for phobia-related pictures in individuals with, but not without, blood phobia, irrespective of go or no-go trial types. Passive avoidance of phobia-related stimuli subtended by the increased alpha in the right prefrontal cortex, associated with increased emotional salience indexed by theta synchronization, represents a possible neurophysiological correlate of the conflicting motivational response in blood phobia. Through the novel use of time-frequency decomposition in an emotional go/no-go task, the present study contributed to clarifying the neurophysiological correlates of the overlapping motivational tendencies in blood phobia.