Attentional bias to threat following acute stress induction : an ERP study

This study employed trauma-exposed and non-trauma-exposed individuals to explore group differences in physiological arousal, ERP components, and attentional bias to threat: a bias towards threatening stimuli often seen in individuals with posttraumatic stress disorder (PTSD). Attentional bias was assessed using reaction time measures in a dot-probe task and the amplitudes of ERP components P1, N1, and P3; while arousal was assessed using salivary alpha-amylase (sAA), a biomarker of noradrenergic reactivity. Eighteen trauma-exposed (non-PTSD) and 19 non-trauma-exposed individuals undertook the dot-probe task, with saliva tested before and after a cold pressor stress (CPS) task that was used to induce acute stress. The CPS task was successful in inducing acute stress and significantly increasing sAA in both groups, although no significant difference was found between the groups on physiological arousal. Unexpectedly, no significant attentional bias effect was found in the reaction time data for either group, in contrast to empirical literature. The major finding was that trauma-exposed individuals displayed increased amplitude of the P3 ERP component to threatening images following the CPS task, an effect not found in the non-trauma-exposed group. This finding suggests that trauma-exposed individuals show an attentional bias to threatening stimuli even in the absence of PTSD.