SHORT-TERM SENSITIZATION TO CONSECUTIVE AFFECTIVE IMAGES

Abstract

Specific phobias, which are caused by faulty affective processing and regulation, cause distress when an individual confronts the subject of the phobia, disrupting daily activities and affecting their quality of life. While current treatments have high rates of success (Adler & Cook-Nobles, 2011), exposing subjects to phobic stimuli as part of these treatments may be detrimental to their mental health due to the distress caused (Meuret, Seidel, Rosenfield, Hofmann, & Rosenfield, 2012). Brain regions involved in affective processing and regulation show some overlap with those involved in pain. Perceived pain can be reduced by exposing one to a painful stimulus of greater intensity beforehand. If this effect is mediated by neural pathways shared by pain and affective processing, then it is reasonable to hypothesize that emotional responses could similarly be reduced by prior exposure to highly emotive stimuli. Healthy subjects were asked to rate their emotional response to two images presented in quick succession. Contrary to our hypothesis, we found that images of high arousal led to an increased emotional response to the subsequently presented medium arousal images. There was also evidence suggesting the slow buildup of the effect over time. Overall, these results are consistent with the interpretation that high-arousal negative images sensitize the subjects to assess subsequent images as more arousing. While pain and affective processing in the brain share certain pathways, our results suggest that non-overlapping pathways mediate the adaptation to painful stimuli and sensitization to affective stimuli.