Disgust exposure and explicit emotional appraisal enhance the LPP in response to disgusted facial expressions

The influence of prior exposure to disgusting imagery and the conscious appraisal of facial expressions were examined in an event-related potential (ERP) experiment. Participants were exposed to either a disgust or a control manipulation and then presented with emotional and neutral expressions. An assessment of the gender of the face was required during half the blocks and an affective assessment of the emotion in the other half. The emotion-related early posterior negativity (EPN) and late positive potential (LPP) ERP components were examined for disgust and neutral stimuli. Results indicated that the EPN was enhanced for disgusted over neutral expressions. Prior disgust exposure modulated the middle phase of the LPP in response to disgusted but not neutral expressions, but only when the emotion of the face was explicitly evaluated. The late LPP was enhanced independently of stimuli when an emotional decision was made. Results demonstrated that exposure to disgusting imagery can affect the subsequent processing of disgusted facial expressions when the emotion is under conscious appraisal.