Emotional and feature-based modulation of the early posterior negativity.

The early posterior negativity (EPN) has been shown to be enhanced by emotional relative to neutral scene perception. A subset of studies has also reported a bias in the EPN toward pleasant relative to unpleasant scenes. Functional MRI research has also identified a region in lateral occipital cortex that shows a sensitivity to the visual perception of body parts, which may contribute to the EPN. Here, we assess the roles of rated scene pleasantness and the depiction of body parts on modulation of the EPN in two studies, using scenes that are chosen to be of equivalent perceptual complexity. In Study 1, we presented two distinct highly pleasant and arousing scene contents (erotic couples and moments of jubilant victory) as well as neutral people, threat, and mutilation scenes. As in prior research, the EPN was enhanced by emotionally arousing scenes, with the greatest modulation evoked by erotic scenes, although victory scenes elicited stronger ratings of pleasantness and equivalent ratings of arousal. This result suggests that the EPN may be sensitive to distinct features found in erotic scenes. To determine the extent to which body part perception modulates the EPN, Study 2 compared EPN modulation evoked by erotic scenes with nonerotic nudist scenes. Ratings of pleasantness and arousal were reduced, yet nudist scenes led to stronger modulation of the EPN compared to erotic scenes. These data indicate that, in addition to the emotional intensity of scenes, modulation of the EPN may in part reflect the discrimination of unclothed body parts.