Affective modulation of the LPP and α-ERD during picture viewing.

Brain responses to engaging stimuli may be reflected both in event-related potentials (ERPs) and in electroencephalogram (EEG) oscillations. Previous studies investigating the effects of top-down factors on stimulus encoding revealed similar modulation of late ERPs and alpha-band desynchronization (α-ERD) by relevant target stimuli. Focusing on the bottom-up effects of emotional content and picture size, the present study aimed to investigate the relationship of the late positive potential (LPP) and α-ERD during the viewing of emotional pictures. Results showed similar affective modulation by picture arousal of the LPP and α-ERD. Moreover, picture size reduction diminished overall magnitude of both responses, but did not dampen affective modulation of either response. These results suggest that, during affective picture viewing, these two brain responses similarly reflect the engagement of motivational systems in order to facilitate perception.