The modulation of delta responses in the interaction of brightness and emotion

•We compared delta oscillatory responses to original and bright IAPS pictures.•Significant main effect of condition (bright versus original) for the arousal dimension was found•Bright unpleasant emotional stimuli influenced delta oscillatory responses by affecting their amplitudes•Lower delta oscillatory responses were observed upon presentation of bright unpleasant pictures compared to thir originals.

The modulation of delta oscillations (0.5-3.5 Hz) by emotional stimuli is reported. Physical attributes such as color, brightness and spatial frequency of emotional visual stimuli have crucial effect on the perception of complex scene. Brightness is intimately related with emotional valence. Here we explored the effect of brightness on delta oscillatory responses upon presentation of pleasant, unpleasant and neutral pictures. We found that bright unpleasant pictures elicited lower amplitude of delta response than original unpleasant pictures. The electrophysiological finding of the study was in accordance with behavioral data. These results denoted the importance of delta responses on the examination of the association between perceptual and conceptual processes while in the question of brightness and emotion.