Suppressed Emotional Modulation on Early Auditory Processing of Predictable Stimuli

Emotion influences how we perceive the world, but the neural substrates of this modulationare not completely understood. Here, we aimed to evaluate how emotional state modulatesthe early sensory processing of auditory stimuli. We recorded auditory event-relatedpotentials while participants were listening to neutral tones and watching emotionalpictures simultaneously. To verify the emotional responses, we collected the subjectiveassessment of pictures, heart rate, and brain rhythms. We found that the emotional statesfailed in modulating N1 and P2 amplitudes. However, N1 amplitude decreased when wepresented a picture, compared to a white background. These results suggest a suppressedemotional modulation over the processing of periodic neutral events, probably due to thepredictability of these events. Nonetheless, we observed a deceleration of the heart rateduring presentation of emotional pictures and an increase in theta power during thepresentation of positive pictures, which confirms the induction of emotional reactions.