Gender effect in affective processing: Alpha EEG source analysis on emotional slides and film-clips

Past research on gender-related brain asymmetries in emotions was limited and not univocal. The present study analyzed EEG alpha activity (indexing cortical de-activation) from 64 scalp sites in 20 women and 20 men during a counterbalanced block presentation of emotional slides and short video-clips. Stimuli consisted of 45 brief clips of 13 s, divided into 15 erotic (pleasant), 15 neutral and 15 fear (unpleasant) contents. Slides consisted in 45 photo shots (presented for 13 s each) extracted from the videos. As expected, women perceived fear stimuli as more arousing and more unpleasant compared to men. Alpha EEG source analysis revealed gender effects depending on stimulus. Emotional film-clips elicited in both groups a pattern of greater right than left occipital activation. Instead, emotional pictures activated opposite occipital regions, as women showed greater activation in the left, men in the right hemisphere. Men also showed greater activation to Erotic compared to Fear stimuli (i.e., pictures/clips) in the posterior parietal complex. Results point to the relevance of emotional stimulus type to reveal gender effects: clips are ecological, dynamic and engaging, and forced a unified pattern of emotional responses that reset individual differences. Emotional pictures, less engaging, allowed individual differences to emerge and interact with the stimulus category.