Interaction effects. (a) For all categories of stimuli, participants rated them as more positive (i.e. regarding the Affective Valence dimension) following beta and theta stimulations, showing an enhancement in subjective ratings following those neurostimulations, but not the sham mode. (b) For all categories of stimuli, participants rated them as more calming (i.e. regarding the Arousal dimension) following theta stimulation, showing a decrease in how participants rated the arousing of images Error bars represent the standard error of the mean (±SEM).