Disrupting SMA activity modulates explicit and implicit emotional responses: An rTMS study

Supplementary Motor Area (SMA) has been considered as an interface between the emotional/motivational system and motor effector system. Here, we investigated whether it is possible to modulate emotional responses using non-invasive brain stimulation of the SMA. 1 Hz repetitive transcranial magnetic stimulation (rTMS) trains were applied over the SMA of healthy subjects performing a task requiring to judge the valence and arousal of emotional stimuli. rTMS trains over the SMA increased the perceived valence of emotionally negative visual stimuli, while decreasing the perceived valence of emotionally positive ones. The modulatory effect on emotional valence was specific for stimuli with emotional content, since it was not observed for neutral visual stimuli. The effect was also specific for the site of stimulation, since rTMS of the visual cortex failed to modulate either perceived valence or arousal. These findings provide the first example of neuromodulation of emotional responses based on non-invasive brain stimulation.