Prefrontal cortex modulation of mood and emotionally induced facial expressions: a transcranial magnetic stimulation study.

Repetitive transcranial magnetic stimulation (rTMS) can serve as a tool to experimentally test hypotheses of prefrontal cortex (PFC) modulation of emotions. The present study used rTMS to test whether self-rated mood and emotionally induced facial expressions are hemispherically lateralized depending on their valence, as indicated by previous studies. Healthy volunteers underwent mood self-rating and computerized analysis of emotionally induced facial expressions before and after rTMS of left or right PFC. Facial expression analysis revealed lateralized changes of facial expressions after rTMS, whereas changes of subjective mood ratings did not show a hemispheric lateralization. On the basis of this study, the authors propose to combine rTMS and facial expression analysis for further studies of the cortical modulation of emotions in humans.