Empathy, approach attitude, and rTMs on left DLPFC affect emotional face recognition and facial feedback (EMG)

Empathic trait (Balanced Emotional Empathy Scale [BEES]) and emotional attitude (Behavior Activation System [BAS]) were supposed to modulate emotional face recognition, based on left dorsolateral prefrontal (DLPFC) cortex contribution. High-empathic trait (high- BEES) was compared with low-empathic trait (low-BEES), when detection performance (Accuracy Index; Response Times [RTs]) and facial activity (electromyogram, EMG, i.e., zygomatic and corrugators muscle activity) were analyzed. Moreover, the implication of the left DLPFC was tested by using low-frequency rTMS (repeated Transcranial Magnetic Stimulation) to induce a decreased response to facial expression of emotions when subjects (N = 46) were required to empathize with the emotional stimuli. EMG and behavioral responses were found to be modulated by BEES and BAS, with a decreased performance and a reduced facial responsiveness in response to happiness for high-BEES and high-BAS in the case of TMS on left DLPFC. Secondly, an emotion-specific effect was found: the DLPFC effect was observed for the positive emotion (happiness) more than for the negative emotions (anger and fear) with a decreased performance (lower Accuracy Index [AI] and higher RTs) and a decreased zygomatic muscle activity. Finally, a direct correlation was found between BEES and BAS and the latter was revealed to be predictive (regression analysis) of the behavioral and EMG modulation induced by TMS. These results suggest significant effect by empathic and emotional attitude component on both EMG and behavioral level in emotional face recognition. This mechanism appears to be supported and regulated by DLPFC. The lateralization (left) effect was discussed in light of the valence model of emotions.