Voluntary facial expression and hemispheric asymmetry over the frontal cortex

Brain activity was monitored while 36 participants produced facial configur ations denoting anger, disgust, fear, joy, and sadness. EEG alpha power was analyzed during each facial pose, with facial conditions grouped according to the approach/withdrawal motivational model of emotion. This model sugge sts that "approach" emotions Lire associated with relatively greater left f rontal brain activity whereas "withdrawal" emotions are associated with rel atively greater right frontal brain activity. In the context of a bilateral decrease in activation, facial poses of emotions in the withdrawal conditi on resulted in relatively less left frontal activation in the lateral-front al, midfrontal and frontal-temporal-central region, but not in the parietal region, as predicted. Findings in the approach condition were less consist ently supportive of predictions of the approach/withdrawal model. Implicati ons for the approach/withdrawal model and for the emotion eliciting potenti al of voluntary facial movement are discussed.