The neural correlates of discriminating bodily displays of emotion

Aims: As complex social beings, people intentionally or unintentionally engage in bodily actions including facial expressions or gestures to convey information about their emotional state to others. The addressee has to evaluate the intention of the addresser and to categorize the bodily displays of emotion in order to react appropriately. In this functional magnetic resonance imaging (fMRI) study we wished to explore the brain areas underlying the discrimination of bodily expressions of emotions. Method: Sixteen non-alexithymic healthy subjects were presented with video-clips showing emotional face expressions or gestures evolving from a neutral to a meaningful expression. In a forced-alternative choice paradigm, subjects were instructed to discriminate by a button-press an angry expression from other emotional expressions and a negative from a positive gesture, respectively. Results: There was a main effect related to perception of face expressions and gestures in the right inferior temporal gyrus (ITG). The ITG was also active at the time point of discrimination. During perception of face expressions, the right inferior frontal gyrus (IFG) and the dorsal medial frontal cortex (DMFC) became also activated. IFG activation increased during discrimination whereas DMFC activation decreased. Activation of the DMFC was correlated with the activations in the ITG and right IFG. Moreover, there was an activation of the right dorsolateral frontal cortex (DLFC) which occurred only in relation to discrimination and correlated with the ITG, IFG and DMFC activations. Conclusion: The activation of the ITG is likely to reflect the formal visual analysis of the emotional face expressions and gestures. Discrimination involved frontal brain areas related to valuation of emotions. Thus, we believe that this study sheds light on the brain system underlying non-verbal communication in everyday face to face situations.