The neural correlates of affect reading: an fMRI study on faces and gestures

As complex social beings, people communicate, in addition to spoken language, also via nonverbal behavior. In social face-to-face situations, people readily read the affect and intentions of others in their face expressions and gestures recognizing their meaning. Importantly, the addressee further has to discriminate the meanings of the seen communicative motor acts in order to be able to react upon them appropriately. In this functional magnetic resonance imaging study 15 healthy non-alexithymic right-handers observed video-clips that showed the dynamic evolution of emotional face expressions and gestures evolving from a neutral to a fully developed expression. We aimed at disentangling the cerebral circuits related to the observation of the incomplete and the subsequent discrimination of the evolved bodily expressions of emotion which are typical for everyday social situations. We show that the inferior temporal gyrus and the inferior and dorsal medial frontal cortex in both cerebral hemispheres were activated early in recognizing faces and gestures, while their subsequent discrimination involved the right dorsolateral frontal cortex. Interregional correlations showed that the involved regions constituted a widespread circuit allowing for a formal analysis of the seen expressions, their empathic processing and the subjective interpretation of their contextual meanings. Right-left comparisons revealed a greater activation of the right dorsal medial frontal cortex and the inferior temporal gyrus which supports the notion of a right hemispheric dominance for processing affective body expressions. These novel data provide a neurobiological basis for the intuitive understanding of other people which is relevant for socially appropriate decisions and intact social functioning.