Emotion specific neural activation for the production and perception of facial expressions.

The distinction between different facial emotions is crucial for interpersonal communication. Shared neural circuits for facial emotion production and perception are considered to facilitate the ability to understand other's emotional state via mirror neuron mechanisms. Little is known about how diverse emotions differentially activate the Mirror Neuron System (MNS) during facial expression processing. In a functional magnetic resonance imaging (fMRI) task, 178 healthy subjects perceived and produced emotional (happy vs angry) and non-emotional (lip-protrusion vs no movement) facial expressions. Dynamic facial expressions were displayed as 5 sec video clips. We identified three overlapping networks of neural activation for happy, angry, and non-emotional (lip-protrusion) facial expression production and perception. Importantly, this overlap was largely due to the common motor component of facial expressions. However, for happy facial expressions, we found specific MNS activation in the right temporal pole. For angry facial expressions we found such activation in the left inferior frontal gyrus, pars orbitalis, and the cerebellum (lobules VII and VIII). We extend knowledge on mirror neuron mechanisms as our results provide evidence for emotion specific shared neural activation for the production and perception of facial emotions. This emotion specific representation of other's emotion in one's own neural production system might facilitate understanding of other's mental or emotional states.

Conflicting group memberships modulate neural activation in an emotional production-perception network.

Social group membership modulates the neural processing of emotional facial expressions, which, in turn, recruits part of the neural production system. However, little is known about how mixed - and potentially conflicting - social identity cues affect this mechanism. In this study, we tested the hypothesis that incongruent cues of two group memberships (ethnic and experimentally created minimal groups) elicit conflict processing for neutral and, in particular, angry facial expressions. We further expected this interaction of ethnic group, minimal group and emotion to also modulate activation in an emotional production-perception network. Twenty-two healthy German subjects saw dynamic angry and neutral facial expressions, presented in short video clips during functional MRI scanning. All depicted actors belonged to an ethnic in- or outgroup (German or Turkish descent) as well as an ad hoc experimentally created minimal in- or outgroup. Additionally, subjects produced angry or neutral expressions themselves. The whole-brain interaction of ethnic group, minimal group and emotion revealed activity in the right parietal lobule and left cerebellum. Both showed strongest activation for angry faces with conflicting group memberships (e.g., 'ethnic outgroup/minimal ingroup'). In addition, a sub-region of the left cerebellum cluster was also activated for both perceiving and producing angry versus neutral expressions. These results suggest that incongruent group members displaying angry facial expressions elicit conflict processing. Group interaction effects in an emotional production-perception network further indicate stronger neural resonance for incongruent group members.

Intergroup empathy: Enhanced neural resonance for ingroup facial emotion in a shared neural production-perception network.

INTRODUCTION: Empathic behavior and related neural processing are strongly modified by group membership. Shared neural circuits for the production and perception of facial emotional expressions represent mirror neuron mechanisms which play a pivotal role for empathy. In this study, we investigate the influence of group membership on mirror neuron mechanisms for emotional facial expressions. METHODS: In a functional magnetic resonance imaging task, 178 healthy subjects perceived emotional and neutral facial expressions of artificial ingroup and outgroup members, displayed as 5 s video clips, and produced these facial expressions themselves. Before scanning, artificial group membership was manipulated ad-hoc through a minimal group paradigm. RESULTS: Shared neural activity for emotional facial expression production and perception was revealed in a large network with right-hemispheric preponderance encompassing motor mirror neuron regions, i.e., inferior frontal gyrus, supplementary motor area and middle temporal gyrus, in addition to limbic regions, i.e., amygdala, hippocampus, para-hippocampus, and insula. Within this network there was greater neural activation for ingroup compared to outgroup members in temporal poles, amygdalae, the left insula, the left inferior frontal gyrus, and the inferior and middle temporal gyrus, the right hippocampus and parahippocampus. DISCUSSION: We validate and extend knowledge on brain regions with mirror neuron properties. Most crucially, we provide evidence for the influence of group membership on regions within the mirror neuron system, indicating more neural resonance (mirroring) for ingroup facial emotional expressions.