Increased neural reactivity to socio-emotional stimuli links social exclusion and aggression

We investigated changes in the neural processing of social information as possible link between social exclusion and aggression. Participants played a virtual ball game with two putative game partners, during which half of the 34 participants were excluded. Then, participants played the Taylor Aggression Paradigm (TAP) against the same partners. An empathy paradigm followed, in which participants watched pictures of neutral and emotional social scenes, while undergoing functional magnetic resonance imaging (fMRI). Excluded participants showed stronger neural reactivity to emotional compared to neutral pictures than included participants in regions associated with cognitive mentalizing and the mirror neuron system (bilateral superior, middle and inferior temporal gyrus, bilateral precuneus, right precentral gyrus). Reactivity of left inferior temporal gyrus and right precentral gyrus was positively correlated with aggressive behavior in the TAP. Our results support previous behavioral findings which suggest changes in social information processing as mediator between exclusion and aggression.