Hippocampal contributions to the processing of social emotions.

Inducing and experiencing emotions about others' mental and physical circumstances is thought to involve self-relevant processing and personal memories of similar experiences. The hippocampus is important for self-referential processing during recall and prospection; however, its contributions during social emotions have not been systematically investigated. We use event-related averaging and Granger causal connectivity mapping to investigate hippocampal contributions during the processing of varieties of admiration and compassion pertaining to protagonists' mental versus physical circumstances [admiration for virtue (AV) versus for skill; compassion for social/psychological pain (CSP) versus for physical pain]. Data were collected using a multistep emotion-induction paradigm that included psychosocial interviews, BOLD fMRI, and simultaneous psychophysiological recording. Given that mnemonic demands were equivalent among conditions, we tested whether: (1) the hippocampi would be recruited more strongly and for a longer duration during the processing of AV and CSP; and (2) connectivity between the hippocampi and cortical systems involved in visceral somatosensation/emotional feeling, social cognitive, and self-related processing would be more extensive during AV and CSP. Results elucidate the hippocampus' facilitative role in inducing and sustaining appropriate emotional reactions, the importance of self-related processing during social emotions, and corroborate the conception that varieties of emotional processing pertaining to others' mental and physical situations engage at least partially distinct neural mechanisms.