Remembering my friends: Medial prefrontal and hippocampal contributions to the self-reference effect on face memories in a social context.

Memories associated with the self are remembered more accurately than those associated with others. The memory enhancement related to the self is known as the self-reference effect (SRE). However, little is known regarding the neural mechanisms underlying the SRE in a social context modulated by social relationships. In the present fMRI study, we investigated encoding-related activation of face memories encoded with the self-referential process in a social context that was manipulated by imagining a person-to-person relationship. Healthy young adults participated in the present study. During encoding, participants encoded unfamiliar target faces by imagining a future friendship with themselves (Self), their friends (Friend), or strangers (Other). During retrieval, participants were presented with target and distracter faces one by one, and they judged whether each face had been previously learned. In the behavioral results, target faces encoded in the Self condition were remembered more accurately than those encoded in the Other condition. fMRI results demonstrated that encoding-related activation in the medial prefrontal cortex (mPFC) was significantly greater in the Self condition than in the Friend or Other conditions. In addition, the generalized psycho-physiological interaction (gPPI) analysis showed that functional connectivity between activation in the hippocampus and the cortical midline structures (CMSs), including the mPFC and precuneus, was significant in the Self but not in the Other condition. These findings suggest that the SRE in a social context could be involved in the interaction between the CMS regions, which are related to the self-referential process, and the hippocampus related to the memory process. Hum Brain Mapp 38:4256-4269, 2017.