When I think about me and simulate you: medial rostral prefrontal cortex and self-referential processes.

While neuroimaging studies implicate medial rostral prefrontal cortex (mrPFC) in self-referential processing, simulation accounts of social cognition suggest that this region also supports thinking about other people. This study tested the prediction that mrPFC might be involved in appraising the personality traits of another person to the degree that this person is perceived as similar to oneself. We also examined whether recruiting common processes for thinking about oneself and others might impact on subsequent memory for those judgments. Functional MRI was used while two factors were crossed: (i) the requirement to engage in personality trait or episodic source memory judgments and (ii) the reference for these judgments (i.e., oneself or a friend). The results link haemodynamic changes in mrPFC to both personality judgments about oneself and subsequent episodic memory retrieval of these judgments. The degree to which BOLD signal in this region was also associated with thinking about others correlated with perceived similarity in both tasks, thus corroborating simulation accounts. Moreover, participants who perceived themselves as having similar traits to their friends tended to be poorer at remembering whether they had made trait judgments in reference to themselves or their friend. This behavioral effect was reflected in the BOLD signal in mrPFC: there was a positive correlation between signal change for self versus friend judgments and subsequent memory for the reference of such judgments. The results suggest that investigations of mrPFC activity in the context of self/other judgments should take into account this psychological similarity effect.