Modulation of cortical midline structures by implicit and explicit self-relevance evaluation.

Recent neuroimaging work has observed activity in cortical midline structures (CMS) such as medial prefrontal and posterior cingulate cortices during self-referential processing. Moreover, items rated as self-relevant produce increased activity in these regions relative to items that are deemed not self-relevant. A common thread among previous reports has been reliance on experimental tasks that encourage or require online self-referential processing. In this paper, we report findings from two experiments that manipulated requirements for self-reflection. In Experiment 1, subjects rated trait adjectives for social desirability and for self-relevance. Results revealed increasing activity in CMS with increasing self-relevance, but only during explicit ratings of self-relevance. In Experiment 2, we examined CMS activity during passive viewing of personal semantic facts (such as subjects' own first names). Taken together, these results suggest that highly self-relevant information captures attention through neural mechanisms that are comparable to those engaged during explicit self-reflection, namely via recruitment of CMS structures.