60 Neural Correlates of the Self-Reference Effect: Neuronal Mechanisms Supporting Self-Referential Encoding.

Objective: Self-concept is a mental representation of the self—an internal sense of personal identity. This complex representation is unique to the human mind. Behavioral studies on self-concept have demonstrated that self-relevant information is remembered better than other types of information, a phenomenon commonly known as the "self-reference effect" (SRE). However, the underlying neural mechanisms of SRE remain largely unknown. Participants and Methods: Here, we recorded neural activity from ∼600 neurons from 15 neurosurgical epilepsy patients, who were implanted with depth electrodes for seizure monitoring. The SRE paradigm consisted of an incidental learning (encoding) task and subsequent memory recognition test. During the incidental learning task, participants were asked to rate various personality traits in three distinct encoding conditions: the self, a friend, and a celebrity. In the recognition part of the task, participants were asked to distinguish between traits that were presented during the encoding phase (old) and traits that were not presented (new). Results: Our behavioral findings showed the highest memory accuracy on the recognition test for traits that were associated with the "self" condition, which is consistent with previous studies on SRE. Additionally, we found that traits associated with the "friend" category were more accurately recognized than those associated with a celebrity, indicating that personally familiar information—even if not self-related— improves memory recognition. Through single-unit analyses from target brain regions, including the medial temporal lobe (MTL) and medial prefrontal cortex (mPFC), we identified unique patterns of neural activity during the memory encoding phase, specifically increased responses during self-referential encoding in a subset of the neuronal population. Conclusions: Future analyses will explore the relationship between increased MTL activity during self-referential encoding and improved memory recognition of traits rated in relation to the self, and network interactions between MTL and mPFC in self-oriented memory processes. [ABSTRACT FROM AUTHOR]