社会的文脈における記憶と内側前頭前皮質の役割

Contribution of the Medial Prefrontal Cortex to Social Memory

他者との相互作用の中で経験する出来事の記憶は，社会的文脈でのさまざまな要素的処理によって影響を受け，内側前頭前皮質が重要な役割を果たすとされている。先行する脳機能画像研究から，社会的文脈における記憶には，主に①報酬，②自己参照，③認知制御／他者認知，の3つの処理過程が関与しており，それぞれ内側前頭前皮質の下位領域である眼窩前頭皮質，腹内側前頭前皮質，背内側前頭前皮質が関連することが示唆される。

Abstract

Social memory is a form of episodic memories in multiple domains of social context. Functional neuroimaging studies have demonstrated that the medial prefrontal cortex (mPFC) plays an important role in social memories. However, little is known about the dissociable roles within mPFC in social memories. The purpose of this article was to summarize functional neuroimaging studies investigating social memories, and to propose a hypothetical model regarding the contribution of mPFC sub-regions to social memories. In this article, we divided mPFC into three sub-regions of the orbital, ventral, and dorsal regions. Functional neuroimaging studies have shown that the orbital mPFC (orbitofrontal cortex) contributes to the reward process in episodic memory, and that the reward-related activation is identified in primary, secondary, and social rewards. A role of the ventral mPFC has been found in the self-referential process, and the encoding operation of this process produces the self-reference effect in episodic memory. Activation in the dorsal mPFC has been observed in high demanding processes including cognitive control and in social cognition such as impression formation for others during episodic encoding and retrieval. The interactive mechanisms within three sub-regions of mPFC and between mPFC and the medial temporal lobe could contribute to social memories.