Functional organization of the human medial temporal lobe

Abstract

Episodic events are composed of multiple features such as where the event took place, what happened and who was involved. Which features we later remember from different events often varies. A fundamental question is how does the medial temporal lobe (MTL), a region essential to memory formation, support the encoding of these varied episodic details? Do different MTL subregions contribute to the encoding of different features of an event? A series of fMRI studies addressing these questions are presented. Data show content-specific differential engagement of MTL subregions, particularly perirhinal cortex and parahippocampal cortex. Further, data show that these regions differentially contribute to the recollection of objects and scenes, respectively. The underlying nature of item representation within these regions is considered. Data provide evidence suggesting potential conceptual contributions to such representations in MTL. The implications of these findings on the present understanding of episodic memory are discussed.