Neural organization of episodic memory and navigation in children and adults

Episodic memory and spatial navigation are often viewed as two sides of the same coin, in part due to their shared reliance on medial temporal lobe (MTL) structures. At the same time, there are important differences, in both the acquisition format (for instance, natural spatial navigation requires moving one’s body through space while episodic memory does not) and in the neuroanatomical underpinnings that extend beyond the MTL. Here we investigated whether the retrieval of naturalistically encoded memories that were either episodic or additionally embedded in a navigational experience, relies on overlapping or distinct networks. In addition, we examined the development of these processes, given that prior work has revealed distinct developmental profiles for navigation and episodic memory. Children ages 8 to 13 years old and young adults viewed objects that they had previously encountered in real-world experiences, either on a tour of a new environment or seated in a room. Univariate fMRI analyses revealed a signal for navigational representations in entorhinal and perirhinal cortices that increased through early adolescence. Functional connectivity between these two regions for episodic representations decreased with age. Exploratory findings suggested behavior-driven connectivity among the hippocampus, entorhinal cortex, and lateral occipital cortex to support reconstruction of the spatial context. Episodic and navigational representations are coded in overlapping brain regions, but these regions may interact differently for people in late childhood and early adolescence as opposed to early adulthood.