Cortico-hippocampal interactions underlie schema-supported memory encoding in older adults

Although episodic memory is typically impaired in older adults (OAs) compared to young adults (YAs), this deficit is attenuated when OAs can leverage their rich semantic knowledge, such as their knowledge of schemas. Memory is better for items consistent with pre-existing schemas and this effect is larger in OAs. Neuroimaging studies have associated schema use with the ventromedial prefrontal cortex (vmPFC), angular gyrus (AG), and hippocampus (HPC), but most of this research has been limited to YAs. This fMRI study investigated the neural mechanisms underlying how schemas boost episodic memory in OAs. Participants encoded scene-object pairs with varying congruency, and memory for the objects was tested the following day. Congruency with schemas enhanced object memory for YAs and, more substantially, for OAs. fMRI analyses examined cortico-hippocampal interactions at encoding. We found that a vmPFC-HPC interaction was related to enhanced subsequent memory for congruent objects in both age groups, whereas an AG-HPC interaction contributed to subsequent memory for congruent objects only in OAs. Individual difference analyses of the AG-HPC interaction suggested that OAs made use of semantic knowledge to facilitate encoding. Collectively, our findings illustrate age-related differences in how schemas influence episodic memory encoding via distinct cortico-hippocampal interactions.