Neural Correlates of Category-Specific Associative Memory

Poster presented at the annual meeting of the Cognitive Neuroscience Society 2022.

Mrinmayi Kulkarni, Lydia Jiang, Jessica Robin, Anika Choi, Bradley R. Buchsbaum, Rosanna K. Olsen
Episodic memory relies on the brain’s ability to flexibly recombine disparate elements across episodes to form new associations. In this study, we examined whether the category of items that form the memory associations influences neural recruitment of the hippocampus. Participants completed interleaved study-test phases of an associative inference task while undergoing fMRI scanning. During study, they encoded overlapping scene-object or face-object pairs. During each block, 16 pairs were presented (8 AB pairs and 8 partially-overlapping BC pairs). A/C items were always objects, but the linking B item was either a face or a scene. During test, memory for the direct associations (AB and BC pairs) and indirect associations (AC inference pairs) was probed. Behavioral performance was similar across categories; however, fMRI data revealed that distinct brain regions were recruited for associative memory and inferences involving scenes and faces. Successful retrieval of face-object pairs was associated with increased activity in fusiform gyrus, whereas correct identification of scene-object pairs was associated with parahippocampal cortex (PHC) activity. Activity in the PHC persisted during tests of indirect associations involving scenes, even though only objects were presented. Anteromedial hippocampal activity was significantly greater for correctly identified indirect associations involving scenes, relative to incorrect trials. Results suggest that retrieval of indirect associations involves reactivation of temporal lobe regions involved in the initial sensory processing of the linking items. Associative inference involving scenes may recruit the hippocampus to a greater extent than faces to aid in spatial relational binding specific to scenes.