Poster E87, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
The primacy of 'place' in neural representations of events containing people, places and objects
Jessica Robin1,2, Sigal Gat Lazer2, Bradley R. Buchsbaum1,2, Morris Moscovitch1,2; 1University of Toronto, 2Rotman Research Institute, Baycrest Health Sciences
Some theories of episodic memory hypothesize that spatial context plays a fundamental role in episodic memory, acting as a scaffold on which episodes are based (Maguire & Mullally, 2013). Accordingly, spatial context should be discernible based on the neural representation of an event. To test this hypothesis, we performed fMRI scans while healthy participants imagined novel events, comprising familiar places, people and objects. We used Multi-Voxel Pattern Analysis (MVPA) to determine which neural areas could discriminate events based on each cue type. The largest network of areas could discriminate events based on location, including the parahippocampal cortex and posterior hippocampus, retrosplenial cortex, posterior cingulate cortex, precuneus and medial prefrontal cortex. Events were discriminable based on person and object cues in smaller networks of regions. Representational Similarity Analyses (RSA) revealed that in a set of regions associated with autobiographical memory, events that shared a location were more similar to one another than events in which location differed. This effect was marginal for events sharing a person, and only significant for events sharing an object when they also had a common location, suggesting that under these conditions, spatial context is the dominant defining factor. Together, these results indicate that location and person information both contribute to the neural representation of a complex episode, though location effects were stronger and were in a larger network of areas. This study offers support for theories suggesting that spatial context underlies episodic memory in the autobiographical memory network.
Topic Area: LONG-TERM MEMORY: Episodic