Schedule of Events | Symposia

Neural and behavioral correlates of spatiotemporal memory organization and recall

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Colin Bruce^1,2 (brucec8@mcmaster.ca), Deepti Tantry^2,3, Michael Kahana²; ¹McMaster University, ²University of Pennsylvania, ³Johns Hopkins University

We investigated the neural and behavioral mechanisms of memory encoding and retrieval during a quasi-naturalistic spatial-episodic memory task, where epilepsy patients undergoing intracranial electroencephalographic (EEG) monitoring delivered items to landmarks in a virtual town and later recalled both the items and their corresponding locations. Transition probabilities and latencies revealed the spatial and temporal organization of memory, showing that as patients gained experience navigating the virtual town, their spatial knowledge improved, leading to more efficient navigation and enhanced spatial organization during recall. Intracranial EEG signals demonstrated a subsequent memory effect, with increased gamma and decreased alpha activity marking periods of successful encoding in multiple brain regions including both lateral and medical temporal cortices (LTC and MTL) and prefrontal cortex (PFC). This subsequent memory effect survived correction for serial position confounds. Increased gamma, decreased alpha, and increased theta activity were observed in these same regions immediately prior to recalling an item. These findings extend our understanding of the behavioral and neural signatures associated with successful memory encoding and retrieval to a naturalistic task that incorporates both spatial and temporal components of learning.

Topic Area: EXECUTIVE PROCESSES: Working memory