The impacts of aging on hippocampal place cell sequences during movement and replay

Poster Session E - Monday, March 9, 2026, 2:30 – 4:30 pm PDT, Fairview/Kitsilano Ballrooms

Gabrielle F. Shvartsman¹ (gshvarts@uw.edu), Ian O'Leary¹, Anna K. Gillespie¹; ¹University of Washington, Seattle

Age gradually degrades memory function, often leading to changes in behaviors that rely on these memories. The hippocampus is a brain region central to memory processes. Prior work suggests that compressed sequences of spatially-tuned hippocampal cell (place cell) firing play an important role in memory consolidation, recall, and memory-based decision-making. These occur during movement (referred to as theta sequences) as well as during immobility (referred to as hippocampal replay). However, it remains unclear how these neural sequences change throughout the aging process and whether they contribute to behavioral changes. In this study, we collected electrophysiological recordings from the CA1 subregion of the hippocampus in young (4-9m) and aged (28-32m) rats while they performed a complex memory-guided spatial task. Here we compare the recorded hippocampal activity between the young and aged subjects and evaluate how the neural patterns correlate with the subjects' performance on the task. Decoded sequences of place cell firing exhibited differences during both movement and immobility that correlate with age. These results shed light on how age-related changes in hippocampal patterns of neural activity may contribute to memory impairment in advanced age.

Topic Area: LONG-TERM MEMORY: Development & aging