Date of Award

Spring 5-2020

Author's School

Graduate School of Arts and Sciences

Author's Department


Degree Name

Master of Arts (AM/MA)

Degree Type



Introduction: With increasing age, many adults experience reduced spatial navigation ability, with the most prominent reductions in tasks dependent on the hippocampus. Hippocampal dysfunction may be linked to age-related increases in sleep fragmentation, which results in reduced neurogenesis and long-term potentiation. This project aims to determine if age-related reductions in hippocampal-dependent navigation ability and strategy selection are mediated by impaired sleep. Further, we propose that the effects of sleep on navigation are moderated by psychological stress and physical activity. Methods: 36 older (m: 70, sd: 7) and 33 younger (m: 20, sd: 1.5) adults recorded one week of sleep via wrist actigraphy. Sleep parameters included sleep fragmentation and total sleep time. Subsequently, participants completed navigation tasks probing hippocampal-dependent navigation performance (i.e., cognitive mapping) and striatal dependent navigation performance (i.e., route learning), as well a measure of spontaneous hippocampal vs. striatal strategy selection. Self-reported stress and physical activity were also collected. Results: Age was significantly associated with reduced performance on the hippocampal-dependent and striatal-dependent navigation tasks as well as reduced use of a hippocampal-dependent strategy (psps>0.1) but was associated with reduced total sleep time (ps<0.05). Sleep fragmentation and total sleep time were associated with lower cognitive mapping performance across age groups (pppps>.05). Discussion: Fragmented sleep impairs hippocampal-dependent navigation performance and may be independent of age-related impairment. However, total sleep time may be one factor contributing to age-related reductions in hippocampally-based navigation performance.


English (en)

Chair and Committee

Denise Head

Committee Members

David Balota Jeffrey Zacks