0099 Napping After Learning Boosts Long-Term Ambulatory VR Spatial Navigation Through Sleep Spindles

Abstract Introduction Spatial navigation is a complex behavior requiring the integration of memory, perception, attention, motor movement, and decision making, and relies on the hippocampus. Since NREM sleep supports hippocampal-dependent memory, NREM may also benefit navigation. Yet prior findings are mixed, likely due to heavy reliance on stationary, two-dimensional desktop tasks. Additionally, many studies lack EEG data to examine the role of sleep electrophysiology, e.g. sleep spindles (12-15Hz), in navigation. To address this gap and the lack of immersive tasks mirroring human navigation, we systematically investigated sleep’s contribution to spatial navigation using a nap paradigm and an immersive, ambulatory virtual reality (VR) task. Methods 60 healthy young adults (18-35y, mean 22.55; 17 wake, 43 nap) completed an ambulatory VR spatial navigation task where participants freely explored a maze to locate and remember 12 object locations. They were tested three times: immediately after encoding (Test 1), at the end of the experimental day (Test 2), and at the follow-up visit (Test 3; 2-3 days later). Between Tests 1 and 2, participants either took an EEG-monitored nap or remained quietly awake, and spindles were detected. Navigation efficiency improvement (i.e. change in proportion of actual to optimal path length) was analyzed using two linear models with sex, age, and group (nap vs. wake; model1) or sleep spindles and total sleep time (model2) as predictors. Results Although there were not group differences directly after a nap, participants who napped right after learning showed greater benefits at the 48–72-hour follow-up. Within the nap group, spindle density (N3) significantly predicted greater improvements in navigation efficiency from Test 2 to 3. Sex and age were not significant predictors in either analysis. Conclusion Using an ambulatory VR navigation task, we found that sleep benefits spatial navigation, with a nap immediately after learning improving navigation efficiency after 48 hours. Navigation efficiency reflects consolidation of a cognitive map, i.e., a mental representation of the environment, and was enhanced specifically through sleep spindles, suggesting that spindles facilitate shortcuts and novel routes to remembered target locations. Future studies should examine how spindles modulate hippocampal engagement during the development of cognitive map representations. Support (if any) UCI Internal Grant