Schedule of Events | Symposia

Age-Related Changes in the Cortical Replay of Landmark-Based Navigational Episodic Memory

Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Jeonghyun Lee¹ (jeonghyun.lee@snu.ac.kr), Sang-Eon Park¹, Sang Ah Lee¹; ¹Seoul National University

How does the human brain replay memories of navigational sequences, and how does the retrieval of spatial information from a mental map of the environment contribute to this process? To examine the EEG correlates underlying map-based memory replay, we conducted a passive navigation task in which subjects were navigated through a virtual environment containing either proximal landmarks, distal landmarks, or uninformative buildings. The navigation episode included several turning events before reaching the final destination. Subjects were subsequently asked to identify the correct route or destination while viewing an overhead map. We recorded scalp EEG and eye-gaze during navigation (encoding) and map-viewing (retrieval) phases in younger (age: 20–44, n=27) and older subjects (age: 45–65, n=35). During retrieval, EEG activity in younger subjects showed a replay-like pattern of the turn events that comprised the episode, characterized by a transition from stronger reactivation of earlier turns to later turns over the retrieval period. The replay index (measuring linear changes in this temporally sequenced reactivation bias) correlated with memory performance, and was notably higher in conditions that included distal landmarks compared to other conditions. Older adults, in contrast, did not show a replay pattern during retrieval nor its correlation with memory performance. Across all participants, we found that distal landmarks (both across conditions and in the reactivation of landmark-related EEG activity) affected overall memory performance, mediated by the replay index. These findings suggest that distal landmarks during navigation enhance the formation of map representations and may facilitate mental replay during retrieval.

Topic Area: LONG-TERM MEMORY: Episodic