Older Adults Show Reduced High Frequency Power in Both Recent and Remote Spatial Memory Retrieval Compared to Younger Adults

OBJECTIVES: The concept of healthy aging and its impact on spatial navigation and memory ability is well-established in the literature. However, the neural basis of these age-related changes is not well understood. There is limited research that examines the impact of healthy aging on the neural mechanisms underlying spatial memory retrieval for memories encoded recently (24 hours ago) compared to those encoded remotely (1 month ago). METHODS: This study explores the neural basis of recent and remote spatial memory during navigation in older (n = 16) compared to younger adults (n = 30) using electroencephalography (EEG) and a virtual Morris water task. RESULTS: Our results suggest that though recent and remote memories were poorer in older compared to younger adults, older adults' remote memories were preserved. We showed reduced high-frequency oscillations in older adults for recent and remote conditions compared to younger adults. Specifically, older adults showed decreased activation at 15-30 Hz (beta) as well as failure to increase activation at 30-40 Hz (gamma) compared to younger adults. While remote memory evoked increases in delta and theta (2-7 Hz) frequencies compared to recent memories in both age groups, older adults showed significantly less increase. DISCUSSION: The results are discussed in terms of age-related compensation for spatial navigation skills in healthy aging.