The Role of Sleep Duration and Age in Neural Reactivation and Episodic Memory Performance Across the Adult Lifespan ^*

Sleep is essential for episodic memory consolidation, involving the reactivation of neural patterns during encoding and retrieval. This study examined how sleep duration influences encoding-retrieval similarity (ERS) and memory performance across the adult lifespan. Fifty-five adults (18–79 years) participated in a seven-day protocol, combining actigraphy-based sleep monitoring with EEG and memory assessments during a paired associate learning task. Significant correlations between sleep duration and ERS were observed, with clusters showing positive and negative associations across brain regions. In match context trials, ERS in the left frontal region correlated with sleep duration, and age moderated these effects. In mismatch context trials, positive correlations were identified in the left posterior, left frontal, and right posterior regions. These results highlight the role of sleep in modulating neural reactivation patterns during memory retrieval and emphasize the influence of age. The study advances our understanding of how sleep variability impacts memory consolidation and provides a basis for exploring targeted sleep interventions.