Sleep and episodic memory consolidation: ‘No-report’ paradigms, brain mechanisms, and dementia

Episodic memory is a core element of the human mind, but how experiencing an episode consolidates into long-term memory remains a central unsolved question in cognitive science. We will test the hypothesis that hippocampal-cortical dialogue (HCD) during sleep promotes memory consolidation, a hypothesis that has been largely beyond direct testing in humans to date. Moreover, transcending report is essential, since it remains unclear if sleep improves memory per-se, or the ability to access and report memories. Conventional paradigms do not facilitate sleep and memory research in dementia, where it is vital. Based on my expertise, ongoing studies, and preliminary results, I propose a unique approach to address these gaps by combining novel approaches to recording and stimulating brain activity in human sleep with novel ‘no-report’ memory paradigms. We will go beyond the state-of-the-art in three synergistic domains: (1) Develop an ecological ‘no-report’ paradigm to study episodic memory, and its consolidation during sleep. (2) Test the role of sleep HCD in mediating human memory consolidation. (3) In dementia and aging, we will investigate to what extent disrupted HCD during sleep impairs memory consolidation, and whether noninvasive neuromodulation can improve memory in dementia. The proposed research has the potential to elucidate fundamental principles and transform conceptual insights of how sleep promotes episodic memory consolidation.