State Dependent Aspects of Cognition

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DESCRIPTION (provided by applicant): The last 10 years have witnessed an almost explosive growth in our knowledge of the roles that sleep may play in learning and memory consolidation, but several major issues remain. Much of the problem is due to the complexity of the systems involved; there are multiple forms of memories, multiple steps in memory consolidation, and multiple stages of sleep which might contribute to these processes. It thus becomes necessary to first ask what kinds of memory are affected by sleep, and then to ask what stages of sleep and what steps of memory consolidation are involved. Evidence exists for both declarative and procedural memory systems being sleep dependent, and in some cases, distinct components of the consolidation process may be sleep-dependent. But relatively few findings have been validated by multiple groups, and several are only being presented for the first time in the Preliminary Results section of this application. We propose to address these three fundamental unresolved issues. We will attempt to show (1) that sleep mediates consolidation of a new declarative memory task (Mandarin language study), (2) that slow wave sleep stabilizes and REM sleeps enhance perceptual learning, and (3) that sleep temporarily destabilizes motor skill learning as part of a process of sleep dependent consolidation. Confirming these hypotheses will significantly broaden our basic knowledge of the role of sleep in learning and memory consolidation. Western society has become a sleep deprived society, and this is especially true in the United States. There is a popular belief that the consequence of sleep deprivation is simply tiredness, that this can be overcome with effort or drugs, and that a good night's sleep on the weekend can completely reverse any deleterious effects of mid-week deprivation. Nowhere is this practice of "sleep bulimia," of weekly deprivation followed by weekend binge sleeping, more prevalent than on college campuses, although medical, public safety, and transportation personnel are also notoriously sleep deprived. All of these groups depend on continued education and learning for the effective performance of their tasks, and a clear understanding of exactly how sleep loss contributes to a failure of memory consolidation should provide important arguments to help counter this cultural drift towards less and less sleep. In addition, elucidation of the "sleep-memory connection" will enrich our understanding of the normal processes of learning and memory consolidation so critical to effectiveness in school and work, and help explain how sleep loss and sleep disorders lead to cognitive impairments in otherwise healthy individuals.