Healthy aging is accompanied by decreased cognitive abilities and a parallel decline in sleep quantity and quality. Given a wealth of researc in healthy young adults and animal models illustrating a benefit of sleep on memory and other cognitive processes, our overarching objective is to understand whether changes in sleep may account for changes in cognitive abilities in healthy aging. The specific objective of this application is to probe whether learning is benefitted by sleep in healthy older adults as compared to healthy young adults. In addition to probing memory following intervals of sleep and wake, we will investigate whether the memories were restructured over sleep and the neurophysiological underpinnings of observed changes. Sleep's function on declarative and procedural learning is unique, each being associated with distinct sleep stages and physiological markers. Therefore, we will separately probe declarative and procedural learning.
In Specific Aim 1 we will examine whether procedural memories are benefitted by sleep in older adults. Preliminary data suggests an age-related decline in sleep-dependent memory consolidation for such tasks, a deficit we predict is associated with fragmentation of the critical sleep stage.
In Specific Aim 2 we will examine whether declarative memories are benefitted by sleep in healthy older adults. Preliminary data suggest that declarative memory performance of older adults is greater following sleep relative to wake, similar to young adults. We will probe whether this result reflects a reorganization of the memory and whether it is a general property of the declarative memory domain. The proposed research is innovative as it applies a novel concept to the field of cognitive aging, utilizes novels techniques (polysomnography) for this field, and seeks to shift the treatment and preventive strategies for age-related cognitive deficit to sleep targets. Moreover, the proposed work is significant in advancing our understanding of cognitive deficits in other diseases in which sleep disturbances are frequently observed by describing the scope of the sleep-cognition relationship in the control population.
The proposed research is relevant to public health because understanding the sleep-memory relationship in healthy aging will underlie novel treatments of cognitive decline in older adults and other populations with sleep-effecting diseases. Thus, this research is well-suited to the NIH mission, seeking fundamental knowledge of sleep and memory in older adults in order to enhance health and reduce the burden of aging and disease.
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