Sleep has been demonstrated to promote the reactivation ("replay") and consolidation of important memories and the pruning of irrelevant memories. Consolidation and pruning typically occur during slow wave sleep (i.e., deep sleep), in which memories are transferred from temporary storage in hippocampal regions to long-term storage in neocortical regions. Thus, sleep is vital to daytime cognitive functioning. Nearly all sleep-dependent memory consolidation and pruning research has examined sleep and memory in college-aged adults, thereby ignoring how memory consolidation and pruning may change with normal aging and in clinical sleep disorders. This omission may be particularly crucial because substantial sleep physiology changes (including slow wave sleep declines) and profound memory declines have been reported in healthy older adults and those with mild cognitive impairment and sleep-disordered breathing. The current proposal focuses on this intriguing sleep-memory-aging relationship to determine how age-related sleep changes impact age-related memory changes. Younger adults, healthy older adults, and adults who have mild cognitive impairment as well as sleep-disordered breathing, will encode memories that they are either told will be important in the future or irrelevant in the future, and then they will take a polysomnography-recorded nap. Following the nap, they will be tested on their ability to remember "important" memories and forget "irrelevant" memories. Memory performance will be correlated with polysomnography-defined sleep features such as amount of slow wave sleep. The results will shed light on whether sleep-dependent memory consolidation and pruning processes are impaired in healthy older adults and those with clinical sleep disorders. The results will also provide information regarding how the sleep-memory relationship may change from younger adults to older adults;such knowledge can subsequently be used to develop cognitive rehabilitation treatments for healthy older adults, mild cognitive impairment patients, and sleep-disordered breathing patients. For example, if slow wave sleep changes mediate group deficits in memory then a potentially effective treatment might entail prescribing slow wave sleep enhancers. Or, if sleep-disordered breathing events cause memory consolidation/pruning declines then continuous positive airway pressure (CPAP) treatment might be appropriate. Finally, if memory consolidation and/or pruning are relatively preserved during sleep in older adults then a useful intervention may include strategically timed naps during the day. This research will advance knowledge of cognitive aging beyond the waking brain to the exciting new frontier of the sleeping brain.

Public Health Relevance

Deep sleep is critical to memory functioning in college-aged adults. Older adults, however, often show dramatic changes in their sleep physiology, implying that they may not receive the full memory benefits of sleeping. The proposed research will investigate how sleep and memory changes in normal aging and in sleep-disordered breathing patients so that we may eventually develop effective sleep-based interventions to help ameliorate memory declines in these populations.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32AG041543-04
Application #
8594215
Study Section
Special Emphasis Panel (ZRG1-F02B-M (20))
Program Officer
Mackiewicz, Miroslaw
Project Start
2012-01-09
Project End
2015-01-08
Budget Start
2014-01-09
Budget End
2015-01-08
Support Year
4
Fiscal Year
2014
Total Cost
$52,190
Indirect Cost
Name
Emory University
Department
Neurology
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Scullin, Michael K; Harrison, Tyler L; Factor, Stewart A et al. (2014) A Neurodegenerative Disease Sleep Questionnaire: principal component analysis in Parkinson's disease. J Neurol Sci 336:243-6
Bliwise, Donald L; Scullin, Michael K; Trotti, Lynn Marie (2014) Fluctuations in cognition and alertness vary independently in dementia with Lewy bodies. Mov Disord 29:83-9
Scullin, Michael K; McDaniel, Mark A; Shelton, Jill Talley (2013) The Dynamic Multiprocess Framework: evidence from prospective memory with contextual variability. Cogn Psychol 67:55-71
Scullin, Michael K (2013) Sleep, memory, and aging: the link between slow-wave sleep and episodic memory changes from younger to older adults. Psychol Aging 28:105-14
Scullin, Michael K; Sollinger, Ann B; Land, Julia et al. (2013) Sleep and impulsivity in Parkinson's disease. Parkinsonism Relat Disord 19:991-4