Sleep, circadian rhythms, and cognitive function Rebecca M. C. Spencer, PhD Associate Professor of Psychological & Brain Sciences
Current funding: Disclosures University of Massachusetts National Institutes of Health National Heart, Lung & Blood Institute (NIH R01 HL111695) National Institute on Aging (NIH R01 AG040133) Other financial relationships: Past funding from: Avery Dennison, Jawbone Conflicts of interest: National Institute on Aging and University of Massachusetts funds contributed directly to the work presented in this talk.
Significance Sleep impairments are prevalent in normal aging Cognitive impairments (e.g., long-term memory, executive functions) are prevalent as well Sleep Cognition Sleep Efficiency Total Sleep Time Z-score Age Age
Significance Sleep impairments are prevalent in normal aging Cognitive impairments (e.g., long-term memory, executive functions) are prevalent as well Parallel trajectories with aging and evidence from young adults suggest that age-related changes in sleep and cognition may be related If so, sleep may be a target for improving cognitive function in older adults.
Chronotype changes with age State-of-the-art knowledge 60 60 Percent evening-type 50 40 30 20 10 50 40 30 20 10 Percent morning-type 0 10-17 a 19-31 b 30-49 c 59-79 d Age (yrs) 0
State-of-the-art knowledge Shift in chronotype affects performance Alertness Alertness Young adult 0 6 12 18 0 6 12 18 0 Older adult 0 6 12 18 0 6 12 18 0 Peak alertness: Reaction time Inhibitory control Working memory Recognition memory Performance is more equated when individuals are tested at their preferred time with respect to chronotype (see Schmidt et al., 2007)
State-of-the-art knowledge Sleep also contributes to cognitive performance Young adult decay consolidate 0 6 12 18 0 6 12 18 0 Older adult decay? 0 6 12 18 0 6 12 18 0
State-of-the-art knowledge Sleep benefits cognition in young adults SLEEP WAKE
State-of-the-art knowledge Sleep benefits cognition in young adults 80 75 pre post Accuracy (%) 70 65 60 55 50 Wake Sleep
State-of-the-art knowledge Sleep benefits cognition in young adults Correlations between slow wave sleep (SWS) and change in declarative memory over sleep Parahippocampal gyrus activity during SWS Recall accuracy (%) 100 80 60 40 5 15 25 35 SWS (%)
Declarative memories State-of-the-art knowledge
Mood regulation and emotional processing State-of-the-art knowledge
Procedural/skill memories State-of-the-art knowledge
State-of-the-art knowledge Sleep contributes to cognitive performance Young adult decay consolidate REM 0 6 12 18 0 N2 12 18 0 Older adult decay? REM SWS SWS N1 Do changes in sleep change the function of sleep on cognition? 0 6 12 18 6 12 18 0 N2 N1
State-of-the-art knowledge Is sleep-dependent cognitive processing reduced with age? it depends Consolidation of declarative memories largely preserved % of studies preserved reduced absent Consolidation of procedural memories Is reduced n=7 n=13 n=2 Consolidation of positive memories is preserved negative memories is absent Declarative/ SWS-dependent Procedural/ n2-dependent Emotional/ REM-dependent
Knowledge gaps What are the implications of the deficit in procedural memory consolidation? What activities of daily living benefit from sleep in older adults? Decisionmaking? Temporal judgments (scheduling, remembering lists)? What underlies changes in sleep s benefit on memory? Changes in a sleep stage? Neural basis of storage?
Research opportunities Would an intervention to improve sleep (CBT, nap intervention) improve cognitive processing? What is the relationship between the changes in circadian rhythms and sleep (and sleep stages)? How does the quality of sleep stages change with aging?
Thank you. Cognition & Action Lab Cognition & Action Lab rspencer@umass.edu
State-of-the-art knowledge Is sleep-dependent cognitive processing reduced with age? it depends Absent Reduced Spared Declarative 5 17 10 2 8 20 22 Procedural 1 3 6 12 13 14 15 18 19 21 7 11 16 Emotional 9 9 neg pos