Sleep Deprivation History and Memory Consolidation Mikiko Fujiwara MCB 186

Introduction Memory is improved in a sleep-dependent manner Memory is improved in a sleep-dependent manner Motor skills and memory: possible improvement in stage 2 sleep Motor skills and memory: possible improvement in stage 2 sleep Sleep deprivation reduces overall alertness, reaction time, and causes many physiological changes in sleep profile Sleep deprivation reduces overall alertness, reaction time, and causes many physiological changes in sleep profile To date, most studies on sleep-dependent motor skill enhancement do not explore sleep deprivation effects on learning To date, most studies on sleep-dependent motor skill enhancement do not explore sleep deprivation effects on learning

Problems Does prior sleep history affect learning? Does prior sleep history affect learning? How does prior sleep history affect memory consolidation? How does prior sleep history affect memory consolidation? Does the second night of sleep always improve learning equally? Does the second night of sleep always improve learning equally?

Hypothesis Learning ability will correlate with amount of sleep obtained Learning ability will correlate with amount of sleep obtained Performance improvement due to post training sleep will correlate with amount of sleep obtained, but will also plateau at ~9h of sleep. Performance improvement due to post training sleep will correlate with amount of sleep obtained, but will also plateau at ~9h of sleep.

Methods 120 healthy volunteers, age 18-30, screened for sleep disorders and substance abuse, little to mild caffeine usage, normal sleep schedules 120 healthy volunteers, age 18-30, screened for sleep disorders and substance abuse, little to mild caffeine usage, normal sleep schedules split into 6 groups of 20 split into 6 groups of 20 Sleep 8-9 h for 2 weeks at home; confirmed using sleep logs/actigraphy watches Sleep 8-9 h for 2 weeks at home; confirmed using sleep logs/actigraphy watches First night in lab: groups sleep 4, 6, 8, 9, 10, 12h First night in lab: groups sleep 4, 6, 8, 9, 10, 12h Subjects trained every 3h starting 1h post wake Subjects trained every 3h starting 1h post wake Evaluated on task 1h before sleep. Evaluated on task 1h before sleep. Second night in lab: All groups sleep for 8.5h Second night in lab: All groups sleep for 8.5h Evaluated on task 1, 4, and 7h post wake. Evaluated on task 1, 4, and 7h post wake.

Methods (Cont.) Sequential finger-tapping task: Sequential finger-tapping task: Subjects asked to type using standard PC keyboard repeatedly and as quickly as possible for 30s period Subjects asked to type using standard PC keyboard repeatedly and as quickly as possible for 30s period Sequence always displayed, white dots indicate typed number Sequence always displayed, white dots indicate typed number Training: 12 30s trials with 30s rest period Training: 12 30s trials with 30s rest period Averages of trials taken for each evaluation. Averages of trials taken for each evaluation.

Expected Results

Significance of Results Day 1: zero, equal, or gradated improvement? Day 1: zero, equal, or gradated improvement? Day 2: equal or gradated improvement? Day 2: equal or gradated improvement? Factors involved: preoccupation with sleep debt recovery-->differing stages of sleep Factors involved: preoccupation with sleep debt recovery-->differing stages of sleep Too much of a good thing? Too much of a good thing? Implications for sensitive hands-on learning (i.e., surgery, operating machinery/vehicles, music) Implications for sensitive hands-on learning (i.e., surgery, operating machinery/vehicles, music) Further insight into memory consolidation and learning Further insight into memory consolidation and learning

Future Directions Explorations of mechanisms behind memory consolidation of motor skills --> Ach involvement? Explorations of mechanisms behind memory consolidation of motor skills --> Ach involvement? Similar effects in other types of learning? (i.e., visual, auditory, perceptive, etc.) Similar effects in other types of learning? (i.e., visual, auditory, perceptive, etc.) EEG or MRI study on motor skill improvement with sleep deprivation EEG or MRI study on motor skill improvement with sleep deprivation

Acknowledgements Profs. C.A.Czeisler and J.W.Hastings Profs. C.A.Czeisler and J.W.Hastings Dr. J.J.Gooley Dr. J.J.Gooley MCB 186 classmates MCB 186 classmates

References S. Fischer, M.Hallschmid, A.L.Elsner, and J. Born. Sleep forms memory for finger skills :18: 11987–11991 PNAS. K. Kuriyama, R. Stickgold, and M.P. Walker. Sleep-dependent learning and motor-skill complexity : Learn. Mem. M.E. Smith, L.K. McEvoy, A.Gevins. The Impact of Moderate Sleep Loss on Neurophysiologic Signals during Working-Memory Task Performance. Sleep November 1; 25(7): 784–794. R. Stickgold. Sleep-dependent memory consolidation : Nature. M.P. Walker, T.Brakefield, J.Seidman, A.Morgan, J.A.Hobson and R.Stickgold. Sleep and the Time Course of Motor Skill Learning : Learn. Mem.