Practice with Sleep Makes Perfect: Sleep-Dependent Motor Skill Learning by Matthew Walker, Tiffany Brakefield, Alexandra Morgan, Allan Hobson, and Robert Stickgold Neuron, 2002 A Review and Critique by Timothy Rickard

Background Performance on perceptual and motor skills has been shown to improve for up to 24 hours post training, consistent with a consolidation process that enhances skill rather than just protecting it from forgetting. Performance on perceptual and motor skills has been shown to improve for up to 24 hours post training, consistent with a consolidation process that enhances skill rather than just protecting it from forgetting. In the sensory domain, those improvements have been attributed to sleep. In the sensory domain, those improvements have been attributed to sleep. In the motor domain, however, the relative contribution of wake and sleep periods to motor consolidation have not been addressed. In the motor domain, however, the relative contribution of wake and sleep periods to motor consolidation have not been addressed. The authors addressed this issue for the case of a sequential motor skill task. The authors addressed this issue for the case of a sequential motor skill task.

Hypothesis The authors hypothesized that, as with perceptual skills, sleep-based rather them time-based consolidation is the driver of off-line skill enhancement. The authors hypothesized that, as with perceptual skills, sleep-based rather them time-based consolidation is the driver of off-line skill enhancement. They predict that sequential motor skill will improve after a delay involving sleep, but not after a delay involving no sleep. They predict that sequential motor skill will improve after a delay involving sleep, but not after a delay involving no sleep.

Method Sixty-two right-handed adult subjects were divided into five groups. Sixty-two right-handed adult subjects were divided into five groups. Task was sequential finger tapping on a keyboard ( ) Task was sequential finger tapping on a keyboard ( ) Training: twelve 30-second training blocks with 30-second rest periods Training: twelve 30-second training blocks with 30-second rest periods in between. in between. Test (and retests): two 30-second blocks with a 30-second intervening rest. Test (and retests): two 30-second blocks with a 30-second intervening rest. Five groups: Five groups: Group A: Trained at 10 am, tested same day at 2, 6, and 10 pm. Group A: Trained at 10 am, tested same day at 2, 6, and 10 pm. Group B: Trained at 10 am, tested at 10 pm and again at 10 am. Group B: Trained at 10 am, tested at 10 pm and again at 10 am. Group C: Trained at 10 am, then total hand rest, tested at 10 pm and again at 10 am. Group C: Trained at 10 am, then total hand rest, tested at 10 pm and again at 10 am. Group D: Trained at 10 pm, tested at 10 am and again at 10 pm. Group D: Trained at 10 pm, tested at 10 am and again at 10 pm. Group E: Trained at 10 pm, tested at 10 am (slept in lab). Group E: Trained at 10 pm, tested at 10 am (slept in lab).

Results

Author’s Conclusions Sleep but not wakefulness enhances motor sequence performance. Sleep but not wakefulness enhances motor sequence performance. A circadian or homeostatic confound account, while possible, is unlikely. A circadian or homeostatic confound account, while possible, is unlikely. A daytime motor activity interference account is unlikely. A daytime motor activity interference account is unlikely. The enhancement occurs during fourth-quarter stage 2 NREM. The enhancement occurs during fourth-quarter stage 2 NREM. Possible relation to sleep spindles Possible relation to sleep spindles

Questions

Critique Circadian and homeostatic factors not directly tested or controlled. Circadian and homeostatic factors not directly tested or controlled. Enhancement always occurred on the 10 am test. Enhancement always occurred on the 10 am test. Mitten control may have been ineffective Mitten control may have been ineffective Averaging over two 30-second blocks may distort the training vs. test comparison by averaging over on-line learning Averaging over two 30-second blocks may distort the training vs. test comparison by averaging over on-line learning Correlations between enhancement and each quarter of night not shown for all sleep stages. Fishing expedition likely. Correlations between enhancement and each quarter of night not shown for all sleep stages. Fishing expedition likely. Conclusion: Authors’ conclusions are interesting but follow-up research that provides more experimental control data analysis is needed. Conclusion: Authors’ conclusions are interesting but follow-up research that provides more experimental control data analysis is needed.

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