Practice with Sleep Makes Perfect:Practice with Sleep Makes Perfect:Sleep-Dependent Motor Skill LearningSleep-Dependent Motor Skill Learning

by Matthew Walker, Tiffany Brakefield, Alexandra by Matthew Walker, Tiffany Brakefield, Alexandra Morgan, Morgan,

Allan Hobson, and Robert StickgoldAllan Hobson, and Robert Stickgold

Neuron, 2002Neuron, 2002

A Review and CritiqueA Review and Critique

by by

Timothy RickardTimothy Rickard

BackgroundBackground

Performance on perceptual and motor skills has been shown to improve for up to 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 24 hours post training, consistent with a consolidation process that enhances skill rather than just protecting it from forgetting. 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 In the motor domain, however, the relative contribution of wake and sleep periods to motor consolidation have not been addressed.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.

HypothesisHypothesis

The authors hypothesized that, as with perceptual skills, The authors hypothesized that, as with perceptual skills, sleep-based rather them time-based consolidation is the sleep-based rather them time-based consolidation is the driver of off-line skill enhancement. driver of off-line skill enhancement.

They predict that sequential motor skill will improve after a They predict that sequential motor skill will improve after a delay involving sleep, but not after a delay involving no sleep.delay involving sleep, but not after a delay involving no sleep.

MethodMethod

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 (4-1-3-2-4)Task was sequential finger tapping on a keyboard (4-1-3-2-4)

Training: twelve 30-second training blocks with 30-second rest periodsTraining: 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 ConclusionsAuthor’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

CritiqueCritique

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 ineffectiveMitten control may have been ineffective

Averaging over two 30-second blocks may distort the training vs. test comparison by averaging over on-line learningAveraging 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: Conclusion: Authors’ conclusions are interesting but follow-up research that provides more experimental control Authors’ conclusions are interesting but follow-up research that provides more experimental control data analysis is needed. data analysis is needed.

Thank you.