Post-training sleep modulates motor adaptation and task-related beta oscillations

Abstract

Motor adaptation reflects the ability of the sensorimotor system in the brain to flexibly deal with changes in the environment to generate effective motor behaviour. How and whether sleep contributes to the consolidation of motor adaptation remains elusive. In this study, a new motor task was employed which utilizes a highly automatized motor skill to explore the effect of sleep on motor adaptation. We hypothesized that sleep-mediated beta band (13-30Hz) desynchronization would enhance motor adaptation performance. Healthy human experts in typing on the regular computer keyboard, were trained to type on a vertically mirrored keyboard while we recorded electroencephalography (EEG). Their typing performance was assessed after either a full night of sleep with polysomnography, or a similar period of daytime wakefulness. We show that motor adaptation performance improved after overnight sleep but not after daytime wakefulness. Beta oscillatory power as well as the spectral slope of the EEG (1-45Hz) were reduced during mirrored typing compared to regular typing. Notably, sleep caused an even further decrease in the power of beta oscillations. Additionally, overnight changes in the EEG spectral slope during mirrored typing was associated with the overnight changes in adaptive performance. Finally, an increase in fast sleep spindle density (13-15Hz) during the night following motor adaptation training, predicted successful motor adaptation. These findings suggest that sleep plays a crucial role in modulating neural activity and its impact on motor functions. Therefore, our results may be useful for directing and monitoring the effectiveness of rehabilitation interventions.