sleep`n cycle - sleep and gross-motor learning in school aged children and adults

The proposed interdisciplinary project aims at investigating the beneficial effects of sleep on gross-motor learning in school aged children and adults by means of an innovative and ecologically valid task: inverse steering bicycling. In the last decades, growing evidence has supported the hypothesis that sleep plays a functional role in the consolidation of memory, including procedural memories and motor learning in particular. Regarding the latter domain, available data suggest that sleep promotes the offline processing or reprocessing of fine-motor skills (e.g., finger tapping, mirror tracing). However, corresponding data on gross-motor skills involving whole body movements (e.g., bicycling, skiing) remain extremely scarce, despite their utmost importance in children`s development. In this perspective, our current proposal aims at addressing three related fundamental questions: (1) Is there a functional role of sleep in the consolidation of real-life gross-motor skills? (2) Are there specific developmental differences with regards to sleep-dependent gross-motor consolidation, and are different sleep mechanisms guiding the integration of new gross-motor memories depending on age? (3) Is there a direct relationship of brain activity recorded during gross-motor learning/retrieval, subsequent sleep and gross-motor performance changes? To investigate our hypotheses concerning sleep and gross-motor learning a suitable study environment and device that allows us to exactly assess gross-motor performance will be developed in collaboration with the Department of Sports and Kinesiology. 40 healthy male subjects aged between 20 and 30 years will be tested by a combined between- and within-subjects design either in a sleep or in a wake condition after learning to ride the inverse steering bicycle, requesting major adaptation of the whole body motoric system. Additionally, a school aged children population (9-10 years; N=40) will participate in our study to evaluate age-related mechanisms of sleep and gross-motor learning. Gross-motor performance will be quantified by a specially designed bicycle that allows to precisely assess bicycling trajectories and riding behaviour. By sophisticated quantitative EEG analyses techniques (e.g., event-ask-related synchronization, phase coherence, Gabor wavelet based power-frequency analyses) we will be able to identify neurocognitive key mechanisms during learning, consolidation and subsequent gross-motor retrieval. The collected data will allow new insights in cognitive functioning of adults as well as school aged children and elucidate whether real-life, gross-motor learning is indeed supported by sleep over different age groups as theoretical frameworks indicate. Therefore the outcomes of this project are intrinsically bound to reveal potential information and material deserving publication of ground-braking scientific papers at the international level, and will contribute to our understanding of the acquisition and consolidation of gross-motor skills in children and adults, and the role played by sleep in these processes.

Are there beneficial effects of sleep on motor learning and motor adaptation (i.e. the capacity to modify motor behavior in response to changes in the environment or organism)? Consider the following situations: #1- you borrow a friends laptop, but find that the mouse moves the cursor faster than you expect, resulting in inaccuracies (and annoyance). Luckily, it only takes a matter of minutes for your brain to adjust and account for the new mousecursor settings. #2 - you are running downstairs and slightly misestimate the height of a step. Your motor system uses this small and hardly noticeable error immediately on the next step to adjust your stride. #3 - you are used to the US standard QWERTY keyboard layout and during visiting central Europe you have to answer your emails on a QWERTZ keyboard, causing typing errors and time delays in typing. These three phenomena nicely describe motor adaptation in day-to-day life. We ourselves utilized an innovative and ecologically valid task: inverse steering bicycling. Cycling performance was assessed by speed (riding time) and accuracy (standard deviation of the steering angle) measures. In a first study we trained healthy male subjects aged between 20 and 30 years on this bicycle and we could show that sleep in comparison to wakefulness appears to support gross-motor performance concerning speed. Furthermore, subjects that were trained in the evening and retested after sleep in the morning showed almost no overnight decrease in gross-motor performance accuracy, whereas subjects that were trained in the morning and retested after 8h of wakefulness reduced their performance. Concerning our hypothesis regarding brain activity during sleep (i.e., sleep spindle activity) and its impact on gross-motor performance, we found that subjects showing more sleep spindles during the night following inverse steering bicycle training were those being able to enhance gross-motor performance overnight. In a second study we trained healthy children aged between 11 and 14 years on such an inverted bicycle. Behavioral results showed no evidence for sleep-dependent memory consolidation. However, an increase in sleep spindle activity from a control night without preceding motor adaptation to a learning night after motor adaptation was found to be associated with overnight performance gains in cycling accuracy. Furthermore, a decrease in REM sleep was related to higher overnight accuracy improvements, whereas regarding speed, an increase in REM duration was favorable for higher overnight performance gains in riding time. Thus, although not yet detectable on a behavioral level, sleep seems to play also a role in the acquisition of gross-motor skills in children.