Offline Learning in Children: The Effect of Night Sleep and Wakefulness on Memory Consolidation of a Complex Motor Task

Abstract

Background and Aims Sleep after a new sequence memory training can enhance the explicit memory in children. However, children’s sleep-dependent motor memory consolidation particularly in implicit complex sequence tasks is unclear. Therefore, this study aims to investigate the role of night-time sleep and wakefulness on children’s motor memory consolidation following an implicit complex task. Methods In the current study, 26 boys aged 9-12 years were randomly assigned in two groups of sleep and awake. Acquisition phase included 10 blocks of 96 trials. The sleep group performed initial training at 8 (±1) PM while the awake group performed it at 8 (±1) AM by using the dynamic arm movement task. The participants were not aware of the sequence order. After training, the children’s performance was tested after 12 hours. Results The results of 2×2 Mixed ANOVA in the consolidation phase showed the significant main effect of block on response time (P=0.000) and prediction error (P=0.023). However, the interaction effect of block and group were not significant on response time (P=0.566) and prediction error (P=0.887). Conclusion The sequence memory consolidation in children under an implicit complex task can be improved offline regardless of having sleep between training and test sessions. Hence, sleep is not necessary for offline enhancement of motor sequence skills. Passage of time is effective for improvement in dynamic arm movement task. Therefore, the role of sleep in offline learning of motor skills depends on the nature of the task used in training.