Reconsidering the role of sleep for motor memory.

Previous studies suggest that sleep may play an important role in memory consolidation of motor skills. It has been difficult, however, to tease apart the effect of sleep from circadian and homeostatic factors. We examined the effect of sleep on a popular motor sequence task, utilizing a design that controlled for time of day and time since sleep between wake and sleep groups. When these factors were controlled, there was no benefit of sleep to motor memory, suggesting that previous work may have been influenced by circadian and homeostatic confounds.