Sleep and motor skill learning

The improvement of a perceptual or motor skill continues after training has ended. The central question is whether this improvement is just a function of time or whether sleep, a certain circadian phase, or their interaction (sleep occurring in a particular circadian phase) is favorable to the reprocessing of recent memory traces. In this issue of Neuron, Walker et al. (2002) provide behavioral evidence that most of the improvement of a motor skill depends on nocturnal sleep.