Different Roles for REM and Stage 2 Sleep in Motor Learning: A Proposed Model

It is now clear that states of sleep are involved with the off-line memory reprocessing or consolidation of a variety of tasks. The large majority of these sleep sensitive tasks has been of the procedural type, tasks that are usually learned implicitly. It is still unclear which states of sleep are most important. For motor skills tasks, Stage 2 sleep has sometimes been implicated, while at other times the important sleep state appears to be rapid eye movement (REM). This paper is an attempt to more clearly identify the characteristics that differentiate REM-dependent from Stage 2-dependent motor tasks and to examine the nature of the brain state differences between the two stages at the neurophysiological and neurochemical levels. We have developed a model to explain how motor skills tasks involving REM and Stage 2 sleep might be dependent on two separate, but overlapping, neural systems.