Multiple hypotheses explain the possible connections between sleep and learning in humans. Research indicates that sleep does more than allow the brain to rest; it may also aid the consolidation of long-term memories.
REM sleep and slow-wave sleep play different roles in memory consolidation. REM is associated with the consolidation of nondeclarative (implicit) memories. An example of a nondeclarative memory would be a task that we can do without consciously thinking about it, such as riding a bike. Slow-wave, or non-REM (NREM) sleep, is associated with the consolidation of declarative (explicit) memories. These are facts that need to be consciously remembered, such as dates for a history class.[1]