Researchers have long debated the connection between REM (rapid eye movement) sleep and learning. A popular notion has been that REM sleep, which occurs late in the sleep cycle, allows the brain lo consolidate memories and thereby facilitates learning. It's a way to replay and analyze the day's experiences and to adapt to them. The theory supposes that the longer the REM sleep period, the quicker new knowledge can be acquired. Hence, young mammals require far more sleep than adults because their daily lives are bombarded with new situations and experiences.
  But one group of scientists is shaking up the old ideas. The team's latest research has found that quick learners don't seem to have any pattern of greater REM sleep than slower learners and the mentally disabled. Likewise, some of the smartest mammals like dolphins and whales-got very little REM sleep.
  Might this provide justification for the “all-nighter” before that important exam the next day? After all, if sleep is not a factor in learning, why not spend more time on books and less in the sack? Unfortunately, however, sleep deprivation does have undesirable effects, such as the inability to prevent the head from slumping and the eyes from closing during the exam. While not directly linked to cognitive learning, REM sleep plays a pivotal role in concentration, according to researcher Jerome Siegel. So, while sleep deprivation doesn't inhibit the transfer of newly acquired knowledge to long-term memory―since this process occurs during alert waking hours―it definitely leaves a person disoriented and fatigued.
  What REM sleep an do is aid in “procedural” learning, where the mind is learning “how” rather than “what.” Studies show that there is significant improvement in muscle-related motor skills after a good night's sleep. This is the case in muscle tasks that require repetitive but delicate and precise patterns of movement, such as in dancing and playing the piano. These are also activities that require deep concentration, since any mental lapse would result in such undesirable consequences as stepping on a partner’s toes or mixing up the chord combinations.
  Research shows that reprocessing this kind of information occurs in the brain's neocortex rather than the hippocampus, the latter being responsible for episodic details such as phone numbers and, most likely, answers to at exam question on quantum mechanics.During REM sleep, the neocortex receives a “procedural map” that imprints the various motions of the body for that activity, when the time comes to perform the game motions while the person is fully awake, the muscles perform more efficiently with fewer chances of error―as if they had been programmed to perform those actions the night before.
  Imprint the procedural map enough times and soon the whole process will become almost autonomous. When the nerve impulses travel unconsciously between the spinal cord and the body part concerned, it's as if the brain is thinking, “You know the drill. Stop bothering me!”