Sleep Disorders

REM Sleep

REM (rapid eye movement) sleep plays a major role in facilitating memory storage and retention, organization and reorganization, as well as new learning and performance. When sleep is disrupted, the brain's ability to transfer short-term memory into long-term memory is impaired.

REM sleep behavior (paralyzed skeletal muscles and twitching eyelids) had been observed for centuries, and was first noted in the scientific literature in the 1930s. It was known that if you wake up a person with twitching eyelids he would often (but not always) report being in the middle of a dream. In the 1950s scientists established rapid eye movement as a stage of sleep. It is sometimes called the 5th stage. It was first thought, and is still widely believed by the lay public, that REM=dream state. That's not true; we now know dreams can occur anytime in the sleep cycle, but the most vivid dreams tend to happen in REM.

Poor sleepers are more likely to remember their dreams because their periodic awakenings are more likely to happen in REM.

All mammals experience REM except dolphins and seals, so it is wrong to think of REM as a hallmark of a particularly advanced brain. Even dumb animals like horses go through REM.

During REM we are “vigilant” and it is pretty weird. A loud sound might not wake you up, but a whispered familiar name might. There are anti-depressant drugs that suppress REM. When the medication is discontinued,. REM sleep rebounds, but not as much is removed as was lost.