Neuroscience

Why the dreaming phase matters

Scientists have long wondered why almost all animals sleep, despite the disadvantages to survival of being unconscious. Now, researchers led by a team from the University of Tsukuba have found new evidence of brain refreshing ...

Psychology & Psychiatry

Mindfulness training helps kids sleep better, study finds

At-risk children gained more than an hour of sleep per night after participating in a mindfulness curriculum at their elementary schools, a study from the Stanford University School of Medicine found.

Neuroscience

Study finds real-time dialogue with a dreaming person is possible

Dreams take us to what feels like a different reality. They also happen while we're fast asleep. So, you might not expect that a person in the midst of a vivid dream would be able to perceive questions and provide answers ...

Medical research

How the brain paralyzes you while you sleep

We laugh when we see Homer Simpson falling asleep while driving, while in church, and even while operating the Springfield nuclear reactor. In reality though, narcolepsy, cataplexy and rapid eye movement (REM) sleep behavior ...

Medical research

Gut microbes: The key to normal sleep

With fall and winter holidays coming up, many will be pondering the relationship between food and sleep. Researchers led by Professor Masashi Yanagisawa at the University of Tsukuba in Japan hope they can focus people on ...

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Rapid eye movement sleep

Rapid eye movement (REM) sleep is a normal stage of sleep characterized by rapid movements of the eyes. REM sleep is classified into two categories: tonic and phasic. It was identified and defined by Kleitman and Aserinsky in the early 1950s.

Criteria for REM sleep includes not only rapid eye movements, but also low muscle tone and a rapid, low voltage EEG -- these features are easily discernible in a polysomnogram, the sleep study typically done for patients with suspected sleep disorders.

REM sleep in adult humans typically occupies 20-25% of total sleep, about 90-120 minutes of a night's sleep. During a normal night of sleep, humans usually experience about 4 or 5 periods of REM sleep; they are quite short at the beginning of the night and longer toward the end. Many animals and some people tend to wake, or experience a period of very light sleep, for a short time immediately after a bout of REM. The relative amount of REM sleep varies considerably with age. A newborn baby spends more than 80% of total sleep time in REM. During REM, the activity of the brain's neurons is quite similar to that during waking hours; for this reason, the sleep stage may be called paradoxical sleep. This means that there are no dominating brain waves during REM sleep.

REM sleep is physiologically different from the other phases of sleep, which are collectively referred to as non-REM sleep (NREM). Vividly recalled dreams mostly occur during REM sleep.

This text uses material from Wikipedia, licensed under CC BY-SA