Do you dream? Why?

Some people report frequent dreams. Others claim to dream rarely. Others not at all. Do dreams have a purpose?

A number of different types of sleep are recognised. Dreaming occurs during REM type sleep, which begins some time after falling asleep. People deprived of REM sleep will begin to enter REM sleep immediately after falling asleep. Apparently, attempting to make up a REM & dreaming deficit. This implies that REM sleep & dreaming perform an important function.

Rats deprived of REM sleep for four weeks, die. Perhaps more puzzlingly, this has not been demonstrated with any other species.

Strange but true: less sleep means more dreams
http://www.scientificamerican.com/article/strange-but-true-less-sleep-means-more-dreams/

Why some remember dreams, while others don't
http://www.livescience.com/38856-why-people-recall-dreams.html

People who do not dream
https://www.psychologytoday.com/blog/dream-catcher/201204/people-who-do-not-dream

And how much sleep do you need? Is three or four hours enough?
http://nymag.com/scienceofus/2015/02/what-its-like-to-need-hardly-any-sleep.html?mid=outbrainrc / need much less sleep than the average person short sleepers Eva Salem crocodile she woke up dreams vivid crazy active breast-feeding daughter crocodile-attack dream living on four hours of sleep a night sleep a full night dreams vivid lack of sleep soon after eyelids close sleep deprived greater sleep intensity greater brain activity during sleep dreaming definitely increased more vivid neurologist Mark Mahowald University of Minnesota director Minnesota Regional Sleep Disorders Center Minneapolis phenomenon REM rebound REM rapid eye movement darting of the eyes under closed lids dream the most brain activity resembles that of waking life muscles go slack lie paralyzed toe might wiggle essentially we can't move brain protecting body bodies acting out dreams REM four stages non-REM distinct brain wave frequency stage one of non-REM nodding off period between sleeping and waking sensation of falling into a hole stage two brain slows only a few bursts of activity brain practically shuts off stages three four shifts into slow-wave sleep heart and breathing rates drop dramatically 70 minutes non-REM sleep first period of REM lasts only five minutes total non-REM–REM cycle 90 minutes pattern repeats five times over the course of a night non-REM stages shorten REM periods grow 40-minute dreamscape just before waking study REM deprivation torturous sleep deprivation electroencephalogram subjects moving into REM wake them up psychologist Tore Nielsen director Dream and Nightmare Lab Sacré-Coeur Hospital in Montreal rob them of REM pressure for them to go back into REM starts to build go directly into REM as soon as they are asleep non-REM rebound as well brain gives priority slow-wave sleep REM states are independent of each other 2005 study published journal Sleep losing 30 minutes of REM 35 percent REM increase the next night subjects 74 minutes of REM rebound of 100 minutes dream intensity increased REM deprivation subjects quality of dreams REM deprivation subsequent rebound alcohol nicotine both repress REM blood pressure drugs antidepressants REM suppressants take away the dreams the depression lifts scary rebound persistence of REM rats are robbed of REM for four weeks die we spend 27 years dreaming average life scientists can't agree on why it's important Psychiatrist Jerry Siegel head of the Center for Sleep Research University of California Los Angeles UCLA REM nonexistent some big-brained mammals dolphins whales dying die death lack of REM species other than a rat helps regulate body temperature neurotransmitter levels evidence dreaming helps assimilate memories fetuses babies spend 75 percent of their sleeping time in REM platypuses experience more REM than any other animal Minnesota Mahowald rats run through dream mazes lab mazes some purpose meaningful information in dreams John Antrobus professor psychology sleep research City College of New York dream content tied to our anxieties extreme vividness REM rebound higher level of brain activity action-packed dreams brain interpretive organ purpose of thought /