User:Fmei00/Non-rapid eye movement sleep

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NREM sleep is characteristic of dreamer-initiated friendliness, compared to REM sleep where it's more aggressive, implying that NREM is in charge of simulating friendly interactions.

Dreaming
It was initially thought that NREM sleep is the absence of dreaming, or dreams occur more rarely compared to REM sleep because 90-95% of those who wake up in the middle of REM sleep will report that they have had a dream, but only 5-10% of those waking up in the middle of non-REM sleep will report they've had a dream However, when asked for more general thought processes or feelings, 70% of people who awaken from NREM sleep reports of having dream-like feelings, which is characteristic of NREM dreams, potentially disproving that theory.

Self in NREM Dreams
It is suggested that dreaming involves two selfs: aggressive self (REM) and friendly self (NREM). It seems that in NREM dreams, the self are put in different situations, largely negative, but are found to respond in a way that befriends or embraces the unfamiliar. It's sometimes thought that in NREM sleep, the dreamers are "aware of being aware", also known as "secondary awareness", which allows them to make better decisions and be able to reflect on them.

NREM in other animals
Not much is known about NREM, so scientists have conducted studies in other animals to potentially understand more, in particular why the brain has evolved to have two distinct states. In their studies, it was found that between birds and certain mammals like dolphins, their brains exhibit similar behavior. It was found that certain species of birds have half their brain's hemisphere release brain waves similar to a human's during NREM sleep, and the other half of it fully conscious, allowing them to fly while sleeping. Certain species of dolphins also exhibit similar behavior as birds in order to be able to swim while sleeping.

In rats, after a 24-hour sleep deprivation, it was found that there was an increase of slow-wave activity in NREM sleep, which corresponds directly with the human brain which when sleep deprived, prioritizes NREM sleep over REM sleep, implying that the NREM sleep is responsible for regulating and compensating for missed sleep.