Unexpectedly, deep sleep is so "dangerous"

Photo: Joanna B. Pinneo, National Geographic

In dry Mali, a Tuareg family sleeps in a tent.

One sleep can make people experience "brain death" and "mental illness" at the same time! Do you dare to sleep? From shallow to deep, human beings will have four periods of sleep every night, and there will be a crazy "REM" state. To outsiders, you seem to sleep peacefully; In your subjective consciousness, your brain is actually acting recklessly and releasing yourself again and again, which is more enjoyable than a roller coaster, sometimes making you close to the state of suspended animation, and sometimes making you more excited than when you are awake .......

We just fell asleep during sleep 1-2

At this stage,

our senses are covered, and our brain remains active and

.

A total of about 86 billion neurons communicate with each other through electrical signals and chemical signals. When awake, neurons form a bustling large group, which is dynamic like a thunderstorm at the cell level; If they are excited smoothly and rhythmically, and neat ripple lines appear on the EEG, it means that the work center of the brain has turned inward, away from the hustle and bustle of waking life. At the same time, all kinds of sensory receivers are blocked, and we will soon fall asleep. This is the first stage of sleep, which is the shallowest end of sleep and lasts about 5 minutes.

photography: Magnus Wennman

what makes us sleepy? The airtight cabin of the Sleep Research Institute of the University of Tsukuba in Japan enables researchers to accurately track the oxygen consumption of sleepers, then calculate their metabolic rate, and measure the influence of external factors (such as the brightness and color of ambient light) on the data. Finding the best conditions to trigger sleep may be the first step to cure insomnia.

Then, a string of sparks rose from the depths of the brain, and shocked the wrinkled gray matter in the cerebral cortex, the center of language and consciousness! This kind of electric shock of half a second at a time is called "sleep shuttle wave". As long as this wave of operation occurs, it indicates that the human body has entered the second stage of sleep.

According to the new theory, shuttle waves will give specific stimulation to the cerebral cortex, so that it can preserve the recently acquired information. The more shuttle waves, the better people will perform the next day.

photography: Magnus Wennman

if you have just experienced something bad,

don't fall asleep at once!

at night, we switch from recording mode to editing mode. The brain will actively identify which memories should be kept and which should be deleted, but this selection is not necessarily correct.

And sleep is very efficient in strengthening memory, which is not only reflected in the second stage, which occupies about half of the sleep time, but also in the whole cycle of sleep.

Photo: TIM HETHERINGTON, MAGNUM

In the Korengal Valley in Afghanistan, an American soldier is sleeping. He had just finished his night mission in frontline base the night before.

For example, an exhausted soldier has just returned from a dangerous battlefield, so don't just lie down and fall asleep. Gina Bo, a neuroscientist at UCLA, believes that in order to prevent post-traumatic stress disorder (PTSD), these soldiers should persist for six to eight hours before going to sleep.

photography: Magnus Wennman

Mike Morris, an American army veteran who served in Iraq for two rounds, wore an EEG measuring cap while sleeping and held his therapeutic dog Oliver. This study reveals the influence of animal companionship and sleep silence on the recovery of mental trauma.

If we go to sleep immediately after a great change, and some suffering experiences are not digested psychologically, then they will have a higher possibility of entering long-term memory and even affect our cognition for life.

So, don't quarrel before going to bed, don't get angry, and don't take the initiative to cause unpleasant things. But if unhappiness is inevitable, please stay awake and buffer for a few hours before going to sleep!

photography: piroska b

goes into a deep sleep state in stage 3-4 sleep

,

in other words, this state

is not far from the state of brain death!

No wonder the ancients in China called sleep "a little death".

photography: SEBASTIAN WAHLHUETTER

the fourth stage of sleep is not far from brain death!

The three-toed sloth dozes off for 1 hours every day;

Fruit bats can sleep for 15 hours;

A rat-eared bat sleeps for 2 hours;

giraffes sleep less than 5 hours;

The horse sleeps standing for a while at night and lying down for a while;

The two brain hemispheres of dolphins sleep in turn,

One side is always awake and never delays swimming;

frigate birds can fly and sleep while gliding!

Photography: STEPHANE GRANZOTTO

In the Indian Ocean, more than 3 adult female sperm whales are taking a nap about 15 meters below the sea surface. They fall asleep in an upright posture, ranging from a few minutes to dozens of minutes, while their cubs play on the sea.

It is a natural rule that a creature, as big as cetaceans and as small as cells, can't run with full throttle for 24 hours.

photography: Magnus Wennman

76-year-old Joe Diemand has been a truck driver for the past 2 years, and sometimes he needs to drive all night. He said that such a job would make people "too tired to sleep". The World Health Organization once commented on night shift work, "It is likely to cause cancer to human beings".

For humans, the main recovery occurs in deep sleep in stages 3 and 4. Our cells secrete the most growth hormone during deep sleep, and we rely on this hormone to maintain bones and muscles all our lives. Moreover, sleep is indispensable for maintaining body temperature, blood pressure and a healthy immune system.

Photography: Magnus Wennman

Paris Philharmonic Concert Hall refers to the arrangement of scientific theory, and the program "Sleep" is interpreted with a minimalist lineup, aiming to lead the audience into a sweet rest state. The whole program lasts for more than eight hours!

When awake, neurons are tightly packed together, but after falling asleep, the volume of some brain cells will be reduced by 6%, and the spacing will be widened. The intercellular space is the dumping ground of metabolic wastes-especially, a substance called β -amyloid protein, which can disturb the communication between neurons, is closely related to Alzheimer's disease. Only in sleep can cerebrospinal fluid wash β -amyloid away along the widened gap.

photography: Magnus Wennman

various sleep-aiding "artifacts" are very popular among urban people in China.

while all kinds of brain repairs are going on, our muscles are fully relaxed. We usually don't dream in stage 4, and we may not even feel pain. Stage 4 sleep is not far from coma and brain death. Although it is full of repair effect, it is absolutely impossible to be greedy!

So, we stay in Phase 4 for about 3 minutes at most, and then our brain will kick ourselves awake. At this time, we often go backwards through Phase 3, Phase 2 and Phase 1 until we regain consciousness.

photography: Magnus Wennman

an old man is dozing under a tree, and many middle-aged and elderly people are prone to drowsiness during the day because of sleep-induced respiratory syndrome.

When you don't get enough sleep, the first part of your brain is the frontal cortex, which is the core functional area for us to make decisions and solve problems. People who don't get enough sleep are more likely to get angry, emotional and irrational. And daytime naps can't make up for the lack of sleep at night; Anyone who is used to sleeping less than 6 hours a night has a higher risk of depression, stroke and mental illness; Lack of sleep is also directly related to obesity: if there is not enough sleep, the stomach and other organs will over-secrete growth hormone-releasing peptide, commonly known as "hunger hormone", which makes people eat more than they actually need.

crazy "REM" state

In fact, every night,

we will have a "mental illness"!

because we

REM every night.

Photography: Dawn Kish, National Geographic Creative

In the Grand Canyon, a lonely traveler fell asleep on the sandbar of the Colorado River.

rapid eye movement (REM) sleep was discovered by Eugene aselinski and Nathaniel Cleitman of the university of Chicago in 1953. Before that, REM was usually regarded as the deformation of stage 1 sleep and had no special importance. However, the unique rapid eye movement and the congestion of sexual organs that always accompany it have been reported repeatedly.

among adults, the duration of REM accounts for about one-fifth of all rest time.

Every time we experience REM rapid eye movement sleep, it is equivalent to committing mental illness! Mental illness is defined as a state characterized by hallucinations and delusions. Some sleep scientists say that dreaming is a state of mental illness-we see the nonexistent scene but believe it, and we are comfortable with the time and space and people changing or disappearing for no reason.

Newborns can sleep for 17 hours every day, but nearly half of the time is spent in a brain activity similar to REM. The pregnant fetus has been sleeping with REM for about one month from the 26th week. There is a theory that these dreamlike experiences in the early life are equivalent to the "software test" of the brain, which is to prepare for full online. This process is called telencephalonization.

Photography: COLIN MONTEATH, MINDEN PICTURES

This experienced Antarctic tourist sleeps on a deck chair and enjoys the snow near amundsen sea.

During REM sleep, the human body no longer regulates its body temperature, and its internal temperature is kept at the lowest point within the set range, and the whole body is frozen. The heart rate is faster than other sleep stages, and the depth is uneven. Muscles can't move except for a few parts-eyes, ears, heart and diaphragm.

photography: Magnus Wennman

in the research room of the national children's medical system in Washington, USA, a 1-year-old boy, Francis Iowa, who was covered with tubes and electrodes, was waiting to turn off the lights and began to have an all-night sleep check. This time, I checked sleep apnea, that is, repeated symptoms of respiratory interruption after falling asleep.

We believe incredible things in REM sleep because the management right of the brain is no longer in the logic center and impulse control area.

At this time, serotonin and norepinephrine are completely discontinued. They are key neurotransmitters that enable brain cells to exchange information. Without them, people's learning and memory abilities will be seriously damaged and they will fall into a distorted state of consciousness.

photography: Magnus Wennman

in Sweden, hundreds of immigrant children, whose families are facing the situation of being deported, suffer from the so-called "obedience syndrome", and their inexplicable maladjustment manifestations include: autism, even if they don't respond to painful stimuli, they can only get nutrition through nasal feeding tubes, and some have to continue feeding for several years.

but this is different from the coma-like state like stage 4 sleep. In the REM stage, our brains are fully active, and the energy consumption is even less than when we are awake.

REM sleep is controlled by the limbic system deep in the brain, which can be said to be the primitive jungle in the field of thinking-our most savage and deepest instincts haunt here. Freud was right. Dreams do trigger our primitive emotions.

photography: Magnus Wennman

new memories are consolidated at night. what happened to the brain at night? The University of Tsukuba in Tokyo uses optogenetics's method to explore this problem-mice are genetically modified to have specific sensitivity to light, and then a single brain cell is activated and turned off by a laser.

The limbic system contains our sexuality, aggression and fear, but it can also make us feel joy, joy and love. Although sometimes there are more nightmares than good dreams, it is probably an illusion. It's just that terrible dreams are more likely to touch the brain's instruction change system and wake us up.

Photography: Frank Lapena

When we fall asleep and start the first REM sleep, the brain, the most exquisite and complicated instrument known in the universe, can finally do what we like happily. It fully activates itself to play and dream! Some sleep theorists suspect that REM sleep is the smartest, wisest, most creative and freest time for us-

That is to say,

after you fall asleep, there is always an hour or two,

your brain finally releases itself and

starts to do whatever you want.

At this point, the brain makes you a

complete little mental derangement.

So, the brain is so naughty,

Do you dare to sleep?

at the end of the article, we should solemnly remind: we must dare to sleep! And have a good sleep on time! Although the REM state makes people close to psychotic episode, and even though the fourth stage of sleep is a virtual state of brain death, we must face this "small death" frankly-< P > After all, without "small death", there will be no great work.

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