Does the brain work during sleep. Sleep phase activity. The main human organ, its structure and functions

Everyone knows that a person cannot stay awake all the time - the body needs healthy sleep. Does the brain rest during sleep? Let's figure it out.

Scientists have been studying the work of the brain during sleep only for the last 100 years. Therefore, there are still many questions and mysteries regarding sleep.

We all sleep and dream every day, and not many people know why and how they arise. Sleep is natural physiological processes during which the response to the world, and the level brain activity minimal. In a dream human brain processes information received not only for the past day, but throughout life. It comes to him in the form of free associations: separate pieces of information in a dream are collected into a whole picture and are subjected to careful analysis. It is important to note that not a single dream happens without dreams, simply, we don’t remember a lot - more precisely, the brain “does not want” us to remember it.

Sleep has two main phases: non-REM and REM sleep. Slow-wave sleep is 75% of the total, the remaining 25% are REM sleep. Slow-wave sleep has only 4 stages: the first is drowsiness, dreams; the second - increased perception techniques (for example, hearing) and a person can easily be awakened; the third - the perception of the surrounding world is slightly lowered; the fourth is deep sleep. Scientists believe that during slow sleep, a person recovers energy costs, or, more simply, “reboots”.

REM sleep can be attributed to the fifth stage of sleep. In this state, the work of the brain resembles the state of wakefulness. The most interesting thing is that the person is completely relaxed and motionless! The only thing that makes fast movements is eyeballs under closed eyelids. Phase interruption REM sleep negatively affects the psyche, while the interruption of the non-REM sleep phase does not have such serious consequences. This is due to the fact that during REM sleep there is a serious work of the brain - the processing of information, and it also provides psychological help body.

Recent studies by scientists from the University of California have shown that brain activity during sleep is even greater than during wakefulness. They claim that the brain works seven times faster during sleep. This data is carefully checked and we will soon find out if this is true or not.

The main thing that anyone needs to know is that a person needs sleep! During sleep, the brain “works on mistakes” to help resolve conflicts that arise in our inner self. Sleep disruption leads to serious psychological problems, as well as to the failure of the whole organism. Healthy sleep should last at least 8-9 hours a day (according to other sources, at least 10-12 hours). The quality of sleep is also important - the daily regimen of sleep and wakefulness must be observed, clothing should not be constraining, and the situation in the room should interfere with your rest. Try to switch off before going to bed from all sorts of thoughts about work, financial affairs and family troubles. If you don't have healthy sleep, it will be much more difficult to solve the issues that concern you. Remember: sleep quality is key good rest. Have a nice sleep!

Brain activity is maintained during sleep. Departments of the central nervous system, responsible for hearing, vision, smell, tactile sensitivity, motor functions, solve all kinds of problems that life puts in moments of wakefulness. Let's take a closer look at what happens to the brain during sleep.

Good rest is provided by the consistent alternation of slow and fast sleep. The complex of both phases is a complete cycle. The orthodox phase in an adult is up to 75%, and the paradoxical phase is a quarter of the structure of sleep. During the night, there can be a successive change of four to six cycles lasting from eighty to one hundred minutes.

The duration of the slow-wave phase is longer at first, and by the time of awakening it is shortened, giving way to REM sleep. The orthodox phase is divided into four periods (scientists call them stages) - drowsiness, slow depth, the rhythm of "sleep spindles", delta waves. The REM phase is also heterogeneous, it includes emotional and non-emotional stages.

Brain activity during the night

Healthy sleep ensures the full functioning of the whole organism. A sleepy person will not be able to drive a car or solve a mathematical problem. Scientists have proven that the brain does not turn off during sleep, there is a processing of the knowledge gained during the day, negative emotional experiences, memory consolidation. Detoxification of brain structures starts, activity increases immune system, work is restored internal organs. The main hormone of the night - melatonin, produced by the pineal gland, protects against premature aging.

The main human organ, its structure and functions

The nervous system acts as the main regulator, ensuring the coordinated activity of the whole organism. Anatomists divide it into central department(brain and spinal cord) and peripheral (nerves). Clusters of cells form gray matter, and myelinated fibers form white matter. The human brain consists of two cortical lobes, the brainstem and the cerebellum.

Let's try to figure out which part of the brain is responsible for sleep.

Attention! Scientists have proven that anatomical isolated centers of sleep and wakefulness do not exist.

Neurophysiologists distinguish three types of zones:

• providing the function of the orthodox phase;
• structures “responsible” for RBD;
• cycle controls.

Hypnogenic centers are clusters of neurons. The activity of the reticular formation of the spinal basal departments forebrain and thalamus provides the generation of falling asleep. The reticular formation of the midbrain, the vestibular nuclei of the oblongata, and the superior colliculus are centers that support the paradoxical phase. Separate areas of the cortex and a bluish spot (locus coeruleus) regulate the change of phases.

Brain behavior in different phases of sleep

Scientists have described in detail how the brain works during sleep. The picture of the electroencephalogram during drowsiness corresponds to the EEG in the period calm state, rest (alpha rhythm). The second phase of slow sleep is characterized by the registration of sleep spindles - bursts of wave activity with high frequency and low amplitude (sigma rhythm).

Electrical impulses during deep sleep (the third phase of the orthodox stage) are characterized by large amplitude and low frequency. They are called delta waves and are never recorded while awake.

Man consistently plunges into an even deeper realm of Morpheus. There is a decrease in body temperature, a slowdown in heart rate, respiration, a decrease in brain activity. And suddenly after twenty or thirty minutes of the fourth phase, the brain rewires itself and moves into the second phase of non-REM sleep, as if it wants to wake up. But instead of waking up, the part of the brain responsible for sleep leads it to the next phase - the paradoxical one.

Its unusualness is amazing: the body and muscles are completely turned off, and brain activity corresponds to the period of wakefulness.

It's important to know! During sleep, brain activity is highest during the REM phase. A person has a jump blood pressure, there is an increase in the frequency of respiration and heart rate, hyperthermia is observed. BDG-Phase Combine Trip motor function and amplification - cerebral.

Theta rhythm is registered in the emotional stage. In an unemotional one, it weakens, giving way to an increase in the alpha rhythm.

Conscious and subconscious

REM theta rhythms are produced by the hypothalamus, a part of the brain that remains active during wakefulness, and is also the main one in neuroendocrine regulation, homeostasis correction, involved in the formation of memory and emotions. Falling asleep turns off the influence of the cortex, the mind is freed from the framework of conventions while the subconscious mind continues to work. Thanks to activity subcortical structures arise original ideas and come up with unconventional solutions.

The essence of the night work of the brain

The significance of the process is enormous. An adult needs to sleep at least seven hours a day. If the function of sleep was limited only to physical rest, nature would not force a person to completely disconnect from reality for a third of the day.

Researchers tracked what happens to the brain during sleep:

• The functional connections of individual parts of the brain are temporarily interrupted during non-REM sleep.
• In the paradoxical phase, there is an exchange of information between cerebral structures.
• Memories are processed and sorted.
• Associative chains are being built.
• The intercellular space is cleared of toxins.

It's important to know! An amazing phenomenon was noted - the need for sleep for the body is inversely proportional to the intensity mental stress. The brain of a person relaxing in front of the TV wants to rest more than during the preparation for the defense of the dissertation.

Formation of dreams

From ancient times to the present, the interest of mankind in the question of why dreams have not faded.

Oneirology does not indicate a specific mechanism for the emergence of night stories and experiences, but offers a list of interesting hypotheses.

A short list of some of them:

The famous psychiatrist Hartman admits that dreams arose in the process of human evolution as healing mechanism to get rid of negative feelings mental health. It has been proven that dreams are produced by the brain during REM sleep. In 2004, during the experiments, it was possible to confirm that the parts of the brain that form emotions and visual perceptions are responsible for the occurrence of night dreams.

Methods for studying brain activity

Used in neurology various methods research. Some of them give an idea of ​​the anatomical picture, help to identify a tumor, abscess or congenital anomaly. This is magnetic resonance computed tomography, ultrasound diagnostics, some others. There are methods for recording the electrical potentials of the brain, allowing to assess its functional state:

• Rheoencephalography is a study of the system of arteries and veins of the head. The value of tissue resistance is recorded when a weak electric current is applied to them.
• Magnetoencephalography - registration of magnetic fields resulting from cerebral activity.

Advice! To understand whether the brain is resting during sleep, electroencephalography is most often used - recording impulses from various parts brain. EEG helps to diagnose disorders, identify the localization of the focus, specify the nosology, and evaluate the quality of treatment.

The Phenomenon of Hypnopedia

In connection with the increasing flow of information, there is an increasing interest in the phenomenon of hypnopedia - learning in the process of physiological sleep. The offer of advertising agents to wake up in the morning with a good amount of knowledge is tempting. We will not enter into a dispute either with opponents or with followers this method Let's just recall a few recommendations:

For full assimilation, it is important that the brain has time to go through the required number of cycles. With insufficient sleep time, a person runs the risk of getting daytime sleepiness, and not fresh knowledge.

Brain pathologies: impact on sleep quality

Any illness negatively affects the quality of sleep. In turn, dyssomnias are risk factors somatic diseases- hypertension, diabetes, cancer, thyroid disease, obesity.

Brain diseases - neoplasms, cysts, epilepsy, inflammation meninges, traumas and cerebrovascular pathology cause disturbances in memory, motor, speech functions. They not only cause trouble falling asleep, but also contribute to a change in the structure of sleep.

Conclusion

For normal life, it is important not only the ratio of sleep and wakefulness, but also compliance with circadian rhythms. Even when consciousness is turned off, the human brain does not stop working. The activity of this the most important body at the moment of immersion in the arms of Morpheus, it has been studied enough, however, there are a lot of questions that remain to be answered.

Sleep remains one of the biggest mysteries for neuroscience. Although we spend about a third of our lives sleeping, this process is still largely unexplored. But fortunately, over the past few years, scientists have been able to make significant progress in studying the neural circuit in the brain responsible for the sleep process.

It is generally accepted that sleep consists of several different phases, and that the daily process of sleep is an interaction of these phases, which is done in a very complex mechanism. In addition, sleep phases are influenced by factors such as circadian rhythms, body temperature, hormones, etc.

Sleep is very important for such functions. human body like concentration, memory and coordination. As a result of insufficient sleep, a person may experience difficulty with concentration and reaction speed - in fact, lack of sleep can lead to just as negative effect that and the adoption of alcohol.

Also, sleep is very great importance for emotional state person. There is more and more evidence that lack of sleep increases the risk of various heart and cardiovascular diseases including heart attacks, stroke, high or low blood pressure, and obesity or various kinds infections.

Sleep disturbance is one of the most common problems affecting about 70 million people, most of whom do not even think about how serious consequences she can bring.

The diseases listed above are only a small part; lack of sleep can even lead to death: medical costs, injuries at work, lost productivity - all this costs no less than 100 billion dollars. Scientists around the world have promised to develop new ways to combat sleep deprivation, and so far they have been quite successful in fulfilling their promise.

brain activity during sleep

Although it would seem that sleep is a passive process and a process of complete rest, in fact it requires a very active interaction of various parts of the brain in order for one phase of sleep to succeed another.

Sleep phases were discovered in the 1950s with the help of electroencephalography (EEG), when the oscillations of the brain during sleep were studied.

Eye and limb movements were also studied. Scientists have found that during the first hour of sleep, the brain goes through certain processes that lead to a slowdown in neural oscillations. This phase of sleep, the so-called "slow sleep", is also accompanied by muscle relaxation, including the eye muscles. There is also a decrease in heart rate, blood pressure and body temperature. If a person is awakened at this moment, he will remember only various fragments of thoughts and images, but not the whole dream.

Over the next half hour or so, the brain changes dramatically in its activity. The level of cortical neural oscillations in this phase of sleep is very similar to the level of oscillations of a waking person. Incredibly, a period of increased neural activity is accompanied by atony - all muscles human body fetters a kind of paralysis (only the muscle groups responsible for breathing and eye movement remain active). This phase of sleep is called REM sleep. During this phase, a person, as a rule, always sees dreams. Heart rate, blood pressure and body temperature become more stable. Men often experience erections at this time. The first phase of REM sleep usually lasts 10-15 minutes.

Throughout the night, the phases of slow-wave sleep and REM sleep alternate with each other, and each time, until the very awakening, the slow-wave sleep phase becomes less and less deep, and the REM sleep phases become longer and longer. The duration of one or another phase of sleep largely depends on the age of the person. Children under the age of 7 usually sleep up to 18 hours a day, and the phase of non-REM sleep prevails in them. As children grow older, they begin to spend less and less time on sleep, the non-REM sleep phase is also significantly reduced. Well, adults can sleep for 6-7 hours a day, often complaining that they have to wake up early, while slow-wave sleep takes them a very small amount of time.

An example of the sleep process

The neuronal oscillations of a person aged 20-25 recorded by an electroencephalograph (EEG) gradually slow down and at the same time become more intense as the person enters more deep stages slow sleep. Approximately an hour later, the human brain goes through this cycle in the same sequence, each time necessarily passing through the phase of REM sleep (highlighted in the graph). purple), during which neural oscillations become as intense as during wakefulness. The body at this moment is completely relaxed, the person is unconscious and often begins to dream. The closer to the morning, the longer the duration of the REM sleep phases becomes, and vice versa - the duration of the non-REM sleep phases is significantly reduced.

Sleep disorders

• The most common sleep disorder, and probably familiar to many people, is insomnia. Some find it difficult to fall asleep at all, and some do fall asleep but wake up at night and cannot fall asleep again. While fast-acting sedatives or anti-depressants can help, none of these will help you achieve truly natural and relaxing sleep. they often simply interrupt the deepest periods of non-REM sleep.

• Sleep apnea syndrome - during deep sleep, the muscles of the pharynx relax until they begin to block the airway. This leads to forced cessation of breathing, why man wakes up immediately. As a result, deeper periods of non-REM sleep simply do not have time to occur.

Treatment for sleep apnea includes a variety of attempts to prevent overlap respiratory tract during sleep. It is fair to say that if you drop excess weight If you avoid alcohol and drugs, it is very likely to improve your sleep. But for people who suffer sleep apnea syndrome, you just need a certain device that would put pressure on the airway, why it would remain open. There is a special mask that is worn over the nose and produces a rather strong air flow just for this purpose. In more complex cases, it is sometimes necessary surgical intervention– correction of the airway.

• Involuntary movements of the limbs during sleep - in other words, these are periodic sharp jerks of the arms or legs, not human controlled. As a rule, they occur when entering the phase of non-REM sleep and can lead to awakening. And some people cannot control movements even during the REM phase, clearly showing what they are dreaming at a particular moment. This aberration, called REM sleep behavioral aberrations, can also severely impair normal course sleep. Both of the above syndromes are often characteristic of people suffering from Parkinson's disease. Accordingly, it is also possible to get rid of them with the help of medications aimed at treating Parkinson's disease or also with the help of clonazepam, a type of benzodiazepine.

• Narcolepsy is a relatively rare disease - it affects only one person in two and a half thousand. Narcolepsy is a disruption in the functioning of the mechanisms responsible for falling asleep (or in the REM phase if a person has already fallen asleep).

A person suffering from narcolepsy, at any time of the day, may undergo seizures, as a result of which he falls asleep, unexpectedly for everyone around him, if they do not know about his illness. This is very disturbing in everyday life, and besides, it is dangerous - imagine, for example, what will happen if an attack of narcolepsy catches a person behind the wheel.

Narcoleptics enter REM sleep very quickly and may dream as soon as they are asleep, a phenomenon called hypnagogic hallucinations". Seizures may also occur, during which a person completely loses muscle tone- this state is similar to the complete inactivity of all muscles during REM sleep. This pathology is called "cataplexy" and the next attack, as a rule, occurs as a result of emotional experiences, often even a funny joke heard by a person is enough.

Recent research into narcolepsy has shed some light on the processes that control a person's transition from wakefulness to sleep and the transition between sleep phases.

What and how is sleep regulated?

When a person is awake, his brain is in an active and excited state. This is due to two main neural networks that use either acetylcholine or monoamines as neurotransmitters (chemical transmitters of impulses between nerve cells) - for example, norepinephrine, serotonin, dopamine and histamine. Nerve cells containing acetylcholine and located in the upper part of the pons, as well as in the midbrain, actively contribute to the activation of the thalamus.

When the thalamus is active, it, in turn, transmits information about the world around it, received from the sense organs, to the cerebral cortex.

The second group of nerve cells containing norepinephrine, serotonin and dopamine and located in the upper part brain stem, send the results of their activity to the hypothalamus, forebrain and cortex.

Then in the hypothalamus nerve cells containing the neurotransmitter orexin and another group of cells containing acetylcholine or gamma-aminobutyric acid combine the information received and transmit it to the cerebral cortex. As a result of these processes, the cerebral cortex is activated, so that the human brain can correctly respond to the information that the thalamus has received from the senses.

During REM sleep, cholinergic cells activate the thalamus, which causes a burst of neural oscillations, like that observed in an awake person. However, the flow of monoamines from the upper brainstem to the cortex does not experience such activity. As a result, the information transmitted by the thalamus to the cortex is perceived by us as a dream. When nerve cells containing monoamine neurotransmitters are activated, they end REM sleep.

The brainstem cells responsible for awakening a person from sleep are exposed to two groups of nerve cells in the hypothalamus (which, by the way, is responsible for the main cycles of our body).

One of these groups of nerve cells contains inhibitory (i.e. inhibitory) neurotransmitters such as galanin and gamma-aminobutyric acid. When this group of neurons is activated, it, according to scientists, "turns off" the motor system and puts a person into sleep. Any harm done to this group of cells immediately leads to insomnia.

The second group of nerve cells, located in the lateral part of the hypothalamus, causes a person to wake up from sleep and exit from REM sleep. It contains orexin, through which it can send excitatory impulses to the motor system, and in particular to nerve cells containing monoamines.

During experiments conducted on animals, orexin was completely removed from their brains, as a result of which they showed symptoms of narcolepsy.

A similar result was given by another experiment: the brains of two dogs with natural narcolepsy were studied. The examination showed that they had abnormalities in the gene responsible for the production of orexin.

Although narcolepsy is rarely associated with any genetic disorder in humans, many narcolepsy sufferers between the ages of 13 and 25 have been found to lack orexin-containing nerve cells. Recent studies have confirmed that orexin levels in the brain and cerebrospinal fluid are unusually low in patients with narcolepsy. In general, orexin plays very important role in the activation of the monoamine system, and also prevents the unnatural transition from the state of wakefulness to the state of REM sleep.

Homeostasis and circadian rhythms

Our need for sleep and the pattern of sleep itself is controlled two main indicators. The first one is homeostasis, the human need to maintain an even sleep pattern. There are several ways to signal to the body that it needs sleep. It has been scientifically proven that the level of the so-called adenosine in the brain is directly related to the activity of the brain itself and homeostasis. If a person is awake for a long time, then adenosine begins to accumulate and thus affects homeostasis. By the way, caffeine, widely used just as a way to cope with drowsiness, blocks the action of adenosine.

If a person does not get enough sleep, then the need for sleep gradually leads him to a decline in mental activity. Then, when he has the opportunity to sleep, a person usually sleeps more than usual - "sleep off", so to speak. By the way, this very “sleeping” always begins with a phase of slow sleep.

The second indicator that affects sleep patterns is circadian rhythms.

The suprachiasmatic nucleus is a small group of nerve cells that serves as the internal clock of the human body. These nerve cells go through a 24-hour biochemical cycle, determining the time to physical activity body, for sleep, hormone release and other natural human needs.

The suprachiasmatic nucleus also receives signals from the retina to right time if necessary, adjust the internal clock of the body in accordance with the natural cycle of day and night. The suprachiasmatic nucleus sends signals to the neighboring part of the brain - the paraventricular nucleus. That, in turn, interacts with the dorsomedial nucleus of the hypothalamus, and it interacts with the ventrolateral nucleus, in which orexin-containing cells control the sleep process and determine the time of transition to awakening.

Waking and sleeping brain

Article content

Need daily sleep conditioned not only by human desire and physiology, but also by science. Absolutely every person spends about a third of his life on this occupation. Everything that he did the whole previous day, what tasks he solved, what he thought about, what he planned, what memories he came across, the brain digests and puts them “on the shelves” when a person is fast asleep. It turns out that when a person is unconscious and plunges into the arms of Morpheus, the brain continues its active work. Consider how the brain functions during sleep, what it actually does and how it behaves.

What does the brain do at night

When we sleep, our brain continues to function. This activity, activity of the brain is due to the peculiarities of its structure. The list of his tasks at this moment is as follows:

1. Acceptance is vital important decisions. Studies have shown that the brain is able to take operational decisions for any questions or concerns. The source Current Biology published the results of studies in which respondents were asked to sort words into categories by pressing a button, while still being able to fall asleep. The experiment continued into sleep, as the brains of the participants demonstrated the ability to make decisions even after the body fell asleep.
2. Memory classification. When studying the question of what happens to our brain during sleep, it can be noted that it is engaged in the processing of memories and the loss of connections with old moments. He sorts human memory so that the right moments are not forgotten. According to Dr. M. Walker, who works at the University of California, if a person attends a piano lesson after a healthy sleep and sleeps the right amount of time the next night, then the material will be learned and reproduced 20-30% better than when checking knowledge immediately after how the session ends.

3. Gets rid of waste and toxins. As soon as the body falls into sleep, the brain continues to work actively, relieving it of harmful substances. This fact is confirmed and supported by a series of research activities. But an increased amount of these elements can lead to many pathological conditions, so the benefit of the brain in this direction is undeniable.

4. Training in physical labor. During REM sleep, information about motor options is transferred from the cerebral cortex to temporal region. This phenomenon allows you to carefully think through and flawlessly perform tasks related to physical labor. Now it is clear which part of the brain is responsible for the execution exercise and daily activities.

As can be seen from the above, the functioning of the brain during sleep continues, and even when we sleep, it performs a large number of tasks.

The work of the brain in cycles

The whole process of human sleep at night consists of several cycles of "slow - fast process". According to the public theory, we sleep to ensure the processing of information received during the day or the previous day. Classical sleep includes 4 stages of non-REM and 2 stages of REM sleep. Information is transmitted in a reorganized form only after the completion of the third cycle. But the brain does not turn off in the next 1-2 cycles, but continues to work.

In the process of immersion in the world of Morpheus, brain structures temporarily lose their functional interconnections that promote wakefulness. This phenomenon can be tracked on electroencephalograms. Each of these structures closes in on itself, and then tunes in the right way and is subject to regulation, which cannot be done during wakefulness, when the "gray matter" is in active interaction With environment. A sleeping person's head works a little differently.

Even when we sleep, our brain is still working.

At the stage of slow sleep, the regulation of internal rhythms occurs with respect to each structure of the brain, while at the stage of the fast process, harmonic relationships are established between these elements. In general, sleep has one main task - to adjust the biorhythms of the body to optimal mode which is individual for each person. This standard is created in the process of wakefulness, and this or that behavioral program, laid down at the genetic level, acts as a base. If the model is formed and works smoothly, it is enough to rest a small amount of sleep. If there are failures, the person sleeps longer.

Interestingly, the need for sleep has an inverse relationship with the amount of information received: the more it enters the gray matter, the less sleep necessary. This may be due to the fact that in the process of obtaining enhanced mental load a person sleeps less than in the case when he most spends his time watching TV.

Rest of the brain during sleep

Does our brain rest during sleep? The issue is the subject of controversy among many people. And this is not unreasonable. In fact, as soon as a person goes into the world of dreams, the brain is rebuilt to a different mode of operation. If during wakefulness he did not have the opportunity to analyze events and classify thoughts, then when a person fell asleep, she appeared. Therefore, in the first cycles, the brain is engaged in these tasks, and at the end of this work (usually closer to the morning) it has a little time to rest. But this does not mean that it completely “turns off” along with the body, we can say that it simply turns on the “economy” mode. Therefore, from the side of the brain, sleep is perceived differently than from the side of the body.

Brain function and dreams

When the brain structures function, they establish mutual connections with each other, as if talking. This fact is fully proven various dreams. Also in this process there is an active training nerve centers: Cells that were inactive when awake begin to perform a kind of functional gymnastics to maintain optimal shape. It is for this reason that after stress a person sleeps “like a log”, because his cells have already received a shake-up and do not need additional information in the form of dreams.

Slow phase of dreams

In total, the slow stage accounts for about 75-85% of all sleep, and it includes several states:

• nap;
• sleep spindles;
• delta sleep;
• deep dream.

As a person sinks into sleep, many bodily functions change. In the first stage, called drowsiness, and also in the second stage, the pulse becomes more rare, blood pressure is subject to decrease, blood flows more slowly. As soon as the sleeper plunges into the state of delta sleep, his pulse noticeably quickens, and the pressure rises. Non-REM sleep is the phase responsible for regulating internal rhythms for each brain structure and every organ.

The work of the body in the fast phase

The way the brain works during REM sleep is somewhat different. Basically, the process of REM sleep can be divided into 2 main stages:

• emotional;
• unemotional.

They alternately come to replace each other and act like this several times, and the first stage is always longer.

How does REM sleep differ from slow sleep?

There are several points that distinguish one phase of sleep from another, and you should take them into account.

1. Number of stages in slow sleep- 4, and in fast - 2.
2. During slow-wave sleep, eye movements are smooth at first, and at the end of the stage they stop altogether. In the fast phase, the opposite is true - the eyes move continuously.
3. The state of the autonomic nervous system also differs: in the first case, a person grows faster, since there is a more active production of growth hormone.
4. Dreams are also different. If a we are talking about the fast phase, the pictures are saturated various actions, are brightly colored. In slow-wave sleep, the plot is more calm or may be absent.
5. Awakening process. If an individual is awakened during REM sleep, he wakes up much easier and subsequently feels much better than a person woken up in non-REM sleep.
6. The temperature of the brain on the approach to the slow phase of sleep gradually decreases, and in the fast phase, due to a rush of blood and active metabolism, on the contrary, it rises. Sometimes it can exceed normal rate observed during wakefulness.

Another important question is which part of the brain is responsible for sleep. After all, until recently it was not known in which area of ​​the brain the work associated with dreams takes place. Scientists from the University of Wisconsin as a result of the study were able to make sensational discovery. It was proposed to take part in the experiment 46 people who had registration of electric waves. High-density EEG was used to isolate regions of neurons responsible for dreams regardless of the sleep phase. The subjects were awakened several times and asked about their dreams. And then the received answers were compared with electrical activity.

The data obtained during the study showed that during sleepy state decreased activity in the posterior cortex was directly related to the occurrence of dreams. Conversely, when an increase in low-frequency activity was observed in the same area, the subjects said that there were no dreams, that is, nothing was dreaming at that time.

Brain cleansing

American scientists in the course of some studies found that sleep is also needed to cleanse the brain of toxic elements. According to their observations, during sleep, the brain consumes the same or even more energy than during wakefulness. During tests on rodents, experts found that during sleep, activity does not decrease, but only goes into a different direction. At night, when the internal organs are cleansed of accumulated toxins with the help of lymph, the brain is also cleansed.

Doctor from New York medical center reported that the resource of the brain implies certain limitations. Gray matter is capable of doing one thing: either actively processing thoughts, or ensuring the removal of toxins. If this process were observed in daytime, not a single person would have the possibility of normal decision-making. And if there was a gradual accumulation of toxins in the brain, there would be huge probability occurrence of Alzheimer's disease.

What conclusion can be drawn

Thus, we studied how the human brain works during sleep, how much energy it consumes, and in what mode it functions as soon as we fall asleep. Our "gray matter" is the object of observation and debate by many scientists. When we are in the arms of Morpheus, he begins his work, unknown to us, solving a large number of tasks. During wakefulness, he is also active, but acts in other directions. The human brain is a complex structure that requires detailed study and research.

Those who like to sleep have continuous holidays: March 1 was celebrated as World Sleep Day, established at the suggestion of World Fund mental health, and today, March 21, is another World Sleep Day - as part of the World Health Organization (WHO) project on sleep and health.

At a press conference on the eve of the WHO event, Russian somnologist, academician of the Russian Academy of Natural Sciences, academician of the Academy of Sciences, Professor Yakov Levin refuted 11 myths about sleep.

Myth #1: The brain rests during sleep. In fact, the brain works with the same intensity as during wakefulness: it analyzes the events that have occurred, checks the state of the internal organs and makes possible scenarios for the development of events in the future. Thus, only the muscles rest, but the point of sleep is not at all to give them rest. His main function- allow the brain to do all the work mentioned above.
Myth two: there are prophetic dreams. The professor claims that this is complete nonsense. This, by the way, is just the case when science requires sacrifice - when he recently said this on the set of a television show, the ladies present in the studio almost filled him with hefty dream books. In fact, a person sees possible scenarios in a dream that the brain is working on. Most of them he immediately forgets. How far the dream turns out to be prophetic depends solely on the analytical abilities of the sleeping person: “Someone already from the first page of the detective guesses who the killer is. And someone needs to read the book to the end. Therefore, janitors rarely have "prophetic" dreams, and mathematicians often.

Myth three: there are people who never sleep at all. They say that there are a lot of such sleepless among yogis. In fact, not a single such person is known to science in the entire history of observations.

Myth four: there are people who suddenly fall asleep and then cannot wake up for many years. If the sleepless, according to myths, live somewhere in Tibet, then those who sleep for 20 years live mainly in Russian villages. “People from remote villages constantly call our center to tell us that they have some kind of grandmother who has been sleeping for several years. deep sleep. We begin to ask - how does your grandmother go to the toilet, how does she eat? They say: "With our help." What kind of dream is this? - said Yakov Levin.

Myth #5: You can sleep well on weekends. In real extra hour weekend sleep brings more harm than good. Sleeping is not very harmful, but even more harmful is getting out of the schedule. “If you sleep little and get up at six in the morning, then at least make sure that you get up every day at this time - not earlier and not later,” Levin warns. Sleeping ahead for a few days, as well as eating, will not work. The body will use up the received charge of vigor on the very first Sunday - you will simply go to bed later than usual. “A few years ago, Americans noticed that on Monday morning the number of accidents on the road is several times higher than on other days. We started to figure out why. It turned out that on weekends, Americans slept longer on average by 1 hour and 20 minutes and went to bed an hour later, ”said the somnologist. This caused a crash life cycle, the state of health worsened and attention on the road decreased.

Myth six: if you work a day after three, then you can sleep in three days. Science has proven that if a person does not sleep for at least a single day, the body will suffer significant damage: everything changes biochemical indicators including brain biochemistry. These indicators are restored on the second or third day, but full recovery the body still does not occur - in the USA, people were examined who, due to their work, did not sleep 24 hours a week for six months. It turned out that they are five times more likely to develop diabetes, hypertension and two dozen other diseases.

Myth seven: that lunatics walk in their sleep. Say, they can go out the window instead of the door or play the piano, and some even have sex, after which they do not want to recognize the children conceived in an unconscious state. All these facts are indeed proven by science. However, "dreamwalking" is an extremely rare phenomenon. Most lunatics do not go anywhere in their sleep - they just sit on the bed and, after sitting for a while, lie down again.

Myth eight: the phase of dreams alternates with the phase when we do not see anything at all. Previously, it was believed that a person sees dreams only in the REM phase of sleep. Now it has been proven that slow phase also accompanied by dreams. But that's why it is slow to slow everything down - if in the fast phase we see a full-fledged movie, then in the slow phase - pictures and photographs.

Myth nine: everyone sleeping pills harmful. Modern drugs, unlike the old ones, are harmless, the professor assures. It is only necessary not to confuse old drugs with new ones - after all, no one has canceled the production of obsolete drugs either. For Russians, by the way, sleep disorder is an everyday matter: “We live in a country of upheavals, and we have the right to bad dream”, Levin remarked to Yakov.

Myth tenth: without sleep, a person dies on the fifth day. Indeed, if an animal, such as a rat, is not allowed to sleep, then on the fifth or sixth day it will die. But man is not like that. After five days, he does not die - he begins to sleep with his eyes open. “You can keep him awake, wake him up - he will walk, talk, answer your questions, do some work, but at the same time do all this in a dream,” the somnologist said. After awakening, such a person, like a sleepwalker, will remember absolutely nothing.
Myth #11: Women sleep longer than men. “A huge amount of research has been done on this topic,” said Yakov Levin. - Some studies have shown that women do sleep longer than men by 15-20 minutes. Other studies have given completely the opposite result - it turned out that men sleep longer, and for the same 15-20 minutes. In the end, scientists agreed that men and women have the same amount of sleep.” Only pregnant women sleep longer.

However, in different sexes different attitude to sleep. It usually seems to a man that he slept well; a woman, on the contrary, often declares: “Oh! I slept so badly!” However, studies show that the quality of sleep for both is about the same.

It has been proven that sanguine people sleep the longest - 8-9 hours. They are so impressionable that if they watch a porn movie before going to bed or experience some other emotional shock, and the duration fast phase sleep, during which the brain digests the received information, immediately increases. Well, melancholics sleep the least - they usually need 6 hours to get enough sleep.