Lecture
Sleep is a natural physiological process of staying in a state with a minimum level of brain activity and a reduced reaction to the surrounding world, inherent in mammals, birds, fish and some other animals, including insects (for example, fruit flies) [1] .
In a dream the level of anabolic processes increases and the catabolism decreases.
Sleep normally occurs cyclically, approximately every 24 hours. These cycles are called circadian rhythms. They are redefined every day, the most important factor is the level of lighting. The concentration of specific photo-dependent proteins depends on the natural light cycle. The circadian cycle is usually tuned to the length of the day [1] . In addition to a night's sleep, in some cultures there is a physiologically caused short-term daytime sleep — a sest.
Immediately before bedtime comes a state of drowsiness, a decrease in brain activity, characterized by:
Professor Richard R. Budzin has been studying sleep disorders for many years at the University of Arizona's Sleep Research Lab and recommends rapid sleep techniques based on six steps. In the annual report on clinical psychology, he described various psychological approaches that were used to treat insomnia (Bootzin & Epstein, 2011). Such treatment was even earlier called treatment stimulus control (Morin et al., 2006). Tips include: go to bed, only when you want to sleep, use the bed only for sleep and sex, do not lie in bed for more than 10 minutes, if you cannot sleep, make the bed only associated with a fast sleep, wake up in the morning with an alarm clock one and the same time, do not sleep during the day [3] .
Sleep is a special state of consciousness of humans and animals, including a series of stages, regularly repeated during the night (with a normal daily schedule). The appearance of these stages is due to the activity of various brain structures.
In a healthy person, sleep begins with the first stage of slow sleep (Non-REM sleep), which lasts 5-10 minutes. Then comes the 2nd stage, which lasts about 20 minutes. Another 30-45 minutes falls on a period of 3-4 stages. After that, the sleeper again returns to the 2nd stage of slow sleep, after which the first episode of REM sleep occurs, which has a short duration of about 5 minutes. This whole sequence is called a loop. The first cycle has a duration of 90-100 minutes. Then the cycles are repeated, while the share of slow sleep decreases, and the share of fast sleep (REM-sleep) gradually increases, the last episode of which in some cases can reach 1 hour. On average, with full healthy sleep, there are five full cycles. The sequence of stages and their duration is conveniently represented in the form of a hypnogram, which clearly reflects the structure of the patient's sleep.
Slow sleep (syn .: slow wave sleep, orthodox sleep) lasts 80-90 minutes. It comes immediately after falling asleep.
In a healthy person, the third stage takes 5-8%, and the fourth stage is still about 10-15% of the total sleep time. The first four slow-wave sleep stages normally occupy 75–80% of the entire sleep period. It is believed that slow sleep is associated with the restoration of energy consumption. Studies have shown that it is the phase of slow sleep that is key to consolidating conscious “declarative” memories [5] .
Fast sleep (synonym: fast-wave sleep, paradoxical sleep, stage of rapid eye movements, or abbreviated BDG sleep, REM sleep). This is the fifth stage of sleep, it was discovered in 1953 by Kleitman and his graduate student Acerinsky. Fast sleep follows slow and lasts 10-15 minutes.
On the EEG, rapid fluctuations in electrical activity are observed, which are close in meaning to the beta waves of a sawtooth wave. During this period, the electrical activity of the brain is similar to the waking state. However, (and this is paradoxical) in this stage a person is in complete immobility, due to a sharp drop in muscle tone. However, the eyeballs very often and periodically make quick movements under closed eyelids. There is a clear connection between the BDG and dreams. If at this time to wake the sleeper, then in 90% of cases you can hear the story of a bright dream.
Electroencephalogram reflects the state of activation and is more like the EEG of the 1st stage of sleep. The first episode of REM sleep comes about 70-90 minutes after falling asleep, lasts 5-10 minutes. In the course of sleep, the duration of subsequent episodes of REM sleep increases, reaching several tens of minutes in the morning. In an adult, the proportion of the REM phase is about 20-25% of the total sleep time. The sleep phase from cycle to cycle is extended, and the depth of sleep decreases. Interrupting REM sleep causes more severe mental impairments compared to REM sleep disorders. Some of the interrupted fast sleep should be replenished in the following cycles.
It is assumed that fast sleep provides the functions of psychological protection, processing of information, its exchange between the conscious and subconscious.
Blind from birth dreams and sensations; in the REM sleep phase, they don’t have the BDG proper.
Vegetation , or "vegetative storm." Increased secretion of adrenal hormones, increased cerebral blood flow, changes in heart rate, various forms of arrhythmias, rise and fall in blood pressure, changes in breathing patterns, erection of the penis and clitoris.
In the brain there are clusters of neurons, the excitation of which causes the development of sleep (hypnogenic centers). Three types of structures:
The visceral theory of sleep suggests that in a dream the central nervous system is involved in the analysis and regulation of the work of internal organs [6] .
The average duration of a person’s sleep usually depends on numerous factors: from age, gender, lifestyle, nutrition, and degree of fatigue, to external factors (general noise level, location, etc.). The duration of sleep in newborns, adults and the elderly is 12-16, 6-8, and 4-6 hours per day, respectively. Also, in spring and summer, with a sedentary lifestyle, with a small amount of carbohydrates in a meal, as well as outside the city, the normal duration of sleep can be only 5-6 hours, and with sudden loud sounds (or during loud music) and bright lighting it is possible even a complete lack of sleep. In general, for sleep disorders, its duration can range from a few seconds to several days.
There are also cases that an adult needs 12 hours to sleep with a supply of energy or to recover from hard work and sleepless nights. Sleep durations of less than 5 hours (hyposomnia) or impaired physiological structure are considered risk factors for insomnia.
Sleep deprivation is a very difficult test. Within a few days, a person’s consciousness loses clarity, he feels an overwhelming desire to fall asleep, and periodically “falls” into a borderline state with a tangled consciousness. This method of psychological pressure is used during interrogation, and is considered as sophisticated torture.
Recent studies of the functionality of dreams at the University of Helsinki (led by prof. En: Pekka Sutola) have shown that the REM sleep phase sometimes occurs quickly in mammals, and then they enter the deep sleep phase. This explains why epileptics have a REM-like phase during an attack and are unable to recall events several hours before the attack. More complete structure of the functioning of this system has not yet been established.
The afternoon short rest- siesta is a historical element of the culture of many nations. Most often it is found in hot countries. A recent study conducted jointly by the University of Athens Medical School and Harvard in Greece showed that a half-hour afternoon rest at least three times a week reduces the risk of death from a heart attack by 37% [7] .
With persistent sleep disorders, there are situations when a doctor’s intervention is necessary.
Sometimes a sleeping person may be aware that he is in a dream. This can happen either spontaneously or after various workouts. This condition is called lucid dreaming.
Healthy sleep requires 4 to 8 hours, but these numbers are quite relative. The need for a longer sleep manifests itself, for example, with a large amount of physical work. About a third of life we spend in a dream, because it is important to maintain its natural rhythm.
Drugs are sometimes prescribed symptomatically, as well as sedatives. Pharmacological regulation of sleep without a prescription can be very dangerous, in addition, with prolonged use of hypnotics, their effect decreases. However, the abuse of sedatives and sedatives is a common and dangerous phenomenon in industrialized countries.
For a long time such drugs as opium and morphine were counted among soothing and hypnotic drugs, however, because of the danger of drug addiction, they are not currently used in this capacity.
For a very long time, more than 100 years, luminal and other barbiturates have been used as a hypnotic.
Melatonin is one of the most modern drugs, which have high hopes because of its physiology.
According to recent studies, magnesium deficiency often leads to nervousness, irritability, as well as bruxism - the involuntary gnashing of teeth in a dream. It is also found that magnesium contributes to the production of melatonin. However, magnesium itself plays an independent role in creating a calm, comfortable state, relieving stress and relaxing over-stressed muscles. Therefore, magnesium intake should be an integral part of any dietary program to improve sleep.
Electrosleep is a method of neurostimulating therapy in which a state of drowsiness or sleep arises as a result of exposure to the patient's central nervous system with pulsed current of low frequency and low power. This is a method of treating a person with a constant pulse current, of low frequency (1–160 Hz), of small strength (up to 10 mA), with a pulse duration of 0.2 to 2 ms. Electrosleep has tranquilizing, sedative, as well as stimulating and some other effects and is recommended as a restorative procedure for a wide range of disorders and diseases [8] [9] .
In the history of the “science of sleep” an important role was played by the research of M. M. Manaseina (1843-1903), a student of the physiologist I. R. Tarkhanov. In the 1870s she studied the value of sleep for the body on puppies. Analyzing the results, M. Manaseina came to the conclusion that sleep for the body is more important than food.
Modern ideas about the nature of sleep were formed in the second half of the 20th century, after the appearance of methods for recording the bioelectrical activity of the brain (electroencephalogram, EEG), muscles (electromyogram, EMG) and eyes (electrooculogram, EOG). A major achievement in this area was the discovery in the 1950s. N. Kleitman, W. Dement (USA) and M. Juve (France) of the phenomenon of “paradoxical sleep”.
In addition to the physiological characteristics of sleep, we study its psychological features. For this, there are methods for the subjective assessment of sleep quality, such as the following questionnaires include: sleep severity index - a scale developed by Morin for assessing sleep quality in insomnia; a questionnaire of thought content at bedtime. Glasgow was developed by K. Harvey and K. Espy to assess cognitive ruminations at bedtime, which prevent people from falling asleep in chronic insomnia.
Horses and sheep can sleep standing or lying down, but in a dream while standing, the BDG phase does not appear. Cats sleep around 16 hours a day [10] . Cetaceans, dolphins and birds have an interesting ability to unilateral sleep . They sleep "halfway": with one waking hemisphere. Sleeping and waking hemispheres are changing. Эта способность животных, живущих в море, объясняется необходимостью поддерживать дыхание — им требуется всплывать время от времени, чтобы набрать воздух. А бутылконосые дельфины и косатки в первый месяц жизни вообще не нуждаются во сне [11] . У птиц функция одностороннего сна помогает обезопасить себя от врагов.
Жирафы спят на коленях, заворачивая шею вокруг ног; львы лежат на спине, сложив передние лапы на груди, крысы укладываются на бок, а хвост закручивают к голове. Так же спят и лисы. Летучие мыши засыпают, только подвесившись вниз головой [1] .
Холоднокровные животные, вроде ящериц, черепах и рыб, тоже спят, хотя ранее считалось, что они просто замирают с наступлением ночи [1] .
Птицы также могут спать сидя, стоя, а некоторые даже на лету или «на плаву» (например, утки). Мигрирующие птицы выработали интересный механизм, который позволяет им спать во время длительных перелетов: каждые 10-15 минут птица залетает в центр стаи и лишь слегка машет крыльями. Она парит на воздушных потоках, которые создает вся стая. Потом птицы меняются местами [1] .
Некоторые позвоночные не спят вовсе [12] .
Дыхание во сне существенно изменяется в соответствии с фазой сна.
Существует тесная связь между сном ребёнка и различными формами расстройств дыхания. Сон ребёнка — это то состояние, при котором нарушения реализуются наиболее отчётливо, а в ряде случаев эти нарушения выявляются исключительно во время сна [13] .
| Физиология сна | Типы сна и нарушения сна | Обряды и специальные техники |
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Psychophysiology
Terms: Psychophysiology