More than a quarter of our lives we are asleep, which means that we have been dreaming for several years. Although much is already known about the mechanisms of visions, scientists have not yet come to a consensus on their values and functions.
From time immemorial people try to interpret dreams. In the Old Testament, the dreams of Jacob, Pharaoh and Joseph were given the meaning of prophecy. Ancient Greek philosopher Plato also considered dreams as signs, indicating events that will occur in the future. At the same time, the ancient Roman writer and orator Cicero in the I century BC rejected the idea of the divine origin of dreams. In the XVII century among Europeans, the view was widespread that dreams are a reflection of the inner life and character of a person. People began to write down dreams and look for the hidden meaning in them. Some like Harvey de Saint-Denis (late XIX century), even believed that they could affect their dreams. The French philosopher Henri Bergson (1859-1941) represented dreams as internal images obtained through sight. For other thinkers, dreams were mirror reflections of the soul.
At the beginning of the 20th century, a systematic study of meanings began. This involved Sigmund Freud (1856-1939) and Carl Gustav Jung (1875-1961). Freud, considered the founder of psychoanalysis, regarded dreams as an expression of certain motivations and desires that are suppressed during the waking period. In the eyes of Jung, who at first worked with Freud, dreams gave access to the important archetypes inherent in all civilizations.
Ideas of psychoanalysis were further developed in the research in the field of neurophysiology — the science of the mechanisms of the nervous system. Since the late 50's, the study of dreams has turned into a discipline designed to reveal the mechanisms that enable us to see dreams. Now scientists can already accurately determine the moment of the beginning of the dream period. Based on the data, using electroencephalography (EEG) and other physiological indicators, it was possible to identify three specific sleeps: superficial sleep, deep sleep and fast sleep, or sleep with rapid eye movement. During superficial and deep sleep, high-amplitude slow waves are recorded. Rapid sleep is characterized by low-amplitude fast waves generated by the brain.
Dreams of furry and feathered
Animals also see dreams. Not only man, but also mammals and birds, capable of fast sleep, during which there is a dream. In fish, amphibians and reptiles, the brain does not generate this type of waves, as in mammals and birds. Accordingly, scientists believe that the ability to dream developed in higher vertebrates over 130 million years ago.
It is interesting to note that in animals with the longest period of childhood the longest phases of dreams are recorded. So, chickens and cows see dreams for 25 minutes, chimpanzees — 90 minutes, and cats — up to 200 minutes. In humans, the phase of fast sleep takes about 100 minutes per night. The phases of fast sleep in birds are more rare and short — from 5 to 15 seconds.
Stages of sleep
The first stage of sleep is characterized by a constant slowing of the rhythm of waves generated by the brain. The sleeper reacts to sounds, and it is easy to wake him up. Then the body calms down and plunges into a phase of deep sleep. At the same time, eyeballs do not move, but muscle tone, or tension, remains at the same level. In the stage of fast sleep, the bioelectric activity of the brain again rises and is triggered through the streams of waves. Eyeballs come in motion under closed eyelids, hence "sleep with rapid eye movement," and the overall muscle tone falls. Sometimes there are muscle spasms, especially in the fingers and toes. During this period, the sleeper is immersed in the dream phase, and it is difficult to wake him up. This stage is repeated approximately every 100 minutes and lasts from 10 to 20 minutes.
In adults, 75-80% of sleep consists of superficial and deep sleep and 20-25% of fast sleep. In the embryo, on the contrary, the proportion of fast sleep accounts for almost 90% of the total sleep time. These observations led scientists to the following conclusion: in the first few months of life, fast sleep phases contribute to structural maturation of the brain. The babies show all six facial expressions that are typical for a person: joy, fear, surprise, anger, sadness and disgust, but most often it happens in a dream. The change of facial expressions is the result of strong experiences during a dream and reflects the content of sleep.
Higher and higher …
Many of us happened to fly in a dream or soar in space, scorning the laws of gravity. In such cases, after awakening, a pleasant feeling of lightness remains. For this reason, psychoanalysts interpret such dreams as expressions of sexual aspirations. However, neurologists note that during sleep the muscles are turned off and it is the relaxation of the muscles that affects the content of dreams. A person feels free from physical shackles and can effortlessly rise above the ground.
Training in a dream?
Not so long ago, attempts were made to identify a possible relationship between a fast sleep and the ability to learn. For example, the French researcher Michel Juve, one of the initiators of the study of dreams, is convinced that such a connection exists. According to his theory, the phase of dreams is the time when the brain displays the elements of the collective memory of mankind in combination with the innate features of the personality of the sleeper. This means that you can use the ancient patterns of behavior according to the genetic code of the sleeper, allowing the brain to receive new information every night, that is, to study.
The frequency of fast sleep in infants and birds and its absence in other highly developed animals seems to confirm the theory of Juve. Observations of animals that have the ability to see dreams, show that the structure of their brain is sufficiently formed at birth. Thus, dreams serve to constantly update the program of the neural network of the brain. Nerve cells of cold-blooded animals — fish and reptiles are divided throughout their lives, therefore, any regular activation of them would be meaningless.
The specialists are basically unanimous in that dreams are a kind of learning tool. During this period, the information accumulated during the day is stored in permanent memory. In the day-time consciousness acts as a hindrance to the activity of neurons, since vast areas of the brain are engaged in processing the current flow of information and impressions perceived by the senses.
In the light of the moon
Sleepwalking is a real phenomenon. People who walk in a dream sometimes make dangerous trips, climbing stairs or walking on rooftops. The next morning somnambulists do not remember anything about night walks. According to statistics, somnambulism occurs in 20% of children aged 5 to 12 years, with 70% of them boys. The electroencephalogram shows that it is not observed during the phase of fast sleep or the dream phase, but during a deep sleep, when the bioelectric activity of the brain is reduced. Consciousness is disabled, but the muscles receive coordinated commands from the motor centers. Sleepwalking can be caused by genetic predisposition, stress or the influence of the moon.
Dreams of a loaded brain
Experiments in rats have shown that the learning process stimulates dreams. If you force the rodents to find a way out of the tangled labyrinth, the duration of the fast sleep stages will increase to 50-60%. When they find a way out, the duration of the dream phase returns to normal.
It can be assumed that a quick sleep is necessary to strengthen the acquired knowledge. If a person is constantly awakened, as soon as he begins to see a dream, his ability to learn will soon decrease. If you interrupt the dream phase for several days, a disorder known as futurigous amnesia develops, that is, weakening the ability to think about future events. Such people are not able to foresee the development of the situation.
Two points of view
Psychoanalysts explain that dreams reflect subconscious desires and fears suppressed during wakefulness. According to neurophysiologists, with the help of quick dreams in nerve cells, the knowledge, information and skills acquired during the day are memorized. Despite the difference in points of view, both agree that dreams help preserve new events and ideas in memory and process them with the participation of emotions.