Why is it said that nerve cells do not regenerate. Nerve cells are restored. Why nerve cells die
A huge reserve of neurons is laid at the genetic level during embryonic development. With the onset of adverse factors, nerve cells die, but new ones are formed in their place. However, as a result of large-scale studies, it was found that the natural decline somewhat exceeds the appearance of new cells. The important thing is that, contrary to the previously existing theory, it has been proven that nerve cells are restored. Experts have developed recommendations for enhancing mental activity, which make the process of neuronal recovery even more effective.
Nerve cells are restored: proven by scientists
In humans, a huge reserve of nerve cells is laid down at the genetic level during the period of embryonic development. Scientists have proven that this value is constant and when lost, neurons do not recover. However, in the place of dead cells, new ones are formed. This happens throughout life and every day. Within 24 hours, the human brain produces up to several thousand neurons.
It was found that the natural loss of nerve cells somewhat exceeds the formation of new ones. The theory that nerve cells regenerate is indeed true. It is important for each individual to prevent the disruption of the natural balance between the death and restoration of nerve cells. Four factors will help maintain neuroplasticity, that is, the ability to brain regenerate:
- the constancy of social ties and a positive orientation in communication with loved ones;
- the ability to learn and the ability to implement it throughout life;
- sustainable outlook;
- balance between desires and real possibilities.
As a result of large-scale studies, it has been proven that any amount of alcohol kills neurons. After drinking alcohol, erythrocytes stick together, this prevents nutrients from entering the nerve cells and they die in almost 7-9 minutes. In this case, the concentration of alcohol in the blood is absolutely irrelevant. Women's brain cells are more susceptible than men's, so alcohol addiction develops at lower doses.
The brain cells are especially susceptible to any stressful conditions in pregnant women. Nervousness can provoke not only a deterioration in the well-being of the woman herself. There is a high risk of developing various pathologies in the fetus, including schizophrenia and mental retardation. During pregnancy, increased nervous excitability threatens that the programmed cell death of 70% of already formed neurons will occur in the embryo.
Proper nutrition
Refuting the well-known theory that nerve cells do not regenerate, the latest scientific research proves that cell regeneration is possible. It does not require expensive drugs or sophisticated medical equipment. Experts say that you can restore neurons with proper nutrition. As a result of clinical studies involving volunteers, it was revealed that a low-calorie and rich in vitamins and minerals diet has a positive effect on the brain.
The resistance to diseases of a neurotic nature increases, life expectancy increases and the production of neurons from stem cells is stimulated. It is also recommended to increase the time interval between meals. This will improve overall well-being more effectively than calorie restriction. Scientists claim that malnutrition in the form of improper diets reduces the production of testosterone and estrogen, thereby reducing sexual activity. The best option is to eat well, but less often.
Aerobics for the brain
Scientists have proven that in order to restore nerve cells, it is important to use the maximum number of brain regions every minute. The simple techniques of such training are combined into a common complex called neurobics. The word is quite easy to decipher. "Neuro" means neurons, which are nerve cells in the brain. "Obika" - exercise, gymnastics. Simple neurobic exercises performed by a person make it possible to activate not only brain activity at a high level.
All cells of the body, including nerve cells, are involved in the training process. For a positive effect, it is important to remember that “brain gymnastics” should become an integral part of life, and then the brain will really be in a state of constant activity. Experts have proven that many of the daily habits of a person are so automated that they are performed almost at an unconscious level.
A person does not think about what happens in his brain during certain actions. Being an integral part of everyday life, many habits simply slow down the work of neurons, because they are performed without minimal mental effort. You can improve the situation if you change the established rhythm of life and daily routine. Eliminating predictability in actions is one of the techniques of neuroscience.
morning awakening ritual
For most people, one morning is similar to another, down to the smallest worker. Performing morning procedures, coffee, breakfast, jogging - all actions are scheduled literally in seconds. In order to sharpen the senses, you can do the entire morning ritual, for example, with your eyes closed.
Unusual emotions, the connection of imagination and fantasies contribute to the activation of the brain. Unusual tasks will become neurobics for cells and a new stage in the improvement of mental activity. Experts recommend replacing traditional strong coffee with fragrant herbal tea. Instead of scrambled eggs, you can have sandwiches for breakfast. The unusualness of habitual actions will be the best way to restore neurons.
New route to work
Habitual to the smallest detail is the way to work and back. It is recommended to change your habitual path, allowing brain cells to connect to remember the new route. Counting steps from the house to the parking lot is recognized as a unique method. It is recommended to pay attention to the sign of the nearest store or to the inscription on the billboard. Focusing on the little things around is another sure step in neuroscience.
Decades of discussions, sayings that have long come into use, experiments on mice and sheep - but still, can the adult human brain form new neurons to replace the lost ones? And if so, how? And if he can't, why not?
A cut finger will heal in a few days, a broken bone will heal. Myriads of red blood cells succeed each other in short-lived generations, grow under muscle load: our body is constantly updated. For a long time it was believed that only one outsider remained at this celebration of rebirth - the brain. Its most important cells, the neurons, are too highly specialized to divide. The number of neurons drops year after year, and although they are so numerous that the loss of a few thousand does not have a noticeable effect, the ability to recover from damage would not interfere with the brain. However, scientists have long failed to detect the presence of new neurons in the mature brain. However, there were no fine enough tools to find such cells and their "parents".
The situation changed when, in 1977, Michael Kaplan and James Hinds used radioactive [ 3 H]-thymidine, which can integrate into new DNA. Its chains actively synthesize dividing cells, doubling their genetic material and at the same time accumulating radioactive labels. A month after the drug was administered to adult rats, scientists obtained sections of their brains. Autoradiography showed that the labels are located in the cells of the dentate gyrus of the hippocampus. Still, they reproduce, and "adult neurogenesis" exists.
About people and mice
During this process, mature neurons do not divide, just as muscle fiber cells and erythrocytes do not divide: various stem cells are responsible for their formation, retaining their “naive” ability to multiply. One of the descendants of the dividing progenitor cell becomes a young specialized cell and matures into a fully functional adult. The other daughter cell remains a stem cell: this allows the progenitor cell population to be maintained at a constant level without sacrificing renewal of the surrounding tissue.
The precursor cells of neurons were found in the dentate gyrus of the hippocampus. Later they were found in other parts of the rodent brain, in the olfactory bulb and subcortical structure of the striatum. From here, young neurons can migrate to the desired area of the brain, mature in place and integrate into existing communication systems. To do this, the new cell proves its usefulness to its neighbors: its ability to excite is increased, so that even a slight impact causes the neuron to produce a whole volley of electrical impulses. The more active the cell, the more bonds it forms with its neighbors and the faster these bonds stabilize.
Adult neurogenesis in humans was only confirmed a couple of decades later using similar radioactive nucleotides, in the same dentate gyrus of the hippocampus, and then in the striatum. The olfactory bulb in our country, apparently, is not updated. However, how actively this process takes place and how it changes over time is not exactly clear even today.
For example, a 2013 study showed that up to a very old age, approximately 1.75% of the hippocampal dentate gyrus cells are renewed each year. And in 2018, results appeared, according to which the formation of neurons here stops already in adolescence. In the first case, the accumulation of radioactive labels was measured, and in the second, dyes were used that selectively bind to young neurons. It is difficult to say which conclusions are closer to the truth: it is difficult to compare the rare results obtained by completely different methods, and even more so to extrapolate to humans the work performed on mice.
Model problems
Most studies of adult neurogenesis are carried out in laboratory animals, which reproduce rapidly and are easy to manage. This combination of traits is found in those who are small and have a very short life - in mice and rats. But in our brains, which are just finishing maturation in our 20s, things can happen quite differently.
The dentate gyrus of the hippocampus is part of the cerebral cortex, albeit a primitive one. In our species, as in other long-lived mammals, the bark is noticeably more developed than in rodents. It is possible that neurogenesis covers its entire scope, being realized according to some own mechanism. There is no direct confirmation of this yet: studies of adult neurogenesis in the cerebral cortex have not been performed either in humans or in other primates.
But such work has been done with ungulates. The study of sections of the brain of newborn lambs, as well as sheep a little older and mature individuals did not find dividing cells - precursors of neurons in the cerebral cortex and subcortical structures of their brain. On the other hand, in the cortex of even older animals, already born, but immature young neurons were found. Most likely, they are ready at the right time to complete their specialization, having formed full-fledged nerve cells and taking the place of the dead. Of course, this is not exactly neurogenesis, because new cells are not formed during this process. However, it is interesting that such young neurons are present in those areas of the sheep brain that in humans are responsible for thinking (the cerebral cortex), the integration of sensory signals and consciousness (the claustrum), and emotions (the amygdala). There is a high probability that we will find immature nerve cells in similar structures. But why might an adult, already trained and experienced brain need them?
Memory hypothesis
The number of neurons is so great that some of them can be painlessly sacrificed. However, if the cell is switched off from working processes, this does not mean that it has died yet. The neuron may stop generating signals and respond to external stimuli. The information accumulated by him does not disappear, but is “conserved”. This phenomenon allowed Carol Barnes, a neuroscientist at the University of Arizona, to make the extravagant suggestion that this is how the brain accumulates and shares memories of different periods of life. According to Professor Barnes, from time to time a group of young neurons appears in the dentate gyrus of the hippocampus to record new experiences. After some time - weeks, months, and maybe years - they all go into a state of rest and no longer give signals. That is why memory (with rare exceptions) does not retain anything that happened to us before the third year of life: access to this data at some point is blocked.
Given that the dentate gyrus, like the hippocampus as a whole, is responsible for transferring information from short-term memory to long-term memory, this hypothesis even looks logical. However, it still needs to be proven that the hippocampus of adults really forms new neurons, and in a sufficiently large number. There is only a very limited set of possibilities for conducting experiments.
history of stress
Typically, human brain preparations are obtained during autopsy or neurosurgical operations, as in temporal lobe epilepsy, the seizures of which are not amenable to medical treatment. Both options do not allow us to trace how the intensity of adult neurogenesis affects brain function and behavior.
Such experiments were carried out on rodents: the formation of new neurons was suppressed by directed gamma radiation or by turning off the corresponding genes. This exposure increased the susceptibility of the animals to depression. Mice incapable of neurogenesis almost did not enjoy sweetened water and quickly gave up trying to stay afloat in a container filled with water. The content in their blood of cortisol - the stress hormone - was even higher than in mice stressed by conventional methods. They were more likely to become addicted to cocaine and were less likely to recover from a stroke.
One important note to these results is that it is possible that the shown relationship “fewer new neurons - more acute reaction to stress” closes on itself. Unpleasant life events reduce the intensity of adult neurogenesis, which makes the animal more sensitive to stress, so the rate of formation of neurons in the brain decreases - and so on in a circle.
Business on nerves
Despite the lack of accurate information about adult neurogenesis, businessmen have already appeared who are ready to build a profitable business on it. Since the early 2010s, a company that sells water from the springs of the Canadian Rockies has been producing bottles of Neurogenesis Happy Water. It is claimed that the drink stimulates the formation of neurons due to the lithium salts contained in it. Lithium is indeed considered a drug useful for the brain, although there is much more of it in tablets than in “happy water”. The effect of the miracle drink was tested by neuroscientists from the University of British Columbia. For 16 days they gave the rats “happy water”, and the control group - simple, from the tap, and then examined sections of the dentate gyrus of their hippocampus. And although the rodents who drank Neurogenesis Happy Water, new neurons appeared by as much as 12% more, their total number turned out to be small and it is impossible to speak of a statistically significant advantage.
So far, we can only state that adult neurogenesis in the brain of representatives of our species definitely exists. Perhaps it continues until old age, or maybe only until adolescence. Actually it's not that important. More interesting is that the birth of nerve cells in the mature human brain generally occurs: from the skin or from the intestines, the renewal of which is constantly and intensively, the main organ of our body differs quantitatively, but not qualitatively. And when the information about adult neurogenesis forms into a whole detailed picture, we will understand how to translate this quantity into quality, forcing the brain to “repair”, restore the functioning of memory, emotions - everything that we call our life.
Doctor of Medical Sciences V. GRINEVICH.
The winged expression "Nerve cells do not recover" is perceived by everyone since childhood as an indisputable truth. However, this axiom is nothing more than a myth, and new scientific data refute it.
Schematic representation of a nerve cell, or neuron, which consists of a body with a nucleus, one axon, and several dendrites.
Neurons differ from each other in size, branching of dendrites, and length of axons.
The concept of "glia" includes all cells of the nervous tissue that are not neurons.
Neurons are genetically programmed to migrate to one or another part of the nervous system, where, with the help of processes, they establish connections with other nerve cells.
Dead nerve cells are destroyed by macrophages that enter the nervous system from the blood.
Stages of formation of the neural tube in the human embryo.
Nature lays in the developing brain a very high margin of safety: during embryogenesis, a large excess of neurons is formed. Almost 70% of them die before the birth of a child. The human brain continues to lose neurons after birth, throughout life. Such cell death is genetically programmed. Of course, not only neurons die, but also other cells of the body. Only all other tissues have a high regenerative capacity, that is, their cells divide, replacing the dead. The regeneration process is most active in epithelial cells and hematopoietic organs (red bone marrow). But there are cells in which the genes responsible for reproduction by division are blocked. In addition to neurons, these cells include heart muscle cells. How do people manage to keep their intellect to a very advanced age, if nerve cells die and are not renewed?
One of the possible explanations is that not all, but only 10% of neurons "work" simultaneously in the nervous system. This fact is often cited in popular and even scientific literature. I repeatedly had to discuss this statement with my domestic and foreign colleagues. And none of them understands where such a figure came from. Any cell simultaneously lives and "works". In each neuron, metabolic processes take place all the time, proteins are synthesized, nerve impulses are generated and transmitted. Therefore, leaving the hypothesis of "resting" neurons, let us turn to one of the properties of the nervous system, namely, its exceptional plasticity.
The meaning of plasticity is that the functions of the dead nerve cells are taken over by their surviving "colleagues", which increase in size and form new connections, compensating for the lost functions. The high, but not unlimited, effectiveness of such compensation can be illustrated by the example of Parkinson's disease, in which the gradual death of neurons occurs. It turns out that until about 90% of neurons in the brain die, the clinical symptoms of the disease (trembling of the limbs, limited mobility, unsteady gait, dementia) do not appear, that is, the person looks practically healthy. This means that one living nerve cell can replace nine dead ones.
But the plasticity of the nervous system is not the only mechanism that allows the intellect to be preserved until old age. Nature also has a backup option - the emergence of new nerve cells in the brain of adult mammals, or neurogenesis.
The first report on neurogenesis appeared in 1962 in the prestigious scientific journal Science. The paper was titled "Are New Neurons Formed in the Adult Mammalian Brain?". Its author, Professor Joseph Altman from Purdue University (USA), used an electric current to destroy one of the structures of the rat brain (the lateral geniculate body) and introduced a radioactive substance there, penetrating into newly emerging cells. A few months later, the scientist discovered new radioactive neurons in the thalamus (section of the forebrain) and the cerebral cortex. Over the next seven years, Altman published several more papers proving the existence of neurogenesis in the brain of adult mammals. However, at that time, in the 1960s, his work aroused only skepticism among neuroscientists, and their development did not follow.
And only twenty years later, neurogenesis was "discovered" again, but already in the brain of birds. Many researchers of songbirds paid attention to the fact that during each mating season, the male canary Serinus canaria performs a song with new "knees". Moreover, he does not adopt new trills from his brothers, since the songs were updated even in isolation. Scientists began to study in detail the main vocal center of birds, located in a special part of the brain, and found that at the end of the mating season (in canaries it falls on August and January), a significant part of the neurons of the vocal center died, probably due to excessive functional load. . In the mid-1980s, Professor Fernando Notteboom from Rockefeller University (USA) managed to show that in adult male canaries, the process of neurogenesis occurs constantly in the vocal center, but the number of neurons formed is subject to seasonal fluctuations. The peak of neurogenesis in canaries occurs in October and March, that is, two months after the mating season. That is why the "record library" of songs of the male canary is regularly updated.
In the late 1980s, neurogenesis was also discovered in adult amphibians in the laboratory of the Leningrad scientist Professor A. L. Polenov.
Where do new neurons come from if nerve cells don't divide? The source of new neurons in both birds and amphibians turned out to be neuronal stem cells of the wall of the ventricles of the brain. During the development of the embryo, it is from these cells that the cells of the nervous system are formed: neurons and glial cells. But not all stem cells turn into cells of the nervous system - some of them "hide" and wait in the wings.
New neurons have been shown to emerge from adult stem cells and in lower vertebrates. However, it took almost fifteen years to prove that a similar process occurs in the nervous system of mammals.
Developments in neuroscience in the early 1990s led to the discovery of "newborn" neurons in the brains of adult rats and mice. They were found for the most part in evolutionarily ancient regions of the brain: the olfactory bulbs and the hippocampal cortex, which are mainly responsible for emotional behavior, the response to stress, and the regulation of sexual functions in mammals.
Just as in birds and lower vertebrates, in mammals neuronal stem cells are located near the lateral ventricles of the brain. Their degeneration into neurons is very intensive. In adult rats, about 250,000 neurons are formed from stem cells per month, replacing 3% of all neurons in the hippocampus. The life span of such neurons is very high - up to 112 days. Stem neuronal cells travel a long way (about 2 cm). They are also able to migrate to the olfactory bulb, turning into neurons there.
The olfactory bulbs of the brain of mammals are responsible for the perception and primary processing of various odors, including the recognition of pheromones - substances that are similar in chemical composition to sex hormones. Sexual behavior in rodents is primarily regulated by the production of pheromones. The hippocampus is located under the cerebral hemispheres. The functions of this complex structure are associated with the formation of short-term memory, the realization of certain emotions and participation in the formation of sexual behavior. The presence of constant neurogenesis in the olfactory bulb and hippocampus in rats is explained by the fact that in rodents these structures carry the main functional load. Therefore, the nerve cells in them often die, which means that they need to be updated.
In order to understand what conditions affect neurogenesis in the hippocampus and olfactory bulb, Professor Gage from Salk University (USA) built a miniature city. Mice played there, went in for physical education, looked for ways out of the labyrinths. It turned out that in "urban" mice, new neurons arose in much greater numbers than in their passive relatives, mired in routine life in a vivarium.
Stem cells can be taken from the brain and transplanted to another part of the nervous system, where they will turn into neurons. Professor Gage and his colleagues have conducted several similar experiments, the most impressive of which was the following. A piece of brain tissue containing stem cells was transplanted into the destroyed rat retina. (The light-sensitive inner wall of the eye has a "nervous" origin: it consists of modified neurons - rods and cones. When the light-sensitive layer is destroyed, blindness sets in.) The transplanted brain stem cells turned into retinal neurons, their processes reached the optic nerve, and the rat received his sight! Moreover, when brain stem cells were transplanted into an intact eye, no transformations occurred with them. . Probably, when the retina is damaged, some substances (for example, the so-called growth factors) are produced that stimulate neurogenesis. However, the exact mechanism of this phenomenon is still not clear.
Scientists were faced with the task of showing that neurogenesis occurs not only in rodents, but also in humans. To do this, researchers led by Professor Gage recently performed sensational work. In one of the American oncology clinics, a group of patients with incurable malignant neoplasms took the chemotherapy drug bromdioxyuridine. This substance has an important property - the ability to accumulate in dividing cells of various organs and tissues. Bromdioxyuridine is incorporated into the DNA of the mother cell and is retained in the daughter cells after the mother cell divides. A pathoanatomical study showed that neurons containing bromdioxyuridine are found in almost all parts of the brain, including the cerebral cortex. So these neurons were new cells that arose from the division of stem cells. The finding unequivocally confirmed that the process of neurogenesis also occurs in adults. But if in rodents neurogenesis occurs only in the hippocampus, then in humans it can probably capture larger areas of the brain, including the cerebral cortex. Recent studies have shown that new neurons in the adult brain can form not only from neuronal stem cells, but also from blood stem cells. The discovery of this phenomenon caused euphoria in the scientific world. However, the October 2003 publication in the journal Nature did much to cool off enthusiastic minds. It turned out that blood stem cells indeed penetrate the brain, but they do not turn into neurons, but merge with them, forming binuclear cells. Then the "old" nucleus of the neuron is destroyed, and it is replaced by the "new" nucleus of the blood stem cell. In the rat body, blood stem cells mostly fuse with giant cerebellar cells - Purkinje cells, although this happens quite rarely: only a few merged cells can be found in the entire cerebellum. A more intense fusion of neurons occurs in the liver and heart muscle. It is not yet clear what the physiological meaning of this is. One of the hypotheses is that blood stem cells carry with them new genetic material, which, getting into the "old" cerebellar cell, prolongs its life.
So, new neurons can arise from stem cells even in the adult brain. This phenomenon is already widely used to treat various neurodegenerative diseases (diseases accompanied by the death of brain neurons). Stem cell preparations for transplantation are obtained in two ways. The first is the use of neuronal stem cells, which in both the embryo and the adult are located around the ventricles of the brain. The second approach is the use of embryonic stem cells. These cells are located in the inner cell mass at an early stage of embryo formation. They are able to transform into almost any cell in the body. The greatest difficulty in working with embryonic cells is to get them to transform into neurons. New technologies make it possible.
Some hospitals in the US have already created "libraries" of neuronal stem cells derived from fetal tissue and are transplanting them into patients. The first attempts at transplantation give positive results, although today doctors cannot solve the main problem of such transplants: the uncontrolled reproduction of stem cells in 30-40% of cases leads to the formation of malignant tumors. So far, no approach has been found to prevent this side effect. But, despite this, stem cell transplantation will undoubtedly be one of the main approaches in the treatment of such neurodegenerative diseases as Alzheimer's and Parkinson's diseases, which have become the scourge of developed countries.
"Science and Life" about stem cells:
Belokoneva O., Ph.D. chem. Sciences. Prohibition for nerve cells. - 2001, No. 8.
Belokoneva O., Ph.D. chem. Sciences. Mother of all cells. - 2001, No. 10.
Smirnov V., acad. RAMS, corresponding member. RAN. Restorative therapy of the future. - 2001, No. 8.
Everyone knows such a popular expression as "nerve cells are not restored." From childhood, absolutely all people perceive it as an indisputable truth. But in fact, this existing axiom is nothing more than a simple myth, since new scientific data as a result of the studies carried out completely refute it.
Animal experiments
Every day, many nerve cells die in the human body. And in a year, the human brain can lose up to one percent or even more of their total number, and this process is programmed by nature itself. Therefore, whether nerve cells are restored or not is a question that worries many.
If you conduct an experiment on lower animals, for example, on roundworms, then they do not have any death of nerve cells at all. Another kind of worm, the roundworm, has one hundred and sixty-two neurons at birth, and dies with the same number. A similar picture is found in many other worms, mollusks and insects. From this we can conclude that nerve cells are restored.
The number and arrangement of nerve cells in these lower animals are firmly genetically determined. At the same time, individuals with an abnormal nervous system very often simply do not survive, but clear restrictions in the structure of the nervous system do not allow such animals to learn and change their habitual behavior.
The inevitability of death of neurons, or why nerve cells are not restored?
The human organism, if compared with the lower animals, is born with a large predominance of neurons. This fact is programmed from the very beginning, since nature lays a huge potential in the human brain. Absolutely all nerve cells in the brain randomly develop a large number of connections, however, only those that are used in learning are attached.
Whether nerve cells are restored is a very topical issue at all times. Neurons form a fulcrum or connection with the rest of the cells. Then the body makes a solid selection: neurons that do not form a sufficient number of connections are killed. Their number is an indicator of the level of activity of neurons. In the case when they are absent, the neuron does not take part in the information processing process.
The nerve cells present in the body are already quite expensive in terms of oxygen and nutrients (compared to most other cells). In addition, they use a lot of energy even when a person is resting. That is why the human body gets rid of free non-working cells, and nerve cells are restored.
Intensity of neuron death in children
Most of the neurons (seventy percent) that are laid down in embryogenesis die even before the birth of the baby. And this fact is considered completely normal, since it is at this childhood age that the level of ability to
Learning should be maximized, so the brain should have the most significant reserves. They, in turn, are gradually reduced in the learning process, and, accordingly, the load on the whole organism as a whole is reduced.
In other words, an excessive number of nerve cells is a necessary condition for learning and for the diversity of possible variants of human development processes (his individuality).
Plasticity lies in the fact that numerous functions of dead nerve cells fall on the remaining living ones, which increase their size and form new connections, while compensating for lost functions. An interesting fact, but one living nerve cell replaces nine dead ones.
Age value
In adulthood, cell death does not continue so rapidly. But when the brain is not loaded with new information, it hones the old skills that are present and reduces the number of nerve cells that are needed to implement them. Thus, the cells will decrease, and their connections with other cells will increase, which is a completely normal process. Therefore, the question of why nerve cells are not restored will disappear by itself.
Older people have significantly fewer neurons in their brains than, say, infants or young people. At the same time, they can think much faster and much more. This is due to the fact that in the architecture built during training there is an excellent connection between neurons.
In old age, for example, if there is no learning, the human brain and the whole body begin a special program of coagulation, in other words, the aging process, which leads to death. At the same time, the lower the level of demand in various body systems or physical and intellectual loads, and also if there is movement and communication with other people, the faster the process will be. That is why it is necessary to constantly learn new information.
Nerve cells are able to regenerate
Today it has been established by science that nerve cells are restored and generated at once in three places of the human body. They do not arise in the process of division (compared to other organs and tissues), but appear during neurogenesis.
This phenomenon is most active during fetal development. It originates from the division of the preceding neurons (stem cells), which subsequently undergo migration, differentiation and, as a result, form a fully functioning neuron. Therefore, to the question of whether nerve cells are restored or not, the answer is yes.
The concept of a neuron
A neuron is a special cell that has its own processes. They have long and short sizes. The first are called "axons", and the second, more branched, are called "dendrites". Any neurons provoke the generation of nerve impulses and transmit them to neighboring cells.
The average diameter of neuron bodies is approximately one hundredth of a millimeter, and the total number of such cells in the human brain is about one hundred billion. Moreover, if all the bodies of the brain neurons present in the body are built into one continuous line, its length will be equal to a thousand kilometers. Nerve cells are restored or not - a question of concern to many scientists.
Human neurons differ from each other in their size, the level of branching of the dendrites present, and the length of the axons. The longest axons have a size of one meter. They are the axons of huge pyramidal cells in the cerebral cortex. They stretch directly to the neurons located in the lower parts of the spinal cord, which control all the motor activity of the trunk and muscles of the limbs.
A bit of history
For the first time, the news about the presence of new nerve cells in an adult mammalian organism was heard in 1962. However, at that time, the results of Joseph Altman's experiment, which were published in the journal Science, were not taken too seriously by the people, so neurogenesis was not recognized at that time. It happened almost twenty years later.
Since that time, direct evidence that nerve cells regenerate has been found in birds, amphibians, rodents, and other animals. Later in 1998, scientists were able to demonstrate the emergence of new neurons in humans, which proved the direct existence of neurogenesis in the brain.
Today, the study of such a concept as neurogenesis is one of the main areas of neuroscience. Many scientists find great potential in it to treat degenerative diseases of the nervous system (Alzheimer's and Parkinson's). In addition, many specialists are really concerned about the question of how nerve cells are restored.
Migration of stem cells in the body
It has been established that in mammals, as well as in lower vertebrates and birds, stem cells are located in close proximity to the lateral ventricles of the brain. Their transformation into neurons is quite strong. So, for example, in rats in one month, from the stem cells they have in their brains, approximately two hundred and fifty thousand neurons are obtained. The level of life expectancy of such neurons is quite high and is about one hundred and twelve days.
In addition, it has been proven not only that the restoration of nerve cells is quite real, but also that stem cells are able to migrate. On average, they cover a path equal to two centimeters. And in the case when they are in the olfactory bulb, they reincarnate there already into neurons.
Movement of neurons
Stem cells can be taken out of the brain and placed in a completely different place in the nervous system, where they become neurons.
Relatively recently, special studies have been carried out that have shown that new nerve cells in the brain of an adult can appear not only from neuronal cells, but from stem compounds in the blood. But such cells cannot turn into neurons, they can only fuse with them, while forming other binuclear components. After that, the old nuclei of neurons are destroyed and replaced by new ones.
Inability of nerve cells to die from stress
When there is any stress in a person's life, cells may not die from excess stress at all. They generally do not have the ability to die from any
overload. Neurons can simply slow down their immediate activity and rest. Therefore, the restoration of nerve cells of the brain is still possible.
Nerve cells die from a developing lack of various nutrients and vitamins, as well as due to a violation of the blood supply process in the tissues. As a rule, they result in intoxication and hypoxia of the body due to waste products, and also due to the use of various medicines, strong drinks (coffee and tea), smoking, taking drugs and alcohol, as well as with significant physical exertion and infectious diseases. diseases.
How to restore nerve cells? It's very simple. To do this, it is enough to study all the time and continuously and develop greater self-confidence, getting strong emotional connections with all close people.
