Human brain cells

Why does the brain begin to age after 20 years, is the brain of geniuses and criminals different, are nerve cells restored, why do they die en masse in babies?

1. Even babies lose nerve cells.

How many neurons (nerve cells) are there in the human brain? We have about 85 billion of them. For comparison, the jellyfish has only 800, the cockroach has a million, and the octopus has 300 million.

Many believe that nerve cells die only in old age, but most of them are lost by us in childhood, when the process of natural selection takes place in the child's head.

As in the jungle, the most efficient and fit survive among the neurons. If a nerve cell is idle without work, its self-destruction mechanism is activated.

Entire networks of neurons in toddler's brains struggle to survive. They solve the same urgent problems with different speed and different efficiency, answer countless questions, like teams of experts in the game “What, where, when?”.

Having lost in a fair fight, weak teams are eliminated, making room for the winners. This is neither bad nor good, this is normal. Such is the harsh but necessary natural selection process in the brain - neuro-Darwinism.

2. Neurons - billions.

There is an opinion that each nerve cell is the simplest element of memory, like one bit of information in the memory of a computer. Simple calculations show that in this case the cortex of our brain would contain only 1-2 gigabits or no more than 250 megabytes of memory, which in no way corresponds to the volume of words, knowledge, concepts, images and other information that we possess. Of course, there are a huge number of neurons, but they certainly won't be enough to accommodate all this. Each neuron is an integrator and carrier of a set of memory elements - synapses.

3. Genius does not depend on brain size

The human brain weighs approximately 1200 - 1400 grams. Einstein's brain, for example, is 1, 230 grams, not the largest. The elephant's brain is almost four times larger, the largest brain in a sperm whale is 6800 grams. This is not about the mass.

What is the difference between the brain of a genius and an ordinary person? You can never tell by the cover of a book or by the number of pages whether it came from the pen of a master or a graphomaniac. By the way, there are some very smart people among the criminals. For the assessment, completely different units of measurement are needed, which do not yet exist. But in general, the power of the brain depends on the number of synaptic contacts (the brain is by no means composed of neurons, it contains a huge number of auxiliary cells. It is intersected by large and small blood vessels, and in the center of the brain there are four so-called cerebrospinal fluid filled ventricles. ..).

The main intellectual power of the brain is made up of the neurons of its cortex. The density of synaptic contacts between neurons is especially important, and not physical weight. After all, we will not begin to determine the speed of a computer by weight in kilograms.

According to this indicator, the brain of animals, even of great primates, is significantly smaller than a human. We lose to animals in running speed, in strength and endurance, in the ability to climb trees ... Actually, in everything except the mind.

Thinking, consciousness is what distinguishes man from animals. Then the question arises: why shouldn't a person acquire an even more capacious brain?

The limiting factor is the human anatomy itself. The size of our brains is, after all, determined by the size of the birth canal of a woman who cannot give birth to a baby with an oversized head. In a sense, we are prisoners of our own structure. And in this sense, a person cannot become significantly smarter, unless one day he changes himself.

4. Many diseases can be treated by introducing new genes into nerve cells.

Genetics is an incredibly successful science. We have learned not only to study genes, but also create new ones, reprogram them. So far, these are just experiments on animals, and they are more than successful. The time is approaching when many diseases can be cured by introducing new or modified genes into cells. Are not experiments being carried out on a person? Secret laboratories only exist in science fiction films. Such scientific manipulations are feasible only in large scientific centers and require a lot of effort. Concerns about unauthorized hacking of the human genome are groundless today.

5. Does a person use only a fraction of the capabilities of their brain? It is a myth.

For some reason, many believe that a person uses only a small part of the capabilities of his brain (say, 10, 20, and so on percent). It's hard to say where this strange myth came from. You shouldn't believe in him. Experiments show that nerve cells that are not involved in the work of the brain die.

Nature is rational and economical. Nothing is put aside in it just in case, in reserve. It is unprofitable and simply harmful for living beings to contain “idlers” in their brains. We have no extra cells.

6. Nerve cells regenerate.

Several years ago, at the age of 83, a very famous patient, American Henry Mollison, died. Even in his youth, doctors, in order to save his life, completely removed from the brain the hippocampus (from the Greek - seahorse), which was the source of epilepsy. The result was difficult and unexpected. The patient has lost the ability to remember anything. He remained a completely normal person, he could maintain a conversation. But as soon as you walk out the door for just a few minutes, and he perceived you as a complete stranger. Every morning for decades, Mollison had to re-learn the world in that part of it, what the world became after the operation (the patient remembered everything that preceded the operation). So, by chance, it was found that the hippocampus is responsible for the formation of new memory. In the hippocampus, the restoration of nerve cells (neurogenesis) occurs relatively intensively. But the importance of neurogenesis should not be overestimated, its contribution is still small.

It's not that the body is maliciously willing to harm itself. The central nervous system is like a complex network of fibers, like a tangled bundle of wires. It would be easy for the body to create a new nerve cell. However, the network itself has long been formed. How can a new cell integrate into it so as not to interfere with it? This could be done if there was an engineer in the brain who would sort out the bundle of "wires". Unfortunately, there is no such position in the brain. Therefore, the restoration of brain cells to replace the lost ones is difficult. The layered structure of the cerebral cortex helps a little, it helps new cells to integrate in the right place. Thanks to this, a small recovery of nerve cells still exists.

7. How one part of the brain saves another

Ischemic cerebral stroke is a serious illness. It is associated with blockage of the blood vessels that supply blood. The brain tissue is extremely sensitive to oxygen starvation and dies off quickly around the clogged vessel. If the affected area is not located in one of the vital centers, the person survives, but at the same time may partially lose mobility or speech. Nevertheless, after a long time (sometimes months, years), the lost function is partially restored. If there are no more neurons, then how is this happening? It is known that the cerebral cortex has a symmetrical structure. All its structures are divided into two halves, left and right, but only one of them is affected. Over time, you can notice a slow germination of neuronal outgrowths from the preserved structure to the damaged one. The shoots surprisingly find the right path and partially compensate for the deficiency that has arisen. The exact mechanisms of this process remain unknown. If we learn to manage the recovery process, regulate it, this will not only help in the treatment of strokes, but also reveal one of the biggest mysteries of the brain.

8. Once upon a time the left hemisphere defeated the right one

The cerebral cortex, as we all know, consists of two hemispheres. They are asymmetrical. As a rule, the left is more important. The brain is designed so that the right side controls the left side of the body, and vice versa. That is why most people are dominated by the right hand, controlled by the left hemisphere. There is a kind of division of labor between the two hemispheres. The left one is responsible for thinking, consciousness and speech. It is it that thinks logically and performs mathematical operations. Speech is not just a communication tool, not just a way to convey a thought. To understand a phenomenon or an object, we absolutely need to name it. For example, by designating a class with the abstract concept "9a" we save ourselves from having to list all the students every time. Abstract thinking is characteristic of man, and only to a small extent - of some animals. It incredibly speeds up and strengthens thinking, therefore speech and thinking are, in a sense, very close concepts.

The right hemisphere is responsible for pattern recognition, emotional perception. It hardly knows how to speak. How is this known? Epilepsy helped. Usually the disease nests only in one hemisphere, but it can spread to the second. In the 60s of the last century, doctors thought about whether it is possible to cut the connections between both hemispheres in order to save the patient's life. Several such operations have been performed. When the natural connection of the left and right hemispheres is interrupted in patients, then the researcher also has the opportunity to "talk" with each of them separately. It was found that the right hemisphere has a very limited vocabulary. It can be expressed in simple phrases, but abstract thinking is not available to the right hemisphere. Tastes and outlooks on life in the two hemispheres can be very different and even come into obvious contradictions.

Animals do not have speech centers, therefore, no apparent asymmetry of the hemispheres was revealed in them.

There is a hypothesis that several thousand years ago, the hemispheres of the human brain were completely equal. Psychologists believe that the "voices" so often mentioned in ancient sources were nothing more than the voice of the right hemisphere, and not a metaphor or artistic device.

How did it happen that the left hemisphere began to dominate? With the development of thinking and speech, one of the hemispheres simply had to "win", and the other "yield", because dual power within one personality is irrational. For some reason, the victory went to the left hemisphere, but often there are people who, on the contrary, are dominated by the right hemisphere.

9. The right hemisphere has a child's vocabulary, but imagination is cooler

The most important function of the right hemisphere is the perception of visual images. Imagine a picture hanging on a wall. Now let's mentally draw it into squares and begin to gradually paint over them in a random way. The details of the drawing will begin to disappear, but it will take quite a long time before we no longer understand what exactly is depicted in the picture.

Our consciousness has an amazing ability to recreate a picture in separate fragments.

In addition, we see a dynamic, mobile world, almost like in a movie. The film is not drawn to us in the form of separate changing frames, but is perceived in constant motion.

Another amazing ability that we are endowed with is the ability to see the world in three-dimensional, three-dimensional. A perfectly flat picture does not seem flat at all.

With the power of imagination alone, the right hemisphere of our brain gives depth to the picture.

10. The brain begins to "age" after 20 years

The main task of the brain is to assimilate life experience. Unlike inherited traits, which remain unchanged throughout life, the brain is able to learn and remember. However, it is not dimensionless and at some point may simply overflow, so that there will be no more free space in memory. In this case, the brain will begin to erase old "files". But this is fraught with the serious danger that something important will be erased for some nonsense. To prevent this from happening, evolution has found an interesting way out.

Until the age of 18-20, the brain actively and indistinctly absorbs any information. Having successfully lived up to these years, which in the past were considered a solid age, the brain gradually changes its strategy from memorizing to preserving what has been learned, so as not to expose the accumulated knowledge to the danger of accidental erasure. This process occurs slowly and systematically throughout the life of each of us. The brain is becoming more and more conservative. Therefore, over the years it becomes more and more difficult for him to master new, but the acquired knowledge is reliably fixed.

This process is not a disease, it is difficult and even almost impossible to fight it. And this is another argument in favor of how important it is to study at a young age, when learning is easy. But there is good news for older people too. Not all of the properties of the brain weaken over the years. Vocabulary, the number of abstract images, the ability to rationally and soundly think are not lost and even continue to grow.

Where a young, inexperienced mind gets confused, sorting through various options, the older brain will find an effective solution faster thanks to a better thinking strategy. By the way, the more educated a person is, the more he trains his brain, the less the likelihood of brain diseases.

11. The brain cannot be hurt

The brain is devoid of any sensitive nerve endings, so it is neither hot nor cold, nor ticklish, nor painful. This is understandable if we consider that it is better than any other organ protected from the influences of the external environment: it is not easy to get to it. Every second, the brain receives accurate and varied information about the state of the most remote corners of its body, knows about any needs, and is entitled to satisfy them or put them off for later. But the brain does not feel itself in any way: when we have a headache, this is only a signal from the pain receptors of the meninges.

12. Healthy Brain Food

Like all organs in the body, the brain needs energy sources and building materials. It is sometimes said that the brain feeds exclusively on glucose. Indeed, about 20% of all glucose is consumed by the brain, but it, like any other organ, needs the whole complex of nutrients. Whole proteins never enter the brain, before they are broken down into individual amino acids. The same goes for complex lipids, which are digested to fatty acids such as omega-3 or omega-6. Some vitamins, such as C, enter the brain on their own, while such as B6 or B12 are carried by conductors.

Be careful when consuming zinc-rich foods such as oysters, peanuts, and watermelon seeds. There is a hypothesis that zinc accumulates in the brain and, over time, can lead to the development of Alzheimer's disease.