Neurobiologist Ilya Martynov - about the main mysteries of the brain.
There are a lot of experiments showing that when viewing / reading / thinking about an object and in direct contact with it, the same parts of the brain work. For example, reading the word "coffee" activates the olfactory cortex. Why is this happening?
According to Pavlov, nature has endowed us with the opportunity to develop a second signaling system. It is called speech. In general, to think about something, you first need to name it, come up with / pick up a word. In order to formulate a thought, you need to combine words.
Our brain is divided into a huge number of functional areas, but they all work as a single system. We have primary areas of the cortex that perceive only one type of information, for example, a visual image. There are secondary and tertiary areas that generalize stimuli. Tertiary regions are also called associative - signals from primary and secondary regions are mixed inside them (association).
Ilya Martynov.
Since in childhood, parents encoded information with words, we learned to compare the image with them. For example, they show us a toy and call it (“this is a car”). In the occipital regions of the cortex (perception of vision), cells are activated to recognize the image of the toy. In the temporal areas of the cortex (hearing perception), there are cells that respond to a sound stimulus (in our case, the name of a toy). In the associative areas, different parameters of the stimulus are compared, and so we got a general image of the machine, corresponding to a certain appearance, tactile sensations from it, the word "machine", its sound, etc. For this case, even a "speech" neuron is formed.
It turns out that the brain records life experience through associations?
In fact, the brain learns according to the type of complex conditioned reflex complexes. Carrots are orange. Bunny - with two ears. The more associated repetitions, the stronger the network of connected cells in the brain forms. That is, the more often your mother told you: "Look, this is a carrot, it is orange," the more strongly it settled in the brain at the level of synaptic connections. Interestingly, any experience in some sense "solders" our connections in the brain. The brain is very plastic and, like soft clay, adjusts to the environment (leaving its imprints on itself). Even reading this text, you are rebuilding the connections between brain cells.
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Why don't we actually smell coffee when we see the word "coffee"?
Associative regions collect information from different parts of the brain. That is why the drawing of a cup of coffee or the word "coffee" itself is associated with a particular aroma. You don't actually smell the smell, but the speech neuron (for the word "coffee") automatically draws information from the olfactory system. This is an extremely simplified diagram, but it roughly works like this.
How, then, does the brain distinguish between real and imagined coffee smells?
So far, there is no consensus on the physiological mechanism. It is believed that the signal is suppressed because the sensory systems are not stimulated. The brain does not see the chemical stimulus at the olfactory receptors and does not receive a signal from them. Associative neurons simply extract information from memory. This allows us not to turn the brain into a complete mess.
But in a dream or in the case of hallucinations, inhibition of sensory systems is turned off, so we see, hear and feel what is not.
What happens in the brain of a person who is hallucinating?
In psychiatry, hallucinations are divided into true and pseudo-hallucinations. True images are when images are projected by a person outside and for a person do not differ from real objects or stimuli. In fact, such hallucinations are a perception error with the senses. With the help of equipment, we can fix that a person really hears, sees or smells something that does not exist in reality.
Pseudo-hallucinations are "seeing" images of non-existent objects within consciousness, something that seems to live in a person's head. Often found in people with schizophrenia, when the very nature of conscious activity is distorted. A person perceives signals not with his eyes or ears, but with a kind of “inner eye”, “inner ear”. He may think that he sees through a wall or is endowed with superpowers (which will seem realistic to him), that he “hears” voices from Venus or the Moon.
We know from scanning studies that when a healthy person speaks words, the parts of the cerebral cortex responsible for hearing are suppressed. This does not happen in patients with schizophrenia. They mistakenly perceive their own inner speech as the speech of another.
During hallucinations, the areas of the cortex involved in the formation of inner speech are activated before the areas associated with the awareness of verbal material. That is, something inside says or shouts, and the patient realizes that something has sounded only after some delay.
How do hallucinations occur in people who are not schizophrenic?
Hallucinations arise for various reasons - with severe fatigue, intoxication, with pathological processes in the structures of the brain, often - while taking psychotropic substances. The mechanisms of their occurrence are always different, and many of them are not yet fully understood. Hallucinations can be viewed from a biochemical point of view (at the molecular level) and neurophysiological (at the level of brain structures).
Take the example of the effect of psychoactive substances on the brain. Our body has an extensive serotonin system, represented in different parts of the brain. This is a group of cells that use serotonin to communicate with each other. Serotonin neurons play a major role in mood regulation. If the synthesis of a substance is disturbed, then a person may experience depression. Normally, serotonin is produced in the lumen between the processes of nerve cells, for which there are special receptors on the cell membrane. When serotonin molecules "touch" the receptors, a nerve impulse occurs, and the signal flows from one cell to another.
Psychoactive molecules such as LSD bind to these receptors. They seem to deceive the cells by posing as a serotonin molecule. Since LSD molecules bind to a large number of receptors, different regions in the brain are randomly excited, which leads to an uncontrolled mixing of images. Moreover, the brain can mistakenly perceive information from sensory systems, believing that it is real. This is how we get true hallucinations. This is just one of the mechanisms, there are others.
Neurophysiologically, hallucinations appear in people with epilepsy in a similar way. Images arise from uncontrolled excitation of various areas of the brain and their inadequate response to external stimuli. Such patients have visions in which non-existent people approach them, an airplane flies at great speed, a wall of fire moves, etc.
The temporal regions are often involved in the pathological process. When these parts of the brain are damaged, a person experiences auditory, olfactory, and gustatory hallucinations.
They are also called the "zone of God" because the activation (or stimulation) of certain parts of the temporal lobe can cause divine insights or religious experiences. Is it possible to somehow fix when a person imagines, and when he actually perceives?
Sure. For example, according to the activities of the conducting and perceiving links (in particular, on the evoked potentials). These are the responses of various structures of the nervous system to stimuli. But how the brain will interpret these signals (what will be the distortions), whether synesthesia will arise is another question. Science does not yet have definite answers regarding the subjective criteria of perception. The line between imaginary and real is very thin.
How does our brain as a whole distinguish between the imaginary and the real? If we are talking not only about sensory stimuli, as is the case with the word "coffee"
Actually, it's bad. Moreover, nobody knows what is real. Reality is infrasound, ultraviolet waves around us, and much more. We “look” at it, we “listen”, “smell” it, etc., without even knowing about it. There is no need to talk about the conscious distinction between the imaginary and what we call reality. Let's say there is a person with a lens defect, blind from birth. At twenty, he had a lens replaced. But he can still calmly go out the window! Why? Because his brain in the corresponding period of development did not learn to see the world as three-dimensional. For such a person, in principle, there may be no visual difference in "closer-further".
The writer Ayn Rand tried in her books to reflect the idea that objective reality exists independently of the person who perceives it. The problem is that today the objective reality is not fully comprehensible by the methods of science. What do we actually know about a black hole when we look at it through a telescope using X-rays? In fact, the brain of the astronomer sees some fluctuations of radiation, then the scientist looks at the interpretations of the computer on the screen, after which he completes the model-drawing of the object in his imagination.
The same problem with sleep. In a dream, everything seems incredibly real to you. According to one of the hypotheses, sleep is a psychophysiological process, within which the cerebral cortex sees its own work (as if a reflection of itself).
Physiologists in this regard like to recall the great IM Sechenov, who wrote: "There is no difference in the processes that provide real events in the brain, their consequences or memories of them." It turns out that the same elements work in the brain, and they don't care.
In the 1990s, Giacomo Risolatti discovered amazing cells in the brain that activate when we follow other people's actions. They were called mirror neurons. From these experiments it followed that these cells, like a mirror, "reflect" someone else's behavior in our own head. This allows us to feel what is happening to the other person as if we were performing the actions ourselves.
It is they who help us identify with literary and film characters. Do you think you can get life experience from books and films?
I'm not sure that you can get a full-fledged life experience, because, firstly, I don't know what it is, and secondly, for the brain, any experience is an experience.
In general, the brain doesn't care how it specializes its neural networks. But if we mean by full-fledged experience the ability to communicate with other people, to solve life problems, then the answer is obvious - it is impossible. In any case, the brain will need experience of interacting with real people.
If we are talking about the modern world, where you can become successful virtually, then it is quite possible to become very experienced in something. You can learn programming and become an employee of a large corporation from the comfort of your home, sitting in front of your computer and TV.
However, books and films are also different. Much depends on the objectives and ultimate goals. We again run into the criteria for assessing the "usefulness" of experience.
Studies show that well-read and well-read people have a more developed capacity for empathy. That is, we partly live the life of the characters, work through their psychological and life situations as our own. Does the brain capture them just as if they were real?
Difficult question in terms of evaluation. It is difficult to judge the causal relationship, since it is unclear whether people developed the ability to empathize after reading books and watching films, or they were initially more sympathetic and therefore read and watched more (and, apparently, certain genres). But if we argue from the standpoint of plasticity, then we can assume that the experience gained from books will really re-solder synapses, forming certain stereotypes of perception of relationships between people.
By the way, love is almost always described distortedly. I myself recently finished writing the second fiction book (this is my hobby) and I understand that I lied about the storyline about love five times. And all why? Because no one will look at ordinary relationships from the outside - you need a zest, emotions, unusual actions. Often people, after reading fiction with scenes of vivid confessions, start looking for something similar in reality, pedaling similar feelings and situations. But, alas, the chemistry of life is much more prosaic than the "physiological cocktail of love" pouring from the pages of novels. And just from research we know that "literary" love cannot live long. A month, two or three. And then - gray everyday life.
A similar situation with dialogues. People rarely talk like they do in books (maybe a shame). In general, reading books encourages you to enrich your vocabulary, build grammatically more complex sentences. Subject to careful reading of complex literature with good editing and proofreading. Plasticity here works with a bang.
It is believed that before Turgenev wrote about his famous young ladies, in reality they were not met - everyone began to see them precisely because he created them. Or that the fogs in London did not exist for everyone until they were painted by painters. How correct are these arguments?
I believe that the question with Turgenev's ladies and mists is the same story from childhood with a toy. A person is programmed to see and perceive something in conjunction. In fact, it is easy for the brain to think in stereotypes, that is, in simple speech constructions. And if they also evoke vivid images, then generally excellent. For the same reason, we put labels. When we have put a label, we can calm down, because now we seem to understand everything about a person, a phenomenon, etc.
This phenomenon is rather cultural. By the way, I would be very careful with generalizations here. I can assume that not all of Turgenev's young ladies began to exist for everyone, but for those who, firstly, were able to understand this (not everyone was able to read in those days), and secondly, they were sufficiently conformable to react.
Evolutionarily, a mechanism has been formed in us to take on faith what people who are significant to us (authorities) say. We even know the areas in the brain responsible for this mechanism (cingulate cortex, some parts of the frontal, temporal lobes). So, for some people, Turgenev turned out to be an authority and they picked up his idea (a similar story with fogs, only there the effect of mass character could work). Of course, there were no special "Turgenev ladies". Simply conforming girls began to imitate what Ivan Sergeevich (by the way, one of my favorite Russian writers) had written. Hence all these fainting spells (naturally simulated!). “Turgenev's young ladies”, and the fogs of London for many, do not exist even today. Rather, they are only for people who have read a lot and are impressionable.
That is, someone may well remember the fogs in London, although they were not there, and "there is no difference in the processes that provide the brain with real events, their consequences or memories of them." How “virtual” is our memory?
These questions are complex, specific, and I am not an expert on molecular mechanisms of memory. As I said, synapses are constantly re-soldered under the influence of the experience. In 2000, Eric Kandel received the Nobel Prize for his discovery of the molecular mechanisms of memory, proving the restructuring of synapses while learning a new skill. Kandel and colleagues also discovered a cascade of chemical reactions through which the CREB factor, which regulates RNA synthesis, is activated. In other words, they found a whole chemical pathway that affects the work of the genes of the nerve cell. Just think about it! You study something, and your genes begin to work differently. Moreover, this happens constantly with repeated presentation of the stimulus.
Studies in chickens have shown that recourse to a memory and the initial recording of the memory itself induces similar molecular processes.
In this case, we can say that our memory is not “virtual”, but very dynamic. It is like a hard disk on which everything (or a lot) would change when new information was recorded. In fact, we do not fully know to what extent the incoming information affects synapses in different regions of the brain.
Plus, this is just a piece of a much more complex and complex process. We still have a lot to learn about the mechanisms of memory, and that's great, because we have a lot to learn!