Changeable brain

One of the main conclusions of neurophysiological studies of the last two decades is formulated as follows: you are able to change your brain. Now it is safe to say that the adult brain formed is capable of reorganization. More recently, there were great doubts about this. However, recently, first of all, thanks to the improvement of equipment and new scanning methods, it has become possible to move from the field of assumptions and hypotheses to experimental observations.

In the mid-1990s, the neurologist Alvaro Paskuual Leone conducted a not quite ordinary experiment. He asked people to play the piano. The group of volunteers offered simple exercises on the music keyboard, which they were supposed to perform every weekday for two hours. It was supposed to play with one hand. Despite the relative ease, the tasks required a certain training and did not immediately get the subjects. But by the end of the first week, after five days of classes, the number of errors decreased markedly. The brain gradually adapted to the task.

Pasqual Leone was interested in the question of how such an adaptation would be reflected in brain tissue. Is it possible to detect traces of such adaptation in it. Most likely, he believed, the changes should affect the motor areas of the bark associated with the fingers of the training hand. Therefore, at the beginning of the experiment, each volunteer determined the zones of the brain, where the signals of the muscles of the flexors and extensors of the middle finger of the brush were projected. For this purpose, the method of focal transcranial magnetic stimulation (TMS) was used, which allows you to build cortical cards with high resolution. The motor area associated with the middle finger was checked, for all subjects every day, before and after playing music. For control purposes, cortical cards were built for the fingers of both hands. Similar indications from control groups that did not perform exercises were also removed. TMS measurements showed: as a result of exercises, the motor zone of the fingers of the trained hand grew rapidly. By the end of the first week, it increased significantly (Fig. A).

"Material" of thought

Obviously, in the early days, the brain responded to new experience with a surge of neuronal connections. He used the adjacent regions of the bark, and the movement of the finger was now more engaged in more neurons. In this way, control over the mechanics of movements was enhanced in order to ensure their accuracy. However, the rapid expansion of the cortical “finger” zone was observed only in the first week. The next four weeks its size gradually declined (Fig. B), despite the fact that the subjects continued to engage. As the training was going on, the exercises were increasingly shifted in the phase of the stereotype and less and less required corrective effects. According to Pasqual Leone, the rapid and short-term expansion of the motor zones that he discovered is the first necessary stage of training, which follows a deeper reorganization of the cortex, which translates the recently acquired skill into long-term automatism.

Volunteers of another group received a similar task: play with one hand on the keyboard every day for two hours. However, they were not provided with exercises, allowing you to play anything. Despite the load on the fingers similar to the main group, the growth of their cortical zones was much weaker. From the experiment, it followed that motor activity itself does not lead to significant shifts in the excitation of the bark. Apparently, the main component of the expansion of the motor zones in the main group was focus on the task and conscious control of movements.

Pascual Leone developed this idea, excluding the influence of movements. He suggested that another group perform the same exercises in the same mode, only mentally. During the experiment, the fingers of the subjects remained motionless. As a result, the motor zones not only reacted to imaginary movements - their dynamics almost completely repeated the growth noted in the main group. The motor areas of people who performed exercises in the mind were like the size of the corresponding sections of those who were truly engaged on the keyboard (Fig. C). Mental training led to real training - to a change in the neurophysiological properties of brain tissue.

Other experiments have been conducted over the past time; The concept of Mental rehearsal (mental rehearsal) has become scientific use, and the mental visualization method is used, including to reduce phantom pain. Now it is clear that playing situations in the mind really enriches the brain with new experience. In a certain sense, at the level of a physical substrate, consciousness does not distinguish between real and modeling movements, initiating similar brain changes. The good news is that, using the indicated property, you can prepare yourself for the upcoming motor activity by developing the corresponding areas of the neocortex. This is especially useful for athletes, military, rescuers and other professionals. The bad news concerns everyone: imagining certain negative situations, scrolling them in the mind, the brain is really capable of living as real ones. And this often is reflected in a state of nervous tissue.

See without eyes

We will try to illustrate how far it extends the possibility of the brain to restructure your own information flows. As you know, signals coming from the outside are processed in various areas of the brain, depending on the type of sensory system that transmitted the data. The names of the neocortex departments reflect this dependence: visual cortex, auditory bark, somatosensory cortex. It is obvious that, for example, if the eyes damage, the information ceases to enter the visual centers and a person loses vision, despite the performance of the corresponding field of the cortex. How will the brain behave if visual signals begin to come to it through a different type of sensory system? The modern level of development of electronics allows you to answer this question.

Currently, a device has been developed and tested to help the blind see with the help of a language. The device is called BrainPort and consists of a miniature video camera mounted in the forehead area, as well as the processor that is placed in the hand, and a small grate of electrodes overlapping in the tongue. The video signal enters from the camera into a processor, which converts pixels into electrical impulses. Further, they are directed to the surface of the tongue, and each electrode is associated with a certain bundle of pixels. The intensity of light corresponds with the current force and the duration of the electrical signals that the language feels.

The lattice also provides a spatial correlation: the flash in the center of the visual field will be accordingly displayed in the form of a pulse in the middle of the grate.

The blind begins to see. Naturally, the resolution of their black and white field of view is limited by the number of electrodes, which is still low. But even in this case, they manage to see not spots, but objects. For example, a person is able to press the elevator button, read letters and numbers or take a cup from the table without splashing the contents. The brain of people who had the opportunity to use Brainport very quickly mastered the new situation. Probably analyzing incoming signals, the brain recognized the pattern in them, which in the basic features is characteristic of information usually coming from the organs of vision. Having combined these signals with knowledge of the movements of the head, the brain tried to build a picture. When he was convinced of the presence of feedback, he began to learn to interpret the impulses coming from the language as visual information. Roughly speaking, he recruited a language to perform the function of the eyes.

Language as an “eye” may seem an exotic choice, but this is not a whim of researchers. The saliva serves as an excellent conductor of electrical impulses, and the nerve fibers are located in the tongue very close to the surface. At the same time, their density per unit area is high, due to which the language is an extremely sensitive organ. Almost perfect for vision. After the eye.

You can

Modern technologies allow you to demonstrate another facet of the ability of the brain to rebuild its work. As in the first example with an experiment, Pascual Leone, we are talking about the possibility of consciously affecting the electrical activity of the brain. If in real time to provide consciousness with information about the current physiological parameters of the body (usually inaccessible to it), then these indicators can gradually learn to change and return to normal. As you know, in a natural situation, many processes going in the body, consciousness does not directly control. The activities of internal organs, glands, blood and lymph vessels, the metabolism and constancy of the environment are monitored by the autonomic nervous system. A person does not know how to change his blood pressure, the temperature of the limbs or the value of the alpha rhythm of the brain. However, he can receive current information about the state of his body through special visualizations, for example, geometric shapes or charts on the computer screen. To do this, sensors are connected to the subject, which in real time take readings and transmit them to the processor. After the necessary transformations, cleansing and enhancement of signals, data are displayed on the screen. Observing them for a long time, a person is able to consciously lead this data to the desired values. Usually it looks like a change in the color of the figures or the height of the columns. Sound may also be involved. In other words, the brain learns to enter a state corresponding to “correct” visualizations, and remain in it.

As in the previous example with linguistic vision, the brain uses feedback to guess the purpose of the incoming data and then rebuild its work. Conditional-reflex training in the autonomic nervous system occurs by reinforcements in the form of video, audio or tactile images. The described ability of the brain to self -regulation gave development to a separate direction of scientific medicine. In this regard, as a rule, they use the term Neurofedback (neurofidbek), or biological feedback. Currently, therapy is used to correct various psychosomatic disorders, including epilepsy, neurosis, panic attacks, attention deficit, migraines, muscle clamps, etc.

Self -repair of the brain

The above examples illustrate the ability of the brain to quickly respond to changed circumstances and rebuild its work. Electrical activity (rhythms, passage of signals, turning on-off groups of neurons)-this is something that can be corrected within minutes, hours. At the same time, there is another class of problems, first of all, injuries, the consequences of which can be eliminated, or at least to some extent to compensate only through anatomical changes in the structure of the brain. The damaged part is not able to grow again, as a lost finger or limb cannot grow. But the brain is sometimes able to convert the existing tissue, forming unique structures and laying new nervous paths. This is a much longer process, and it can occupy years.

Not so long ago, doctors were shocked by the case of American Terry Wallis, who in 1984 at the age of 20 he fell into a car accident, after which he fell into a coma. The brain received serious damage, doctors excluded the possibility of any improvement of the situation in the future. Wallis was 19 years old in the so -called “state of minimal consciousness” (Minimally Conscious state) and came to his senses in 2003. Within three days, the ability to talk was returned to him. He remembered his life before the disaster and believed that he was in the mid-80s. Over time, most cognitive functions have restored, although there were problems with memory. Twice his brain was studied by diffusion-intoxone visualization, Diffusion Tensor Imaging (DTI). Studies have shown the presence of anatomically unique, not characteristic of an ordinary brain of structures. Walles's brain was not ordinary. Faced with the task of restoring functions after extensive damage, he developed an alternative connection scheme, initiating the growth of axons in the preserved sections. Over the years, inconspicuous from the side, there was a careful and painstaking construction of a new brain. And all this time, homeostasis and life support were supported.

The above examples serve as an illustration of only a small part of the phenomenal skills of the brain to modify itself on the go. Not so long ago, this was considered unlikely. In recent years, with the advent of modern equipment, it has become possible to look into the transformations that are taking place and explore them with scientific methods. There is no doubt that in the future we are waiting for more amazing cases.

Having dealt with the mechanisms of plasticity, scientists will learn over time to provoke useful changes in the brain to help him cope with various kinds, such as mental disorders, aging, injuries. This promises improving the quality of life (and sometimes its salvation) of millions of people. The diagnosis will cease to sound as a sentence.