The cerebrum (cerebrum) consists of two hemispheres (right and left). Each cerebral hemisphere consists of three phylogenetically and functionally different systems: 1) the olfactory brain; 2) basal ganglia, or subcortex; 3) cerebral cortex (cortex, cortex), or cloak (pallium, pallium). Concepts such as forebrain and telencephalon are often used in the literature. The forebrain (prosencepnalony) develops from the terminal part of the neural tube and includes the diencephalon and telencephalon. The telencephalon develops from the forebrain and consists of the cerebral cortex, corpus callosum, striatum and olfactory brain.

The basal ganglia, or basal ganglia, are a collection of gray matter of the brain in the thickness of the white matter of the cerebral hemispheres (mainly in the frontal lobes). They are called the subcortical nuclei of the brain. The basal nuclei in each hemisphere include several nuclei (globus pallidus, striatum, etc.), which regulate motor automatisms, and also ensure the normal distribution of tone and adequate dynamics of movement. Functionally, the substantia nigra of the midbrain belongs to the basal ganglia. The amygdala is located deep in the temporal lobe and also belongs to the basal ganglia.

Vertical and horizontal organization of the cortex

The cerebral cortex (cortex cerebri, pallium) is a layer of gray matter (2 - 5 mm) on the surface of the cerebral hemispheres, it is formed by the bodies of neurons and glial cells, arranged in layers. The cortex is the place of higher analysis and synthesis of all information entering the brain, integration of all forms of complex behavior and higher mental functions. Currently, ideas about the exclusive participation of the neocortex in the formation of complex forms of behavior, including conditioned reflexes, have been replaced by the idea of ​​it as the highest level of thalamocortical systems functioning together with the thalamus, striopallidal, limbic and other brain systems.

The cerebral cortex is represented by the ancient cortex (paleocortex), old cortex (archicortex, archiocortex), intermediate or middle cortex (mesocortex) and new cortex (neocortex). An important distinctive feature of the structure of the cortex is the presence of grooves and convolutions. Each hemisphere is divided into five lobes - frontal (frontal); parietal; occipital, temporal and insular. The frontal lobe is separated from the parietal lobe by the central (Rolandian) fissure. The frontal lobe is divided into the precentral gyrus, superior, middle and inferior gyri. The lateral, or Sylvian, fissure separates the temporal lobe from the frontal and parietal lobes. The parietal lobe contains gyri such as the postcentral, superior and inferior parietal lobules.

The ancient and old cortex includes a number of cerebral hemisphere structures that phylogenetically arose earlier than the neocortex. The ancient cortex, or paleocortex, is the most simply structured cerebral cortex, which contains 2 - 3 layers of neurons. The components of the ancient cortex are the olfactory tubercle and the surrounding cortex. The olfactory brain is topographically divided into two sections: the peripheral section (olfactory lobe) and the central section (brain convolutions). The peripheral section includes formations lying at the base of the brain - the olfactory bulb; olfactory tract; olfactory triangle; medial and lateral olfactory gyri; medial and lateral olfactory stripes; anterior perforated space or substance; diagonal stripe, or Broca's stripe. The olfactory brain also includes formations such as the hippocampus and the amygdala.

The main structural feature of the cortex is the screen principle of its organization, which is most characterized by the correct organization of cells and fibers running perpendicular to the surface or parallel to it. This similar orientation of many cortical neurons provides opportunities for the grouping of neurons. The cellular composition in the neocortex is very diverse; the size of neurons ranges from 8 - 9 microns to 150 microns. In humans, the new cortex, i.e., gray matter, occupies approximately 96% of the entire surface of the cerebral hemispheres (the thickness of the gray matter ranges from 1.5 to 4.5 mm) and is characterized by multi-layering. In the adult human cortex, 6 layers (plates) can be distinguished, which have their own morphological characteristics - neural composition, orientation of neurons, location of dendrites and axons.

In different mammals and in different parts of the neocortex of the same animal or person, there are certain features in the fine neural organization, the number and size of neurons, the course of fibers, the branching of dendrites, and the thickness of the layers. Based on such cytoarchitectonic differences, cytoarchitectonic fields and regions are distinguished in the cerebral cortex (for example, Brodmann's cytoarchitectonic map). Along with the horizontal organization by layers, the neo-cortex has a clear vertical organization in the form of systems of neurons united in vertical groupings of cells from all layers of the cortex. This vertically organized group of cells, which is the functional unit of the cortex, was called the vertical column of the cortex. Columns of cortical neurons are characterized by subtle functional specialization. Within the columns, neurons have a topography of partial overlap. Due to the presence of return collaterals, the columns interact with each other, for example, by the type of lateral inhibition. The next stage of integration of neurons in the cortex is the combination of several vertical microcolumns into a larger unit - a macrocolumn, or functional cortical module. The structural basis for the formation of such cortical modules is the horizontal branching of the axons of stellate cells, as well as the horizontal connections of the axons of stellate cells and the axon collaterals of pyramidal neurons. The diameter of the functional cortical module is several times greater than the diameter of the vertical column and is 300 - 600 µm. As brain organization becomes more complex in phylogeny, features of modular organization appear in different areas of the neocortex. The processes of intracortical inhibition, implemented by the system of inhibitory interneurons, are of great importance in the functioning of cortical modules. Inhibitory and excitatory interactions between functional modules of the cortex underlie the formation of larger associations - distributed systems of the cerebral cortex. The modules that make up distributed systems are interconnected in serial and parallel associations, so such a system has several inputs and outputs. Its command function is dynamically distributed among those areas where the most important information is currently received.

Depending on the functions performed, different areas of the cortex are divided into: projection (somatosensory, visual and auditory); motor (primary - motor, secondary - premotor); associative (prefrontal, frontal, or anterior associative, and parietotemporo-occipital, parietal, or posterior associative) and limbic cortex (obitofrontal, or orbital)

The projection (sensory) zones of the cortex carry out the highest level of sensory analysis. They receive afferent impulses from specific relay nuclei of the thalamus and, spatially distributing it on the screen projection, have a topical principle of organization. Along with complex analysis, sensory areas integrate and critically evaluate information that comes here through specific afferent inputs. Sensory afferentation entering the cortex has multiple representations: each of the sensory zones includes a zone of primary projection, secondary and tertiary. The main sensory areas are the visual, auditory and somatic sensory systems of the cortex.

Associative zones of the cortex in the course of phylogenetic development acquire an increasingly important role in complex forms of behavior and occupy a significant part of the neocortex in primates. The main association areas are the parietal and frontal association areas. The parietal associative area ensures the reconstruction of holistic images of objects or phenomena. Here the integration of afferent streams of different sensory systems takes place, which is necessary for the implementation of adaptive behavior. On the neural groups of the parietal region, convergence of afferent flows of different modalities occurs, i.e. from different sensory receptors, which creates optimal opportunities for afferent synthesis, which underlies the perception of a holistic image of an object and its spatio-temporal relationships with other objects. Most neurons in the parietal cortex respond to stimuli from two or three sensory modalities. There are nerve cells that are excited only by a complex of multisensory stimuli. A large number of efferent outputs from the parietal cortex go to the motor cortex, where the formation of a voluntary action command on the basis of afferent synthesis occurs. Frontal association areas of the cortex are fully formed only in primates and humans. They are also characterized by the absence of specialized afferent inputs, the multisensory nature of neural reactions, the abundance and complexity of connections with cortical areas and deep structures of the brain. The association frontal cortex is divided into two large regions: the prefrontal and orbitofrontal cortex (related to the limbic association cortex). The primary function of the prefrontal cortex is to formulate plans for executing sets of motor actions. The prefrontal region receives most of the information necessary for voluntary activity from the posterior parietal association cortex. After the integration of sensory information of different types occurs in the posterior parietal areas of the cortex, primarily somatosensory with visual and auditory, activation of the prefrontal cortex begins, which is connected to the posterior parietal areas by numerous intracortical and subcortical connections, for example, through the thalamus. Thanks to this, the prefrontal cortex receives a complete spatial map of the objects in the field of view. Information about external space is combined here with information about the position of the body and its individual parts, and the prefrontal cortex includes all this data in short-term working memory. On this basis, a plan for upcoming actions is created, i.e., from the many possible options for activities, the necessary ones are selected and in the most rational sequence. First of all, the position of the eyes directed to the desired object is programmed, coordination of the actions of both hands is provided, etc. Most of the signals emerging from the prefrontal cortex enter the premotor area of ​​the cortex. In humans, the anterior areas of the frontal region are involved in the implementation of the most complex processes associated with the preservation of personality and the formation of social relationships. The frontal areas of the cortex in humans are directly involved in the activity of the second signaling system - speech signaling.

Analytical and synthetic activity of the cerebral cortex

Analysis is the distinction, separation of different sensory signals, differentiation of various effects on the body. Although the analysis of sensory signals begins already in the receptor apparatus, and various subcortical centers are involved in this process, the main analytical process takes place in the cerebral cortex (therefore it is called higher analysis). It is here, in the cerebral cortex, that depending on the strength, duration and steepness of the increase in the stimulus, a unique spatio-temporal pattern of excitation arises each time, due to which the discrimination of stimuli with similar properties is achieved. A form of analysis specific to the cerebral cortex consists of distinguishing (differentiating) stimuli according to their signal value, which is achieved by the participation in this process of the mechanism underlying internal inhibition. The degree of analysis performed by cortical cells varies. It can be quite simple and primitive, for example, in conditions when the body is affected by only two separate stimuli. But the analysis can also be very complex, for example, when the body is exposed to a complex of stimuli. With the participation of the mechanism of internal inhibition, the cerebral cortex is able to perceive not only individually each component of this complex, and not only in total, but also in a certain sequence. In addition to analyzing stimuli, the cerebral cortex also carries out synthetic activity, that is, linking, generalization, and combining excitations that arise in different areas of the cortex. Cortical cells are characterized by both simple and complex forms of synthesis. It is believed that the brain’s ability to predict and foresee future events is realized thanks to the complex synthetic activity of the brain. The processes of analysis and synthesis in the cerebral cortex are inextricably linked. Therefore, it is customary to talk about the analytical-synthetic activity of the cerebral cortex as a single process that ensures the formation of various forms of human behavior.

The analytical and synthetic activity of the human cerebral cortex is characterized, in comparison with animals, by an immeasurably higher level of development. The higher level of development of the analytical and synthetic activity of the human cerebral cortex is due to the presence of a second signaling system. It is the participation of the word that gives specific features to the process of formation of systems of temporary connections.

3. Analytical and synthetic activity of the cerebral cortex

The mechanisms of higher nervous activity in higher animals and humans are associated with the activity of a number of parts of the brain. The main role in these mechanisms belongs to the cerebral cortex (I.P. Pavlov). It has been experimentally shown that in higher representatives of the animal world, after complete surgical removal of the cortex, higher nervous activity sharply deteriorates. They lose the ability to subtly adapt to the external environment and exist independently in it. In humans, the cerebral cortex plays the role of “manager and distributor” of all life functions (I.P. Pavlov). This is due to the fact that during phylogenetic development a process of corticalization of functions occurs. It is expressed in the increasing subordination of the somatic and vegetative functions of the body to the regulatory influences of the cerebral cortex. In the event of the death of nerve cells in a significant part of the human cerebral cortex, it turns out to be non-viable and quickly dies with a noticeable disruption of the homeostasis of the most important autonomic functions. A feature of the cerebral cortex is its ability to isolate individual elements from the mass of incoming signals, to distinguish them from each other, i.e. she has the ability to analyze. Of all the signals perceived, the animal selects only those that are directly related to one or another function of the body: obtaining food, maintaining the integrity of the body, reproduction, etc. in response to these stimuli, impulses are transmitted to the corresponding effector organs (motor or secretory). The analysis and synthesis of stimuli in the simplest form can also be carried out by the peripheral parts of the analyzers - the receptors. Since receptors are specialized in the perception of certain stimuli, therefore, they produce their qualitative separation, i.e. analysis of certain signals from the external environment. With a complex structure of the receptor apparatus, for example the organ of hearing, its structural elements may differ in sounds of unequal pitch. At the same time, a complex perception of sounds is also produced, which leads to their synthesis into one whole. Analysis and synthesis carried out by the peripheral ends of the analyzers are called elementary analysis and synthesis. But excitation from the receptors also reaches the central cortical ends of the analyzers, where more complex forms of analysis and synthesis occur. Here, excitation, in the process of forming a conditioned reflex, comes into contact with numerous foci of excitation in other areas of the cortex, which contributes to the unification of numerous stimuli into a single complex, and also makes it possible to more subtly distinguish between elementary stimuli. Analysis and synthesis carried out by the cortical ends of the analyzers are called higher analysis and synthesis. The analytical activity of the cortex is based on the process of inhibition, which limits the irradiation of excitation. As a result of the analysis of perceived irritations, their differentiation is possible. In the environment, the biological significance of its individual elements with others is constantly changing. In this regard, the relationship between analysis and synthesis in the cerebral cortex is constantly changing. Both processes are constantly interconnected, and therefore they are considered as a single analytical-synthetic process, a single analytical-synthetic activity of the cerebral cortex.

4. Reality signaling systems

In 6935, Pavlov wrote about the “extraordinary increase in the mechanisms of nervous activity” that occurred in the developing animal world during the process of human development. In an animal, afferent impulses signal phenomena and events that directly affect the body's receptors. Such a direct signaling system of reality is also inherent in humans. However, there is another, specifically our, human signaling system of reality. In humans, “signals of the second degree appeared, developed and were extremely improved, the signals of these primary signals - in the form of words, spoken, audible and visible” (Pavlov). Thus, a person is characterized by a double signaling of reality: 1. A common system of direct signals of reality with animals; 2. A special system of indirect, speech signals. Speech signals underlie a special principle, a special form of reflection of reality. They can not only replace direct signals, but also generalize them, highlight and abstract individual features and qualities of objects and phenomena, establish their connections and mutual dependence, as well as the processes of their formation and change. It is this system of signals that determines the most important features of human higher nervous activity and makes possible “specially human, higher thinking” (Pavlov), leading to limitless orientation in the surrounding world, to the development of science and its practical reflection - technology. A remarkable feature of the second signaling system is the speed of formation of conditioned connections: it is enough for a person to hear something once or read something in a book for new conditioned connections to appear in the cerebral cortex. Sometimes they are so strong that they last for many years without needing reinforcement. The second signaling system, associated in its development with mental activity, has characteristics in each person that depend on individual life experience, and is not inherited. An illustration of this is when children grow up among animals and are deprived of the influence of human society. Such people experience a sharp decline in intelligence and an inability to develop abstract, abstract thinking. Many people ask the question: do the mind, speech, and human psyche develop if a child grows up in isolation from human society? Nature itself answered this question. Such children were physically strong, ran quickly on all fours, saw and heard well, but were devoid of intelligence. "In 1920, in India, Dr. Singh discovered two girls in a wolf den along with a litter of wolf cubs. One of them looked 7-8 years old, the other 2 years old. The girls were sent to an orphanage. At first they walked and ran only on all fours, and only at night, and during the day they slept, huddled in a corner and huddled together like puppies. The youngest girl soon died, and the eldest, they named her Kamala, lived for about 10 years. All these years, Sing kept a detailed diary of observation of Kamala. She walked on all fours for a long time, leaning on her hands and feet. She drank, lapping, and only ate meat from the floor. When people approached her while eating, she bared her teeth like a wolf and growled. in the dark and was afraid of strong light and fire. During the day she slept, squatting in the corner, facing the wall. She tore off her clothes and even threw off her blanket after 2 years, but after 6 years she started to feel bad. walk, but still ran on all fours. Within 4 years she had learned only 6 words, and after 7 years she had learned 45 words. Kamala's vocabulary subsequently expanded to 100 words. By this time, she fell in love with the company of people, stopped being afraid of light, and learned to eat with her hands and drink from a glass. Having reached approximately 17 years of age, Kamala, in terms of mental development, resembled a 4-year-old child" (Kuznetsov O.N., Lebedev V.I. "Psychology and psychopathy of loneliness" 1972). There are cases when children were deliberately isolated from the team Growing up, they were no different from children who grew up among animals. “About 350 years ago, the Indian padishah Akbar argued with his court sages, who argued that every child would speak the language of his parents, even if no one taught him. Akbar doubted the validity of this opinion and conducted an experiment worthy of the cruelty of the eastern feudal lords of the Middle Ages. Small children of various nationalities were seized and placed one at a time in separate rooms. The children were served by dumb servants. During the 7 years of this “experiment,” the children never heard a human voice. When people came to them 7 years later, instead of human speech they heard incoherent screams, howls, meows" (Kuznetsov O.N., Lebedev V.I. "Psychology and psychopathy of loneliness" 1972)

These examples convince us that the process of human mental development depends on learning, starting from early childhood. A child isolated from human society does not develop a second signaling system. The influence of human society on the formation of a child’s mental sphere is very important for proper upbringing. The more adequate stimuli a child receives, the better abstract thinking and consciousness develops. This is better perceived in childhood, when a certain morphological restructuring of the nervous system occurs, which has huge hereditary reserves. Isolation from the social environment of an adult also causes known functional disorders and mental illnesses.

The mobility of his mental processes, their stability, but does not determine either the behavior or actions of a person, or his beliefs, or moral principles. 2. Analysis of the relationship between the properties of the nervous system and the types of human temperament 2.1 The main properties of personality temperament It has been proven that there are no two people on earth with the same finger patterns, that there are no two exactly the same on a tree...

But the connections between them are complexly mediated by living conditions, characteristics of upbringing and development, and other factors. Chapter 2. Empirical study of the influence of the properties of the nervous system on the development of human character 2.1 Purpose, objectives, program and research methods The great Russian physiologist, academician, Nobel Prize laureate I.P. Pavlov (1849-1936), studying the processes of excitation and...

Complexes of these properties, since a scientifically based solution depends entirely on knowledge of individual properties and the relationships between them. I will now turn to the fundamentally important question of the relationship between the properties of the nervous system, on the one hand, and the characteristic forms of behavior or mental properties of the individual, on the other. I have already emphasized that the properties of the nervous system are ...

Nervous system in successful and unsuccessful schoolchildren Research objectives: 1 Conduct a theoretical analysis of the influence of the properties of the nervous system on the success of learning in younger schoolchildren 2 Conduct an empirical study of the relationship between the types of nervous system and academic success in younger schoolchildren. 3 Analyze the research results 4 Draw conclusions and conclusions Hypothesis: we assume ...

Analysis and synthesis of stimuli- the most important functions of the cerebral cortex.

Synthesis of stimuli manifests itself in the binding, generalization, and unification of excitations that arise in different parts of the cerebral cortex due to the interaction established between different neurons and their groups. A manifestation of the synthetic activity of the cerebral cortex is , which underlies the development of any conditioned reflex.

Irritation analysis consists of distinguishing, separating different signals, differentiating different effects on the body.

The analysis of irritations begins already in the receptor apparatus, the different elements of which react to irritations of different nature; it also occurs in the lower parts of the nervous system. However, the processes of analysis reach their highest development in the cerebral cortex.

The nerve pathways and structure of the sensory zones of the cortex are such that impulses from each type of receptor enter certain groups of nerve cells in the cortex. In addition, the number of cells involved in the reaction and the frequency of impulses in each of them vary widely depending on the strength, duration and steepness of the increase in the stimulus. Therefore, conditions are created under which each peripheral stimulation corresponds to its own spatio-temporal pattern of excitation, according to I. P. Pavlov, its own “dynamic structural complex.” In this way, discrimination between stimuli that are similar in their properties is achieved.

A form of analysis specific to the cerebral cortex consists of distinguishing - differentiating - stimuli according to their signal value, which is achieved by developing internal inhibition.

Analysis and synthesis are inextricably linked. When the body is exposed to two separate stimuli, we encounter the most primitive forms of analysis and synthesis. More complex forms of analytical-synthetic activity of the cerebral cortex can be judged on the basis of an analysis of complex stimuli that include a number of components.

For this purpose as several signals are used, following each other in a certain order; in a different order, the same signals are applied without reinforcement. If differentiation is developed, this indicates that the cerebral cortex perceives the sigials not only individually and not only their sum, but also the order of their alternation, the sequence in which they are used.

To study complex forms of analysis and synthesis, A. G. Ivanov-Smolensky developed a strong conditioned reflex for the sequential use of four sounds: A+B+B+G. Then, over the course of 5 months, attempts were made to differentiate the specified sequence of sounds from another: A+B+B+D. It was not possible to obtain complete discrimination between these complex stimuli in dogs. Such a task is beyond her. In humans, such discrimination is easily achieved, on average, on the 7th application of the differentiable combination.

Simple forms of analysis are much better developed in many animals than in humans. Thus, the subtlety of a dog’s sense of smell is well known, as it differentiates odors incomparably better and more accurately than a human. Likewise, the dog has a highly developed ability to differentiate sound stimuli. In a dog, one can observe the discrimination of two sounds that differ by 1/8 tone if one sound is systematically reinforced and the other is not reinforced by unconditioned stimulation. The dog perceives sounds of such heights that are not perceived by the human ear.

Thus, the discrimination of separately applied stimuli, i.e., the lowest form of cortical analysis, can be more developed in animals than in humans. However, man surpasses animals by a significantly higher development of higher forms of analysis and synthesis of stimuli. According to F. Engels’ definition, “the eagle’s eye sees much further than the human eye, but the human eye notices much more in things than the eagle’s eye.”

In the processes of synthetic activity of the cerebral cortex in humans, an important role is played not only by temporary connections between the cells of the cortical representation of conditioned and unconditioned stimuli, but also by those temporary connections that are formed between groups of nerve cells involved in the perception of a set of indifferent stimuli. Thus, with the sounds of any melody, the corresponding cortical cells of the auditory analyzer are excited in a certain sequence by stimuli coming from the periphery, and temporary connections are formed between these cells. Memorizing a melody is nothing more than the formation of temporary connections in the auditory analyzer.

Their occurrence is evidenced by the fact that the sound of just a few initial notes is sufficient to reproduce the entire melody in memory. When viewing any picture or object, afferent impulses from the retina and eye muscles in a certain sequence enter the cortical cells of the visual and proirioreceptive analyzer, which leads to the formation of temporary connections between these cells. As a result, a visual image is captured.

The more complex the stimulus, i.e., the greater the number of components it consists of, the greater the number of temporary connections should be formed between the perceiving cortical cells.

Physiological processes of analysis and synthesis of stimuli - their highest forms - are the basis for the emergence in humans of qualitatively unique processes of logical analysis and synthesis of phenomena and concepts.

Analysis and synthesis of stimuli in the cerebral cortex.

During the course of its life, the body experiences a huge amount of irritants, many of which are important for maintaining vital processes, and many of which are dangerous and the body must avoid their effects. To evaluate stimuli and respond appropriately, the cerebral cortex performs complex analytical-synthetic activities.

Analysis- this is discrimination, this is the decomposition of the stimulus into its component features, such as: the nature of the stimulus, its strength, place of action, duration of action, etc. Analysis consists of differentiating the stimulus and it begins initially in receptors, and then in those specialized for the perception of certain signs of the stimulus structures of the central nervous system. Depending on the complexity of the stimulus, different parts of the central nervous system are involved in the analysis. Higher analysis takes place in the cerebral cortex on the basis of processes of divergence (irradiation) of excitation in its neural networks, which are capable of identifying individual signs of the stimulus. A special role belongs to the left hemisphere, which is capable of processing information step by step and analytically.

Synthesis- this is a generalization, binding, association of many signs of a stimulus, which are manifested by excitation in various structures of the central nervous system. Synthesis in the cortex is carried out using convergent processes (concentration) on neurons that evaluate complex features. And they are explained by the ability of the right hemisphere to act synthetically, to process information simultaneously under the influence of several stimuli. An example of the synthetic activity of the cortex is the process of forming a temporary connection of a conditioned reflex.

Complex forms of synthetic activity of the cerebral cortex can be observed in the example dynamic stereotype.

Dynamic stereotype- this is a form of response recorded in memory if, for example, in an experiment an animal is presented with the same sequence of various conditioned stimuli day after day, some of which are reinforced by unconditioned stimuli, and some are not reinforced. If the life of animals proceeds day after day in the same type of conditions, then a stereotypical reaction is developed: presenting the animal with only one stimulus instead of all the stimuli from the complex triggers responses of different strengths, as if the animal were presented with the entire complex of stimuli. An example of such behavior is the developed daily routine.

The cerebral cortex in this case reacts according to a pattern. It evaluates only one of the stimulus complex. Conditioned reflex activity is carried out more easily; there is no need to analyze each stimulus in the system. This is associated with facilitation in the processes of learning and adaptation.

A person's dynamic stereotype underlies his habits and skills. The longer a stereotype is maintained, the more difficult it is to change or abandon it. Therefore, older people are objectively conservative, it is difficult for them to give up their usual way of life and it is difficult for them to adapt to new conditions.

The interaction of excitation and inhibition processes in the cerebral cortex based on the irradiation and concentration of these processes. As already noted, in the process of forming a conditioned reflex, the generalization stage develops at the beginning. Pavlov explained the reason for the development of this stage by the irradiation of excitation to many nerve cells and their inclusion in a temporary connection. For example, if a conditioned reflex to the sound of a bell is developed, then at the beginning the sound of any bell causes the manifestation of this reflex, but as differential inhibition to non-reinforced bell sounds is formed, irradiation is limited and the conditioned reflex manifests itself only to the reinforced sound of the bell.

Later it was found that irradiation of excitation is possible due to numerous horizontal and vertical divergent connections between neurons of different centers.

As the conditioned reflex strengthens, the stage of specialization begins, as a result of the concentration of excitation. According to Pavlov, this becomes possible because Only the centers of the reinforced conditioned signal are involved in the implementation of the conditioned reflex. Concentration of excitation is possible on the basis of convergent connections between centers.

Many stimuli from the external world and the internal environment of the body are perceived by receptors and become sources of impulses that enter the cerebral cortex. Here they are analyzed, differentiated and synthesized, combined, generalized. The ability of the cortex to separate, isolate and distinguish individual irritations, differentiate them is a manifestation analytical activity of the cerebral cortex.

First, stimulation is analyzed in receptors that specialize in light, sound stimuli, etc. Higher forms of analysis are carried out in the cerebral cortex. The analytical activity of the cerebral cortex is inextricably linked with its synthetic activity, expressed in the unification, generalization of excitation that arises in its various parts under the influence of numerous stimuli. An example of the synthetic activity of the cerebral cortex is the formation of a temporary connection, which underlies the development of a conditioned reflex. Complex synthetic activity is manifested in the formation of reflexes of the second, third and higher orders. The basis of generalization is the process of irradiation of excitation.

Analysis and synthesis are interconnected, and complex analytical-synthetic activity occurs in the cortex.

Dynamic stereotype. The external world acts on the body not through single stimuli, but usually through a system of simultaneous and sequential stimuli. If a system of successive stimuli is often repeated, this leads to the formation of systematicity, or a dynamic stereotype in the activity of the cerebral cortex. Thus, a dynamic stereotype is a sequential chain of conditioned reflex acts, carried out in a strictly defined, time-fixed order and resulting from a complex systemic reaction of the body to a complex system of positive (reinforced) and negative (non-reinforced, or inhibitory) conditioned stimuli.

The development of a stereotype is an example of the complex synthesizing activity of the cerebral cortex. A stereotype is difficult to develop, but if it is formed, then maintaining it does not require much effort in cortical activity, and many actions become automatic. A dynamic stereotype is the basis for the formation of habits in a person, the formation of a certain sequence in labor operations, and the acquisition of skills. Examples of a dynamic stereotype include walking, running, jumping, skiing, playing musical instruments, using a spoon, fork, knife when eating, writing, etc.

Stereotypes persist for many years and form the basis of human behavior, but they are very difficult to reprogram.

Systematicity in the work of the cerebral cortex.

The cerebral cortex receives information from a large number of highly specialized receptors that are capable of detecting the most minor changes in the external environment. Receptors located in the skin respond to changes in the external environment. In muscles and tendons there are receptors that signal to the brain about the degree of muscle tension and joint movement. There are receptors that respond to changes in the chemical and gas composition of the blood, osmotic pressure, temperature, etc. In the receptor, irritations are converted into nerve impulses. Along sensitive nerve pathways, impulses are carried to the corresponding sensitive zones of the cerebral cortex, where a specific sensation is formed - visual, olfactory, etc. The functional system, consisting of a receptor, a sensitive pathway and a zone of the cortex where this type of sensitivity is projected, I. P. Pavlov called an analyzer. Analysis and synthesis of the received information is carried out in a strictly defined area - the zone of the cerebral cortex. The most important areas of the cortex are motor, sensory, visual, auditory and olfactory. The motor zone is located in the anterior central gyrus in front of the central sulcus of the frontal lobe, the zone of musculocutaneous sensitivity is located behind the central sulcus, in the posterior central gyrus of the parietal lobe. The visual zone is concentrated in the occipital zone, the auditory zone is in the superior temporal gyrus of the temporal lobe, and the olfactory and gustatory zones are in the anterior temporal lobe. In our consciousness, the activity of analyzers reflects the external material world. This fact gives us the opportunity to adapt to environmental conditions by changing behavior. The cortex performs two main functions: interaction of the body with the external environment, behavioral response and integration of body functions, i.e. nervous regulation of all organs. The activity of the cerebral cortex of humans and higher animals was defined by I. P. Pavlov as higher nervous activity, which is a conditioned reflex function of the cerebral cortex. Conditioned reflexes are developed during the individual life of humans and animals.

Therefore, conditioned reflexes are strictly individual: some individuals may have them, while others may not. For such reflexes to occur, the action of the conditioned stimulus must coincide in time with the action of the unconditioned stimulus. Repeated coincidence of these two stimuli leads to the formation of a temporary connection between the two centers.

The principle of conditioned reflex activity, according to which the meaning of conditioned signals can quickly change depending on the situation in which they are used (according to E. A. Asratyan).

11. Inhibition of conditioned reflexes. Unconditioned and conditioned inhibition, their differences, mechanisms and types. External braking: permanent and fading brake, extreme braking. Internal inhibition: extinction, differentiation, delayed inhibition, conditioned inhibition.