Physiological aspects of higher nervous activity. Physiology of higher nervous activity. Cortical inhibition and its types
Higher nervous activity is carried out due to two mechanisms: instincts and conditioned reflexes.
instincts- these are the most complex congenital chain unconditioned reflex reactions, which are manifested mainly due to the activity of the subcortical nuclei (pallid nucleus and striatum) and nuclei of the diencephalon (optic tubercles and hypothalamus). Instincts are the same in animals of the same species, are inherited and are associated with the vital functions of the body - nutrition, protection, reproduction.
Conditioned reflexes- These are individual, acquired reflex reactions that are developed on the basis of unconditioned reflexes. They are carried out mainly through the activities of the KGM.
IP Pavlov divided conditioned reflexes into natural and artificial.
natural conditionals reflexes formedto naturalqualities (properties) of unconditioned stimuli. For example, the formation of a conditioned food reflex to the smell, type of food.
Artificial conditioned reflexes formed on a variety of artificial stimuli for given unconditioned reflex (light, sound,smell, changetemperature, etc.). Conditional signalcan become anychange in the external environmentor internal state of the body.
Inhibition of conditioned reflexes. Conditioned reflexes are not only developed, but also disappear under certain conditions. IP Pavlov distinguished two types of inhibition of conditioned reflexes: unconditional and conditioned.
Unconditional braking is congenital, it can manifest itself in any department of the central nervous system. Unconditional inhibition can be external and transcendental. External inhibition occurs under the influence of a new stimulus that acts simultaneously with the conditioned signal. The external stimulus should be stronger - dominant. For example, pain irritation of the skin in a dog can sharply inhibit food conditioned reflexes. The positive value of external inhibition is that the body switches to a new, more important at the moment, type of reflex activity.
Extreme braking occurs with a significant increase in the strength or duration of the conditioned signal. In this case, the conditioned reflex sharply weakens or completely disappears. For example, a salivary conditioned reflex to a bell was developed in a dog. If you gradually increase the strength of the conditioned signal (bell), then at first the amount of saliva secreted increases. With a further increase in the strength of the conditioned signal, the separation of saliva decreases and, finally, is completely inhibited..
By its nature, transcendental inhibition is pessimal. It performs a protective function, preventing the depletion of nerve cells.
Transmarginal inhibition develops more easily with a decrease in lability, efficiency of neurons of the cerebral cortex, for example, after a severe infectious disease, in the elderly, etc.
Conditional (internal) braking characteristic only of CGM cells. This inhibition, like conditioned reflexes, is developed. The main condition for the manifestation of internal inhibition is the non-reinforcement of the conditioned stimulus by the unconditioned one. For example, if a dog has developed a strong salivary conditioned reflex to light, and then the conditioned signal (light) is applied many times in isolation without reinforcement (without giving food), then salivation gradually decreases and finally stops. The conditioned reflex faded - extinctive inhibition. Reinforcement of the conditioned signal with an unconditioned stimulus restores the conditioned reflex. However, even in the absence of reinforcement, the conditioned reflex may reappear after rest, in the presence of positive emotions. This phenomenon has been named release of conditional reflexes. Fragile, recently developed conditioned reflexes fade faster and easier. Due to extinction inhibition, the body is freed from unnecessary conditioned reflexes that have lost their signal value.
Significance of inhibition of conditioned reflexes. Due to the inhibition of conditioned reflexes, an exact and perfect adaptation of the organism to the conditions of existence is achieved, the organism is balanced with the environment, and the analytical and synthetic activity of the brain is carried out.
The meaning of conditioned reflexes. Conditioned reflexes have a signal (adaptive) value for the organism. They warn a person or animal of danger, let them know about the proximity of food, etc. In the struggle for existence, the animal survives in which conditioned reflexes are formed faster and easier.
I. P. Pavlov, characterizing the meaning of conditioned reflexes, emphasized that conditioned reflexes clarify, refine And complicate relationsorganism with the environment. chains the most complex conditioned reflexes lie inthe basis of the formationdisciplines, education processes and learning.
Consistency in the work of the cerebral cortex.
Adaptation of the organism to a complex system of various stimuli is carried out with the help of the conditioned reflex activity of the CGM. One of the manifestations of this activity is the formation of a dynamic stereotype.
dynamic stereotype- a stable sequence of conditioned reflexes developed and fixed in the cerebral cortex of a person or animal, developed as a result of repeated exposure to the following conditioned signals in a certain order.
In order to form a dynamic stereotype, on the organism complex should operate stimuli in a certain order and through certain time intervals (external stereotype) . So, for example, a dog develops a conditional salivary reflex on a complex consisting of three stimuli: a bell, light and mechanical irritation of the skin. If you change the order of action of stimuli or the interval between them, even for 15 s, the cells of the cerebral cortex are disrupted: the conditioned reflex fades or completely disappears, is inhibited.
During the development of a dynamic stereotype in the central nervous system, an appropriate distribution of the processes of excitation and inhibition occurs. As a result, a connected chain of conditioned and unconditioned reflexes arises in a person or animal (internal dynamic stereotype). The stereotype is called dynamic because it can be destroyed and re-formed when the conditions of existence change. Its restructuring sometimes occurs with great difficulty and can cause the development of neurosis (disturbances in the functions of higher nervous activity). With great difficulty, the breaking of a dynamic stereotype and the formation of a new one occurs in older people, in whom the nervous processes are inactive and weakened.
The restructuring of the dynamic stereotype is observed in the life of every person at different age periods due to changes in living conditions: the child's admission to school, the change of school to a special educational institution, the transition to independent work, etc. A large role in facilitating the restructuring of the dynamic stereotype in a person belongs to social way of life, as well as timely assistance from parents, educators, teachers.
In the presence of a dynamic stereotype, conditioned reflexes proceed more easily and automatically. The dynamic stereotype underlies the development of various habits, skills, automatic processes in labor activity. As a result, an experienced worker performs his usual work faster and with less fatigue than a beginner. The dynamic stereotype determines the nature of the behavior of animals and humans in the environment.
Interrelations of processes of excitation and inhibition in CGM.
The most complex relationships between the organism and various conditions of life are achieved due to the most subtle interactions of the main nervous processes - excitation and inhibition - in the central nervous system and, especially, in the neurons of the cerebral cortex.
Excitation alone cannot ensure the normal functioning of the body. Unrestrained excitation (lack of inhibition) will gradually lead to the exhaustion of the nervous system and the death of the body. If only the process of inhibition constantly existed in the nervous system, then the organism would turn out to be non-vital, unable to respond to all signals coming from the external and internal environment.
Nervous processes are subject to certain patterns: irradiation, concentration and induction. Nervous processes have the ability to spread (radiate) and then gather (concentrate) in the area of the central nervous system where they originated.
The processes of excitation and inhibition are interconnected according to the principle of induction (induction). Distinguish between mutual and sequential induction.
Mutual induction. When a focus of excitation or inhibition occurs in the central nervous system along its periphery, a change in the functional properties of nerve cells occurs. Around the site of excitation, the excitability and lability of neurons decreases, and the process of inhibition easily develops in these cells (the focus of excitation induces a zone of inhibition). This phenomenon has been named negative mutual induction. An example of such a state of nervous processes is the relationship between the centers of swallowing and breathing. When the swallowing center is stimulated, the activity of the respiratory center is inhibited and breathing is delayed.
Along the periphery of the site of inhibition, the activity of nerve cells increases, and the process of excitation easily occurs in these neurons (the focus of inhibition induces a zone of excitation). This phenomenon has been named positive mutual induction.
Sequential induction. Excitation that has arisen in neurons, after some time in the same nerve cells, is successively replaced by inhibition and vice versa, inhibition turns into excitation. An example of this type of induction is the change of wakefulness and sleep.
FEATURES OF THE HIGHER NERVOUS ACTIVITY OF THE HUMAN.
FIRST AND SECOND SIGNAL SYSTEMS.
Distinguish between the first and second signal systems. The first signaling system is present in humans and animals. The activity of this system is manifested in conditioned reflexes that are formed to any stimuli of the external environment (light, sound, mechanical irritation, etc.), with the exception of the word. In a person living in certain social conditions, the first signaling system has a social connotation.
Conditioned reflexes of the first signaling system are formed as a result of the activity of the cells of the cerebral cortex, except for the frontal region and the region of the brain section of the speech-motor analyzer. The first signaling system in animals and humans provides subject-specific thinking.
The second signaling system arose and developed in as a result of labor activities man and the appearance of speech. Labor and speech contributed to the development of hands, brain and sense organs.
The activity of the second signal system is manifested in conditioned speech reflexes. We may not see some object at the moment, but its verbal designation is enough for us to clearly imagine it. The second signaling system provides abstract thinking in the form of concepts, judgments, conclusions.
Speech reflexes of the second signaling system are formed due to the activity of neurons in the frontal areas andareas of motor speech analyzer. Peripheral department this analyzer is represented by receptors,which are located in word-pronouncing bodies (receptors in the larynx, soft palate, tongue, etc.). From receptors impulses arrive on relevant afferent pathways in the brain section of the speech-motor analyzer, which is a complex structure that includes several areas of the cerebral cortex. The function of the motor speech analyzer is especially closely related to activities of motor, visual and sound analyzers. Speech reflexes, like ordinary conditioned reflexes, obey the same laws. However, the word differs from the stimuli of the first signaling system in that it is multi-comprehensive. A kind word said in time contributes to a good mood, increases ability to work, but a word can hard to hurt a person. Especially this refers to relationships between patients people and medical workers. carelessly spoken word in presence sick on about his illness can significantly worsen his condition.
Animals and humans are born only with unconditioned reflexes. In the process of growth and development, the formation of conditioned reflex connections of the first signal system, the only one in animals, takes place. In a person, on the basis of the first signal system, connections of the second signal system are gradually formed when the child begins to speak and learn about the surrounding reality.
The second signaling system is the highest regulator of various forms of human behavior in the natural and social environment surrounding him.
However, the second signal system correctly reflects the external objective world only if its coordinated interaction with the first signal system is constantly preserved.
TYPES OF HIGHER NERVOUS ACTIVITY.
The type of higher nervous activity should be understood as a set of properties of nervous processes due to the hereditary characteristics of a given organism and acquired in the process of individual life.
I. P. Pavlov based the division of the nervous system into types on three properties of nervous processes: strength, balance and mobility (excitation and inhibition).
Under the power of nervous processes understand the ability of the cells of the cerebral cortex to maintain adequate responses to strong and superstrong stimuli.
Under poise it should be understood that the processes of excitation and inhibition are equally pronounced in strength. Mobility of nervous processes characterizes the speed of transition of the process of excitation into inhibition and vice versa.
Based on the study of the characteristics of nervous processes, IP Pavlov identified the following main types of the nervous system: two extreme and one central type. The extreme types are strong unbalanced and weak inhibitory.
Strong unbalanced type. It is characterized by strong unbalanced and mobile nervous processes. In such animals, the process of excitation prevails over inhibition, their behavior is aggressive (unrestrained type).
Weak braking type. It is characterized by weak unbalanced nervous processes. In these animals, the process of inhibition predominates, they are cowardly, getting into an unfamiliar environment; tuck their tail, hide in a corner.
Central type strong and balanced nervous processes are characteristic, but depending on their mobility, it is divided into two groups: a strong balanced mobile and a strong balanced inert type.
Strong balanced mobile type. The nervous processes in such animals are strong, balanced and mobile. Excitation is easily replaced by inhibition and vice versa. These are affectionate, inquisitive, interested in everything animals (living type).
Strong balanced inert type. This type of animal is distinguished by strong, balanced, but inactive nervous processes (calm type). The processes of excitation and especially inhibition change slowly. These are inert, sedentary animals. Between these main types of the nervous system there are transitional, intermediate types.
The basic properties of nervous processes are inherited. The totality of all genes inherent in a given individual is called genotype. In the process of individual life under the influence environment genotype undergoes certain changes, as a result of which phenotype- the totality of all the properties and characteristics of an individual at a certain stage of development. Consequently, the behavior of animals and humans in the environment is determined not only by the inherited properties of the nervous system, but also by the influences of the external environment (upbringing, training, etc.). When determining the types of higher nervous activity in a person, it is necessary to take into account the relationship between the first and second signal systems. Based on these provisions, I. P. Pavlov singled out four main types, using the terminology of Hippocrates for their designation: melancholic, choleric, sanguine, phlegmatic.
Choleric- strong, unbalanced type. The processes of inhibition and excitation in the cerebral cortex in such people are characterized by strength, mobility and imbalance, excitation predominates. These are very energetic people, but excitable and quick-tempered.
melancholic- weak type. Nervous processes are unbalanced, inactive, the process of inhibition predominates. The melancholic sees in everything and expects only the bad, the dangerous.
sanguine- strong, balanced and mobile type. Nervous processes in the cerebral cortex are characterized by great strength, balance and mobility. Such people are cheerful and efficient.
Phlegmatic person- strong and balanced inert type. Nervous processes are strong, balanced, but inactive. Such people are even, calm, persistent and hard workers.
Taking into account the peculiarities of the interaction of the first and second signal systems, IP Pavlov additionally identified three true human types.
Artistic type. In people of this group, according to the degree of development, the first signal system prevails over the second; in the process of thinking, they widely use sensory images of the surrounding reality. Very often they are artists, writers, musicians.
Thinking type. In persons belonging to this group, the second signaling system significantly predominates over the first, they are prone to abstract, abstract thinking and are often mathematicians and philosophers by profession.
Medium type. It is characterized by the same value of the first and second signal systems in the higher nervous activity of a person. Most people belong to this group.
CONSCIOUSNESS.
Consciousness- this is the subjective world of a person from the simplest elementary sensations to abstract thinking.The essence of consciousness is the reflection of the objectively existing material world.
The property of reflection is inherent in all matter (organic and inorganic). Consciousness arises only at the highest stages of its development in man. Consciousness is characterized by an active reflection of the surrounding reality. The spinal cord and other parts of the central nervous system also have a reflective function, but it does not yet have the quality of mental reflection. Only the cerebral cortex performs the highest reflective function - mental activity. The content of consciousness is the world around us. For the emergence of consciousness, it is necessary to influence the stimuli of the external world on the receptors of the body.
Consciousness helps a person to know the properties, qualities of objects, phenomena, to understand their internal patterns, to separate the essential from the inessential.
For the first time in 1878, in his work "Elements of Thought", I. M. Sechenov emphasized that human consciousness is a function of the brain. IP Pavlov revealed the physiological mechanisms by which the reflective activity of the brain is carried out. These include: 1) chains of the most complex unconditioned reflexes (instincts, affects, drives), which are the basis of mental activity; 2) chains of conditioned reflexes (with the exception of conditioned speech reflexes), due to which the organism is widely adapted to the environment, sensations, perceptions, and ideas arise. They constitute the only signaling system in animals and the first signaling system in man, which determines concrete thinking; 3) chains of speech conditioned reflexes that underlie the second signal system, which is available only in humans and is the basis of abstract thinking. In the emergence of consciousness, a large role belongs to the reticular formation, which regulates the activity of the cells of the cerebral cortex.
MEMORY, ITS SIGNIFICANCE AND PHYSIOLOGICAL MECHANISMS.
Memory- the ability of living beings to perceive, select, store and use information to form behavioral responses. Memory is an integral part of mental activity. It helps animal and human to use your past experience and individual) and adaptto the conditions of existence. One from memory mechanisms are conditioned reflexes, mainly trace.
According to modern ideas, there are short term and long term memory. Short-term imprinting in the cerebral cortex of traces of irritations is carried out due to the circulation of nerveimpulses along closed neural circuits. It maylast from a few seconds to 10-20 minutes. Long-term retention of temporary bonds (long-term memory) is based on molecular and plastic changes that occur in synapses and possibly in themselves nerve cells in the brain. Due to long-term memory can be long, sometimes all life, traces of former irritations remain. A certain role in the formation of memory belongs to emotions. With emotional arousal, the circulation of nerve impulses along the chains of neurons increases.
The neurons of the CGM, the reticular formation of the brain stem, the hypothalamic region, the limbic system, especially the hippocampus, are involved in the formation of memory.
PHYSIOLOGY OF SLEEP.
Sleep is a physiological need of the body. It takes up about 1/3 of a person's life. During sleep, a number of changes are observed in the physiological systems of a person: there is no consciousness and reactions to many environmental stimuli, motor reflex reactions are sharply reduced, and the conditioned reflex activity of the body is completely inhibited. Significant changes in the activity of vegetative functions were found: the heart rate and blood pressure decrease; breathing becomes more rare and superficial; the intensity of metabolism decreases and the body temperature decreases slightly; the activity of the digestive system and kidneys decreases. During deep sleep, there is a decrease in muscle tone. In a sleeping person, most of the muscles completely relax.
Changes in the bioelectrical activity of the brain during sleep are characteristic. Analysis of the electroencephalogram indicates that sleep is a heterogeneous state. It is necessary to distinguish between sleep A, slow or orthodox sleep (slow high-amplitude delta waves predominate on the electroencephalogram) and sleep B, fast or paradoxical sleep (frequent, low-amplitude waves resembling beta rhythm are recorded on the electroencephalogram). If a person is awakened at this time, then he usually reports that he had a dream.
In humans, the frequency of sleep and wakefulness is timed to the daily change of day and night. An adult sleeps once a day, usually at night, such a dream is called single-phase. In children, especially young children, sleep is polyphasic.
The need for sleep is related to age. Newborns sleep up to 20-23 hours a day; children 2-4 years old - 16 hours; 4-8 years - 12 hours; 8-12 years old - 10 hours; 12-16 years old - 9 hours; adults sleep 7-8 hours.
Sleep mechanism. There are several theories explaining the physiological essence of sleep. All theories of sleep can be divided into two groups: humoral and nervous.
Among the humoral theories, the theory of "sleep poisons" ("self-poisoning") is most widely used. According to this theory, sleep is the result of self-poisoning of the brain by metabolic products that accumulate during wakefulness (lactic acid, carbon dioxide, ammonia, and others).
In recent years, interest in humoral (chemical) theories of sleep has increased. This is due to the fact that a special substance (low molecular weight polypeptide) was isolated and synthesized, the appearance of which contributes to the onset of sleep, the hypnogenic factor. Serotonin is also a natural hypnogenic factor.
I. P. Pavlov created vertical theory of sleep. The development of natural physiological sleep is associated with the activity of neurons in the cerebral cortex. In the working neurons of the cerebral cortex, fatigue gradually develops, which creates conditions for the onset of the process of inhibition, which contributes to the restoration and rest of nerve cells. Initially, inhibition occurs in a more or less limited group of cells in the cerebral cortex. If inhibition does not meet with an obstacle in the form of a strong focus of excitation, it radiates, embracing the entire cortex, and spreads to the subcortical centers.
IP Pavlov distinguished between active and passive sleep. active sleep arises under the influence of long-acting monotonous stimuli (lullaby, the sound of the wheels of a moving train, etc.). passive sleep develops when the flow of nerve impulses to the cerebral cortex is limited.
In clinical practice, cases of the onset of prolonged sleep in patients with impaired analyzer function are known. Domestic therapist S.P. Botkin observed a patient who, due to a serious illness, had completely lost sight, hearing and skin sensitivity, with the exception of a small area on her right hand. She was in a state of sleep all the time. When they touched the area of the skin that retained sensitivity, the patient woke up, it was possible to establish contact with her.
There are ideas, based on clinical data and the results of experimental studies, about the presence in the brain (in the visual tubercles and hypothalamus) of the “center” of sleep.
Currently, the theory of the "center" of sleep is explained based on the significance of the reticular formation and its relationship with the cerebral cortex. Through the reticular formation, afferent impulses enter the cortex, they activate, tone it, and maintain it in a waking state. If you destroy the reticular formation or turn it off with pharmacological substances (chlorpromazine), sleep sets in.
Lecture 34. Physiology of higher nervous activity.
34. 1. The concept of higher nervous activity. Classification of conditioned reflexes and their characteristics. Methods of studying vnd.
Physiology of higher nervous activity. A necessary condition for the existence of a living organism is a constant exchange of substances with the surrounding nature. In interaction with the external environment, the organism acts as a single whole. The unification of the organism into a single whole and its interaction with the environment is carried out nervous system. The activity of the nervous system, aimed at the implementation of the interaction of the organism with the environment and its own kind is called higher nervous activity.
The external expression of the higher nervous activity and mental functions of a person is behavior.
Higher nervous activity is a reflex activity. This means that it is causally determined by influences from the external and internal environment of the organism. These effects are perceived by the corresponding receptors of the body, are transformed into nervous excitation and enter the nerve centers, where the analysis and synthesis of the information received is carried out and on this basis the body's response is formed. It is caused by nerve impulses coming from the nerve centers along the efferent pathways to the executive organs. This reaction is called a reflex.
Reflexes are divided into two main groups: unconditional and conditional.
Unconditioned reflexes are congenital reflexes that are carried out according to permanent reflex arcs present from birth. An example of an unconditioned reflex is the activity of a saliva gland during the act of eating, blinking when a mote enters the eye, defensive movements during painful stimuli, and many other reactions of this type. Unconditioned reflexes in humans and higher animals are carried out through the subcortical sections of the central nervous system (spinal, medulla oblongata, midbrain, diencephalon and basal ganglia). At the same time, the center of any unconditioned reflex (BR) is connected by nerve connections with certain areas of the cortex, i.e. there is a so-called. cortical representation BR. Different BRs (food, defensive, sex, etc.) can have different complexity. BR, in particular, includes such complex innate forms of animal behavior as instincts.
BR undoubtedly play an important role in the adaptation of the organism to the environment. Thus, the presence of congenital reflex sucking movements in mammals provides them with the opportunity to feed on mother's milk in the early stages of ontogenesis. The presence of innate defense reactions (blinking, coughing, sneezing, etc.) protects the body from foreign bodies entering the respiratory tract. Even more obvious is the exceptional importance for the life of animals of various kinds of innate instinctive reactions (building nests, burrows, shelters, caring for offspring, etc.).
Keep in mind that BRs are not completely permanent, as some people think. Within certain limits, the nature of the innate, unconditioned reflex may vary depending on the functional state of the reflex apparatus. For example, in a spinal frog, irritation of the skin of the foot can cause an unconditionally reflex reaction of a different nature, depending on the initial state of the irritated paw: when the paw is extended, this irritation causes its flexion, and when it is bent, it is extended.
Unconditioned reflexes ensure the adaptation of the organism only under relatively constant conditions. Their variability is extremely limited. Therefore, to adapt to continuously and dramatically changing conditions, the existence of unconditioned reflexes alone is not enough. This is evidenced by the cases often encountered when instinctive behavior, which is so striking in its "reasonableness" under ordinary conditions, not only does not provide adaptation in a drastically changed situation, but even becomes completely meaningless.
For a more complete and subtle adaptation of the body to the constantly changing conditions of life, animals in the process of evolution developed more advanced forms of interaction with the environment in the form of the so-called. conditioned reflexes.
Conditioned reflexes are not innate, they are formed in the process of individual life of animals and humans on the basis of unconditioned ones. The conditioned reflex is formed due to the emergence of a new neural connection (temporary connection according to Pavlov) between the center of the unconditioned reflex and the center that perceives the accompanying conditioned irritation. In humans and higher animals, these temporary connections are formed in the cerebral cortex, and in animals that do not have a cortex, in the corresponding higher sections of the central nervous system.
Unconditioned reflexes can be combined with a wide variety of changes in the external or internal environment of the body, and therefore, on the basis of one unconditioned reflex, many conditioned reflexes can be formed. This significantly expands the possibilities of adapting the animal organism to the conditions of life, since the adaptive reaction can be caused not only by those factors that directly cause changes in the functions of the organism, and sometimes threaten its very life, but also by those that only signal the first. Due to this, an adaptive reaction occurs in advance.
Conditioned reflexes are characterized by extreme variability depending on the situation and on the state of the nervous system.
The higher nervous activity of man and animals is an inseparable unity of congenital and individually acquired forms of adaptation, it is the result of the joint activity of the cerebral cortex and subcortical formations. However, the leading role in this activity belongs to the cortex.
Methods for studying GNI. The main method for studying GNI is the method of conditioned reflexes. Along with it, to study the functions of the higher parts of the central nervous system, it is also used whole line other methods - clinical, methods of switching off different parts of the brain, irritation, morphological, biochemical and histochemical methods, methods of mathematical and cybernetic modeling, EEG, many methods of psychological testing, methods for studying various forms of imposed or spontaneous behavior in standard or changing conditions, etc. .
Conditions for the formation of a temporary connection. A conditioned reflex in animals or humans can be developed on the basis of any unconditioned reflex, subject to the following basic rules (conditions). Actually, this type of reflex was called "conditional", since it requires certain conditions for its formation.
1. It is necessary to coincide in time (combination) of two stimuli - unconditional and some indifferent (conditional).
2. It is necessary that the action of the conditioned stimulus somewhat precede the action of the unconditioned one.
3. The conditioned stimulus must be physiologically weaker than the unconditioned stimulus, and perhaps more indifferent, i.e. not causing a significant reaction.
Rice. 67. Methods for developing conditioned reflexes
4. A normal, active state of the higher departments of the central nervous system is necessary.
5. During the formation of a conditioned reflex (UR), the cerebral cortex should be free from other activities. In other words, during the development of SD, the animal must be protected from the action of extraneous stimuli.
6. A more or less long (depending on the evolutionary advancement of the animal) repetition of such combinations of a conditioned signal and an unconditioned stimulus is necessary.
If these rules are not observed, SDs are not formed at all, or they are formed with difficulty and quickly fade away.
Various methods have been developed to develop UR in various animals and humans (registration of salivation is the classic Pavlovian method, registration of motor-defensive reactions, food-procuring reflexes, labyrinth methods, etc.).
Types of conditioned reflexes. Classification of conditioned reflexes can be carried out according to several criteria.
1. In relation to the conditioned stimulus to the reaction signaled by it, natural and artificial conditioned reflexes are distinguished.
natural called conditioned reflexes, which are formed on stimuli that are natural, necessarily accompanying signs, properties of the unconditioned stimulus on the basis of which they are produced (for example, the smell of meat when feeding it). Natural conditioned reflexes, in comparison with artificial ones, are more easily formed and more durable.
artificial called conditioned reflexes, generated in response to stimuli that are usually not directly related to the unconditioned stimulus that reinforces them (for example, a light stimulus reinforced by food).
2. Depending on the nature of the receptor structures, which are affected by conditioned stimuli, there are exteroceptive, interoceptive and proprioceptive conditioned reflexes.
exteroceptive conditioned reflexes, formed to stimuli perceived by external external receptors of the body, make up the bulk of conditioned reflex reactions that provide adaptive (adaptive) behavior of animals and humans in a changing environment.
Interoceptive conditioned reflexes, produced by physical and chemical stimulation of interoreceptors, provide physiological processes of homeostatic regulation of the function of internal organs.
proprioceptive conditioned reflexes formed on stimulation of their own receptors in the striated muscles of the trunk and limbs, form the basis of all motor skills of animals and humans.
3. Depending on the structure of the applied conditioned stimulus distinguish between simple and complex (complex) conditioned reflexes.
When simple conditioned reflex a simple stimulus (light, sound, etc.) is used as a conditioned stimulus.
In the real conditions of the functioning of the organism, as a rule, not separate, single stimuli, but their temporal and spatial complexes act as conditioned signals. In this case, either the entire environment surrounding the animal, or parts of it in the form complex signals. One of the varieties of such a complex conditioned reflex is stereotyped conditioned reflex, formed on a certain temporal or spatial "pattern", a set of stimuli.
4. There are also conditioned reflexes developed to simultaneous and sequential complexes of stimuli, to a sequential chain of conditioned stimuli separated by a certain time interval.
trace conditioned reflexes are formed in the case when the unconditioned reinforcing stimulus is presented only after the end of the action of the conditioned stimulus.
5. Finally, there are conditioned reflexes of the first, second, third, etc. order. If a conditioned stimulus (light) is reinforced by an unconditioned stimulus (food), conditioned reflex of the first order. Second-order conditioned reflex It is formed if a conditioned stimulus (for example, light) is reinforced not by an unconditioned, but by a conditioned stimulus, to which a conditioned reflex was previously formed. Conditioned reflexes of the second and more complex order are more difficult to form and are less durable.
Conditioned reflexes of the second and higher order include conditioned reflexes developed to a verbal signal (the word here represents a signal to which a conditioned reflex was previously formed when reinforced with an unconditioned stimulus).
Instrumental reflexes are an independent form of conditioned reflexes. They are formed on the basis of active and purposeful activity. This includes training, operanteducation(learning by trial and error).
Physiological significance of conditioned reflexes. Conditioned reflexes:
Produced and accumulated in individual life each subject
They are adaptive in nature, making behavior the most plastic, adapted to specific environmental conditions;
They have a signal character, i.e. precede, prevent the subsequent occurrence of unconditionally reflex reactions, preparing the body for them.
Inhibition processes in the cerebral cortex. The formation of a conditioned reflex is based on the processes of interaction of excitations in the cerebral cortex. However, for the successful completion of the process of closing a temporary connection, it is necessary not only to activate the neurons involved in this process, but also to suppress the activity of those cortical and subcortical formations that impede this process. Such inhibition is carried out due to the participation of the inhibition process.
In its outward manifestation, inhibition is the opposite of excitation. With it, a weakening or cessation of the activity of neurons is observed, or a possible excitation is prevented.
Cortical inhibition is usually subdivided into unconditional and conditional, acquired. Unconditional forms of inhibition include external, arising in the center as a result of its interaction with other active centers of the cortex or subcortex, and beyond, which occurs in cortical cells with excessively strong irritations. These types (forms) of inhibition are congenital and appear already in newborns.
External unconditional braking manifested in the weakening or termination of conditioned reflex reactions under the action of any extraneous stimuli. If a dog calls UR to a bell, and then acts on a strong extraneous irritant (pain, smell), then the salivation that has begun will stop. Unconditioned reflexes are also inhibited (the Turk reflex in a frog when pinching the second paw).
Cases of external inhibition of conditioned reflex activity are encountered at every step and in the conditions of the natural life of animals and humans. This includes a constantly observed decrease in activity and indecision in actions in a new, unusual environment, a decrease in the effect or even the complete impossibility of activity in the presence of extraneous stimuli (noise, pain, hunger, etc.).
External inhibition of conditioned reflex activity is associated with the appearance of a reaction to an extraneous stimulus. It comes the easier, and is the stronger, the stronger the extraneous stimulus and the less strong the conditioned reflex. External inhibition of the conditioned reflex occurs immediately upon the first application of an extraneous stimulus. Consequently, the ability of cortical cells to fall into a state of external inhibition is an innate property of the nervous system. This is one of the manifestations of the so-called. negative induction.
Extreme braking develops in cortical cells under the action of a conditioned stimulus, when its intensity begins to exceed a certain limit. Transmarginal inhibition also develops under the simultaneous action of several individually weak stimuli, when the total effect of the stimuli begins to exceed the working capacity limit of the cortical cells. An increase in the frequency of the conditioned stimulus also leads to the development of inhibition. The development of translimiting inhibition depends not only on the strength and nature of the action of the conditioned stimulus, but also on the state of the cortical cells, on their performance. With a low level of efficiency of cortical cells, for example, in animals with a weak nervous system, in old and sick animals, a rapid development of translimiting inhibition is observed even with relatively weak stimuli. The same is observed in animals brought to considerable nervous exhaustion by prolonged action of stimuli of moderate strength.
Transmarginal inhibition has a protective value for the cells of the cortex. This is a parabiotic type of phenomenon. During its development, similar phases are noted: equalizing, when both strong and moderate in strength conditioned stimuli cause a response of the same intensity; paradoxical, when weak stimuli cause a stronger effect than strong stimuli; ultraparadoxical phase, when inhibitory conditioned stimuli cause an effect, but positive ones do not; and, finally, the inhibitory phase, when no stimuli cause a conditioned response.
Types of conditional inhibition. Conditioned (internal) inhibition develops in cortical cells under certain conditions under the influence of the same stimuli that previously evoked conditioned reflex reactions. In this case, braking does not occur immediately, but after a more or less long-term development. Internal inhibition, like a conditioned reflex, occurs after a series of combinations of a conditioned stimulus with the action of a certain inhibitory factor. Such a factor is the cancellation of unconditional reinforcement, a change in its nature, etc. Depending on the condition of occurrence, the following types of conditioned inhibition are distinguished: extinction, retardation, differentiation, and signal ("conditional brake").
Fading braking develops when the conditioned stimulus is not reinforced. It is not associated with fatigue of the cortical cells, since an equally long repetition of the conditioned reflex with reinforcement does not lead to a weakening of the conditioned reaction. Fading inhibition develops the easier and faster, the less strong the conditioned reflex and the weaker the unconditioned reflex, on the basis of which it was developed. Fading inhibition develops the faster, the shorter the interval between conditioned stimuli repeated without reinforcement. Extraneous stimuli cause a temporary weakening and even complete cessation of extinctive inhibition, i.e. temporary restoration of the extinguished reflex (disinhibition). The developed extinction inhibition also causes suppression of other conditioned reflexes, both weak and those whose centers are located close to the center of the primary extinction reflexes (this phenomenon is called secondary extinction).
The quenched conditioned reflex after some time is restored by itself, i.e. fading inhibition disappears. This proves that the extinction is associated with temporal inhibition, not with a break in the temporal connection. The extinguished conditioned reflex is restored the faster, the stronger it is and the weaker it was inhibited. Repeated extinction of the conditioned reflex occurs faster.
The development of extinction inhibition is of great biological importance, since it helps animals and humans to free themselves from previously acquired conditioned reflexes that have become useless in the new, changed conditions.
delayed braking develops in cortical cells when reinforcement is delayed in time from the onset of action of the conditioned stimulus. Externally, this inhibition is expressed in the absence of a conditioned reflex reaction at the beginning of the action of the conditioned stimulus and its appearance after a certain delay (delay), and the time of this delay corresponds to the duration of the isolated action of the conditioned stimulus. Delayed inhibition develops the faster, the smaller the lag of the reinforcement from the beginning of the action of the conditioned signal. With a continuous action of a conditioned stimulus, it develops faster than with an intermittent one.
Extraneous stimuli cause temporary disinhibition of delayed inhibition. Thanks to its development, the conditioned reflex becomes more accurate, timing to the right moment with a distant conditioned signal. This is its great biological significance.
Differential braking develops in cortical cells under the intermittent action of a constantly reinforced conditioned stimulus and unreinforced stimuli similar to it.
The newly formed SD usually has a generalized, generalized character, i.e. it is caused not only by a specific conditioned stimulus (for example, a tone of 50 Hz), but by numerous stimuli similar to it, addressed to the same analyzer (tones of 10-100 Hz). However, if in the future only sounds with a frequency of 50 Hz are reinforced, while others are left without reinforcement, then after a while the reaction to similar stimuli will disappear. In other words, out of the mass of similar stimuli, the nervous system will respond only to the reinforced one, i.e. biologically significant, and the reaction to other stimuli is inhibited. This inhibition ensures the specialization of the conditioned reflex, vital distinction, differentiation of stimuli according to their signal value.
Differentiation is developed the easier, the greater the difference between the conditioned stimuli. With the help of this inhibition, it is possible to study the ability of animals to distinguish sounds, figures, colors, etc. So, according to Gubergrits, a dog can distinguish a circle from an ellipse with a ratio of semiaxes of 8:9.
Extraneous stimuli cause disinhibition of differential inhibition. Starvation, pregnancy, neurotic conditions, fatigue, etc. can also lead to disinhibition and perversion of previously developed differentiations.
Signal braking ("conditional brake"). Inhibition of the "conditioned brake" type develops in the cortex when the conditioned stimulus is not reinforced in combination with some additional stimulus, and the conditioned stimulus is reinforced only when it is applied in isolation. Under these conditions, the conditioned stimulus, in combination with an extraneous stimulus, becomes, as a result of the development of differentiation, inhibitory, and the extraneous stimulus itself acquires the property of an inhibitory signal (conditioned brake), it becomes capable of inhibiting any other conditioned reflex if it is attached to the conditioned signal.
The conditioned brake easily develops when the conditioned and surplus stimulus act simultaneously. In a dog, it is not produced if this interval is more than 10 seconds. Extraneous stimuli cause disinhibition of signal inhibition. Its biological significance lies in the fact that it clarifies the conditioned reflex.
Internal braking mechanism. Internal conditioned inhibition arises and is localized in the cortical elements of the temporal connection, i.e. where this connection is formed. There are many hypotheses that explain the physiological mechanisms of the development and strengthening of conditioned inhibition. However, with all this, the intimate mechanism of inhibition is associated with the processes of changes in ion transport, which lead to an increase in the difference between the membrane potential and the critical level of depolarization.
Movement and interaction of excitation and inhibition processes in the cerebral cortex. Higher nervous activity is determined by the complex relationship between the processes of excitation and inhibition that occur in cortical cells under the influence of various influences from the external and internal environment. This interaction is not limited only to the framework of the corresponding reflex arcs, but is played out far beyond them. The fact is that with any impact on the body, not only the corresponding cortical foci of excitation and inhibition arise, but also various changes in the most various fields bark. These changes are caused, firstly, by the fact that nervous processes can spread (radiate) from their place of origin to the surrounding nerve cells, and the irradiation is replaced after a while by the reverse movement of the nervous processes and their concentration at the starting point (concentration). Secondly, changes are caused by the fact that nerve processes, when concentrated in a certain place of the cortex, can cause (induce) the emergence of an opposite nervous process in the surrounding adjacent points of the cortex (spatial induction), and after the cessation of the nervous process, induce the opposite nervous process in the same paragraph (temporary, sequential induction).
The irradiation of nervous processes depends on their strength. At low or high intensity, a tendency to irradiation is clearly expressed. With medium strength - to concentration. According to Kogan, the excitation process radiates through the cortex at a speed of 2-5 m/sec, while the inhibitory process is much slower (several millimeters per second).
Strengthening or occurrence of the process of excitation under the influence of the center of inhibition is called positive induction. The occurrence or intensification of the inhibitory process around (or after) excitation is called negative induction. Positive induction is manifested, for example, in an increase in the conditioned reflex reaction after the application of a differentiating stimulus or excitation before sleep. One of the most common manifestations of negative induction is the inhibition of UR under the action of extraneous stimuli. With weak or excessively strong stimuli, induction is absent.
It can be assumed that processes analogous to electrotonic changes underlie the phenomena of induction.
Irradiation, concentration and induction of nervous processes are closely related to each other, mutually limiting, balancing and strengthening each other, and thus determining the exact adaptation of the body's activity to environmental conditions.
Classification of conditioned reflexes is built on the same grounds as the unconditional ones. According to the receptor feature, exteroceptive, interoceptive and proprioceptive UR are distinguished. According to the effector feature, two main groups are distinguished: vegetative and somatomotor. Vegetative - these are food, cardiovascular, respiratory, excretory, sexual, metabolic. Somatomotor are defensive, flexion, shaking, etc. To develop each of them, independent and numerous methods have been developed.
Analytical and synthetic activity of the cerebral cortex. The ability to form SD, temporary connections shows that the cerebral cortex, firstly, can isolate its individual elements from the environment, distinguish them from each other, i.e. has the ability to analyze. Secondly, it has the ability to unite, merge elements into a single whole, i.e. ability to synthesize. In the process of conditioned reflex activity, a constant analysis and synthesis of stimuli of the external and internal environment of the body is carried out.
The ability to analyze and synthesize stimuli is inherent in the simplest form already in the peripheral parts of the analyzers - receptors. Due to their specialization, a qualitative separation is possible, i.e. environmental analysis. Along with this, the joint action of various stimuli, their complex perception creates the conditions for their fusion, synthesis into a single whole. Analysis and synthesis, due to the properties and activity of receptors, are called elementary.
The analysis and synthesis carried out by the cortex are called higher analysis and synthesis. The main difference is that the cortex analyzes not so much the quality and quantity of information as its signal value.
One of the clearest manifestations of complex analytic synthetic activity the cerebral cortex is the formation of the so-called. dynamic stereotype. A dynamic stereotype is a fixed system of conditioned and unconditioned reflexes combined into a single functional complex, which is formed under the influence of stereotypically repeated changes or influences of the external or internal environment of the organism, and in which each previous act is a signal of the next.
The formation of a dynamic stereotype has great importance in conditioned reflex activity. It facilitates the activity of cortical cells during the performance of a stereotyped repetitive system of reflexes, makes it more economical, and at the same time automatic and clear. In the natural life of animals and humans, the stereotypy of reflexes is developed very often. It can be said that the basis of the individual form of behavior characteristic of each animal and man is a dynamic stereotype. Dynamic stereotypy underlies the development of various habits in a person, automatic actions in the labor process, a certain system of behavior in connection with the established daily routine, etc.
A dynamic stereotype (DS) is developed with difficulty, but, having formed, it acquires a certain inertia and, given the invariability of external conditions, becomes ever stronger. However, when the external stereotype of stimuli changes, the previously fixed system of reflexes also begins to change: the old one is destroyed and a new one is formed. Thanks to this ability, the stereotype was called dynamic. However, the alteration of a strong DS presents a great difficulty for the nervous system. It is known how difficult it is to change a habit. Alteration of a very strong stereotype can even cause a breakdown in higher nervous activity (neurosis).
Complex analytical and synthetic processes underlie such a form of integral brain activity as conditioned reflex switching when the same conditioned stimulus changes its signal value with a change in the situation. In other words, the animal reacts differently to the same stimulus: for example, in the morning the call is a signal to write, and in the evening it is pain. Conditioned reflex switching manifests itself everywhere in the natural life of a person in different reactions and different forms of behavior for the same reason in different settings (at home, at work, etc.) and has a great adaptive value.
Specific features of human GNI. The concept of signaling systems. General patterns of conditioned reflex activity, established in animals, are characteristic of human GNI. However, human GNI in comparison with animals is characterized by the highest degree of development of analytical and synthetic processes. This is due not only further development and improvement in the course of evolution of those mechanisms of cortical activity that are inherent in all animals, but also the emergence of new mechanisms of this activity.
Such a specific feature of human GNI is the presence in him, unlike animals, of two systems of signal stimuli: one system, first, consists, as in animals, of direct impacts of external and internal environment organism; the other consists three words indicating the impact of these factors. I.P. Pavlov called her second signal system, since the word is " signal signal"Thanks to the second human signal system, analysis and synthesis of the surrounding world, its adequate reflection in the cortex, can be carried out not only by operating with direct sensations and impressions, but also by operating only with words. Opportunities are created for distraction from reality, for abstract thinking.
This greatly expands the possibilities of human adaptation to the environment. He can get a more or less correct idea of the phenomena and objects of the external world without direct contact with reality itself, but from the words of other people or from books. Abstract thinking allows you to develop appropriate adaptive reactions also outside of contact with those specific life conditions in which these adaptive reactions are appropriate. In other words, a person determines in advance, develops a line of behavior in a new, never seen environment. So, going on a journey to new unfamiliar places, a person nevertheless prepares accordingly for unusual climatic conditions, to specific conditions of communication with people, etc.
It goes without saying that the perfection of a person's adaptive activity with the help of verbal signals will depend on how accurately and fully the surrounding reality is reflected in the cerebral cortex with the help of a word. Therefore, the only true way to verify the correctness of our ideas about reality is practice, i.e. direct interaction with the objective material world.
The second signaling system is socially conditioned. A person is not born with it, he is born only with the ability to form it in the process of communicating with his own kind. Mowgli children do not have a human second signaling system.
Ontogeny of higher nervous activity and the second signaling system. In children, the second signaling system develops especially intensively between the ages of 2 and 5 years.
The formation and subsequent development of the second signaling system proceeds in close and inextricable connection with the activity of the first signaling system. In a newborn, conditioned reflexes are carried out completely by the first signal system. This initial phase of the development of human GNI is characterized by the presence of such temporary connections when direct stimuli exclusively within the first signal system come into contact with direct vegetative and somatic reactions. These are links of the type N-N(immediate stimulus - immediate reaction).
Starting from the second half of the first year of life, from the period of mastering the child, the so-called. "passive" or "sensory" speech (i.e., when the child begins to understand the speech of others), the first conditioned reactions to verbal stimuli appear, i.e. the beginning of joint activity of 1 and 2 signaling systems is laid. However, first this cooperative activity appears in only one form - by type S-N(verbal stimulus - immediate reaction).
After 8 months, the child, thanks to imitative activity and the influence of people around him, has the first attempts to pronounce individual words (mom, dad, baba, etc.) and articulate sounds (“ba”, “ma”, “am”, “gu ”, “yes”, etc.). At first they are pronounced without connection with any specific phenomena or objects of the environment, but then the direct perceptions of individual objects, phenomena, or even certain situations begin to come into contact with certain sound combinations pronounced by the child. At the same time, up to about 1.5 years, with one word or some sound combination (“mine-mine”, “moco”, “give”), the child denotes not only any object, but also actions, experiences and desires associated with this subject. In the future, the meaning of spoken words gradually narrows and begins to be associated only with a certain object or phenomenon. At this phase of human GNI development, to the first two types of temporary connections, connections of the type N-S(immediate stimulus - verbal reaction).
In the second year of life, the child's vocabulary increases more and more, reaching 250-300. At the same time, words begin to combine into the simplest speech chains, consisting of two or three words. By the end of the third year, the vocabulary increases to 500-700, and by the age of 5, children begin to speak fluently. mother tongue. During this period of mastering active speech, it rises to a higher level and degree of development of the second signaling system. There is a connection of the type S-S(verbal stimulus - verbal reaction), when the child begins to establish relationships between phenomena at the word level, "why?" appears. and abstract thinking begins to develop.
So, continuously enriched with more and more new types of communication, human GNI reaches a level of development when the 2nd signaling system begins to play a leading role. This gives the GNI of a person that qualitative originality, which sharply distinguishes him from the GNI of animals.
Types of higher nervous activity. The higher nervous activity of man and animals sometimes reveals rather pronounced individual differences. The individual features of GNI are manifested in different rates of formation and strengthening of conditioned reflexes, in different rates of development of internal inhibition, in different difficulties in remaking the signal value of conditioned stimuli, in different working capacity of cortical cells, etc. Each individual is characterized by a certain combination of the basic properties of cortical activity. She received the name of the VND type.
Features of the VND are determined by the nature of the interaction, the ratio of the main cortical processes - excitation and inhibition. Therefore, the classification of GNI types is based on differences in the basic properties of these nervous processes. These properties are:
1.Strength nervous processes. Depending on the performance of cortical cells, nervous processes can be strong And weak.
2. Equilibrium nervous processes. Depending on the ratio of excitation and inhibition, they can be balanced or unbalanced.
3. Mobility nervous processes, i.e. the speed of their occurrence and termination, the ease of transition from one process to another. Depending on this, nervous processes can be mobile or inert.
Theoretically, 36 combinations of these three properties of nervous processes are conceivable, i.e. a wide variety of types of VND. I.P. Pavlov, however, singled out only 4, the most striking types of GNA in dogs:
1 - strong unbalanced(with a sharp predominance of excitation);
2 - strong unbalanced mobile;
3 - strong balanced inert;
4 - weak type.
Pavlov considered the selected types to be common for both humans and animals. He showed that the four established types coincide with the Hippocratic description of the four human temperaments - choleric, sanguine, phlegmatic and melancholic.
In the formation of the GNI type, along with genetic factors (genotype), the external environment and upbringing (phenotype) also take an active part. In the course of further individual development of a person, on the basis of the innate typological features of the nervous system, under the influence of the external environment, a certain set of GNI properties is formed, which manifests itself in a stable direction of behavior, i.e. what we call character. The type of GNI contributes to the formation of certain character traits.
1. Animals with strong, unbalanced type are, as a rule, bold and aggressive, extremely excitable, difficult to train, can not stand restrictions in their activities.
People of this type (cholerics) characterized by incontinence, easy excitability. These are energetic, enthusiastic people, bold in their judgments, prone to decisive actions, not knowing the measures in work, often reckless in their actions. Children of this type are often capable of learning, but quick-tempered and unbalanced.
2. Dogs strong, balanced, mobile type, in most cases they are sociable, mobile, quickly react to each new stimulus, but at the same time they easily restrain themselves. They quickly and easily adapt to changes in the environment.
People of this type sanguine people) are distinguished by restraint of character, great self-control, and at the same time, seething energy and exceptional performance. Sanguine people are lively, inquisitive people, interested in everything and quite versatile in their activities, in their own interests. On the contrary, one-sided, monotonous activity is not in their nature. They are persistent in overcoming difficulties and easily adapt to any changes in life, quickly restructuring their habits. Children of this type are distinguished by liveliness, mobility, curiosity, discipline.
3. For dogs strong, balanced, inert type characteristic feature is slowness, calmness. They are unsociable and do not show excessive aggression, reacting poorly to new stimuli. They are characterized by the stability of habits and the developed stereotype in behavior.
People of this type (phlegmatic) are distinguished by their slowness, exceptional poise, calmness and evenness in behavior. With their slowness, phlegmatic people are very energetic and persistent. They are distinguished by the constancy of habits (sometimes to the point of pedantry and stubbornness), the constancy of attachments. Children of this type are distinguished by good behavior, diligence. They are characterized by a certain slowness of movements, slow calm speech.
4. In the behavior of dogs weak type, cowardice, a tendency to passive-defensive reactions are noted as a characteristic feature.
A distinctive feature in the behavior of people of this type ( melancholy) is timidity, isolation, weak will. Melancholics often tend to exaggerate the difficulties they encounter in life. They are highly sensitive. Their feelings are often painted in gloomy tones. Children of the melancholic type outwardly look quiet, timid.
It should be noted that there are few representatives of such pure types, no more than 10% of the human population. The rest of the people have numerous transitional types, combining in their character the features of neighboring types.
The type of HNI largely determines the nature of the course of the disease, so it must be taken into account in the clinic. The type should be taken into account at school, when educating an athlete, a warrior, when determining professional suitability, etc. To determine the type of GNI in humans, special methods have been developed, including studies of conditioned reflex activity, processes of excitation and conditioned inhibition.
After Pavlov, his students carried out numerous studies on the types of GNA in humans. It turned out that the Pavlovian classification requires significant additions and changes. Thus, studies have shown that a person has numerous variations within each Pavlovian type due to the gradation of the three main properties of nervous processes. The weak type has especially many variations. Some new combinations of the basic properties of the nervous system have also been established, which do not fit the characteristics of any of the Pavlovian types. These include - a strong unbalanced type with a predominance of inhibition, an unbalanced type with a predominance of excitation, but unlike a strong type with a very weak inhibitory process, unbalanced in mobility (with labile excitation, but inert inhibition), etc. Therefore, work is now underway to clarify and supplement the classification of types of GNI.
In addition to the general types of GNA, a person also distinguishes private types, characterized by a different ratio between the first and second signaling systems. On this basis, three types of GNI are distinguished:
1. Art, in which the activity of the first signal system is especially pronounced;
2. thinking type, in which the second signaling system noticeably predominates.
3. Medium type, in which the 1st and 2nd signal systems are balanced.
The overwhelming majority of people belong to the middle type. This type is characterized by a harmonious combination of figurative-emotional and abstract-verbal thinking. Artistic type supplies artists, writers, musicians. Thinking - mathematicians, philosophers, scientists, etc.
The physiology of higher nervous activity (HNA) studies the mechanisms of the brain that determine the behavior of animals.
Behavior is not limited to manifestations of external motor activity, but includes processes due to which a living organism feels the external world and the state of its body, adequately responds to emerging stimuli. The cerebral cortex and the subcortical formations closest to it play a primary role in these processes, since they are the highest section of the CNS of animals.
The activity of the cerebral cortex is based on conditioned reflex connections. Unlike GNI, which provides the most subtle and perfect adaptation of the organism to the environment, lower nervous activity is aimed at unifying and coordinating functions within the organism.
For the first time, the idea of the reflex nature of the activity of the higher parts of the brain was widely and in detail developed by the founder of Russian physiology, I. M. Sechenov, in his book “Reflexes of the Brain”. Before Sechenov, physiologists and neurologists did not even dare to raise the question of the possibility of an objective physiological analysis. mental processes which remained the object of study of subjective psychology.
The ideas of I. M. Sechenov were brilliantly developed in the remarkable works of I. P. Pavlov, who discovered the ways of objective pilot study functions of the cerebral cortex, who developed the method of conditioned reflexes and created the doctrine of higher nervous activity. Pavlov showed that while in the underlying parts of the central nervous system - the subcortical nuclei, the brain stem, the spinal cord - reflex reactions are carried out by congenital, hereditarily fixed nerve pathways, in the cerebral cortex, nerve connections are developed anew in the process of individual life of animals as a result of a combination of countless, acting on the body and perceived by the cortex, irritations. The doctrine of GNI created by IP Pavlov proved the unity of bodily and mental phenomena.
14.1. THE CONCEPT OF NERVISM
Adaptation to the environment is carried out not with the help of simple reflexes, but as a result of many innate and acquired reactions that form a complex system. The components of this system are connected by diverse connections, and their implementation is accompanied by mental phenomena.
Thus, in physiology, a modern direction was formed - nervism. Nervousness is to be understood as methodological approach, which recognizes the leading role of the central nervous system and the cerebral cortex in the regulation of all body functions. There were other directions; Thus, the Canadian scientist G. Selye believed that the main role in the regulatory mechanisms is played by the endocrine system.
Nervism is based on three main principles: determinism, structure, analysis and synthesis.
The principle of determinism or causality. Every phenomenon has its own cause. I. M. Sechenov wrote: "All acts of conscious and unconscious life are reflexes." And a reflex is a response to irritation, that is, for the occurrence of each reflex there must be a reason, namely the action of one or another stimulus.
The principle of structure. All nervous phenomena take place in definite material substrata. Each new conditioned reflex is accompanied by the formation of a new temporary connection in certain structural formations of the higher parts of the central nervous system.
The question of the localization of functions in the cerebral cortex is still controversial. On the one hand, since the time of Bekhterev it has been known that each section of the cortex has a specific function, that is, it is associated with some receptors, being the center of this analyzer, or with any organs (muscles, internal organs); on the other hand, the functions of cortical neurons can change, since the nerve centers are highly plastic. In addition, cortical neurons can enter different nerve centers, overlap them, therefore, in nervism, it is taken as the basis for the localization of functions in the cortex.
IP Pavlov developed the theory of dynamic localization of functions in the cerebral cortex. According to this doctrine, the cortical end of each analyzer consists of two main parts - the nucleus and peripheral elements. The cells of the nucleus are highly specialized and are capable of finely distinguishing the appropriate stimuli (sound, visual, etc.) and are concentrated in a certain zone. At the same time, there are much less specialized elements in the cortex, incapable of higher analysis and synthesis. Peripheral elements can sometimes take over the functions of the core in case of damage, but are not able to replace it completely. As a result of many studies, it has been proven that the cerebral cortex can
on to a dynamic restructuring of their functions, i.e., the high specialization of the nerve centers is combined with their flexibility and plasticity.
The cerebral cortex has a pronounced specialization of nerve centers. It contains sensory, motor and association areas. Sensory zones are projections of peripheral receptor fields, or the cortical center of analyzers. In each hemisphere there are two zones of representation of sensitivity: somatic(skin and musculoskeletal) and visceral(reception of internal organs). These zones are also called the first and second somatosensory zones. There are also auditory, tactile and visual zones.
The visual zone is located in the occipital lobes of the cerebral hemispheres, the auditory - in the temporal, olfactory - in the ammon horn of the ancient cortex. In the region of the posterior central gyrus lies the tactile zone, where impulses from skin receptors that respond to touch and pressure are received. In the premotor region, the interoreceptive zone receives afferent impulses from the internal organs: irritation or removal of this zone leads to a change in respiration, the work of the heart, the lumen of blood vessels, to a violation of the secretory and motor activity of the gastrointestinal tract, etc.
The more receptors there are in any peripheral receptor fields, the larger the zone of this reception is represented in the cortex.
Motor zones are characterized by strict localization of functions. The localization of the motor zone is different and depends on the type of animal: in carnivores it lies around and in the depth of the cruciate sulcus, in sheep and goats - mainly in the region of the superior frontal gyrus, in pigs - between the coronary sulcus and the anterior branch of the Sylvian sulcus, in horses - on the side of lateral cruciate sulcus, as well as in the region of the middle branch of the superior Sylvian sulcus.
Motor centers are concentrated in the motor zone, sending signals to individual skeletal muscles of the opposite half of the body. Impulses from receptors embedded in the thickness of muscles, tendons and joints come here and are analyzed. Here is the end station of sensitive impulses. The size of the motor cortex depends on the type of animal and the ability of the organism to perform complex movements.
Associative zones, or secondary sensory zones, surround the primary sensory zones with a strip of 1 ... 5 cm. The cells of these zones respond to stimulation of different receptors, i.e., afferent pathways coming from different receptor systems converge on them. The removal of these zones does not entail the loss of this type of sensitivity, but the ability to correctly interpret the meaning of the current stimulus is impaired.
Analysis and synthesis. This is the basic principle of the cerebral cortex. Analysis is the ability to isolate individual elements from the environment. Primary analysis begins in the receptor apparatus due to the specialization of receptors. Here, the signals of the external environment are encoded into nerve impulses and sent to the overlying centers. The second stage of analysis is carried out at the level of the thalamus and subcortical ganglia, and the third - in the cerebral cortex. Signals from each receptor reach specific cells in the cortex. 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 growth of the stimulus. Therefore, conditions are created under which each peripheral stimulation corresponds to its spatio-temporal pattern of excitation in the cortex. Thus, irritations similar in appearance and properties are recognized. This is achieved by developing internal inhibition, limiting the spread of excitation to other cells of the cortex.
The synthesis of stimuli is the binding, generalization, and unification of excitations that arise in different parts of the cortex due to the interaction between neurons. A manifestation of the synthetic activity of the cortex is the formation of temporary connections that form the basis for the development of a conditioned reflex.
The simplest form of analytic-synthetic activity is the development of a conditioned reflex under the action of any one stimulus.
Analysis and synthesis are inextricably linked. The impact on the body of two separate stimuli is the most primitive form of analysis and synthesis. More complex forms of analytic-synthetic activity of the cerebral cortex can be judged on the basis of an analysis of complex stimuli that include a number of components. To do this, several signals are used as a conditioned stimulus, following one after another in a certain order; in a different order, the same signals are used without reinforcement. If differentiation is developed, then this indicates that the signals are perceived by the cortex of the cerebral hemispheres not only separately and not only in total, but also in a certain sequence.
Complex forms of synthetic activity of the cerebral cortex are clearly expressed in the phenomena denoted by the concepts dynamic stereotype. IP Pavlov said that "a dynamic stereotype is a complex balanced system of internal processes of the cerebral hemispheres, corresponding to an external system of conditioned stimuli." A stereotype of cortical reactions is developed to the stereotype of stimuli. The presence of a dynamic stereotype can be seen if, in any experiment, the action of only one of the conditioned stimuli included in the system is re-tested. For example, a stereotype of conditional
salivation reflexes to such conditioned stimuli as knocking, hissing, ringing, light, and then only one of the stimuli is applied - knocking or ringing. It turns out that the effect will be different in strength depending on which stimulus was previously in this place, that is, the applied stimulus gives effects that are not characteristic of it, but of those stimuli that preceded it. The developed stereotype facilitates the activity of the cortex as a regulatory body. The systemic activity of the brain is not strictly constant: it is possible to replace one system with another. In farm animals, a dynamic stereotype is developed in the course of the daily routine, feeding, maintenance, and its violation leads to a breakdown of the nervous system and a decrease in productivity.
The subject and tasks of the physiology of higher nervous activity. Connection with other sciences.
Basic concepts: "unconditioned reflex", "conditioned reflex", "higher and lower nervous activity", "mental activity", "sensory systems".
The history of the development of the doctrine of higher nervous activity.
Modern achievements in the physiology of higher nervous activity.
Methods for studying higher nervous activity (within the framework of a practical lesson).
1. Physiology of higher nervous activity is the science of the neurophysiological mechanisms of the psyche and behavior, based on the principle of reflex reflection of the external world. This is a materialistic doctrine that reveals the laws of the brain, allows you to know the nature and internal mechanisms of learning, memory, emotions, thinking and consciousness.
As part of the discipline of physiology of higher nervous activity and sensory systems, we will study the nature of conditioned and unconditioned reflexes, as well as study the patterns of sensory systems and their role in the formation of mental activity.
The purpose of the discipline "Physiology of GNI and sensory systems" is to reveal the patterns of conditioned reflex activity of the nervous system, as well as to study the features of receiving and processing information in sensory systems.
Discipline tasks:
Find out the neurophysiological mechanisms of conditioned reflex activity in the body;
To reveal the principles of interaction between the processes of excitation and inhibition in the nervous system;
Reveal the features of the functioning and interaction of sensory systems;
Determine the value of sensory information in the implementation of human mental activity.
The discipline "Physiology of Higher Nervous Activity and Sensory Systems" is closely related to the Physiology of the CNS, Psychophysiology and other sciences.
2. The founder of the science of Physiology of higher nervous activity is IP Pavlov. He was the first to discover the principle of conditioned reflex connection. IP Pavlov believed that unconditioned and conditioned reflexes lie at the basis of higher nervous and mental activity.
An unconditioned reflex is an innate species-specific reaction of the body that reflexively occurs in response to a specific effect of a stimulus, to the effect of a biologically significant (pain, food, tactile irritation, etc.) stimulus that is adequate for this type of activity. Unconditioned reflexes are associated with vital biological needs and are carried out within a stable reflex pathway. They form the basis of the mechanism for balancing the influences of the external environment on the body. Unconditioned reflexes arise on direct sensory signs of an stimulus adequate for them and can be caused by a relatively limited number of environmental stimuli.
A conditioned reflex is an individually acquired reaction of the body to a previously indifferent stimulus, reproducing an unconditioned reflex. The basis of the conditioned reflex is the formation of new or modification of existing nerve connections that occur under the influence of changes in the external and internal environment. These are temporary connections that are slowed down when reinforcements are canceled, the situation changes. Studying the features of the development of brain structures in various animals, I.P. Pavlov came to the conclusion that in the process of animal evolution, the ratio of innate and acquired reactions changes naturally: in the behavior of invertebrates and lower animals, innate forms of activity prevail over acquired ones, and in more developed animals they begin to dominate individually acquired forms of behavior that are continuously developing, becoming more complex and improving. Proceeding from this, I.P. Pavlov introduces a division of the concepts of higher nervous activity and lower nervous activity. Higher nervous activity was defined by him as a conditioned reflex activity of the leading parts of the brain (in humans and animals - the large hemispheres), providing adequate and most perfect relations of the whole organism to the outside world, i.e. behavior. Lower nervous activity is defined by him as the activity of the lower parts of the brain and spinal cord, which control the activity of the body systems among themselves.
In addition, Pavlov also introduced the concept of "mental activity" - this is a qualitatively new, higher than conditioned reflex behavior, level of higher nervous activity inherent in man. Mental activity of a person consists not only in the construction of more complex neural models of the surrounding world, but also in the production of new information, various forms of creativity. Despite the fact that many manifestations of the human mental world turn out to be divorced from the direct stimuli of the external world and seem to have no real objective reasons, there is no doubt that the initial, triggering factors are quite deterministic phenomena and objects. This idea was first expressed by I.M. Sechenov in the form of the thesis “all acts of conscious and unconscious human activity by way of origin are reflexes.”
The subjectivity of mental processes lies in the fact that they are a property of an individual organism and cannot exist outside a specific individual brain with its peripheral nerve endings and nerve centers and are not an absolutely exact mirror copy of the real world around us.
The simplest mental element in the functioning of the brain is sensation. It arises as a result of the spatio-temporal distribution of the excitation pattern and serves as an elementary act that, on the one hand, connects our psyche with external influences, and on the other hand, is an element of complex mental processes. Sensation is a conscious reception, which means that it contains a certain element of consciousness and self-consciousness.
At present, the physiology of higher nervous activity has been defined as the science of the brain mechanisms of behavior and the psyche.
The leading role in the perception of the reality surrounding humans and animals belongs to sensory systems. According to the definition proposed by I.P. Pavlov, the sensory system is a part of the nervous system, consisting of perceiving elements - sensory receptors that receive stimuli from the external or internal environment, nerve pathways that transmit information from receptors to the brain, and those parts of the brain that process and analyze this information. The transmission of sensory signals is accompanied by their multiple transformation and ends with a higher analysis and synthesis (image recognition), after which the body's response is formed.
3. The first references to the essence of the psyche are found among ancient Greek and Roman scientists. The very word psychios - spiritual has Greek roots.
In world science, a whole area of research has now been formed, called neuroscience. It is a nourishing source for understanding the higher functions of the brain. By the way, the term "higher nervous activity" in our literature most closely corresponds to the term "cognitive neuroscience" in the English literature.
However, let's go back to today. What discoveries did greatest influence on the development of the physiology of higher nervous activity?
In the first place, one can put a complete understanding of the physicochemical processes that form the basis of excitation and its conduction along nerve fibers, as well as the process of inhibition in neurons. Nobel Prize English physiologists A. Hodgkin, A. Huxley and J. Eccles (1963) Fundamental knowledge was obtained at the very beginning of the 20th century, it was then that the "membrane theory" was formulated (Yu. Bernstein), which served as the basis for the development research in this area.
Another important discovery was the study of synaptic conduction processes, i.e. transmission of signals from a neuron to neurons or other cells in the body. Now there is a complete conviction that the basis of learning (closing a temporary connection, according to I.P. Pavlov), memory, mental illness and many other processes associated with higher nervous activity are synaptic processes. Advances have been made in research on biological models of learning - simple nervous systems of mollusks, insects and other invertebrates, as well as on intravital brain sections (newborn mice, rats, guinea pigs), potentiation (mono- and heterosynaptic) and a number of others. The ideology of such research is based on the fundamental idea of I.P. Pavlova - the repeated combination of two stimuli leads to the blazing of a path in the nervous system that connects them. This idea in the 50s was reformulated by the American theorist D. Hebb for the neuron and was called the Hebb synapse.
Works in the field of neurogenetics. Understanding that in certain cell types during synaptic activation, the expression of early genes occurs, which, through the appropriate promoters, turn on the work of late genes, protein synthesis occurs, which is built into the postsynaptic membrane. From the postsynaptic neuron, an information signal (for example, molecules of nitric oxide or arachidonic acid) can pass to the presynaptic neuron. Today's discoveries are, apparently, only the beginning of understanding the processes of synaptic plasticity. This is an unconditional point of growth of modern scientific knowledge in the field of physiology of higher nervous activity.
Important achievements of recent decades include the identification of genome loci responsible for the synthesis of a number of biologically active substances (hormones, neuropeptides, mediators) involved in the activity of the nervous system. It is extremely important to study the genetic aspects of the differentiation of individual elements of the nervous tissue ( various types glia and neurons with different chemical specificity) from cells of the primary epithelium of the neural tube. Now it is quite obvious that neurons in genetic terms are very active cells: for example, polyploidy of neurons is known in the nervous system of both invertebrates and higher mammals.
The next problem, which has a huge impact on the accumulation of knowledge in the field of the physiology of higher nervous activity, is the ontogeny of the processes of higher nervous activity. From the work of ethologists on brood and nestlings, it became obvious that the formation of species-specific behavior (for example, singing, following the mother, choosing a sexual partner, and some others) occurs only in the so-called sensitive periods of development. K. Lorentz called this phenomenon imprinting (imprinting). Now it is obvious that this is the biological principle of the formation of neural structures - in certain periods of ontogeny (prenatal and postnatal), they are formed under the influence of
external (and possibly internal) signals. This is true for higher mammals, including humans. For example, a newborn is born with about 1/4 the weight of an adult brain, but with a full set of neurons. Then begins a long journey, about two decades, until puberty, during which the knowledge necessary for later life is acquired. At the heart of this process is learning, or it is often called early education. For example, object vision in a person is formed up to 15 years of his life. It turned out that if during this period a person's vision was impaired due to cataracts, then after the restoration of vision at a later age, object vision is no longer formed. Speech is formed in the period up to 4 years. The lack of speech practice, for example, in deaf children, leads to the "Mowgli effect".
There are many such examples. This is an extremely important area of the physiology of higher nervous activity, which has practical projections not only into medicine, but also pedagogy, and even sociology. It is now well known that social forms behaviors, for example, in monkeys, are also formed in the early period of development of the cub. We can cite the well-known works of H. Harlow on raising cubs on stuffed animals, which led to irreversible violations of maternal behavior in females who became adults: they treated their cubs as inanimate objects which often led to the death of the cub.
Enormous progress has been made in the study of the functions of individual structures and systems of the brain. This is primarily due to the development of research methods. During this time, behavioral techniques have been improved, a huge arsenal of instrumental methods has appeared (numerous modifications of electrophysiological techniques - from microelectrode to clinical ones, as well as a whole set of tomographic ones). In the field of experimental morphology, a huge variety of intravital dyes for neurons, methods using monoclonal antibodies to identify neurotransmitter receptors, and many others have appeared.
Significant progress has been made in the field of sleep physiology. The classical studies of G. Magun, D. Moruzzi (1949) and others finally solved the problem of sleep physiology in favor of the reticular structures of the brain stem.
The study of the limbic system underlies the main problems of the physiology of higher nervous activity, such as, for example, motivation, emotions, reinforcement. All this is directly related to the formation of both instinctive (unconditioned reflex) and conditioned reflex behavior of both animals and humans. It is now clear that all the mechanisms of neuroendocrine regulation underlying seasonal behaviors, reproductive behavior, and many other types of behavior are inextricably linked with the physiology of limbic system structures.
Among the global problems of the physiology of higher nervous activity, which were formulated by I.P. Pavlov, refers to the physiology of the second signaling system. Now it is quite obvious that the basis of this function is the asymmetry of the cerebral hemispheres. This is directly indicated by the discoveries in the last century of the motor and sensory centers of speech in the left hemisphere in right-handers (P. Broca, K. Wernicke). Hymenoptera, cetaceans and other animals have highly developed tongues. Chimpanzees can be taught the language of the deaf and dumb or other ways of signaling. But all these languages cannot be compared with human language. Perhaps this is due to the fact that only humans have "innate grammars" according to N. Chomsky, i.e. innate ability to acquire language.
The most important properties of the language should be listed. First of all, this is the possibility of doubling the surrounding world - the left hemisphere makes a logical copy, and the right - figurative. The second property of the language is the mastery of memory, not only current, but also historical. It is thanks to this that our civilization has appeared, which continues to rapidly accumulate knowledge. It should be noted that the emergence of language is a unique phenomenon in the natural history of the Earth.
Neuroscience has now reached the point where it becomes possible to solve the problem of consciousness among other scientific problems. At the same time, it is currently impossible to state whether there are biological precursors of this function. For example, P.V. Simonov believes that "... consciousness is defined as knowledge that can be transmitted with the help of words, mathematical symbols and generalizing images of works of art, can become the property of other members of society. Consciousness is knowledge together with someone (compare with sympathy, empathy, cooperation, etc.) To realize means to acquire the potential opportunity to communicate, to pass on one's knowledge to another, including to other generations in the form of cultural monuments...". In other words, only humans are conscious. However, a rather complex semantic analysis can take place without the participation of consciousness. For example, the phenomenon of "blind-sighted" patients. These are people who have received extensive brain injuries in the area of the cortical projection of vision. They themselves characterize themselves as "blind", but they are able to copy the drawing, but are not able to understand "what is drawn?". According to the concept of A.M. Ivanitsky, for the act of sensation as a mental phenomenon, a synthesis of sensory information with traces of memory is necessary. Activation of traces of memory occurs by the mechanism of a conditioned reflex. The comparison of sensory and non-sensory information is provided by the mechanism of return of excitation from the subcortical centers of emotions and motivations, as well as other parts of the cortex, including associative zones, to the region of the primary projection of this analyzer. In the case of "blind-sighted", due to the lack of a primary projection zone, such an overlay is impossible and awareness of the visual
the image does not occur. Consciousness and other mental phenomena are the highest level of brain activity, but biologists should have no doubt that they are the result of the brain's neurobiological processes. The problem is to explain in detail how the brain works in these cases. It can be assumed that the solution of the problem of consciousness will constitute the most important discoveries of the present time.
At the beginning of the XX century. I.P. Pavlov defined the study of higher (mental) forms of brain activity as the subject of physiology of higher nervous activity. A conditioned reflex was singled out as a cell of this activity - it reflects the entire complex world processes of higher nervous activity. Reflecting on this topic, L.G. Voronin proposed to distinguish phylogenetic levels of higher nervous activity: preconditioned reflex (summation reflex and other forms of changes in the excitability of the nervous system), unstable conditioned reflex (starting with roundworms), persistent conditioned reflex (starting with annelids), complex forms of conditioned reflex activity - such, for example , as chain conditioned reflexes, transfer, reflexes of the nth order and many others; finally, abstract-logical conditional connections that determine the abstract-logical functions of the brain of higher mammals, primarily humans. Thus, psychogenesis originates even in animals with a very simple nervous system. L.V. Krushinsky singled out another type of higher nervous activity, not conditioned reflex - rational activity, which, according to the author, was the biological forerunner of intelligence. This form of higher nervous activity exists only in higher mammals and in some families of birds. If we talk about man, then his brain, as a product of biological evolution, has features that sharply distinguish him from a number of other mammals. Let's list the main ones.
An increase in the size (according to the cephalization index) of the brain. The area of the cerebral cortex increases especially significantly due to the gigantic growth of associative areas. Pronounced asymmetry of the hemispheres. Each hemisphere creates its own world, and perhaps has its own consciousness. This is especially evident in the brain injury clinic. Emotions have become a system of motivations, replacing biological reinforcement in this sense. All this is due to the development of the limbic system of brain structures. A very long childhood. Recall that a child is born with a full set of neurons, but the weight of his brain is only about 1/4 of the weight of the brain of an adult. An increase in the weight of the brain occurs due to the formation of connections between neurons. It is during this period that a civilized person is formed. Extracortical localization of mental functions. This means that we have entered the age of the noosphere (knowledge), about which V.I. Vernadsky. The basis for this is the extracortical (according to Vygotsky) structure of the language function, which forms the basis of the second signaling system. It is thanks to this property that our civilization accumulates knowledge. Thanks to the unique properties of the second signaling system, a person continuously invents more and more new Information Technology- starting with the invention of writing and ending in our time with the creation of the World Wide Web (Internet). All this may indicate that the natural evolution of the Earth, starting with geochemical evolution, went through a long biological evolution, as a result of which higher nervous activity (the psyche) appeared, but with the advent of man, the evolution of the Earth entered a new phase - the phase of noogenesis. And all this is the subject of study of the physiology of higher nervous activity!
