Higher nervous activity. The nervous system is the leading physiological system of the body.

Higher nervous activity

Higher nervous activity associated with the functions of the cerebral cortex. It provides maximum human adaptability to environmental conditions. The study of higher nervous activity is based on the works of I.M. Sechenov - "Reflexes of the brain", I.P. Pavlova (the theory of conditioned and unconditioned reflexes), P.K. Anokhin (the theory of functional systems) and numerous other works.

The reflexes carried out by the body are divided, according to I.P. Pavlov, on unconditional and conditional.

Unconditioned reflexes inherited and reproduced from generation to generation. They are characteristic of all individuals of a certain species, i.e. group. For example, all individuals of the seahorse build nests for breeding and protecting offspring. Unconditioned reflexes have constant reflex arcs. A complex chain of unconditioned reflexes is called instinct. A mother feeds and protects her child, birds build nests - these are examples of instincts.

Conditioned reflexes acquired by each person throughout life. Each conditioned reflex is the result of a certain experience, habit. Reading, driving a car, salivating at the sight and smell of food are all examples of conditioned reflexes. They are individual, and certain conditions are necessary for their formation. These reflexes may disappear. So, without sufficient practice, a foreign language, a poem once learned, the ability to skate, etc. are forgotten. This process is called conditional. braking. Braking can also be unconditional (external). An example of unconditioned inhibition would be an attack by a dog that is being deprived of food. In the digestive center, external unconditional inhibition sets in, and in the center of "aggression" - excitation. Conditioned reflexes are formed on the basis of unconditioned reflexes and are developed with the direct participation of the cerebral cortex. So the conditioned salivary reflex was formed in the laboratory of I.P. Pavlova when combining feeding and lighting a light bulb or the sound of a bell. As a result, after several repetitions, saliva was released in response to the action of an unconditioned stimulus. This meant that a new, temporary connection was formed in the cerebral cortex between the centers of salivation and visual (auditory). New conditioned reflexes are formed on the basis of old conditioned reflexes.

The features of the higher nervous activity of a person are the following:

- developed mental activity;

- the ability to abstract-logical thinking.

I.P. Pavlov developed the doctrine about the first and second signal systems.

First signal system provides perception of the surrounding world through the senses. With the help of this signaling system, conditioned reflexes are developed to a variety of signals. Second signal system appeared in humans in connection with the development of speech. A word for a person is not a combination of sounds, but an expression of the meaning of a word, a concept. The development of speech made it possible to abstract, generalize, and operate with concepts. The first and second signal systems are closely related. Signals from the first signaling system are sent to the second. It begins to develop in children by 5-7 months of the first year of life.

I.P. Pavlov formulated the concept of individual types of the nervous system. He assessed the strength, balance and dynamism of the main nervous processes (excitation and inhibition). Based on the data obtained, four types of the nervous system or temperament were identified: choleric, sanguine, phlegmatic, melancholic.

Usually a person combines features of different temperaments, but one of them dominates. Temperament assessment is important when choosing the nature of professional activity.

Emotions- these are the subjective reactions of humans and other animals to the impact of external and internal stimuli. Emotions happen positive and negative. Different types of emotions cause corresponding physiological changes in the body. Emotions such as joy, anger, pre-launch excitement increase muscle tone, release adrenaline, and increase cardiovascular activity. Fear, despondency can be accompanied by a decrease in muscle tone, vasospasm. With the help of emotions, a person changes his behavior.

Memory is the ability of the brain to store information and reproduce it at certain intervals. According to the time of storing information, memory is short-term and long-term. The temporal lobes of the brain, the reticular formation of the brain stem, and the hypothalamus are involved in the formation of memory. There are the following types of memory:

– motor;

– visual;

– auditory;

– tactile;

– mixed.

Thinking- a set of mental processes associated with cognition. Concepts are formed in the process of thinking. The more active, the deeper the process of cognition, the deeper the formed concepts, their content and meaning.

The concept of "cell", formed by a 6th grade student, has been developing over several years. As a result, a school graduate has a much deeper understanding of the cell as a biological system than a sixth grader.

Dream- a state of oppression of consciousness and weakening of human ties with the environment. The onset of the state of sleep is associated with the suppression of the ascending influences of the reticular formation. Normal sleep duration is 7-8 hours.

Sleep and wakefulness are manifestations of circadian rhythms. Sleep provides restoration of working capacity, processing and assimilation of information received during wakefulness.

In accordance with these functions of sleep, deep (slow wave) and superficial (fast wave) dreams are distinguished.

A person sees dreams during REM sleep. At this time, you can observe increased brain activity, eyeball movements, sometimes the sleeper begins to speak. This phase occurs approximately every one and a half hours and lasts 15-20 minutes. During deep, slow-wave sleep, the rhythmic activity of the brain decreases. Breathing and heart rate slows down. Thus, sleep is a periodic change of various functional states of the brain. The hormones norepinephrine and serotonin play an important role in the regulation of sleep.

Dreams are a kind of reflection of the information received in the form of visual images.

Behavior- this is a person's activity aimed at satisfying biological, physiological, psychological and social needs.

Human behavior is determined by the neuro-humoral activity of the organism and the social conditions of his life.

Aspects of cerebral (nervous) activities: each hemisphere has its own function.

The right hemisphere - creative thinking, perception of images, music, emotions, feelings, functionality of the left hand; left hemisphere - logic, strategic thinking, reading, counting, functionality of the right hand. The right or left-handedness of a person is laid down in the embryo - the hand, whose finger he sucks, will be functional when he is born and matures.

The cortex is responsible for the higher nervous (psychological) activity of a person, its sections are usually divided into parts of the brain:

The human nervous system operates on the principle of excitation - the main functions of a neuron and nervous tissue are excitability and conduction. However, there is an opposite mechanism, inhibition, blocking of impulses entering the cerebral cortex. This allows the nervous tissue to rest and recover.

The most striking example of inhibition is sleep. At this moment, the nervous system does not stop working, it is reorganized to a different mode of operation - rest, bringing all functions back to normal, relaxation.

During sleep, the brain is resting, but not inactive, while the cells that are active during the day are resting. Many scientists suggest that during sleep there is a kind of processing of information accumulated during the day, but a person is not aware of this, because the corresponding functional systems of the cortex that provide awareness are inhibited.

external braking, it is physiological, it is unconditional- by name and essence, this is some kind of strong influence on the nervous system from the outside, for example, a sharp sound, a painful effect, etc. It turns out that a new nerve impulse, a new "signal" suppresses, interrupts the previous one.

Internal braking comes from within, i.e. from directly from the cerebral cortex, manifests itself during a conditioned reflex, when the body adapts to external stimuli, and therefore excitation occurs under the action of only strictly defined stimuli, while others, even slightly different from the first, cause an inhibitory effect.

1. I.M. Sechenov and I.P. Pavlov, the founders of the doctrine of GNI.

2. Unconditioned reflexes.

3. Conditioned reflexes.

4. The mechanism of the formation of a temporary connection.

5. Inhibition of conditioned reflexes.

6. Features of human GNI.

7. Functional system of a behavioral act.

THEM. Sechenov and I.P. Pavlov, the founders of the doctrine of GNI. GNI is the activity of the cerebral cortex and the subcortical formations closest to it, which provide the most perfect adaptation of highly organized animals and humans in the environment.

The question of the reflex activity of the cortex was first presented by the founder of Russian physiology I.M. Sechenov in the book "Reflexes of the brain" (1863). He believed that all human activity, including mental (mental), is carried out by a reflex path with the participation of the brain. The validity of Sechenov's views was subsequently confirmed by experimental studies by IP Pavlov. He discovered conditioned reflexes - the basis of GNI.

All reflex reactions of the body to various stimuli I.P. Pavlov divided into two groups: unconditional and conditional.

Unconditioned reflexes- these reflexes are congenital and inherited. The most complex of them are called instincts (building honeycombs by bees, nests by birds). Unconditioned reflexes are distinguished by great constancy. These reflexes include sucking, swallowing, pupillary and various defensive reflexes. They are formed on various irritants. So, the salivation reflex occurs when food stimulates the taste buds of the tongue. The resulting excitation is transmitted along the sensory nerves to the medulla oblongata, where the center of salivation is located, from there it is carried along the motor nerves to the salivary glands, causing their secretion. The nerve centers of unconditioned reflexes lie in different parts of the brain and spinal cord. For their implementation, the participation of the cerebral cortex is not necessary. On the basis of unconditioned reflexes, the regulation and coordination of the activity of various organs and systems is carried out, the very existence of the organism is supported.

However, with the help of unconditioned reflexes, the body cannot adapt to changing environmental conditions. The preservation of vital activity and adaptation to environmental conditions is carried out due to the formation of conditioned reflexes in the cerebral cortex.

Conditioned reflexes. These are reflexes developed during an individual life, due to the formation of temporary nerve connections in the higher parts of the central nervous system (cerebral cortex).

For the formation of conditioned reflexes, the following conditions are necessary: ​​1) the presence of two stimuli - indifferent, i.e. one that they want to make conditional, and unconditional, causing some kind of activity of the organism, for example, the separation of saliva (food); 2) an indifferent stimulus (light, sound, etc.) must precede the unconditional one (for example, it is necessary to give light first, and after two seconds food); 3) the unconditioned stimulus must be stronger than the conditioned one (for a well-fed dog with low excitability of the food center, the bell will not become a conditioned food stimulus); 4) the absence of distracting, extraneous stimuli; 5) vigorous state of the cortex.

The mechanism of formation of a temporary connection. According to I.P. Pavlov, under the action of an unconditioned stimulus (food) and due to the excitation of the food center of the cortex and the center of salivation of the medulla oblongata, a salivary reaction occurs. Under the action of a visual stimulus, the focus of excitation occurs in the visual area of ​​the cortex. When the action of the conditioned and unconditioned stimuli coincides in time, a temporary connection is established between the food and visual centers of the cortex.

With a conditioned reflex developed, the excitation that arose in the visual center under the action of a light stimulus spreads to the food center, and from the food center along the afferent pathways it goes to the salivary center and a salivary reaction occurs.

The reflex arc of the conditioned reflex contains the following sections: a receptor that reacts to a conditioned stimulus; sensory nerve and its corresponding ascending path with subcortical formations; the area of ​​the cortex that perceives the conditioned stimulus (for example, the visual center); a section of the cortex associated with the center of the unconditioned reflex (food center); motor nerve; working body.

Inhibition of conditioned reflexes. Conditioned reflexes are not only developed, but also disappear or weaken when the conditions of existence change as a result of inhibition. I.P. Pavlov distinguished two types of inhibition of conditioned reflexes: unconditioned (external) and conditioned (internal). Unconditional inhibition occurs as a result of the action of a new stimulus of sufficient strength. In this case, a new focus of excitation appears in the cerebral cortex, which causes suppression of the existing focus of excitation. For example, an employee has developed a conditioned reflex in a dog to the light of a light bulb and wants to show it at a lecture. The experiment fails - there is no reflex. The noise of a crowded audience, new signals completely turn off conditioned reflex activity / Conditioned inhibition can be of four types: 1) extinction; 2) differentiation; 3) delay; 4) conditional brake.

Fading inhibition occurs when the conditioned stimulus is not reinforced by the unconditioned one several times (they turn on the light, but do not reinforce it with food).

Differential inhibition is developed if one signal stimulus, for example, the note "to", is reinforced by an unconditioned stimulus, and the note "G" is not reinforced. After several repetitions, the note "do" will cause a positive conditioned reflex, and the note "salt" will cause an inhibitory one.

Delayed inhibition occurs when a conditioned stimulus is reinforced by an unconditioned stimulus after a certain time. For example, they turn on the light, and reinforce with food only after 3 minutes. The separation of saliva after delayed inhibition has been developed begins by the end of the third minute.

A conditioned brake occurs when some indifferent stimulus is added to the conditioned stimulus to which the conditioned reflex was developed, and this new complex stimulus is not reinforced.

Features of higher nervous activity of a person. The behavior of any animal is simpler than that of a human being. The features of the higher nervous activity of a person are a highly developed mental activity, consciousness, speech, the ability to abstract-logical thinking. Higher nervous activity of a person was formed historically in the course of labor activity and the need for communication. Based on the features of the higher nervous activity of humans and animals, I.P. Pavlov developed the doctrine of the first and second signal systems. Animals and humans receive signals from the outside world through the corresponding sense organs. Perception of the surrounding world, associated with the analysis and synthesis of direct signals that come from visual, auditory, olfactory and other receptors, making up the first signal system. The second signaling system arose and developed in humans in connection with the appearance of speech. It is absent in animals. The signal meaning of a word is not associated with a simple sound combination, but with its semantic content. The first and second signal systems are in a person in close interaction and interrelation, since the excitation of the first signal system is transmitted to the second signal system.

Emotions. Emotions are the reactions of animals and humans to the impact of external and internal stimuli that have a pronounced subjective coloring and cover all types of sensitivity. Distinguish between positive emotions: joy, pleasure, pleasure, and negative: sadness, sadness, displeasure. Different types of emotions are accompanied by various physiological changes and mental manifestations in the body. For example, with sadness, embarrassment, fear, the tone of skeletal muscles decreases. Sadness is characterized by vasospasm, fright - relaxation of smooth muscles. Anger, joy are accompanied by an increase in the tone of skeletal muscles, with joy, in addition, blood vessels dilate, with anger, coordination of movements is upset, and blood sugar levels increase. Emotional arousal mobilizes all the reserves available to the body.

In the process of evolution, emotions have formed as a mechanism of adaptation. Positive emotions play a huge role in human life. They are important for maintaining human health and performance.

Memory. The accumulation, storage and processing of information is the most important property of the nervous system. There are two types of memory: short-term and long-term. Short-term memory is based on the circulation of nerve impulses through closed neural circuits. The material basis of long-term memory is various structural changes in neuron circuits caused by electrochemical processes of excitation. Peptides produced by nerve cells and affecting the memory process have now been found. The neurons of the cerebral cortex, the reticular formation of the brain stem, and the hypothalamic region are involved in the formation of memory. There are visual, auditory, tactile, motor and mixed memory, depending on which of the analyzers plays the main role in this process.

Sleep and wakefulness. The alternation of sleep and wakefulness is a necessary condition for human life. The brain is kept awake by impulses coming from receptors. In the waking state, a person actively interacts with the external environment. When the flow of impulses to the brain is stopped or sharply limited, sleep develops. During sleep, the physiological activity of the body changes: muscles relax, skin sensitivity, vision, hearing, and smell decrease. Conditioned reflexes are inhibited, breathing is rare, metabolism, blood pressure, heart rate are reduced.

According to electroencephalography (EEG), a person in a dream alternates two main phases of sleep: the phase of slow-wave sleep - a period of deep sleep, during which slow activity (delta waves) can be recorded on the EEG, and the phase of paradoxical, or fast-wave, sleep, during which rhythms characteristic of the state of wakefulness are recorded on the EEG. In this phase, rapid eye movements are observed, the pulse and respiration rate increases; man sees dreams. This phase occurs approximately every 80-90 minutes, its duration is an average of 20 minutes.

Sleep is a protective adaptation of the body, protecting it from excessive irritations and making it possible to restore working capacity. During sleep, in the higher parts of the brain, the information received during the wakefulness period is processed. According to the reticular theory of sleep and wakefulness, the onset of sleep is associated with the suppression of the ascending influences of the reticular formation, which activate the higher parts of the brain. The mediators serotonin and norepinephrine play an important role in the regulation of the sleep-wake cycle.

Functional system of a behavioral act.Functional system as an integrative formation of the brain. The most perfect model of the structure of behavior is set forth in the concept of the functional system by P.K. Anokhin. Functional system- this is a unit of the integrative activity of the body that selectively involves and combines structures and processes aimed at performing any behavioral act or function of the body.

The functional system is characterized by dynamism, the ability to restructure, selective involvement of brain structures for the implementation of behavioral reactions. There are two types of functional systems of the body: 1. Functional systems of the homeostatic level of regulation ensure the constancy of the constants of the internal environment of the body (body temperature, blood pressure, etc.); 2. Functional systems of the behavioral level of regulation provide adaptation of the body through behavioral change.

Stages of a behavioral act. According to P.K. Anokhin, the physiological architecture of a behavioral act is built from sequentially replacing each other stages: afferent synthesis, decision making, acceptor of the results of action, efferent synthesis (action program), formation of the action itself and evaluation of the results achieved.

Afferent synthesis consists in processing and comparing all the information that is used by the body to make a decision and form the most adequate adaptive behavior. Excitation in the CNS caused by an external stimulus does not act in isolation. It interacts with other afferent excitations that have a different functional meaning. The brain produces a synthesis of all signals coming through various channels. And only as a result of this, conditions are created for the implementation of purposeful behavior. In turn, afferent synthesis is determined by the influence of several factors: motivational excitation, situational afferentation, memory, and triggering afferentation.

Motivational arousal arises in the central nervous system with the appearance of any need in humans and animals, it has a dominant character, i.e. suppresses other motivations and directs the behavior of the organism to achieve a useful adaptive result. Dominant motivation is based on the mechanism of A.A. Ukhtomsky.

situational afferentation represents the integration of excitations under the action of the environment on the body. It can promote or, on the contrary, hinder the implementation of motivation. For example, a feeling of hunger that arises at home causes actions aimed at its satisfaction, and if this feeling arises at a lecture, then behavioral reactions associated with the satisfaction of this need do not occur.

Starting afferentation associated with the action of the signal, which is a direct stimulus for triggering a particular behavioral response. An adequate reaction can be carried out only with the interaction of situational and triggering afferentation, which creates pre-launch integration of nervous processes.

Usage memory apparatus occurs when incoming information is evaluated by comparison with memory traces related to a given dominant motivation. Completion of the stage of afferent synthesis is accompanied by a transition to the stage of decision making.

Under decision understand the selective involvement of a complex of neurons, which ensures the occurrence of a single reaction aimed at satisfying the dominant need. The body has many degrees of freedom in choosing a response. When making a decision, one behavioral response is selected, all other degrees of freedom are inhibited. The stage of decision-making is realized through the stage of formation of the acceptor of the results of the action.

Action result acceptor − it is a neural model of the intended outcome. It is formed in the cerebral cortex and subcortical structures due to the involvement of neuronal and synaptic formations in the activity, determining the architecture of the distribution of excitations. Excitation, once in the network of intercalary neurons with ring connections, can circulate in it for a long time, ensuring the retention of the goal of behavior.

Then develops stage of the program of action (efferent synthesis). At this stage, the integration of somatic and vegetative excitations into a holistic behavioral act is carried out. This stage is characterized by the fact that the action is already formed as a central process, but externally it is not realized.

Formation stage action result characterized by the implementation of a program of behavior. Efferent excitation reaches the executive mechanisms and the action is carried out. Thanks to the acceptor of the results of the action, in which the purpose and methods of behavior are programmed, the organism can compare them with afferent information about the results and parameters of the action being performed.

If the signaling of the completed action fully corresponds to the programmed information contained in the acceptor of the results of the action, then the search behavior is completed, the need is satisfied, the person and the animal calm down. In the case when the results of the action do not coincide with the acceptor of the action and their mismatch occurs, then the afferent synthesis is rebuilt, a new acceptor of the results of the action is created, and a new action program is built. This happens until the results of the behavior match the new action acceptor. Then the behavioral act ends.

Higher nervous activity I

integrative activity of the brain, which ensures the individual adaptation of higher animals and humans to changing environmental conditions. Scientific ideas about V. n. were developed by the school of Academician I.P. Pavlova on the basis of the doctrine of the conditioned reflex (Conditioned reflexes) . At the heart of V. n. The physiological mechanisms of unconditioned reflexes (Unconditioned reflexes) and the conditioned reflexes that are formed on their basis in the process of ontogenesis lie. genetically determined, inherent in a certain type of organisms and form, ensuring their survival in relatively constant environmental conditions. Individually acquired forms of behavior that ensure the adaptation of humans and animals to changing environmental conditions are possible only through training, which is based on the neurophysiological mechanisms of memory (Memory) .

The main patterns of V. n. are based on the physiological mechanisms of the formation and disappearance of conditioned reflexes. For the formation of conditioned reflexes, the appearance of a c.n.s. in the structures is necessary. temporal connection between neurons that perceive the conditioned, and neurons that are part of the structure of unconditioned reflexes. A conditioned reflex occurs when some (conditional) is reinforced by an unconditioned one. Due to temporary connections of varying complexity, previously indifferent stimuli that precede this or that activity become a signal of this activity. Acquiring a signal value, the conditioned stimulus leads to the appearance in the central nervous system. excitation, advancing the structures of the brain, providing the formation of future behavior. Such anticipatory excitation not only provides a biologically expedient adaptation of the organism to the environment, but also underlies the active influence on this environment.

In the mechanisms of V.'s formation, n. d. animals and humans, along with conditioned reflex excitation in the central nervous system. braking processes are always involved. There are two types of inhibition: external (unconditional) and internal (conditional). The external arises in the case of the sudden appearance of an extraneous stimulus and is manifested by the fact that the conditioned stimulus is not formed at all or, having begun, stops. A variation of external inhibition is transmarginal inhibition, which is noted with an excessive increase in the strength of the conditioned stimulus. Internal inhibition occurs when the conditioned stimulus is not reinforced by the unconditioned stimulus. Depending on the conditions for the formation of internal inhibition, the following types of it are distinguished: extinction, differential, conditional brake, retarded (see Braking) . The interaction of the processes of conditioned reflex excitation and internal inhibition makes it possible for animals and humans to navigate in the most difficult situations. At the same time, if he constantly performs approximately the same and sequential actions in time, then various stimuli, which are conditional in relation to the ongoing actions, create a stereotype of their performance. The sequence of excitations that occurs in this case in the cerebral cortex and leads to a certain sequence of behavioral acts performed is called a dynamic stereotype. A sharp violation of the dynamic stereotype that has developed throughout a person’s life can cause the development of various diseases and premature aging.

The higher nervous activity of an individual animal (of the same species) and a person has individual characteristics, primarily associated with the innate properties of the central nervous system. (his genotype). Individual development, the possibility of learning skills are determined by differences in the speed and strength of the resulting conditioned reflexes, the intensity of external and internal inhibition, the speed of irradiation and the concentration of nervous processes (i.e., the phenotype). The totality of the genotypic and phenotypic features of an organism determines its V. n. There are four main types of V. n. in animals, which in terms of the main indicators (strength, mobility and balance of the processes of excitation and inhibition) are similar to the classical idea of ​​temperaments in humans. strong, unbalanced with a predominance of excitation coincides with the choleric temperament; strong, balanced, sedentary type - with phlegmatic; strong, balanced, mobile - with sanguine; weak, quickly exhausted, inactive - with melancholic.

The main patterns of V. n. are common in animals and humans. and synthesis of stimuli (signals) from the outside world in the central nervous system. constitute the first signaling system. In humans, unlike animals, along with the first, there is a second signal associated with speech. The word for a person is not only a sound, but also a semantic signal. for example, the word "forward" for a dog only serves as a start signal. For a person, this word can mean the manifestation of a wide variety of forms of activity. The development of verbal signaling made it possible to distract a person from this particular life situation and at the same time generalize many surrounding phenomena. The first and second signaling systems in humans are inseparable from each other. Only in a child before mastering speech, and in an adult in cases of pathology, there can be a separate functioning of the first signaling system.

At the same time, there are differences in the ratio of the development of the first and second signaling systems in different people, which allowed I.P. Pavlov to allocate particular types of V. n. (artistic, mental and intermediate, or average).

With the artistic type of V. n. e. manifestations of the first signal system predominate. Such people are distinguished by a pronounced figurative-emotional type of thinking, extraordinary sharpness, brightness and completeness of direct perception of reality. Most often this type of V. n. e. inherent in artists, writers, musicians, artists; thinking type V. n. d. is characteristic of a person with a tendency to abstract verbal thinking, i.e. with the predominance of the second signal system. People of the thinking type are most often found among scientists, public figures, and lawyers. With the average type of V. n. e. the first and second signaling systems are equally significant for human perception of the environment. To this type V. n. applies to most people.

The complexity and versatility of V. n. in various animals and humans are closely related to the development of the cerebral cortex. Modern methods of research V. n. (, stereotaxic and microelectrode technique, irritation and self-irritation of brain structures) showed a different degree of participation of brain structures in the formation of V. n. e. Intracerebral processes during the formation of V. n. is considered not as a local mechanism for establishing a temporary connection between the foci of conditioned and unconditioned excitation in the cerebral cortex, but as an interaction of excitations associated with the formation of motivations (Motivation) , with memory mechanisms and the work of analyzers (Analyzers) . Within the framework of the theory of functional systems of Academician P.K. Anokhin, the interaction of excitations begins at the stage of afferent synthesis, which is a systemic process of comparison, integration and selection in the structures of the central nervous system. numerous streams of excitations, diverse in functional significance for the body (see. Functional systems) . This can be carried out not only in individual brain structures, but also at the level of individual nerve cells, based on the convergence of multimodal excitations. The subsequent interaction between cells is determined by the mechanisms of functional relationships between individual structures of the brain. First of all, these are the mechanisms of ascending activating influences of subcortical formations on the cerebral cortex (see Subcortical functions) . The unification of the cerebral cortex and subcortical structures is also facilitated by corticofugal influences, which activate the reticular formation of the brain stem and create flows of recurrent generalized influences on the cortex. On this basis, cortical-subcortical reverberation (circulation) of excitations and centrifugal tuning of peripheral receptors can occur, which makes it possible to eliminate excess information. Elimination of redundant information in the CNS there is, in essence, a transition to the next stage of the systemic organization of intracerebral processes - the decision-making stage. As a result of afferent synthesis, it has the ability to perform an infinite number of behavioral acts, the decision-making stage contributes to the formation of an action program. At this stage, a dynamic combination of somatic and vegetative functions is carried out into a holistic behavioral act aimed at obtaining a result useful for the body. Simultaneously with the formation of the program of action in the senior researcher. formed physiological foresight and evaluation of the results of action - . It “anticipates” the afferent properties of the result that should be obtained in accordance with the decision made and, therefore, anticipates the course of events in the relationship between the organism and the outside world. Comparison of the parameters of the result of the action in the form of excitations going to the c.n.s. from peripheral receptors, with an “afferent model” of the result presented in the apparatus of the acceptor of the results of the action, is carried out on the basis of the return afferentation (feedback) entering the brain structures. If the inverse does not correspond to the parameters of the programmed result of behavior, an orienting-exploratory organism arises, accompanied by a search for new forms of adaptive behavior. Such a discrepancy, called mismatch, is the basis for the occurrence of V.'s violations of n. manifested by neurosis, emotional stress. This is confirmed by the so-called experimental studies studied in the laboratories of I.P. Pavlova. The discrepancy between the formed goals of behavior and the physiological possibilities of achieving them, determined by the type of higher nervous activity in each person, is often the cause of diseases. On this basis, medical tactics in treatment can be developed using not only pharmacological drugs, but also non-drug methods of therapy.

Bibliography: Anokhin P.K. System mechanisms of higher nervous activity, M., 1979; Asratyan E.A. Reflex theory of higher nervous activity, M., 1983; Simonov P.F. Higher nervous activity of a person, M., 1975.

1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First aid. - M.: Great Russian Encyclopedia. 1994 3. Encyclopedic dictionary of medical terms. - M.: Soviet Encyclopedia. - 1982-1984.

See what "Higher nervous activity" is in other dictionaries:

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Books

• Physiology and ethology of animals in 3 parts. Part 3. Endocrine and central nervous systems, higher nervous activity, analyzers, ethology. Textbook and workshop for SPO, Skopichev VG This textbook is a presentation of the basic physiological functions of the body. Focusing on modern scientific data, the authors revealed the essence of the mechanisms of the nervous, humoral and ...

GNI is the activity of the higher departments of the central nervous system, which ensures the most perfect adaptation of animals and humans to the environment. According to I.P. Pavlov, GNI is based on conditioned and unconditioned reflexes. In the process of evolution, conditioned reflexes begin to dominate in behavior. Significance of higher nervous activity: 1. normal interactions between the organism and the outside world are ensured. 2. the regulation of the work of internal organs is carried out. 3. the existence of the organism as a whole is ensured. In 1863 Ivan Mikhailovich Sechenov published a paper entitled "Reflexes of the Brain". A reflex is the action of some cause - a physiological stimulus. According to I.M. Sechenov, brain reflexes include three links: 1. The first is excitation in the sense organs caused by external influences. 2.Second - the processes of excitation and inhibition occurring in the brain. 3.Third - the movements and actions of a person, i.e. his behavior. All these links are interconnected and conditioned.

1. The difference between conditioned reflexes and unconditioned.

Reflex - This is the body's response to irritation of receptors, carried out by the nervous system. The path along which the nerve impulse passes during the implementation of the reflex is called the reflex arc.

Unconditional: present from birth during life they do not change and do not disappear; the same in all organisms of the same species; adapt the body to constant conditions; the reflex arc passes through the spinal cord or brain stem.

Conditional : acquired during life, may change or disappear during life, each organism has its own, individual

Development of a conditioned reflex

Conditional (indifferent) stimulus must precede the unconditioned (causing unconditioned reflex). For example: a lamp is lit, after 10 seconds the dog is given meat.

Braking: Conditional (non-reinforcement): the lamp is lit, but no meat is given to the dog. Gradually, salivation to the switched on lamp stops (there is a fading of the conditioned reflex).

Unconditional: during the action of a conditioned stimulus, a powerful unconditioned stimulus arises. For example, when the lamp is turned on, the bell rings loudly. Saliva is not secreted.

1. The mechanism of formation of conditioned reflexes.

Under the action of a conditioned stimulus, a focus of excitation appears in the cortex. After excitation of unconditional irritation, 2 foci appeared. Between the foci there is a closure (temporary connection).

Education takes place on the principle of dominance. The focus of excitation from an unconditioned stimulus is always stronger than from a conditioned one. A stronger focus of excitation from the unconditioned stimulus attracts excitation from the focus of the conditioned stimulus. The degree of his arousal will increase. The dominant focus has the property of a long, stable existence. Consequently, conditioned and unconditioned excitations will interact with each other for a long time.

1. Conditioned reflexes. Conditions necessary for their formation.

1. The action of the conditioned stimulus must precede the impact of the unconditioned one.

2. A multiple combination of conditioned and unconditioned stimuli is necessary.

3. unconditioned stimuli must be strong enough.

4. no extraneous external irritations.

5. the presence of motivation.

1. Inhibition of conditioned reflexes: unconditioned and conditioned.

Unconditional braking - this is a rapid suppression of reflex activity. External - weakening or termination of the conditions of the reflex with an extraneous stimulus. Fading - an extraneous signal that is repeated. Beyond - arises under the action of a conditioned stimulus, yav protective.

Conditional inhibition- it develops slowly, consists in the elimination of activities that are not needed at a given time. Fading - occurs when the conditioned signal is reattached and fixed. Delayed - arose in the absence of fixing 2-3 minutes from the beginning of the unconditional signal. Differentiation - under the action of additional stimulation close to conditional and unreinforced. Conditioned inhibition - occurs when another and unreinforced stimulus is added to the conditioned stimulus.

1. Analysis and synthesis of irritations.

Analysis lies in the fact that with the help of emerging sensations, the body distinguishes existing stimuli (qualitatively - light, sound, etc.) A huge amount of information enters the central nervous system from the peripheral sections of the analyzers, but a significant part of it is eliminated using braking mechanisms - sensory relays .

Synthesis consists in the perception of an object, phenomenon and the formation of an organism's response. Perception is possible in two ways: when an object or phenomenon occurs again or for the first time. Recognition (gnosis) is achieved as a result of comparing the information that is received at the moment with traces of memory.

1. I and II 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 irritation 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 signal system has a social coloring. The first signal system in animals and humans provides subject-specific thinking. The second signal system arose and developed as a result of human labor activity and the appearance of speech. Labor and speech contributed to the development of the hands, the brain and the sense organs. The activity of the second signaling system is manifested in conditioned speech reflexes. The second signaling system provides abstract thinking in the form of concepts, judgments, conclusions.

1. dynamic stereotype.

dynamic stereotype- a stable sequence of conditioned reflexes developed and fixed in the human or animal cerebral cortex. In order to form a dynamic stereotype, a complex of stimuli must act on the body in a certain order and at certain intervals (external stereotype). The stereotype is called dynamic because it can be destroyed and re-formed when the conditions of existence change. 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. 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.

1. Types of human GNI.

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).

Strong unbalanced type. It is characterized by strong unbalanced and mobile nervous processes. Weak braking type. It is characterized by weak unbalanced nervous processes. Strong balanced mobile type. Strong balanced inert type.

I. P. Pavlov identified four main types, using the terminology of Hippocrates to designate them: melancholic, choleric, sanguine, phlegmatic.

Choleric is a strong, unbalanced type. These are very energetic people, but excitable and quick-tempered. Melancholic is a weak type. Sanguine is a strong, balanced and mobile type. Phlegmatic - a strong and balanced sedentary type.

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 . the first signaling system prevails over the second . thinking type . the second signaling system significantly predominates over the first. Medium type.

1. Children's nervousness.

In the nervous system of children in the first years of life, the resulting excitation easily radiates, leading to general motor restlessness, and prolonged or severe irritation leads to inhibition. As more and more conditioned connections are formed and the higher nervous activity becomes more complex, the action of excessive stimuli affects the child's behavior more and more. With a weak type of higher nervous activity, the child becomes shy, touchy, often cries, trembles; with an excitable type - undisciplined, capricious, quick-tempered, overly mobile, fussy. Such children are called nervous. Children of the other two types (balanced mobile and balanced slow) can also be nervous, but their nervousness, as a rule, manifests itself much weaker.

1. Memory, its types. Mechanisms of short- and long-term memory.

1. Neurophysiological foundations of mental activity (perception, attention, motivation, thinking, consciousness).

Consciousness- it is a perfectly subjective reflection through the brain of real activity. Feeling - a form of direct reflection in the mind of a person, presets, properties. Perception is one of the forms of mental activity that consists in recognizing an object. Representation is an ideal image of an object, the appearance of which at the moment does not affect the senses. Attention is a state of active wakefulness. Motivation - an impulse to action; a dynamic process of a psychophysiological plan that controls human behavior, determines its direction, organization, activity and stability; a person's ability to actively satisfy his needs.

1. The mechanism of sleep and wakefulness, dreams.

Sleep is a physiological need of the body. It takes up about 1/3 of a person's life.

Sleep phases: slow (75-80%), fast (10-25%). 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.

Mechanism: slow - drowsiness - falling asleep - superficial sleep - moderately deep - deep sleep. Fast: signs of rapid eye movement, a strong decrease in tone, convulsive movements, increased blood pressure.

1. Attention. Its physiological mechanisms and role in memory processes.

Attention is the direction and concentration of a person's mental activity, expressing the activity of the individual at a given moment and under given conditions, including the regulation and control of mental processes and being an integral part of them, characterizing the dynamics of their processes. types of attention.
1. Involuntary - this is the concentration of consciousness on an object due to the peculiarity of this object as an irritant (strong, contrasting or significant and causing an emotional response).
2. Arbitrary attention - activity; consciously aimed at controlling their behavior and maintaining the stability of electoral activity. The leading role in its mechanisms belongs to the second signaling system. Physiological mechanisms of attention. To understand the physiological foundations of attention, the law of induction of nervous processes is very important, according to which excitation processes that occur in one area of ​​the cerebral cortex cause inhibition in other areas. At each moment of time in the cortex there is a focus of increased excitability, characterized by the most favorable conditions for excitation.

1. Emotions. Their classification and neurophysiological mechanisms.

Emotions are mental reactions that reflect the subjective attitude of the individual to objective phenomena. Emotions arise as part of motivations and play an important role in shaping behavior. There are 3 types of emotional states: 1. Affects - strong, short-term emotions that arise on an already existing situation. 2. Actually emotions are long-term states that reflect the attitude of an individual to an existing or expected situation. Sadness, anxiety, joy.

3. Objective feelings - constant emotions associated with any object (feeling of love for a particular person, for the Motherland, etc.).

When the amygdala is irritated, a person develops fear, rage, and anger. In humans, the frontal and temporal areas of the cortex play an important role in the formation of emotions. For example, if the frontal areas are damaged, emotional dullness occurs. An important role in the emergence of emotions belongs to the balance of neurotransmitters. For example, if the content of serotonin in the brain increases, mood improves, with its deficiency, depression is observed. The same picture is observed with a lack or excess of norepinephrine. Suicides have been found to have significantly reduced brain levels of these neurotransmitters.

The type of higher nervous activity is based on the individual characteristics of the course in two ways: and inhibition. According to the views of I.P. Pavlov, there are three main properties of nervous processes:

1) The strength of the processes of excitation and inhibition (associated with the performance of nerve cells).

The strength of excitation processes characterized by: high performance; initiative; decisiveness; courage; courage; perseverance in overcoming life's difficulties; the ability to solve difficult situations without disruption of nervous activity.

The strength of the braking processes characterized by: self-control; patience; a high ability to concentrate, to differentiate the permissible, the possible from the unacceptable and impossible.

Weakness of nervous processes characterized by: low performance; increased fatigue; weak endurance; indecisiveness in difficult situations, and the rapid onset of neurogenic breakdowns; the desire to avoid difficulties, obstacles, active work and stress; little initiative; lack of perseverance.

2) (associated with the ratio of the processes of excitation and inhibition in terms of their strength).

Balance of nervous processes characterized by: smooth and attitude towards people; restraint; the ability to self-control, concentration, expectation; the ability to fall asleep easily and quickly; smooth speech, with correct and expressive intonation.

Unbalance with a predominance of excitation characterized by: increased impressionability; nervousness, and in a strong type this is expressed in a tendency to scream, in a weak type - in withdrawing into oneself, in tearfulness; restless with frequent nightmarish content; fast speech (patter).

3) Mobility of the processes of excitation and inhibition (associated with the ability of nervous processes to replace each other).

Mobility of nervous processes characterized by: a fairly easy and quick transition to a new business; rapid alteration of habits and skills; ease of falling asleep and waking up.

Inertia of nervous processes characterized by: the difficulty of transition to a new business and alteration of habits and skills; difficulty waking up; calm with dreams without nightmares; slow speech.

On the basis of all possible combinations of the three basic properties of nervous processes, a great variety is formed. According to the classification of I.P. Pavlov, there are four main types of GNI , differing in resistance to neurotic factors and adaptive properties.

1) Strong, unbalanced , ("unrestrained") type characterized by strong excitatory processes that prevail over inhibition. This is a person who is addicted; with a high level of activity; vigorous; hot-tempered; irritable; with strong, quickly emerging, clearly reflected in speech, gestures, facial expressions.

2) Strong, balanced, mobile (labile or live) type is different strong processes of excitation and inhibition, their balance and the ability to easily change from one process to another. This is a man with great self-control; decisive; overcoming difficulties; vigorous; able to quickly navigate in a new environment; mobile; impressionable; with a bright expression and their easy changeability.

3) Strong, balanced, inert (calm) type characterized strong processes of excitation and inhibition, their balance, but low mobility of nervous processes. This is a very efficient person; able to restrain; calm; slow; with a weak manifestation of feelings; difficult to switch from one activity to another; does not like to change his habits.

4) Weak type is different weak excitatory processes and easily occurring inhibitory reactions. This is a weak-willed person; sad; dreary; with high emotional vulnerability; suspicious; prone to gloomy thoughts; with a depressed mood; closed; shy; easily influenced by others.

These types of higher nervous activity correspond to the temperaments described by Hippocrates:

However, such “pure” ones are rare in life, usually the combination of properties is more diverse. I.P. Pavlov also wrote that between these main types there are “intermediate, transitional types and you need to know them in order to navigate in human behavior.”

Along with the indicated types of GNI common to humans and animals, I.P. Pavlov singled out specifically human types (private types) based on the different ratio of the first and second signal systems:

1. Art type characterized by a slight predominance of the first signal system over the second. Representatives of this type are characterized by objective, figurative perception of the surrounding world, operating in the process with sensual images.

2. thinking type differs in the predominance of the second signal system over the first. This type is characterized by a pronounced ability to abstract from reality, to a subtle analysis; operating in the process of thinking with abstract symbols.

3.Medium type characterized by the balance of signal systems. Most people belong to this type, they are characterized by both figurative and speculative conclusions.

This classification reflects the nature of the functional interhemispheric asymmetry of the brain, the features of their interaction.

The doctrine of the types of higher nervous activity is important for understanding the patterns of formation of such important psychological characteristics of a person as temperament and character. The type of GNI is the physiological basis of temperament. However, the type of GNI can be reduced to temperament, because the type of GNI is a physiological property of a person, and temperament is a psychological property of a person and is related to the dynamic side of a person’s mental activity. It should be remembered that temperament does not characterize the content side of the personality (a person's worldview, beliefs, views, interests, etc.). Features of the GNI type and the prevailing temperament form the natural basis of the individual uniqueness of the personality.