There are many various kinds conditioned reflexes. First of all, there are natural and artificial conditioned reflexes. natural called conditioned reflexes that arose in response to such stimuli, which in vivo life act together with unconditioned stimuli. For example, the sight and smell of meat triggers a food reaction in a dog with saliva. However, if meat is not given to a dog from birth, when it first sees it, it will react to it simply as an unfamiliar object. And only after the dog has eaten meat, it will have a conditioned reflex food reaction to its appearance and smell.

artificial called specially developed conditioned reflexes to conditioned stimuli, which in Everyday life unrelated to the given unconditioned stimulus. If you combine the sound of a bell with a blow electric shock, the dog will have a painful defensive reflex - at the sound of a call, it will pull back its paw. This is an artificial conditioned reflex, since the sound of a call is not at all endowed with the property of causing pain. To the same sound in another dog, you can develop a food reflex by combining a call with feeding.

Conditioned reflexes can be divided into groups depending on the unconditioned reflex on the basis of which they are formed: food, defensive, motor conditional reflexes. Often conditioned reflexes, especially natural ones, are complex. For example, smelling food, the dog not only salivates, but also runs to the source of this smell.

A conditioned reflex can be developed on the basis of not only an unconditioned, but also a well-established conditioned reflex. Such reflexes are called conditioned reflexes. second order. The animal first develops a first-order reflex, for example, by combining the flashing of a light bulb with feeding. When this reflex becomes strong, a new stimulus is introduced, say, the sound of a metronome, and its action is also reinforced by a conditioned stimulus - the flashing of a light bulb. After several such reinforcements, the sound of the metronome, never combined with feeding, will begin to cause salivation. This will be the conditioned reflex of the second order. Food reflexes third order do not form in dogs. But they can develop defensive (painful) conditioned reflexes of the third order. Reflexes of the fourth order in dogs can not be obtained. In children preschool age there may even be conditioned reflexes sixth order.

Among the many varieties of conditioned reflexes, it is customary to single out in special group instrumental reflexes . For example, in a dog, reinforcing the lighting of a light bulb by the appearance of a feeder with food develops a conditioned reflex to light - saliva is released. After that, they put more than difficult task: to get food after lighting the light bulb, she must press her paw on the pedal located in front of her. When the light is on and no food appears, the dog gets excited and accidentally steps on the pedal. Here comes the feeder. When such experiments are repeated, a reflex is developed - in the light of a light bulb, the dog immediately presses the pedal and receives food. Such a reflex is called instrumental because it serves as a tool for reinforcing the conditioned stimulus.

Related information:

1. A dynamic stereotype is a system of temporary neural connections in the cerebral cortex, corresponding to the system of action of conditioned stimuli

Higher nervous activity- a system that allows the human body and animals to adapt to changing conditions external environment. Evolutionarily, vertebrates have developed a number of innate reflexes, but their existence is not enough for successful development.

In the process of individual development, new adaptive reactions are formed - these are conditioned reflexes. An outstanding domestic scientist I.P. Pavlov is the founder of the doctrine of unconditioned and conditioned reflexes. He formed a conditioned reflex theory, which states that the acquisition of a conditioned reflex is possible when a physiologically indifferent stimulus acts on the body. As a result, a more complex system of reflex activity is formed.

I.P. Pavlov - the founder of the doctrine of unconditioned and conditioned reflexes

An example of this is Pavlov's study of dogs that salivated in response to a sound stimulus. Pavlov also showed that innate reflexes are formed at the level of subcortical structures, and new connections are formed in the cerebral cortex throughout the life of an individual under the influence of constant stimuli.

Conditioned reflexes

Conditioned reflexes are formed on the basis of unconditional, in the process of individual development of the organism, against the background of a changing external environment.

reflex arc The conditioned reflex consists of three components: afferent, intermediate (intercalary) and efferent. These links carry out the perception of irritation, the transmission of an impulse to the cortical structures and the formation of a response.

The reflex arc of the somatic reflex performs motor functions(for example, a flexion movement) and has the following reflex arc:

The sensitive receptor perceives the stimulus, then the impulse goes to the posterior horns of the spinal cord, where the intercalary neuron is located. Through it, the impulse is transmitted to the motor fibers and the process ends with the formation of movement - flexion.

A necessary condition for the development of conditioned reflexes is:

• The presence of a signal that precedes the unconditional;
• the stimulus that will cause the catching reflex must be inferior in strength to the biologically significant effect;
• the normal functioning of the cerebral cortex and the absence of distractions are mandatory.

Conditioned reflexes are not formed instantly. They are formed for a long time under the constant observance of the above conditions. In the process of formation, the reaction either fades away, then resumes again, until a stable reflex activity sets in.

An example of the development of a conditioned reflex

Classification of conditioned reflexes:

1. A conditioned reflex formed on the basis of the interaction of unconditioned and conditioned stimuli is called reflex of the first order.
2. Based on the classical acquired reflex of the first order, a second order reflex.

Thus, a defensive reflex of the third order was formed in dogs, the fourth could not be developed, and the digestive one reached the second. In children, conditioned reflexes of the sixth order are formed, in an adult up to the twentieth.

The variability of the external environment leads to the constant formation of many new behaviors necessary for survival. Depending on the structure of the receptor that perceives the stimulus, conditioned reflexes are divided into:

• Exteroceptive- irritation is perceived by body receptors, dominated by reflex reactions (gustatory, tactile);
• intraceptive- are caused by action on internal organs (changes in homeostasis, blood acidity, temperature);
• proprioceptive- are formed by stimulating the striated muscles of humans and animals, providing motor activity.

There are artificial and natural acquired reflexes:

artificial arise under the action of a stimulus that has no connection with an unconditioned stimulus (sound signals, light stimulation).

natural are formed in the presence of a stimulus similar to the unconditioned (smell and taste of food).

Unconditioned reflexes

These are innate mechanisms that ensure the preservation of the integrity of the body, homeostasis internal environment and most importantly, reproduction. Congenital reflex activity is formed in the spinal cord and cerebellum, controlled by the cerebral cortex. Characteristically, they persist for life.

reflex arcs hereditary reactions are laid down before the birth of a person. Some reactions are characteristic of a certain age, and then disappear (for example, in small children - sucking, grasping, searching). Others do not show themselves at first, but with the onset certain period appear (sexual).

Unconditioned reflexes are characterized by the following features:

• Occur independently of the consciousness and will of a person;
• species - appear in all representatives (for example, coughing, salivation at the smell or sight of food);
• endowed with specificity - appear when exposed to the receptor (pupil reaction occurs when a beam of light is directed to photosensitive areas). This also includes salivation, secretion of mucous secretions and enzymes. digestive system when food enters the mouth;
• flexibility - for example, different foods lead to the secretion of a certain amount and various chemical composition of saliva;
• on the basis of unconditioned reflexes, conditioned ones are formed.

Unconditioned reflexes are needed to fulfill the needs of the body, they are permanent, but as a result of illness or bad habits may disappear. So, with a disease of the iris of the eye, when scars form on it, the reaction of the pupil to light exposure disappears.

Classification of unconditioned reflexes

Congenital reactions are classified into:

• Simple(quickly remove your hand from a hot object);
• complex(maintaining homeostasis in situations of increased CO 2 concentration in the blood by increasing the frequency of respiratory movements);
• the most difficult(instinctive behavior).

Classification of unconditioned reflexes according to Pavlov

Pavlov divided innate reactions into food, sexual, protective, orienting, statokinetic, homeostatic.

To food refers to the secretion of saliva at the sight of food and its entry into the digestive tract, secretion of hydrochloric acid, motility of the gastrointestinal tract, sucking, swallowing, chewing.

Protective are accompanied by contraction of muscle fibers in response to an irritating factor. Everyone knows the situation when the hand reflexively pulls away from a hot iron or sharp knife, sneezing, coughing, lacrimation.

indicative occur when sudden changes occur in nature or in the organism itself. For example, turning the head and body towards sounds, turning the head and eyes to light stimuli.

Sexual associated with reproduction, preservation of the species, this includes parental (feeding and caring for offspring).

Statokinetic provide bipedalism, balance, movement of the body.

homeostatic- independent regulation blood pressure, vascular tone, respiratory rate, heart rate.

Classification of unconditioned reflexes according to Simonov

vital to maintain life (sleep, nutrition, economy of strength), depend only on the individual.

role-playing arise upon contact with other individuals (procreation, parental instinct).

The need for self-development(the desire for individual growth, for the discovery of something new).

Congenital reflexes are activated when necessary due to a short-term violation of internal constancy or variability of the external environment.

Table comparing conditioned and unconditioned reflexes

Comparison of the characteristics of conditioned (acquired) and unconditioned (innate) reflexes
Unconditional	Conditional
Congenital	Acquired in the course of life
Present in all members of the species	Individual for each organism
Relatively constant	Arise and fade with changes in the external environment
Formed at the level of the spinal cord and medulla oblongata	Carried out by the brain
Are laid in utero	Developed against the background of congenital reflexes
Occurs when an irritant acts on certain receptor zones	Manifested under the influence of any stimulus that is perceived by the individual

Higher nervous activity carries out work in the presence of two interrelated phenomena: excitation and inhibition (congenital or acquired).

Braking

External unconditional braking(congenital) is carried out by the action on the body of a very strong stimulus. The termination of the action of the conditioned reflex occurs due to the activation nerve centers under the influence of a new stimulus (this is transcendental inhibition).

When several stimuli (light, sound, smell) are simultaneously exposed to the organism under study, the conditioned reflex fades, but over time, the orienting reflex is activated and inhibition disappears. This type of inhibition is called temporary.

Conditional inhibition(acquired) does not arise by itself, it must be worked out. There are 4 types of conditional inhibition:

• Fading (disappearance of a persistent conditioned reflex without constant reinforcement by an unconditioned one);
• differentiation;
• conditional brake;
• delayed braking.

Braking is a necessary process in our life. In its absence, many unnecessary reactions would occur in the body that are not beneficial.

An example of external inhibition (the reaction of a dog to a cat and the SIT command)

The meaning of conditioned and unconditioned reflexes

Unconditioned reflex activity is necessary for the survival and preservation of the species. good example is the birth of a child. In the new world for him, many dangers await him. Due to the presence of innate reactions, the cub can survive in these conditions. Immediately after birth, the respiratory system is activated, the sucking reflex provides nutrients, touching sharp and hot objects is accompanied by an instant withdrawal of the hand (manifestation of protective reactions).

For further development and existence have to adapt to the surrounding conditions, this is helped by conditioned reflexes. They provide rapid adaptation of the body and can be formed throughout life.

The presence of conditioned reflexes in animals enables them to quickly respond to the voice of a predator and save their lives. A person at the sight of food carries out conditioned reflex activity, salivation begins, the production of gastric juice for the rapid digestion of food. The sight and smell of some objects, on the contrary, signals danger: the red cap of fly agaric, the smell of spoiled food.

The importance of conditioned reflexes in the daily life of man and animals is enormous. Reflexes help to navigate the terrain, get food, get away from danger, saving one's life.

CLASSIFICATION OF CONDITIONED REFLEXES

Conditioned reflexes are divided according to various criteria:

• according to biological significance: food, sexual, defensive, etc.;
• by the type of receptors that perceive the conditioned stimulus: exteroceptive, interoceptive and proprioceptive;
• by the nature of the response: motor, vascular, respiratory, indicative, cardiac, statokinetic, etc.;
• by complexity: simple and complex;
• in order of development of conditioned reflexes: first order, second, third, etc.

TYPES OF INHIBITION OF CONDITIONAL REFLEXES

The manifestation of complex conditioned reflex reactions that ensure the vital activity and adaptation of the organism to changing environmental conditions is possible only with a strictly balanced coordination of conditioned reflex mechanisms of regulation. This coordination is based on the simultaneous and coordinated excitation of some cortical nerve centers and the inhibition of others.

The biological significance of inhibition lies in the improvement of the necessary conditioned reflexes and in the disappearance of reflexes that have lost their necessity. Inhibition also protects the body from overexertion (protective inhibition).

All types of inhibition of conditioned reflexes are divided into two types: unconditioned (innate) and conditioned (acquired) inhibition. By finding the source of inhibition, unconditioned inhibition can be external, when the cause of inhibition is located outside the arc of the conditioned reflex, and internal. With internal inhibition, the source of inhibition is located inside the arc of the conditioned reflex.

Conditional inhibition can only be internal.

External unconditional inhibition of conditioned reflexes is manifested by a slowdown or complete cessation of conditioned reflex activity when a new stimulus arises that causes an orienting reaction. For example, if a dog has developed a conditioned salivary reflex to turn on a light bulb, then giving a sound signal when the light is turned on inhibits the previously developed salivation reflex.

There are two types of external braking - permanent brake and damping brake. Permanent brake - inhibition of the conditioned reflex by a one-time or reusable strong biological stimulus. So, if a dog has begun a conditioned reflex salivation at the sight of food, then a sudden strong sound irritation (thunder) causes a cessation of salivation. Burning brake - inhibition of the conditioned reflex by a repeatedly repeated stimulus with low biological significance. For example, if a fox's hole is not far from railway, then after a repeated sound stimulus (train noise), her orienting reaction to this sound fades.

Conditioned inhibition of conditioned reflexes is due to the development of an inhibitory reaction that suppresses a positive conditioned reflex. This type of inhibition is also called acquired.

Conditional inhibition is subdivided into four types: extinction, differential, conditional and retarded.

If a conditioned stimulus is not reinforced by an unconditioned stimulus for a long time, it loses its biological significance; fading inhibition and the conditioned reflex disappears.

Differential braking due to the ability of the animal to distinguish between similar stimuli and respond to only one of them. So, if a dog develops a salivary reflex to the light of a 100 W light bulb and reinforces it with food, and uses other similar stimuli (80 or 120 W light bulbs) without reinforcement, then through certain time reflexes on them fade away and a reflex appears only to a reinforced signal (100 W). This type of inhibition allows animals to develop new vital skills.

If the action of a certain conditioned stimulus with an already formed conditioned reflex is accompanied by the action of some other stimulus and this combination is not reinforced by the action of the unconditioned stimulus, then the conditioned reflex to the action of the conditioned stimulus also disappears. This extinction of the conditioned reflex is called conditional brake. For example, an animal has a reflex to the light of a light bulb. In the case of the simultaneous use of light and sound of the metronome for a certain time and not reinforcing it with giving food, after some time already one sound signal will inhibit the manifestation of a conditioned reflex to the light of a light bulb.

delayed braking develops when the reinforcement of the conditioned stimulus by the unconditioned stimulus is carried out with a large delay (by several minutes) in relation to the action of the conditioned stimulus.

important in animal life beyond, or protective, inhibition, which occupies an intermediate position between conditional and unconditional inhibition. This type of inhibition occurs when the conditioned or unconditioned stimulus is too strong, which contributes to the weakening or disappearance of the conditioned reflex reaction.

Stimuli that cause a conditioned reflex are called conditioned stimuli, or signals. For example, the sight and smell of food are natural, natural conditioned stimuli for animals. The conditioned response to these stimuli is called natural.

Natural conditioned stimuli close to natural environment habitats and corresponding to the living conditions of the animal (adequate), have especially great importance for his behavior (I. P. Pavlov, R. Ierks). But any stimulus can be made a food signal, before nutritionally indifferent to the body and natural conditions not related to food, such as ringing, flashing a light bulb, and other agents outside world. These stimuli are referred to as artificial conditioned stimuli. The conditioned response to these stimuli is called artificial. The number of such stimuli is infinite.

Any change in the surrounding world, as well as a change in the state of internal organs and the internal environment, can become a conditioned stimulus, if it reaches sufficient intensity and is perceived by the cerebral hemispheres.

Under natural conditions, almost all changes in the external world and internal state organisms do not become conditioned stimuli. Only very few of them can become conditional under certain conditions. Stimuli that previously caused unconditioned reflexes, for example, orienting or defensive, can also be turned into conditioned stimuli of food reflexes under certain conditions, most often artificial. Therefore, it cannot be considered that a conditioned reflex is a simple combination of two unconditioned reflexes. As a rule, a conditioned reflex - new form neural connection, and not the synthesis of two unconditioned, inherited reflexes.

Conditioned reflexes are also formed in animals to the ratio of stimuli that differ in some way, for example, in shape, color, weight, etc.

Conditions for the formation of conditioned reflexes

For the formation of a conditioned reflex, for example, a food reflex, the following conditions are necessary: ​​1. The action of a food-indifferent stimulus should, as a rule, begin earlier - precede the action of an unconditioned food stimulus. 2. The applied stimulus must not only precede, but also act for some time after the action of the unconditioned stimulus began, i.e., for some short period of time, coincide with the action of the latter. 3. The repeated use of the indifferent and unconditioned stimuli.

Thus, conditioned reflexes are formed, developed on the basis of unconditioned reflexes. Conditioned reflexes are formed faster to sound, more slowly - to visual, skin, even more slowly - to thermal conditioned stimuli. If the intensity of the conditioned stimulus is insufficient, conditioned reflexes are formed with difficulty or are not developed.

For the magnitude of conditioned food reflexes, the intervals between the applications of conditioned stimuli matter. Short-term intervals (4 min) reduce the conditional ones, and longer ones (10 min) increase, since the magnitude of the reflex depends on food excitability, the limit of working capacity and the speed of completion recovery processes in it (S. I. Galperin, 1941). The magnitude of the conditioned reflex is affected by the ratio between the intensity of the conditioned and unconditioned stimuli, which determines the amount of excitation in their centers, the content of hormones, mediators and metabolites. For example, in a hungry animal, food reflexes are developed easily and quickly, while in a satiated animal, they are difficult or not formed. “The ability of the salivary centers to react is determined by the different composition of the blood of a hungry and well-fed animal. From a subjective point of view, this would correspond to what is called attention (IP Pavlov, Poln. sobr. soch., vol. III, 1949, p. 31).

The main condition for the formation of a conditioned reflex is the closure of a temporary nervous connection between two foci of excitation that arose under the action of conditioned and unconditioned stimuli. This temporary nervous connection is formed and strengthened only when a sufficiently strong unconditioned stimulus is applied, which creates sufficient or predominant excitation in the focus of the unconditioned reflex. The unconditioned stimulus must have biological significance, i.e., to support and ensure the life of the organism or threaten its existence.

A conditioned stimulus that is not accompanied by an unconditioned one, not “reinforced” by it, ceases to act and loses its signal value. Therefore, conditioned reflexes are temporary connections of the organism with its environment, in contrast to unconditioned reflexes, which are relatively constantly reproduced when unconditioned stimuli act on receptors and are less dependent on environmental conditions. Even the simplest unconditioned reflexes are not absolutely constant, but relatively changeable and dynamic, but conditioned reflexes are many times more changeable and dynamic. This is a difference in reflexes, a greater or lesser dependence on external conditions underlined by IP Pavlov in the title itself - unconditioned and conditioned reflexes.

A conditioned reflex is easily formed on new stimuli, but this connection is just as easily terminated; the same stimulus under certain conditions can change its meaning and becomes a signal that causes another unconditioned reflex. This allowed I.P. Pavlov to conclude that an essential sign of higher nervous activity consists not only in the fact that countless signal stimuli act, but also in the fact that under certain conditions they change their physiological action. V. M. Bekhterev also discovered this "principle of switching", or variable signaling.

The rate of formation of conditioned reflexes depends on the type of animal, on its individuality, on its life experience, on age, on the functional state of the nervous system, on the nature of stimuli and their significance for the existence of the animal, on external conditions. Conditioned defensive reflexes are formed sooner than conditioned food reflexes.

The latent period of the food motor reflex is 0.08 s in the dog, and 0.06 s for the defensive one. The latent period of the conditioned secretory reaction is longer. In humans, the latent period of the conditioned motor reaction is longer than in animals, it is 0.2-0.3 s, and in some cases it decreases to 0.1 s. The latent period of the conditioned motor reflex is longer than the latent period of the unconditioned motor reflex. The stronger the irritation, the shorter the latent period.

In the laboratory, the subject is isolated from the effects of the external environment, that is, the action of extraneous stimuli is excluded, and the conditioned reflex is formed only when a conditioned stimulus is used, reinforced by an unconditioned one. In addition, in the laboratories of IP Pavlov, conditioned salivary reflexes were developed in dogs. Under these artificial conditions, it was proved that the conditioned reflex salivary gland is a copy of unconditioned reflex salivation. Vegetative conditioned reflexes are copies of unconditioned ones. But conditioned motor reflexes and especially motor skills differ significantly from unconditioned motor reflexes. If there were conditioned stimuli, then there would be no training and education. In this case, people could not acquire new forms of movement, work, household, sports and other skills, would not master speech.

Under natural conditions, along with the conditioned stimulus, extraneous stimuli certainly act, which correct the new movements produced in accordance with the conditions of life. The leading role in the correction of the developed motor skills of people belongs to speech stimuli, acting together with specific ones. Consequently, in the formation of new motor acts and speech movements (oral and writing) the main role belongs to the external feedback that enters the brain from the exteroreceptors (organs of vision, hearing, etc.) (S. I. Galperin, 1973, 1975). Simultaneously with the external figurative information, the correction of new movements is carried out by internal feedback, the arrival of impulses from the vestibular apparatus, proprioceptors and skin receptors. IP Pavlov emphasized the exceptional importance of kinesthesia (a combination of impulses from the motor apparatus and skin) in the formation of voluntary movements and speech. Therefore, new motor acts acquired during life do not repeat unconditioned motor reflexes, but correspond to the situation in which the organism is at the moment.

Kinesthetic impulses reflexively regulate movements mainly through spinal cord and brain stem. A smaller part of kinesthetic impulses enters the cerebral hemispheres.

Thus, higher nervous activity consists of exteroceptive and motor-cerebral reflexes, and lower - of myotatic, interoceptive, viscero-visceral and viscero-motor.

The synthesis of external and internal information takes place in the brain, causing and forming new forms of behavior of people and animals and the motor functions of people's oral and written speech. Under natural conditions, the formation and execution of new motor acts involves not only individual stimuli, but mainly complex information about the current situation and a program of previously learned motor acts. In humans, the decisive role in behavior and speech function belongs to social patterns. The physiological processes of the nervous system, caused by the receipt of external and internal feedback information, are interconnected with motor long-term memory.

Classification of conditioned reflexes according to receptor and effector features

The division of reflexes according to the receptor sign. one. Exteroceptive, formed under the action of a conditioned stimulus of the external world on the eye, ear, organs of smell, taste and skin receptors. 2. proprioceptive- with irritation of the receptors of the motor apparatus, with which the vestibular ones are associated - with irritation vestibular apparatus. Both groups of conditioned reflexes evoke mainly motor reflexes and therefore constitute the highest nervous activity. 3. Interoceptive- with irritation of the receptors of internal organs, related to lower nervous activity. They usually cause autonomic reflexes.

According to the effector basis, conditioned reflexes are divided into the following:

1. Automatic reflexes, formed by combining conditioned stimuli with the direct effect of various chemical stimuli on neurons hemispheres and subcortical centers through the blood. In the laboratory of I. P. Pavlov, after several injections of morphine (V. A. Krylov, 1925) or apomorphine (N. A. Podkopaev, 1914, 1926) to dogs, even before the introduction of these poisons into the blood, with only one rubbing of the skin in that place where the injection was made, or when pricked with a needle, or even only when the animal was placed in the machine in which the injection had previously been made, the picture of poisoning with these poisons already set in advance: profuse salivation, vomiting, defecation, drowsiness and sleep. Automatic reflexes are close to interoceptive ones, since during their formation the stimulation of the exteroceptors is also combined with the stimulation of the chemical receptors of the internal organs.

2. secretory reflexes(salivation reflexes, separation of gastric and pancreatic juices). The physiological significance of these reflexes is to prepare the organs of the alimentary canal for digestion before food enters it, which contributes to the process of digestion. K. S. Abuladze also studied conditioned tear reflexes. In the school of V. M. Bekhterev (1906), the conditioned reflex separation of milk in a sheep during the cry of a suckling lamb was studied.

3. Motor reflexes of skeletal muscles. In the school of IP Pavlov, they were studied in the development of conditioned reflexes to defensive and food unconditioned stimuli.

During the development of conditioned food reflexes, in addition to the secretory component of the food reaction, its motor component was also recorded - chewing, swallowing food (N. I. Krasnogorsky). A conditioned motor reflex can be developed in the form of a dog running to a signal stimulus to certain place room and to the feeder (K. S. Abuladze, P. S. Kupalov) or giving, or raising the animal's paw as a kinesthetic conditioned stimulus, which is reinforced by a defensive unconditioned stimulus (S. M. Miller and Yu. M. Konorsky, 1933, 1936 ).

In the laboratory of Yu. M. Konorsky (Poland), "instrumental" conditioned reflexes, or conditioned reflexes of the "second type", are formed. The dog, under the action of a conditioned stimulus, puts its paw on the pedal or presses on a special device that allows you to register the movement of the limb. This movement of the dog is reinforced by food. According to the hypothesis of Yu. M. Konorsky (1948), active conditioned connections between the two centers of the brain are established during the formation of "instrumental" conditioned reflexes only when potential connections between them have already developed in ontogenesis. The limbic system is the center of unconditioned reflexes of a higher order, connected by potential connections with the kinesthetic analyzer. These connections are transformed into active conditioned reflex connections in the process of training the movements produced by dogs during the formation of "instrumental" conditioned reflexes. Conditioned reflex movements cause tactile and proprioceptive impulses that enter the limbic system and cause the formation of conditioned reflex connections between the proprioceptive (kinesthetic) and motor areas (Yu. M. Konorsky, 1964).

Operant(Yu. M. Konorsky) are called instrumental reflexes of the 2nd type, developed in dogs upon receipt of proprioceptive impulses from the motor apparatus, for example, with repeated passive or active flexion of the paw in combination with food. These include pushing and grasping motor reflexes that allow you to get food from various closed devices (fish, turtles, birds, rats, mice, rabbits, dogs, monkeys). Electrical self-stimulation in rats of the brain is considered operant after they have been taught to press the pedal that closes the circuit with their paw (D. Olds). In case of self-irritation through the implanted electrodes of the centers positive emotions(in the hypothalamus, midbrain) the number of pressures can reach up to 8 thousand in 1 hour, and when the centers are stimulated negative emotions(in the thalamus) the pressure stops. Operant reflexes are formed on the basis of motor long-term memory - strengthened feedback unconditional and conditional centers with a motor analyzer. The high excitability of the motor analyzer due to the influx of proprioceptive impulses is essential.

In monkeys, a conditioned reflex was formed to open the feeder when pulling the stirrup or lever with the paw (D. S. Fursikov; S. I. Galperin, 1934), and in other animals, to pulling the ring or thread with their mouth or beak, after which they received food reinforcement.

Dogs developed conditioned alimentary motor reflexes to irritation of proprioceptors by reinforcing the displayed object with food, which differs from other objects that are identical with it in shape, color and other features, only by a certain weight (N. A. Shustin, 1953).

The enormous biological significance of conditioned motor food reflexes lies in the acquisition of food and in the preparatory changes in the functions of the digestive organs, which ensure the capture and mechanical processing of food and its movement through the digestive canal.

Conditioned motor reflexes are formed in dogs to intensify or inhibit contractions of the smooth muscles of the alimentary canal (SI Galperin, 1941).

Conditioned motor defensive reflexes are developed in response to skin irritation by electric current in animals of Tshkol, IP Pavlov or humans (school of V. M. Bekhterev; V. P. Protopopov et al., 1909), which causes a flexion reflex.

A. G. Ivanov-Smolensky studied the conditioned motor reflexes of children with “speech reinforcement”, that is, after a conditioned stimulus he gave a verbal order (command), I. P. Pavlov recommended a preliminary instruction for the formation of conditioned reflexes in subjects healthy people in other words, he took into account the role of consciousness.

extrapolation(L.V. Krushinsky) are called motor reactions of animals not only to a specific conditioned stimulus, but also the direction of its movement. These adequate movements in new conditions are produced immediately due to irradiation of excitation in nervous system and long-term motor memory.

Conditioned motor defensive reflexes are of exceptionally important biological significance. It consists in the fact that the organism avoids damage and death in advance, long before the damaging agents act directly on it. It has been proven that the action of conditioned stimuli can cause shock (S. A. Akopyan, 1961).

4. Cardiac and vascular reflexes. V. M. Bekhterev developed a method for studying conditioned cardiovascular reflexes in humans.

Cardiac conditioned reflexes were first formed by A.F. Chaly (1914). They are formed as a component of secretory and motor conditioned reflexes, but, as a rule, they appear before the conditioned secretory and motor response (W. Ghent, 1953).

It is possible to develop a conditioned reflex to slow down the heartbeat when pressing on the eyeball. IS, Tsitovich, (1917) developed conditioned vasomotor reflexes. For their study, plethysmography and electrocardiography are used. Conditioned motor-cardiac reflexes of changes in the work of the heart during movement are formed in children (V. I. Beltyukov, 1958). Conditioned reflexes to a persistent increase in blood pressure (hypertension) have been formed (W. Gent, 1960; S. A. Akopyan, 1961).

5. Conditioned reflex changes in breathing and metabolism in humans and animals were studied by employees of V. M. Bekhtereva, E. I. Sinelnikova and K. M. Bykov, who carried out extensive studies of conditioned reflex changes in pulmonary ventilation and gas exchange during muscular work and other conditions.

For the first time, conditioned respiratory reflexes in dogs were formed by V. M. Bekhterev and I. N. Spirtov (1907), and in humans - by V. Ya: Anfimov (1908).

6. Conditioned reflex changes in immunity. S. I. Metalshchikov (1924) developed a conditioned reflex to the formation of antibodies in the blood when the conditioned stimulus coincided with the introduction of a foreign protein or a killed bacterial culture into the body. A. O. Dolin and V. N. Krylov formed a conditioned reflex to agglutination (1951).

IV Zavadsky developed a conditioned reflex to leukocytosis in healthy people (1925).

V. M. Bekhterev (1929) observed an increase or decrease by 10-15% in the number of leukocytes in people during weak or moderate hypnotic sleep.

In the school of I. P. Pavlov, conditioned reflexes were developed for many functions of the body, in addition to those listed. In the school of L. A. Orbeli, a conditioned reflex to urinary retention was formed in animals. Under the action of a conditioned stimulus, motor, secretory, cardiovascular and other reflexes are simultaneously evoked. Conditioned alimentary and defensive reflexes, on which the work of IP Pavlov's school mainly focused, have been studied best of all.

It has been proved that under the action of conditioned stimuli it is possible to form a conditioned reflex to inhibition of the shock reaction. A conditioned reflex to changes that occur during blood loss has also been formed (S. A. Akopyan, 1961), conditioned reflexes to blood clotting (A. L. Markosyan, 1960).

A conditioned reflex to an increase in urination in humans was first formed by A. A. Ostroumov (1895).

When a conditioned reflex is developed for a certain function, for example, secretory or motor, under the action of the same conditioned stimulus, other conditioned reflexes are formed, for example, cardiac and respiratory. But the formation of various conditioned reflexes occurs in this case in different dates. This discrepancy in the formation of different conditioned reflexes is designated as schizokinesis (W. Gent, 1937).

Cash and trace conditioned reflexes

The indifferent stimulus lasts a short time(a few seconds), and then, even during its action, it is accompanied by giving food, “reinforced”. After several reinforcers, the previously indifferent stimulus becomes a conditioned alimentary stimulus and begins to cause salivation and a motor alimentary reaction. This is a conditioned reflex. But not just cash. an irritant can become a signal of an unconditioned reflex, but also a trace of this stimulus in the central nervous system. For example, if you apply light for 10 seconds, and why give food after 1 minute after its termination, then the light itself will not cause a conditioned reflex separation of saliva, but a few seconds after its termination, a conditioned reflex appears. Such a conditioned reflex is called a trace reflex (P. P. Pimenov., 1906). In this case, a temporary connection is formed in the brain between the cortical neurons of the food center, which are in a state of excitation, with the neurons of the corresponding analyzer, which have retained traces of excitation caused by the action of this conditioned stimulus. This means that in this case it is not the present conditioned stimulus that acts, but the trace of its action in the nervous system. Short trace reflexes are distinguished, when reinforcement is given a few seconds after the stimulus has ceased, and late ones, when it is given after a considerable time.

It is more difficult to form a conditioned reflex when an indifferent stimulus is applied after an unconditioned stimulus.

Conditioned reflexes for time

A certain period of time can become a conditioned stimulus (Yu. P. Feokritova, 1912). For example, if an animal is regularly fed every 10 minutes, then after several such feedings a conditioned reflex is formed for a while. In the absence of feeding, salivation and a food motor reaction begin around the 10th minute. In this case, both a short period of time and a very long one, measured by many hours, can become a conditioned stimulus.

The formation of a conditioned reflex for time occurs as a result of the formation of a temporary nervous connection between the focus of the cerebral hemispheres, into which correctly alternating afferent impulses enter, and the focus of the unconditioned reflex, which causes a motor reflex or a change in the function of an internal organ. Many periodic processes take place in the body, for example, the work of the heart, contractions of the respiratory muscles, etc. At the same time, afferent rhythmic impulses from these organs enter the corresponding perceiving areas of the cerebral hemispheres, which, by changes in their functional state, makes it possible to distinguish the rhythm of these signals and distinguish one moment of time from another.

IP Pavlov believed that time as a conditioned stimulus is a certain state of irritated neurons. A certain degree of this state of excitation as a result of internal or external (sunrise and sunset) rhythmic processes is a signal that a certain period of time has passed. It can be assumed that these reflexes are formed on the basis of inherited circadian (circadian) rhythmic biological processes that are rebuilt for a long time with changes in the external environment. In humans, synchronization of biorhythms with astronomical time occurs in about 2 weeks.

Conditioned reflexes are temporarily formed in dogs after dozens of reinforcements.

Conditioned reflexes of higher orders

It is possible to form a new conditioned reflex not only with reinforcement by an unconditioned, but also by a conditioned, firmly reinforced reflex (G. P. Zeleny, 1909). Such a reflex is called a second-order reflex, and the main, strong reflex, reinforced by an unconditioned stimulus, is called a first-order reflex. To do this, it is necessary that a new, previously indifferent stimulus, stop 10-15 seconds before the start of the action of the conditioned stimulus of the first-order conditioned reflex. The new indifferent stimulus must be much weaker than the main stimulus of the first-order reflex. Only under this condition does the new stimulus become a significant and permanent conditioned stimulus of the second-order conditioned reflex. With stimuli of medium physiological strength, this interval between two produced stimuli is approximately 10 s. For example, a strong food reflex to a bell was developed. If after that a black square is shown to the dog and then, having removed it, after 10-15 seconds, a call is given (without reinforcing the latter with food), then after several such combinations of showing the black square and using an unreinforced call, the black square becomes a conditioned food stimulus, despite the fact that that his display was never accompanied by food and was reinforced only by a conditioned stimulus - a call.

Under the action of a secondary conditioned food stimulus, the dog fails to form a third-order reflex. Such a reflex is formed in a dog only if the first-order conditioned reflex was developed on the basis of a defensive reflex, with reinforcement by a strong electric current applied to the skin. AT normal conditions the defensive reflex of the fourth order cannot be developed in dogs. Reflexes of higher orders provide a more perfect adaptation to the conditions of life. Children develop conditioned reflexes of the seventh and higher orders.

Individuals arise during the life and are not fixed genetically (not inherited). They appear under certain conditions and disappear in their absence. They are formed on the basis of unconditioned reflexes with the participation of higher parts of the brain. Conditioned reflex reactions depend on past experience, on the specific conditions in which the conditioned reflex is formed.

The study of conditioned reflexes is associated primarily with the name of I. P. Pavlov and I. F. Tolochinov. They showed that a new conditioned stimulus can trigger a reflex response if it is presented for some time along with the unconditioned stimulus. For example, if a dog is given a sniff of meat, then gastric juice is secreted from it (this is an unconditioned reflex). If the bell rings simultaneously with the appearance of meat, then the dog's nervous system associates this sound with food, and gastric juice will be released in response to the bell, even if meat is not presented. This phenomenon was discovered independently by Edwin Tweetmyer at about the same time as in the laboratory of IP Pavlov. Conditioned reflexes underlie acquired behavior. This is the most simple programs. The world is constantly changing, so only those who quickly and expediently respond to these changes can successfully live in it. As life experience is acquired, a system of conditioned reflex connections is formed in the cerebral cortex. Such a system is called dynamic stereotype. It underlies many habits and skills. For example, having learned to skate, bike, we subsequently no longer think about how we move so as not to fall.

Formation of a conditioned reflex

For this you need:

• The presence of 2 stimuli: an unconditioned stimulus and an indifferent (neutral) stimulus, which then becomes a conditioned signal;
• A certain strength of stimuli. The unconditioned stimulus must be strong enough to cause dominant excitation in the central nervous system. An indifferent stimulus must be familiar so as not to cause a pronounced orienting reflex.
• Repeated combination of stimuli in time, and the indifferent stimulus should act first, then the unconditioned stimulus. In the future, the action of 2 stimuli continues and ends simultaneously. A conditioned reflex will occur if the indifferent stimulus becomes a conditioned stimulus, that is, it signals the action of an unconditioned stimulus.
• permanence environment- the development of a conditioned reflex requires the constancy of the properties of the conditioned signal.

The mechanism of formation of conditioned reflexes

At action of an indifferent stimulus excitation occurs in the corresponding receptors, and impulses from them enter the brain section of the analyzer. When exposed to an unconditioned stimulus, specific excitation of the corresponding receptors occurs, and impulses go through the subcortical centers to the cerebral cortex (the cortical representation of the center of the unconditioned reflex, which is the dominant focus). Thus, two foci of excitation simultaneously appear in the cerebral cortex: In the cerebral cortex, between two foci of excitation, according to the dominant principle, a temporary reflex connection is formed. When a temporary connection occurs, the isolated action of a conditioned stimulus causes an unconditioned response. In accordance with Pavlov's theory, the formation of a temporary reflex connection occurs at the level of the cerebral cortex, and it is based on the principle of dominance.

Types of conditioned reflexes

There are many classifications of conditioned reflexes:

• If the classification is based on unconditioned reflexes, then food, protective, indicative, etc. are distinguished.
• If the classification is based on receptors that are affected by stimuli, there are exteroceptive, interoceptive and proprioceptive conditioned reflexes.
• Depending on the structure of the applied conditioned stimulus, simple and complex (complex) conditioned reflexes are distinguished.
  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. And then the complex of environmental signals acts as a conditioned stimulus.
• There are conditioned reflexes of the first, second, third, etc. order. When a conditioned stimulus is reinforced by an unconditioned stimulus, a first-order conditioned reflex is formed. A conditioned reflex of the second order is formed if the conditioned stimulus is reinforced by a conditioned stimulus, to which a conditioned reflex was previously developed.
• Natural reflexes are formed on stimuli, which are natural, accompanying properties of the unconditioned stimulus, on the basis of which they are developed. Natural conditioned reflexes, compared with artificial ones, are easier to form and more durable.

Notes

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• Symbols (Cartography)
• Conditional pass

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