What is a conditioned and unconditioned reflex. Conditioned and unconditioned reflexes

12.10.2019

Age anatomy and physiology Antonova Olga Alexandrovna

6.2. Conditioned and unconditioned reflexes. I.P. Pavlov

Reflexes are the body's responses to external and internal stimuli. Reflexes are unconditional and conditional.

Unconditioned reflexes- congenital, permanent, hereditarily transmitted reactions inherent in representatives of this type of organisms. The unconditioned include pupillary, knee, Achilles and other reflexes. Some unconditioned reflexes are carried out only at a certain age, for example, during the breeding season, and when normal development nervous system. Such reflexes include sucking and motor reflexes, which are already present in an 18-week-old fetus.

Unconditioned reflexes are the basis for the development of conditioned reflexes in animals and humans. In children, as they grow older, they turn into synthetic complexes of reflexes that increase the adaptability of the body to environmental conditions.

Conditioned reflexes- adaptive reactions of the body, which are temporary and strictly individual. They occur in one or more representatives of a species that have been subjected to training (training) or exposure to the environment. The development of conditioned reflexes occurs gradually, in the presence of certain environmental conditions, for example, the repetition of a conditioned stimulus. If the conditions for the development of reflexes are constant from generation to generation, then conditioned reflexes can become unconditioned and be inherited in a number of generations. An example of such a reflex is the opening of the beak by blind and fledgling chicks in response to the shaking of the nest by a bird that comes to feed them.

Conducted by I.P. Pavlov, numerous experiments have shown that the basis for the development of conditioned reflexes are impulses coming through afferent fibers from extero- or interoreceptors. For their formation, the following conditions are necessary:

a) the action of an indifferent (in the future conditioned) stimulus must be earlier than the action of an unconditioned stimulus (for a defensive motor reflex, the minimum time difference is 0.1 s). In a different sequence, the reflex is not developed or is very weak and quickly fades;

b) the action of the conditioned stimulus for some time must be combined with the action of the unconditioned stimulus, i.e., the conditioned stimulus is reinforced by the unconditioned one. This combination of stimuli should be repeated several times.

In addition, a prerequisite for the development of a conditioned reflex is the normal function of the cerebral cortex, the absence of disease processes in the body and extraneous stimuli. Otherwise, in addition to the developed reinforced reflex, there will also be an orienting reflex, or a reflex of the internal organs (intestines, bladder, etc.).

The mechanism of formation of a conditioned reflex. The active conditioned stimulus always causes a weak focus of excitation in the corresponding zone of the cerebral cortex. The attached unconditioned stimulus creates a second, stronger focus of excitation in the corresponding subcortical nuclei and a section of the cerebral cortex, which diverts the impulses of the first (conditioned), weaker stimulus. As a result, a temporary connection arises between the centers of excitation of the cerebral cortex, with each repetition (i.e. reinforcement) this connection becomes stronger. The conditioned stimulus turns into a signal of a conditioned reflex.

To develop a conditioned reflex in a person, secretory, blinking or motor techniques with verbal reinforcement are used; in animals - secretory and motor techniques with food reinforcement.

The studies of I.P. Pavlov on the development of a conditioned reflex in dogs. For example, the task is to develop a reflex in a dog according to the salivation method, that is, to cause salivation to a light stimulus, reinforced by food - an unconditioned stimulus. First, the light is turned on, to which the dog reacts with an orienting reaction (turns its head, ears, etc.). Pavlov called this reaction the “what is it?” reflex. Then the dog is given food - an unconditioned stimulus (reinforcement). This is done several times. As a result, the orienting reaction appears less and less often, and then completely disappears. In response to impulses that enter the cortex from two foci of excitation (in the visual zone and in the food center), the temporal connection between them is strengthened, as a result, the dog's saliva is released to the light stimulus even without reinforcement. This happens because the trace of the movement of a weak impulse towards a strong one remains in the cerebral cortex. The newly formed reflex (its arc) retains the ability to reproduce the conduction of excitation, i.e., to carry out a conditioned reflex.

The signal for the conditioned reflex can also be the trace left by the impulses of the present stimulus. For example, if you act on a conditioned stimulus for 10 seconds, and then a minute after it stops giving food, then the light itself will not cause a conditioned reflex separation of saliva, but a few seconds after it stops, a conditioned reflex will appear. Such a conditioned reflex is called a follow-up reflex. Trace conditioned reflexes develop with great intensity in children from the second year of life, contributing to the development of speech and thinking.

To develop a conditioned reflex, you need a conditioned stimulus of sufficient strength and high excitability of the cells of the cerebral cortex. In addition, the strength of the unconditioned stimulus must be sufficient, otherwise the unconditioned reflex will go out under the influence of a stronger conditioned stimulus. In this case, the cells of the cerebral cortex should be free from third-party stimuli. Compliance with these conditions accelerates the development of a conditioned reflex.

Classification of conditioned reflexes. Depending on the method of development, conditioned reflexes are divided into: secretory, motor, vascular, reflexes-changes during internal organs and etc.

The reflex, which is developed by reinforcing the conditioned stimulus with an unconditioned one, is called the first-order conditioned reflex. Based on it, you can develop a new reflex. For example, by combining a light signal with feeding, a dog has developed a strong conditioned salivation reflex. If you give a call (sound stimulus) before the light signal, then after several repetitions of this combination, the dog begins to salivate in response to the sound signal. This will be a second-order reflex, or a secondary reflex, reinforced not by an unconditioned stimulus, but by a first-order conditioned reflex.

In practice, it has been established that it is not possible to develop conditioned reflexes of other orders on the basis of a secondary conditioned food reflex in dogs. In children, it was possible to develop a sixth-order conditioned reflex.

To develop conditioned reflexes of higher orders, you need to “turn on” a new indifferent stimulus 10–15 s before the start of the action of the conditioned stimulus of the previously developed reflex. If the intervals are shorter, then a new reflex will not appear, and the one developed before will fade away, because inhibition will develop in the cerebral cortex.

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Reflex- the response of the body is not an external or internal irritation, carried out and controlled by the central nervous system. The development of ideas about human behavior, which has always been a mystery, was achieved in the works of Russian scientists I. P. Pavlov and I. M. Sechenov.

Reflexes unconditioned and conditional.

Unconditioned reflexes- these are innate reflexes that are inherited by offspring from parents and persist throughout a person's life. Arcs of unconditioned reflexes pass through the spinal cord or brain stem. The cerebral cortex does not participate in their formation. Unconditioned reflexes provide only those changes in the environment that many generations of a given species often encountered.

To include:

Food (salivation, sucking, swallowing);
Defensive (coughing, sneezing, blinking, pulling the hand away from a hot object);
Approximate ( skew eyes, turns);
Sexual (reflexes associated with reproduction and care of offspring).
The significance of unconditioned reflexes lies in the fact that thanks to them the integrity of the body is preserved, the maintenance of constancy and reproduction occurs. Already in a newborn child, the simplest unconditioned reflexes are observed.
The most important of these is the sucking reflex. The irritant of the sucking reflex is the touch of an object on the child's lips (mother's breasts, nipples, toys, fingers). The sucking reflex is an unconditioned food reflex. In addition, the newborn already has some protective unconditioned reflexes: blinking, which occurs if a foreign body approaches the eye or touches the cornea, constriction of the pupil when strong light is applied to the eyes.

Particularly pronounced unconditioned reflexes in various animals. Not only individual reflexes can be innate, but also more complex forms of behavior, which are called instincts.

Conditioned reflexes- these are reflexes that are easily acquired by the body during life and are formed on the basis of an unconditioned reflex under the action of a conditioned stimulus (light, knock, time, etc.). IP Pavlov studied the formation of conditioned reflexes in dogs and developed a method for obtaining them. To develop a conditioned reflex, an irritant is needed - a signal that triggers a conditioned reflex, repeated repetition of the action of the stimulus allows you to develop a conditioned reflex. During the formation of conditioned reflexes, a temporary connection arises between the centers and centers of the unconditioned reflex. Now this unconditioned reflex is not carried out under the influence of completely new external signals. These irritations from the surrounding world, to which we were indifferent, can now acquire a vital importance. During life, many conditioned reflexes are developed, which form the basis of our life experience. But this life experience makes sense only for this individual and is not inherited by its descendants.

into a separate category conditioned reflexes allocate motor conditioned reflexes developed during our life, i.e. skills or automated actions. The meaning of these conditioned reflexes is the development of new motor skills, the development of new forms of movements. During his life, a person masters many special motor skills associated with his profession. Skills are the basis of our behavior. Consciousness, thinking, attention are freed from performing those operations that have become automated and become skills. Everyday life. The most successful way to master skills is through systematic exercises, correcting mistakes noticed in time, knowing the ultimate goal of each exercise.

If the conditioned stimulus is not reinforced for some time by the unconditioned stimulus, then the conditioned stimulus is inhibited. But it doesn't disappear completely. When the experiment is repeated, the reflex is very quickly restored. Inhibition is also observed under the influence of another stimulus of greater force.

Reflexes unconditioned and conditional.

Unconditioned reflexes- these are innate reflexes that are inherited by offspring from parents and persist throughout a person's life. Arcs of unconditioned reflexes pass through the spinal cord or brain stem. The cerebral cortex does not participate in their formation. Unconditioned reflexes ensure that the organism adapts only to those changes in the environment that many generations of a given species often encountered.

TO unconditioned reflexes relate:

Food (salivation, sucking, swallowing);
Defensive (coughing, sneezing, blinking, pulling the hand away from a hot object);
Approximate (squinting eyes, turning the head);
Sexual (reflexes associated with reproduction and care of offspring).
The significance of unconditioned reflexes lies in the fact that thanks to them the integrity of the body is preserved, the maintenance of the constancy of the internal environment and reproduction occurs. Already in a newborn child, the simplest unconditioned reflexes are observed.
The most important of these is the sucking reflex. The irritant of the sucking reflex is the touch of an object on the child's lips (mother's breasts, nipples, toys, fingers). The sucking reflex is an unconditioned food reflex. In addition, the newborn already has some protective unconditioned reflexes: blinking, which occurs if a foreign body approaches the eye or touches the cornea, constriction of the pupil when strong light is applied to the eyes.

Particularly pronounced unconditioned reflexes in various animals. Not only individual reflexes can be innate, but also more complex forms of behavior, which are called instincts.

Conditioned reflexes- these are reflexes that are easily acquired by the body during life and are formed on the basis of an unconditioned reflex under the action of a conditioned stimulus (light, knock, time, etc.). IP Pavlov studied the formation of conditioned reflexes in dogs and developed a method for obtaining them. To develop a conditioned reflex, an irritant is needed - a signal that triggers a conditioned reflex, repeated repetition of the action of the stimulus allows you to develop a conditioned reflex. During the formation of conditioned reflexes, a temporary connection arises between the centers of the analyzers and the centers of the unconditioned reflex. Now this unconditioned reflex is not carried out under the influence of completely new external signals. These irritations from the outside world, to which we were indifferent, can now become of vital importance. During life, many conditioned reflexes are developed, which form the basis of our life experience. But this life experience makes sense only for this individual and is not inherited by its descendants.

into a separate category conditioned reflexes allocate motor conditioned reflexes developed during our life, i.e. skills or automated actions. The meaning of these conditioned reflexes is the development of new motor skills, the development of new forms of movements. During his life, a person masters many special motor skills associated with his profession. Skills are the basis of our behavior. Consciousness, thinking, attention are freed from performing those operations that have become automated and become habits of everyday life. The most successful way to master skills is through systematic exercises, correcting mistakes noticed in time, knowing the ultimate goal of each exercise.

8. The individuality of conditioned reflexes is manifested in the fact that 1) an individual inherits only certain conditioned reflexes 2) each individual of the same species has its own life experience 3) they are formed on the basis of individual unconditioned reflexes 4) each individual has an individual mechanism for the formation of a conditioned reflex

20-09-2010 15:22
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Answers (1) Alinka Konkova +1 20-09-2010 20:02

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Story

For the first time, the idea of a conditioned reflex was put forward by the French philosopher and scientist R. Descartes. Somewhat later, the Russian physiologist I. Sechenov created and experimentally proved a new theory regarding the reactions of the body. For the first time in the history of physiology, it was concluded that conditioned reflexes are a mechanism that is activated not only in its work, the entire nervous system is involved. This allows the body to maintain contact with the environment.

Studied Pavlov. This outstanding Russian scientist was able to explain the mechanism of action of the cerebral cortex and cerebral hemispheres. At the beginning of the 20th century, he created the theory of conditioned reflexes. This scientific work has become a real revolution in physiology. Scientists have proven that conditioned reflexes are reactions of the body that are acquired throughout life, based on unconditioned reflexes.

instincts

Certain reflexes of an unconditioned type are characteristic of each type of living organism. They are called instincts. Some of them are quite complex. Examples of this are bees that make honeycombs, or birds that build nests. Due to the presence of instincts, the body is able to optimally adapt to conditions. environment.

Are congenital. They are inherited. In addition, they are classified as species, since they are characteristic of all representatives of a particular species. Instincts are permanent and persist throughout life. They manifest themselves to adequate stimuli that are attached to a specific single receptive field. Physiologically, unconditioned reflexes are closed in the brainstem and at the level of the spinal cord. They are manifested through anatomically expressed

As for the monkey and man, the implementation of most of the complex unconditioned reflexes is impossible without the participation of the cerebral cortex. When its integrity is violated, pathological changes in unconditioned reflexes occur, and some of them simply disappear.

Classification of instincts

Unconditioned reflexes are very strong. Only under certain conditions, when their manifestation becomes optional, they can disappear. For example, the canary, domesticated about three hundred years ago, does not currently have the instinct to make a nest. There are the following types of unconditioned reflexes:

Which is the body's response to a variety of physical or chemical stimuli. Such reflexes, in turn, may be local (withdrawal of the hand) or complex (flight from danger).
- Food instinct, which is caused by hunger and appetite. This unconditioned reflex includes a whole chain of sequential actions - from searching for prey to attacking it and further eating.
- Parental and sexual instincts associated with the maintenance and reproduction of the species.

Comfort instinct for keeping the body clean (bathing, scratching, shaking, etc.).
- Approximate instinct, when the eyes and head turn towards the stimulus. This reflex is necessary to save life.
- The instinct of freedom, which is especially pronounced in the behavior of animals in captivity. They constantly want to break free and often die, refusing water and food.

The emergence of conditioned reflexes

In the course of life, acquired reactions of the organism are added to the inherited instincts. They are called conditioned reflexes. They are acquired by the body as a result of individual development. The basis for obtaining conditioned reflexes is life experience. Unlike instincts, these reactions are individual. They may be present in some members of the species and absent in others. In addition, a conditioned reflex is a reaction that may not persist throughout life. Under certain conditions, it is produced, fixed, disappears. Conditioned reflexes are reactions that can occur to various stimuli applied to different receptor fields. This is their difference from instincts.

The mechanism of the conditioned reflex closes at the level. If it is removed, then only instincts remain.

The formation of conditioned reflexes occurs on the basis of unconditioned ones. For the implementation of this process, a certain condition must be met. At the same time, any change in the external environment must be combined in time with the internal state of the organism and perceived by the cerebral cortex with a simultaneous unconditional reaction of the organism. Only in this case does a conditioned stimulus or signal appear that contributes to the emergence of a conditioned reflex.

Examples

For the appearance of such a reaction of the body as the release of saliva at the ringing of knives and forks, as well as at the knock of a cup for feeding an animal (in humans and dogs, respectively), an indispensable condition is the repeated coincidence of these sounds with the process of providing food.

In the same way, the sound of a bell or the switching on of a light bulb will cause the dog's paw to flex if these phenomena are repeatedly accompanied by electrical stimulation of the animal's leg, as a result of which an unconditioned flexion reflex appears.

The conditioned reflex is pulling the child's hands away from the fire and then crying. However, these phenomena will take place only if the type of fire, even once, coincided with the receipt of a burn.

Reaction components

The body's response to irritation is a change in breathing, secretion, movement, etc. As a rule, unconditioned reflexes are rather complex reactions. That is why they include several components at once. For example, a defensive reflex is accompanied not only by defensive movements, but also by an increase in breathing, an acceleration of the activity of the heart muscle, and a change in the composition of the blood. In this case, voice reactions may also appear. As for the food reflex, there are also respiratory, secretory and cardiovascular components.

Conditional reactions usually reproduce the structure of unconditioned ones. This occurs in connection with the excitation of stimuli of the same nerve centers.

Classification of conditioned reflexes

Acquired body responses to various stimuli are divided into types. Some of the existing classifications are of great importance in solving not only theoretical, but also practical problems. One of the areas of application of this knowledge is sports activities.

Natural and artificial reactions of the body

There are conditioned reflexes that arise under the action of signals characteristic of the constant properties of unconditioned stimuli. An example of this is the sight and smell of food. Such conditioned reflexes are natural. They are characterized by the speed of production and great durability. Natural reflexes, even in the absence of subsequent reinforcement, can be maintained throughout life. The value of the conditioned reflex is especially great at the very first stages of the life of the organism, when it adapts to the environment.
However, reactions can also be developed to a variety of indifferent signals, such as smell, sound, temperature changes, light, etc. Under natural conditions, they are not irritants. It is these reactions that are called artificial. They are developed slowly and in the absence of reinforcement quickly disappear. For example, artificial conditioned human reflexes are reactions to the sound of a bell, touching the skin, weakening or strengthening lighting, etc.

First and highest order

There are such types of conditioned reflexes that are formed on the basis of unconditioned ones. These are first order reactions. There are also higher categories. So, reactions that are developed on the basis of already existing conditioned reflexes are referred to as reactions of a higher order. How do they arise? During the development of such conditioned reflexes, the indifferent signal is reinforced with well-learned conditioned stimuli.

For example, irritation in the form of a call is constantly reinforced by food. In this case, a first-order conditioned reflex is developed. On its basis, a reaction to another stimulus, for example, to light, can be fixed. This will become a second-order conditioned reflex.

Positive and negative reactions

Conditioned reflexes can affect the activity of the organism. Such reactions are considered positive. The manifestation of these conditioned reflexes can be secretory or motor functions. If there is no activity of the organism, then the reactions are classified as negative. For the process of adaptation to the constantly changing conditions of the environment of existence, both one and the second type are of great importance.

At the same time, there is a close relationship between them, since when one kind of activity is manifested, another is certainly oppressed. For example, when the command “Attention!” Sounds, the muscles are in a certain position. At the same time, motor reactions (running, walking, etc.) are inhibited.

Mechanism of Education

Conditioned reflexes arise with the simultaneous action of a conditioned stimulus and an unconditioned reflex. In this case, certain conditions must be met:

The unconditioned reflex is biologically stronger;
- the manifestation of the conditioned stimulus is somewhat ahead of the action of the instinct;
- the conditioned stimulus is necessarily reinforced by the influence of the unconditioned;
- the body must be in a waking state and be healthy;
- the condition of the absence of extraneous stimuli producing a distracting effect is observed.

The centers of conditioned reflexes located in the cerebral cortex establish a temporary connection (short circuit) between themselves. In this case, stimulation is perceived by cortical neurons, which are part of the arc of the unconditioned reflex.

Inhibition of conditioned reactions

In order to ensure adequate behavior of the organism and for better adaptation to environmental conditions, the development of conditioned reflexes alone will not be enough. It will take the opposite direction of action. It is the inhibition of conditioned reflexes. This is the process of eliminating those reactions of the body that are not necessary. According to the theory developed by Pavlov, certain types of cortical inhibition are distinguished. The first of these is the unconditional. It appears as a response to the action of some extraneous stimulus. There is also internal inhibition. It's called conditional.

External braking

This reaction received such a name due to the fact that its development is facilitated by the processes taking place in those parts of the cortex that do not take part in the implementation of reflex activity. For example, an extraneous smell, sound, or change in lighting prior to the onset of the food reflex can reduce it or contribute to its complete disappearance. The new stimulus acts as a brake on the conditioned response.

Food reflexes can also be eliminated by painful stimuli. Inhibition of the reaction of the body contributes to the overflow of the bladder, vomiting, internal inflammatory processes etc. All of them depress food reflexes.

Internal braking

It occurs when the received signal is not reinforced by an unconditioned stimulus. Internal inhibition of conditioned reflexes occurs if, for example, an electric light bulb is periodically turned on in front of the eyes of an animal during the day, without bringing food. It has been experimentally proven that saliva production will decrease each time. As a result, the reaction will die out completely. However, the reflex will not disappear without a trace. He just slows down. This has also been proven experimentally.

Conditioned inhibition of conditioned reflexes can be eliminated the very next day. However, if this is not done, then the reaction of the body to this stimulus will subsequently disappear forever.

Varieties of internal inhibition

Classify several types of elimination of the body's response to stimuli. Thus, at the basis of the disappearance of conditioned reflexes, which are simply not needed under given specific conditions, is extinction inhibition. There is another variation of this phenomenon. This is a distinctive, or differentiated inhibition. So, the animal can distinguish the number of beats of the metronome at which food is brought to it. This happens when the given conditioned reflex has been previously worked out. The animal distinguishes stimuli. This reaction is based on internal inhibition.

The Importance of Eliminating Reactions

Conditioned inhibition plays a significant role in the life of the organism. Thanks to him, the process of adaptation to the environment is much better. Possibility of orientation in various difficult situations gives a combination of excitation and inhibition, which are two forms of a single nervous process.

Conclusion

There are an infinite number of conditioned reflexes. They are the factor that determines the behavior of a living organism. With the help of conditioned reflexes, animals and humans adapt to their environment.

There are many indirect signs of body reactions that have a signal value. For example, an animal, knowing in advance about the approach of danger, builds its behavior in a certain way.

The process of developing conditioned reflexes, which belong to the highest order, is a synthesis of temporary connections.

The basic principles and regularities manifested in the formation of not only complex, but also elementary reactions are the same for all living organisms. This leads to an important conclusion for philosophy and natural sciences that cannot but obey the general laws of biology. In this regard, it can be studied objectively. However, it should be borne in mind that the activity human brain has a qualitative specificity and a fundamental difference from the work of the animal brain.

Conditioned reflex- this is an acquired reflex, characteristic of a separate individual (individual). 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 IP Pavlov and the students of his school. 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 allowed to sniff 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. These are the simplest 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.

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Human Anatomy: Conditioned Reflexes

Conditioned reflexes

Higher nervous activity

Subtitles

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 stimulation 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.
The constancy of the 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 reaction. In accordance with Pavlov's theory, the fixation 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 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, in comparison with artificial ones, are more easily formed and more durable.

Notes

the school of Ivan Petrovich Pavlov conducted vivisectoral experiments not only on dogs, but also on people. Homeless children aged 6–15 years were used as laboratory material. These were harsh experiments, but it was they who made it possible to understand the nature of human thinking. These experiments were carried out in the children's clinic of the 1st LMI, in the Filatov hospital, in the hospital. Rauhfus, in the Department of Experimental Pediatrics of the IEM, as well as in several orphanages. are essential information. In two works by N. I. Krasnogorsky, “The Development of the Teaching on the Physiological Activity of the Brain in Children” (L., 1939) and “The Higher Nervous Activity of the Child” (L., 1958), Professor Mayorov, who was the official chronicler of the Pavlovian school, melancholy noted: “ Some of our collaborators expanded the range of experimental objects and began to study conditioned reflexes in other animal species; in fish, ascidians, birds, lower monkeys, as well as children "(F. P. Mayorov," History of the doctrine of conditioned reflexes ". M., 1954). "Laboratory material" of a group of Pavlov's students (Prof. N. I. Krasnogorsky , A. G. Ivanov-Smolensky, I. Balakirev, M. M. Koltsova, I. Kanaeva) became street children. A complete understanding in all instances was ensured by the Cheka.A. A. Yushchenko in the work "Conditioned Reflexes of the Child" (1928) All this is confirmed by protocols, photographs and documentary The Mechanics of the Brain (another name is Behavior of Animals and Humans; dir. V. Pudovkin, opera. A. Golovnya, production of the Mezhrabprom-Rus film factory, 1926)