Conditioned and unconditioned reflexes are characteristic of the entire animal world.

In biology, they are considered as the result of a long evolutionary process and represent the response of the central nervous system to external environmental influences.

They provide a very quick response to a particular stimulus, thereby significantly saving the resources of the nervous system.

Classification of reflexes

In modern science, such reactions are described using several classifications that describe their features in different ways.

So, they come in the following types:

1. Conditional and unconditional - depending on how they are formed.
2. Exteroceptive (from “extra” - external) - reactions of external receptors of the skin, hearing, smell and vision. Interoreceptive (from “intero” - inside) - reactions of internal organs and systems. Proprioceptive (from “proprio” - special) - reactions associated with the sensation of one’s own body in space and formed by the interaction of muscles, tendons and joints. This is a classification based on receptor type.
3. Based on the type of effectors (zones of reflex response to information collected by receptors), they are divided into: motor and autonomic.
4. Classification based on specific biological role. There are species aimed at protection, nutrition, orientation in the environment and reproduction.
5. Monosynaptic and polysynaptic - depending on the complexity of the neural structure.
6. Based on the type of influence, excitatory and inhibitory reflexes are distinguished.
7. And based on where the reflex arcs are located, they are divided into cerebral (various parts of the brain are included) and spinal (neurons of the spinal cord are included).

What is a conditioned reflex

This is a term denoting a reflex formed as a result of the fact that simultaneously for a long time a stimulus that does not cause any reaction is presented with a stimulus that causes some specific unconditioned reflex. That is, the reflex response eventually extends to an initially indifferent stimulus.

Where are the centers of conditioned reflexes located?

Since this is a more complex product of the nervous system, the central part of the neural arc of conditioned reflexes is located in the brain, specifically in the cerebral cortex.

Examples of conditioned reflexes

The most striking and classic example is Pavlov’s dog. The dogs were presented with a piece of meat (this caused the secretion of gastric juice and salivation) along with the inclusion of a lamp. As a result, after a while, the process of activating digestion started when the lamp was turned on.

A familiar example from life is the feeling of cheerfulness from the smell of coffee. Caffeine does not yet have a direct effect on the nervous system. He is outside the body - in a circle. But the feeling of vigor is triggered only by the smell.

Many mechanical actions and habits are also examples. We rearranged the furniture in the room, and the hand reaches in the direction where the closet used to be. Or a cat who runs to the bowl when he hears the rustling of a box of food.

The difference between unconditioned reflexes and conditioned ones

They differ in that unconditional ones are innate. They are the same for all animals of one species or another, as they are inherited. They are quite unchanged throughout the life of a person or animal. From birth and always occur in response to receptor irritation, and are not produced.

Conditional ones are acquired throughout life, with experience in interaction with the environment. Therefore, they are quite individual - depending on the conditions under which it was formed. They are unstable throughout life and can fade away if they do not receive reinforcement.

Conditioned and unconditioned reflexes - comparison table

The difference between instincts and unconditioned reflexes

Instinct, like reflex, is a biologically significant form of animal behavior. Only the second is a simple short response to a stimulus, and instinct is a more complex activity that has a specific biological goal.

The unconditioned reflex is always triggered. But instinct is only in a state of biological readiness of the body to trigger this or that behavior. For example, mating behavior in birds is triggered only during a certain period of the year when chick survival may be maximum.

What is not typical for unconditioned reflexes?

In short, they cannot change during life. They do not differ between different animals of the same species. They cannot disappear or stop appearing in response to a stimulus.

When conditioned reflexes fade

Extinction occurs as a result of the fact that the stimulus (stimulus) ceases to coincide in time of presentation with the stimulus that caused the reaction. Need reinforcements. Otherwise, without reinforcement, they lose their biological significance and fade away.

Unconditioned reflexes of the brain

These include the following types: blinking, swallowing, vomiting, orientation, maintaining balance associated with hunger and satiety, braking movement in inertia (for example, during a push).

The disruption or disappearance of any type of these reflexes can be a signal of serious disturbances in brain function.

Pulling your hand away from a hot object is an example of which reflex

An example of a painful reaction is pulling your hand away from a hot kettle. This is an unconditional look, the body's response to dangerous environmental influences.

Blink reflex - conditioned or unconditioned

The blink reaction is an unconditional type. It occurs as a result of dry eye and to protect against mechanical damage. All animals and humans have it.

Salivation in a person at the sight of a lemon - what is the reflex?

This is a conditional view. It is formed due to the fact that the rich taste of lemon provokes salivation so often and strongly that simply looking at it (and even remembering it) triggers a response.

How to develop a conditioned reflex in a person

In humans, unlike animals, the conditioned appearance is developed faster. But for all, the mechanism is the same - joint presentation of stimuli. One, causing an unconditioned reflex, and the other, an indifferent one.

For example, for a teenager who falls off a bicycle while listening to some specific music, later unpleasant feelings that arise while listening to the same music can become the acquisition of a conditioned reflex.

What is the role of conditioned reflexes in the life of an animal

They enable an animal with rigid, unchanging unconditioned reactions and instincts to adapt to conditions that are constantly changing.

At the level of the entire species, this is the ability to live in the largest possible areas with different weather conditions, with different levels of food supply. In general, they provide the ability to react flexibly and adapt to the environment.

Conclusion

Unconditioned and conditioned responses are extremely important for the survival of the animal. But it is in interaction that they allow us to adapt, reproduce and raise the healthiest offspring possible.

Reflex– the body’s response 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 conditioned.

Unconditioned reflexes- These are innate reflexes that are inherited by offspring from their parents and persist throughout a person’s life. The arcs of unconditioned reflexes pass through the spinal cord or brain stem. The cerebral cortex is not involved in their formation. Unconditioned reflexes are provided only to those environmental changes that have often been encountered by many generations of a given species.

These include:

Food (salivation, sucking, swallowing);
Defensive (coughing, sneezing, blinking, withdrawing your hand from a hot object);
Approximate (squinting eyes, turns);
Sexual (reflexes associated with reproduction and care of offspring).
The importance of unconditioned reflexes lies in the fact that thanks to them the integrity of the body is preserved, constancy is maintained and reproduction occurs. Already in a newborn child the simplest unconditioned reflexes are observed.
The most important of these is the sucking reflex. The stimulus of the sucking reflex is the touching of an object to the child’s lips (mother’s breast, pacifier, toy, finger). 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 exposed to strong light on 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 throughout life and are formed on the basis of an unconditioned reflex under the action of a conditioned stimulus (light, knock, time, etc.). I.P. Pavlov studied the formation of conditioned reflexes in dogs and developed a method for obtaining them. To develop a conditioned reflex, a stimulus is needed - a signal that triggers the 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 the centers of the unconditioned reflex. Now this unconditioned reflex is not carried out under the influence of completely new external signals. These stimuli from the surrounding world, to which we were indifferent, can now acquire vital significance. Throughout life, many conditioned reflexes are developed that form the basis of our life experience. But this vital experience has meaning only for a given individual and is not inherited by its descendants.

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

If you do not reinforce the conditioned stimulus with the unconditioned stimulus for some time, then inhibition of the conditioned stimulus occurs. But it doesn't disappear completely. When the experience is repeated, the reflex is restored very quickly. Inhibition is also observed when exposed to another stimulus of greater strength.

Continuation. See No. 34, 35, 36/2004

Congenital and acquired forms of behavior

Lessons on the topic: “Physiology of higher nervous activity”

Table. Comparison of unconditioned and conditioned reflexes

Signs of comparison	Unconditioned reflexes	Conditioned reflexes
Inheritance	Congenital, passed on from parents to offspring	Acquired by the body during life, they are not inherited
Species specificity		Individual
Stimulus	Carried out in response to an unconditioned stimulus	Carried out in response to any irritation perceived by the body; are formed on the basis of unconditioned reflexes
Meaning in life	Life without them is usually impossible	Promote the survival of the organism in constantly changing environmental conditions
Duration of existence of a reflex arc	Have ready and permanent reflex arcs	They do not have ready-made and permanent reflex arcs; their arcs are temporary and form under certain conditions
Reflex centers	They are carried out at the level of the spinal cord, brain stem and subcortical nuclei, i.e. reflex arcs pass through the lower levels of the central nervous system	They are carried out due to the activity of the cerebral cortex, i.e. reflex arcs pass through the cerebral cortex

Lesson 5.
Generalization of knowledge on the topic “Acquired forms of behavior. Conditioned reflex"

Equipment: tables, diagrams and drawings illustrating acquired forms of behavior, mechanisms for the development of conditioned reflexes.

DURING THE CLASSES

I. Test of knowledge

Working with cards

1. The advantage of behavior formed as a result of learning is that it:

a) is carried out quickly;
b) is carried out the same way every time;
c) provides answers in changing environmental conditions;
d) done correctly the first time;
e) does not occupy a place in the genetic program of the organism.

2. For experiments on studying conditioned reflexes, two dogs were taken. One of them was given a large amount of water to drink. Then the research began. At first, conditioned reflexes were carried out normally in both dogs. But after some time, the conditioned reflexes disappeared in the dog that drank water. There were no random external influences. What is the reason for the inhibition of conditioned reflexes?

3. As is known, a conditioned reflex can be developed to the action of almost any indifferent stimulus. One dog in the laboratory of I.P. Pavlov never managed to develop a conditioned reflex to the gurgling of water. Try to explain the lack of results in this case.

4. It is known that the strength (biological significance) of the conditioned stimulus should not exceed the strength of the unconditioned stimulus. Otherwise, the conditioned reflex cannot be developed. Therefore, it is very difficult to develop, for example, a conditioned food reflex to painful stimulation (electric current). However, in the laboratory of I.P. In Pavlov’s famous experiments, Erofeeva managed to develop such a conditioned reflex. When exposed to a current (conditioned stimulus), the dog salivated, it licked its lips and wagged its tail. How did you achieve this?

5. During one of the concerts, a listener suddenly began to experience pain in the heart area. Moreover, the onset of pain coincided with the performance of one of Chopin’s nocturnes. Since then, every time the man heard this music, his heart ached. Explain this pattern.

Oral knowledge test on questions

1. Learning and its methods (habituation, trial and error).
2. Imprinting and its characteristics.
3. Methods for developing conditioned reflexes.
4. Mechanisms for the development of conditioned reflexes
5. General properties and classification of conditioned reflexes.
6. Rational activity of animals.
7. Dynamic stereotype and its meaning.

Checking the completion of the table “Comparison of unconditioned and conditioned reflexes”

The children had to fill out the table as homework after the previous lesson.

Biological dictation

The teacher reads out the characteristics of reflexes under numbers, and students, working on the options, write down the numbers of the correct answers: option I – unconditioned reflexes, option II – conditioned reflexes.

1. Passed on by inheritance.
2. Not inherited.
3. Reflex centers are located in the subcortical nuclei, brain stem and spinal cord.
4. Reflex centers are located in the cerebral cortex.
5. There is no species specificity; each individual of the species develops its own reflexes.
6. Species specificity - these reflexes are characteristic of all individuals of a certain species.
7. Stable throughout life.
8. Change (new reflexes arise, and old ones fade away).
9. The reasons for the formation of reflexes are events that are vital for the whole species.
10. The causes of reflexes are signals that arise from personal past experience and warn of an important event.

Answers: Option I – 1, 3, 6, 7, 9; Option II – 2, 4, 5, 8, 10.

Laboratory work No. 2.
“Development of conditioned reflexes in humans on the basis of unconditioned reflexes”

Equipment: rubber bulb for pumping air, metronome.

PROGRESS

1. Turn on the metronome at a rhythm of 120 beats per minute and on the second or third beat, press the bulb, directing a stream of air into the subject’s eye.

2. Repeat the steps described in step 1 until the blinking steadily (at least 2-3 times in a row) precedes the pressing of the bulb.

3. After the blink reflex has been developed, turn on the metronome without directing the air stream to the eye. What do you observe? Draw a conclusion.

What reflex was developed in the subject during the actions you performed? What performs the role of unconditioned and conditioned stimuli in the developed reflex? What is the difference between the arcs of the unconditioned blink and conditioned blink reflexes?

Homework

Repeat the material about the mechanisms of development of conditioned reflexes in animals and humans.

Lesson 6–7.
Congenital and acquired inhibition, their types and characteristics

Equipment: tables, diagrams and drawings illustrating the mechanisms of development of conditioned reflexes, various types of congenital and acquired inhibition.

DURING THE CLASSES

I. Test of knowledge

Working with cards

1. Thanks to what innate nervous mechanisms can an animal distinguish good-quality food from spoiled food? What role do neurons and their synapses play in these processes?

2. What facts can be used to prove that instinct is a chain of interconnected unconditioned reflexes? How do instincts interact with acquired conditioned reflexes?

3. When an infant sees a bottle of kefir, he smacks his lips; a person salivates when he sees a lemon being cut; Wanting to know what time it is, a man looks at his hand, where he usually wears his watch, although he forgot it at home. Explain the described phenomena.

Knowledge test

Choose the correct answers to the given statements.

1. This is an unconditioned stimulus.
2. It is an indifferent stimulus.
3. This is an unconditioned reflex.
4. This is a conditioned reflex.
5. This is a combination of an indifferent stimulus with an unconditioned one.
6. Without these stimuli, the conditioned salivary reflex is not formed.
7. Stimulus that excites the visual cortex.
8. An irritant that excites the gustatory cortex.
9. Under this condition, a temporary connection is formed between the visual and gustatory zones of the cortex.

Answer options

A. Turning on the light bulb before experiments without feeding.
B. Food in the mouth.
B. Turning on the light during feeding.
D. Salivation of food in the mouth.
D. Secretion of saliva to the light of a light bulb.

Answers: 1 – B, 2 – A, 3 – D, 4 – D, 5 – B, 6 – C, 7 – A, 8 – B, 9 – C.

II. Learning new material

1. Excitation and inhibition are the main processes of nervous activity

As you already know, the regulatory function of the central nervous system is carried out through two processes - excitation and inhibition.

Conversation with students on issues

What is excitement?

What is braking?

Why is the process of excitation called the active state of nervous tissue?

What does excitation of motor centers lead to?

Thanks to what process can we mentally imagine them without performing any actions?

What processes enable complex coordinated actions such as walking?

Thus, excitation– this is an active state of nervous tissue in response to the action of various stimuli of sufficient strength. When excited, neurons generate electrical impulses. Braking- This is an active nervous process leading to inhibition of excitation.

2. General characteristics of cortical inhibition

Excitation and inhibition of I.P. Pavlov called them the true creators of nervous activity.

Excitation is involved in the formation of conditioned reflexes and their implementation. The role of inhibition is more complex and varied. It is the process of inhibition that makes conditioned reflexes a mechanism of subtle, precise and perfect adaptation to the environment.

According to I.P. Pavlov, the cortex is characterized by two forms of inhibition: unconditional and conditional. Unconditional inhibition does not require development; it is inherent in the body from birth (reflexive holding of breath when there is a strong smell of ammonia, inhibition in the triceps brachii muscle during the action of the biceps brachii, etc.). Conditioned inhibition is developed in the process of individual experience.

The following types of braking are distinguished. Unconditional braking: beyond (protective); external; innate reflexes. Conditional braking: extinct; differentiation; delayed.

3. Types of unconditional (congenital) inhibition and their characteristics

In the process of life, the body is constantly exposed to one or another irritation from the outside or from the inside. Each of these irritations is capable of causing a corresponding reflex. If all these reflexes could be realized, then the body’s activity would be chaotic. However, this does not happen. On the contrary, reflex activity is characterized by consistency and orderliness: with the help of unconditional inhibition, the most important reflex for the body at a given moment delays all other, secondary reflexes for the duration of its implementation.

Depending on the reasons underlying the inhibition processes, the following types of unconditional inhibition are distinguished.

Transcendental, or protective, braking occurs in response to very strong stimuli that require the body to act beyond its capabilities. The strength of irritation is determined by the frequency of nerve impulses. The more excited a neuron is, the higher the frequency of nerve impulses it generates. But if this flow exceeds known limits, processes arise that prevent the passage of excitation along the chain of neurons. The flow of nerve impulses following the reflex arc is interrupted, and inhibition occurs, which protects the executive organs from exhaustion.

Cause of external braking is outside the structures of the inhibitory reflex, it comes from another reflex. This type of inhibition occurs whenever a new activity is started. The new excitation, being stronger, causes inhibition of the old one. As a result, the previous activity is automatically terminated. For example, a dog has developed a strong conditioned reflex to light, and the lecturer wants to demonstrate it to the audience. The experiment fails - there is no reflex. An unfamiliar environment, the noise of a crowded audience are new signals that completely turn off conditioned reflex activity, and new excitation arises in the cortex. If the dog is brought into the audience several times, then new signals, which turn out to be biologically indifferent, fade away, and conditioned reflexes are carried out unhindered.

To be continued

The body responds to the action of a stimulus, which is carried out with the participation of the nervous system and is controlled by it. According to Pavlov's ideas, the main principle of the nervous system is the reflex principle, and the material basis is the reflex arc. Reflexes are conditioned and unconditioned.

Reflexes are conditioned and unconditioned. - These are reflexes that are inherited and passed on from generation to generation. By the time a person is born, the almost reflex arc of unconditioned reflexes is fully formed, with the exception of sexual reflexes. Unconditioned reflexes are species-specific, that is, they are characteristic of individuals of a given species.

Conditioned reflexes(UR) is an individually acquired reaction of the body to a previously indifferent stimulus ( stimulus– any material agent, external or internal, conscious or unconscious, acting as a condition for subsequent states of the organism. Signal stimulus (also indifferent) is a stimulus that has not previously caused a corresponding reaction, but under certain conditions of formation begins to cause it), reproducing an unconditioned reflex. SDs are formed throughout life and are associated with the accumulation of life. They are individual for each person or animal. Able to fade away if not reinforced. Extinguished conditioned reflexes do not disappear completely, that is, they are capable of recovery.

The physiological basis of the conditioned reflex is the formation of new or modification of existing neural connections, occurring under the influence of changes in the external and internal environment. These are temporary connections (in belt connection- this is a set of neurophysiological, biochemical and ultrastructural changes in the brain that arise in the process of combining conditioned and unconditioned stimuli and form certain relationships between various brain formations), which are inhibited when the situation is canceled or changed.

General properties of conditioned reflexes. Despite certain differences, conditioned reflexes are characterized by the following general properties (features):

• All conditioned reflexes represent one of the forms of adaptive reactions of the body to changing environmental conditions.
• SDs are acquired and canceled during the individual life of each individual.
• All SDs are formed with the participation of.
• SDs are formed on the basis of unconditioned reflexes; Without reinforcement, conditioned reflexes are weakened and suppressed over time.
• All types of conditioned reflex activity are of a warning signal nature. Those. precede and prevent the subsequent occurrence of BD. They prepare the body for any biologically targeted activity. UR is a reaction to a future event. SDs are formed due to the plasticity of the NS.

The biological role of UR is to expand the range of adaptive capabilities of the organism. SD complements BR and allows subtle and flexible adaptation to a wide variety of environmental conditions.

Differences between conditioned reflexes and unconditioned ones

Unconditioned reflexes	Conditioned reflexes
Congenital, reflect the specific characteristics of the organism	Acquired throughout life and reflect the individual characteristics of the body
Relatively constant throughout the life of an individual	Formed, changed and canceled when they become inadequate to living conditions
Implemented along anatomical pathways determined genetically	Implemented through functionally organized temporary (closing) connections
Characteristic of all levels of the central nervous system and carried out mainly by its lower sections (stem, subcortical nuclei)	For their formation and implementation, they require the integrity of the cerebral cortex, especially in higher mammals
Each reflex has its own specific receptive field and specific	Reflexes can be formed from any receptive field to a wide variety of stimuli
React to a present stimulus that can no longer be avoided	They adapt the body to an action that has yet to be experienced, that is, they have a warning, signaling value.

1. Unconditioned reactions are innate, hereditary reactions; they are formed on the basis of hereditary factors and most of them begin to function immediately after birth. Conditioned reflexes are acquired reactions in the process of individual life.
2. Unconditioned reflexes are species-specific, that is, these reflexes are characteristic of all representatives of a given species. Conditioned reflexes are individual; some animals may develop certain conditioned reflexes, while others may develop others.
3. Unconditioned reflexes are constant; they persist throughout the life of the organism. Conditioned reflexes are not constant; they can arise, become established and disappear.
4. Unconditioned reflexes are carried out due to the lower parts of the central nervous system (subcortical nuclei,). Conditioned reflexes are primarily a function of the higher parts of the central nervous system - the cerebral cortex.
5. Unconditioned reflexes are always carried out in response to adequate stimulation acting on a specific receptive field, i.e. they are structurally fixed. Conditioned reflexes can be formed to any stimuli, from any receptive field.
6. Unconditioned reflexes are reactions to direct irritations (food, being in the oral cavity, causes salivation). Conditioned reflex - a reaction to the properties (signs) of a stimulus (food, the type of food causes salivation). Conditioned reactions are always signaling in nature. They signal the upcoming action of the stimulus, and the body meets the influence of the unconditioned stimulus when all the responses that ensure the body is balanced by the factors that cause this unconditioned reflex are already included. So, for example, food, entering the oral cavity, encounters saliva there, released conditionally reflexively (at the sight of food, at its smell); muscular work begins when the conditioned reflexes developed for it have already caused a redistribution of blood, increased breathing and blood circulation, etc. This reveals the highest adaptive nature of conditioned reflexes.
7. Conditioned reflexes are developed on the basis of unconditioned ones.
8. A conditioned reflex is a complex multicomponent reaction.
9. Conditioned reflexes can be developed in real life and in laboratory conditions.

Age anatomy and physiology Antonova Olga Aleksandrovna

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

Reflexes are the body's responses to external and internal stimuli. Reflexes are unconditioned and conditioned.

Unconditioned reflexes are innate, permanent, hereditarily transmitted reactions characteristic of representatives of a given type of organism. Unconditional ones include pupillary, knee, Achilles and other reflexes. Some unconditioned reflexes are carried out only at a certain age, for example during the reproductive period, and during normal development of the nervous system. Such reflexes include sucking and motor, which are already present in an 18-week 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 body's adaptability to environmental conditions.

Conditioned reflexes are adaptive reactions of the body that are temporary and strictly individual. They occur in one or more members of a species that have been subjected to training (training) or environmental influences. 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 over a series of generations. An example of such a reflex is the opening of the beak of blind and fledgling chicks in response to the shaking of the nest by a bird flying in to feed them.

Conducted by I.P. Pavlov's numerous experiments showed that the basis for the development of conditioned reflexes are impulses arriving along afferent fibers from extero- or interoreceptors. For their formation the following conditions are necessary:

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

b) the action of the conditioned stimulus for some time must be combined with the action of the unconditioned stimulus, that is, the conditioned stimulus is reinforced by the unconditioned. 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 painful processes in the body and extraneous stimuli. Otherwise, in addition to the reinforced reflex being developed, an orientation reflex, or a reflex of the internal organs (intestines, bladder, etc.) will also occur.

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

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

The studies of I.P. are widely known. Pavlov on the development of a conditioned reflex in dogs. For example, the task is to develop a reflex in a dog using the salivary method, that is, to induce salivation in response to a light stimulus, reinforced by food - an unconditioned stimulus. First, the light is turned on, to which the dog reacts with an indicative reaction (turns its head, ears, etc.). Pavlov called this reaction the “what is it?” reflex. Then the dog is given food - an unconditioned stimulus (reinforcer). This is done several times. As a result, the indicative reaction appears less and less often, and then disappears altogether. In response to impulses that enter the cortex from two foci of excitation (in the visual zone and in the food center), the temporary connection between them is strengthened, as a result, the dog salivates to the light stimulus even without reinforcement. This happens because a 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, that is, to carry out a conditioned reflex.

The trace left by the impulses of a present stimulus can also become a signal for a conditioned reflex. For example, if you are exposed to a conditioned stimulus for 10 s, and then give food a minute after it stops, then the light itself will not cause the conditioned reflex secretion of saliva, but a few seconds after its termination, the conditioned reflex will appear. This conditioned reflex is called a trace 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, a conditioned stimulus of sufficient strength and high excitability of the cells of the cerebral cortex are needed. In addition, the strength of the unconditioned stimulus must be sufficient, otherwise the unconditioned reflex will be extinguished under the influence of a stronger conditioned stimulus. In this case, the cells of the cerebral cortex must be free from external 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 in internal organs, etc.

A reflex that is produced by reinforcing a conditioned stimulus with an unconditioned one is called a 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 bell (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 in dogs on the basis of the secondary conditioned food reflex. In children, it was possible to develop a sixth-order conditioned reflex.

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

From the book Operant Behavior author Skinner Burres Frederick

CONDITIONED REINFORCEMENTS A stimulus presented in operant reinforcement can be paired with another stimulus presented in respondent conditioning. In ch. 4 we examined the conditions for acquiring the ability to cause a reaction; here we will focus on the phenomenon

From the book Encyclopedia “Biology” (without illustrations) author Gorkin Alexander Pavlovich

Symbols and abbreviations AN - Academy of Scienceseng. – EnglishATP – adenosinite triphosphatev., cc. - century, centuries high. – heightg – grammg., years. - year, years - hectare depth. – depth arr. – mainly Greek. – Greekdiam. – diameter dl. – DNA length –

From the book Dopings in Dog Breeding by Gourmand E G

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From the book Reactions and behavior of dogs in extreme conditions author Gerd Maria Alexandrovna

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From the book Evolutionary genetic aspects of behavior: selected works author

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From the book Service Dog [Guide to the training of service dog breeding specialists] author Krushinsky Leonid Viktorovich

Are conditioned reflexes inherited? The question of the inheritance of conditioned reflexes - individual adaptive reactions of the body carried out through the nervous system - is a special case of the idea of ​​​​the inheritance of any acquired characteristics of the body. This idea

From the book Dog Diseases (non-contagious) author Panysheva Lidiya Vasilievna

2. Unconditioned reflexes The behavior of animals is based on simple and complex innate reactions - the so-called unconditioned reflexes. An unconditioned reflex is an innate reflex that is persistently inherited. An animal for the manifestation of unconditioned reflexes does not

From the book Do Animals Think? by Fischel Werner

3. Conditioned reflexes General concept of conditioned reflex. Unconditioned reflexes are the main innate foundation in the behavior of an animal, which provides (in the first days after birth, with the constant care of parents) the possibility of normal existence

From the book Anthropology and Concepts of Biology author

Sexual reflexes and mating These reflexes in males include: accusatory, erection, copulation and ejaculation reflex. The first reflex is expressed in mounting the female and clasping her sides with the thoracic limbs. In females, this reflex is expressed in the readiness of the prl

From the book Behavior: An Evolutionary Approach author Kurchanov Nikolay Anatolievich

Ivan Petrovich Pavlov. Conditioned reflex There is no need to prove that I.P. Pavlov was an outstanding scientist. During his long life (1849–1936) he achieved enormous success thanks to great diligence, purposeful work, keen insight, theoretical clarity,

From the author's book

Conditional abbreviations aa-t-RNA - aminoacyl (complex) with transport RNAATP - adenosine triphosphoric acidDNA - deoxyribonucleic acid-RNA (i-RNA) - matrix (information) RNANAD - nicotinamide adenine dinucleotide NADP -

From the author's book

Conventional abbreviations AG - Golgi apparatus ACTH - adrenocorticotropic hormone AMP - adenosine monophosphate ATP - adenosine triphosphate VND - higher nervous activity GABA - β-aminobutyric acid GMP - guanosine monophosphate GTP - guanine triphosphoric acid DVP -