Conditioned reflexes and their meaning.

The environmental conditions in which humans and animals find themselves are constantly changing. Because the unconditioned reflexes are quite conservative, they cannot ensure every time the adaptation of the body’s reactions in accordance with these changes. In the process of evolution, animals developed the ability to form reflexes that manifest themselves only under certain conditions, called conditioned reflexes by I. P. Pavlov.

Conditioned reflexes, Unlike unconditional ones, they are temporary and can fade away with changes in environmental conditions. Coinciding in their action with unconditioned stimuli, conditioned stimuli acquire a signaling, warning value. They provide humans and animals with the opportunity to respond in advance to negative or positive stimuli.

Conditioned reflexes are formed on the basis of unconditioned ones. In the process of development of the organism, they subordinate to themselves the function of the unconditioned, adapting them according to the new requirements of the environment. When forming conditioned reflexes, certain rules and conditions must be adhered to. The first and main condition is coincidence in time one-time or repeated action of a conditioned stimulus (indifferent) with an unconditioned stimulus or actions immediately after it. For example, for the formation of a conditioned salivary reflex in dogs to the sound of a bell, this sound must precede feeding several times. After such a combination in time of the conditioned and unconditioned stimuli, saliva is released when only the bell is turned on without accompanying it with food. Consequently, the bell became a conditioned stimulus for salivation. In the same way, conditioned reflexes are formed in humans. For example, drinking lemon causes salivation. This is an unconditional reflex reaction. By combining drinking lemon with turning on the light several times, just turning on the light will cause salivation. This is a conditioned reflex reaction.

An important condition for the formation of conditioned reflexes is a certain sequence of action of stimuli, due to the fact that, under the influence of an unconditioned stimulus, a strong focus of excitation is formed in the cerebral cortex in the nerve center of this stimulus. The excitability of other areas of the cortex decreases, so a weak conditioned stimulus will not cause excitation of the corresponding area of ​​the cortex. For the formation of conditioned reflexes, it is also necessary that the cerebral cortex be free from other types of activity, and that the body be in a normal functional state. The action of constant stimuli and the painful state of the body significantly complicate the formation of conditioned reflexes. Unlike the animal brain, the human brain is capable of forming conditioned reflexes not only in response to specific signals, but also to words, numbers, and pictures heard or read, which provides the possibility of abstraction and generalization. The latter form the basis of our thinking and consciousness.

The mechanism of formation of conditioned reflexes. Research by I.P. Pavlov established that the formation of conditioned reflexes is based on the establishment of temporary connections in the cerebral cortex between the nerve centers of unconditioned and conditioned stimuli. Temporary neural connection is formed as a result of the interaction of the processes of excitation and paving the way for its implementation, which simultaneously and repeatedly arise in the cortical centers of unconditioned and conditioned stimuli. The formation of temporary connections is characteristic not only of the cerebral cortex, but also of other parts of the central nervous system. This is evidenced by experiments in which simple conditioned reflexes were developed in animals with the cortex removed. Reactions such as conditioned reflexes can be developed in animals that do not have a cortex, and even in invertebrate animals with a very primitive nervous system, such as annelids.

However, for higher animals and humans, the main role in the formation of temporary connections is played by the cerebral cortex, although subcortical structures are also important for the formation of conditioned reflexes.

Thus, conditioned reflexes are formed as a result of the mutually coordinated activity of the cortex and subcortical centers, therefore the structure of the reflex arc of conditioned reflexes is quite complex. The role of the cortex and subcortical structures in the formation of various reflexes is different. For example, in the formation of autonomic conditioned reflexes, the cortex and subcortex play the same role, while in complex behavioral reactions the leading role belongs to the cortex. However, even in these cases, the subcortical centers and the reticular formation contribute to the formation of conditioned reflexes.

The activity of various parts of the central nervous system during the formation of complex behavioral conditioned reflexes is manifested in the fact that the processes of their formation are accompanied by the appearance of indicative reflex reactions. Increased excitability of the cerebral cortex contributes to the closure of temporary nerve connections.

So, conditioned reflexes enable a person to adapt his behavior according to changes in the environment. Conditioned reflexes are formed on the basis of unconditioned ones. The basis of the mechanism for the formation of conditioned reflexes is the establishment of temporary nerve connections in the cerebral cortex between the nerve centers of unconditioned and conditioned stimuli.

I. P. Pavlov divided all reflex reactions of the body to various stimuli into two groups: unconditioned and conditioned.
Unconditioned reflexes are innate reflexes inherited from parents. They are specific, relatively permanent and are carried out by the lower parts of the central nervous system - the spinal cord, brain stem and subcortical nuclei.

Unconditioned reflexes (for example, sucking, swallowing, pupillary reflexes, coughing, sneezing, etc.) are preserved in animals without cerebral hemispheres. They are formed in response to certain stimuli. Thus, the salivation reflex occurs when the taste buds of the tongue are irritated by food. The resulting excitation in the form of a nerve impulse is carried along the sensory nerves to the medulla oblongata, where the center of salivation is located, from where it is transmitted through the motor nerves to the salivary glands, causing salivation. On the basis of unconditioned reflexes, the regulation and coordinated activity of different organs and their systems is carried out, and the very existence of the organism is supported.

In changing environmental conditions, the preservation of the vital activity of the organism and adaptive behavior is carried out through the formation of conditioned reflexes with the obligatory participation of the cerebral cortex. They are not congenital, but are formed during life on the basis of unconditioned reflexes under the influence of certain environmental factors. Conditioned reflexes are strictly individual, that is, in some individuals of a species one or another reflex may be present, while in others it may be absent.

Unconditioned reflexes. The meaning of unconditioned reflexes

Maintaining a constant internal environment (homeostasis);
- maintaining the integrity of the body (protection from damaging environmental factors);
- reproduction and preservation of the species as a whole.

Unconditioned reflexes and their importance for child development

Birth is a great shock to a child's body. From a vegetative, plant existence in a relatively constant environment (the mother’s body), it suddenly moves into completely new conditions air environment with an endless number of frequently changing stimuli, into the world where he has to become a rational person.

A child’s life in new conditions is ensured by innate mechanisms. He is born with a certain readiness of the nervous system to adapt the body to external conditions. So, immediately after birth, reflexes are activated, ensuring the functioning of the main systems of the body (breathing, blood circulation - note biofile.ru). In the first days, you can also note the following. Severe irritation skin (an injection, for example) causes a protective withdrawal, the flashing of an object in front of the face causes squinting, and a sharp increase in the brightness of the light causes a narrowing of the pupil, etc. These reactions are protective reflexes.

In addition to protective ones, reactions aimed at contact with an irritant can be found in newborns. These are orientation reflexes. Observations have established that already in the period from the first to the third day, a strong light source causes the head to turn: in the children's room of the maternity hospital on a sunny day, the heads of most newborns, like sunflowers, are turned towards the light. It has also been proven that already in the first days, newborns tend to follow a slowly moving light source. Orienting food reflexes are also easily evoked. Touching the corners of the lips or the cheeks causes a searching reaction in a hungry child: he turns his head towards the stimulus and opens his mouth.
In addition to those listed, the child exhibits several more innate reactions: sucking reflex - the child immediately begins to suck on an object placed in his mouth; clinging reflex - touching the palm causes a grasping reaction; repulsion reflex (crawling) - when touching the soles of the feet and some other reflexes.

Thus, the child is armed with a certain number of unconditioned reflexes, which appear in the very first days after birth. Behind last years Scientists have proven that some reflex reactions appear even before birth. So, after eighteen weeks the fetus develops a sucking reflex.

Most of the innate reactions are necessary for the child to live. They help him adapt to new conditions of existence. Thanks to these reflexes, a new type of breathing and feeding becomes possible for the newborn. If before birth the fetus develops at the expense of the mother's body (through the walls of the blood vessels of the placenta - the child's place - from the mother's blood into the blood of the fetus nutrients and oxygen), then after birth the child’s body switches to pulmonary breathing and so-called oral nutrition (through the mouth and gastrointestinal tract). This adaptation occurs reflexively. After the lungs are filled with air, an entire system of muscles is involved in rhythmic breathing movements. Breathing is easy and free. Feeding occurs through the sucking reflex. The innate actions included in the sucking reflex are, at first, poorly coordinated with each other: when sucking, the child chokes, suffocates, and quickly runs out of strength. All his activity is aimed at sucking for the sake of saturation. Very great importance There is also the establishment of reflex automaticity of thermoregulation: the child’s body adapts better and better to temperature changes.

Education and biological significance conditioned reflexes

Conditioned reflexes are formed as a result of a combination of an unconditioned reflex with the action of a conditioned stimulus. To do this, two conditions must be met:

1) the action of the conditioned stimulus must necessarily somewhat precede the action of the unconditioned stimulus;

2) the conditioned stimulus must be repeatedly reinforced by the action of the unconditioned stimulus.

The mechanism for the formation of a conditioned reflex consists of establishing a temporary connection (closure) between two foci of excitation in the mayor of the brain. For the example considered, such foci are the centers of salivation and hearing.
The arc of the conditioned reflex, in contrast to that of the unconditioned reflex, is significantly more complicated and includes receptors that perceive conditioned stimulation, a sensory nerve that conducts excitation to the brain, a section of the cortex associated with the center of the unconditioned reflex, a motor nerve and a working organ.

Conditioned reflexes in higher animals and especially in humans are constantly developed. This phenomenon is explained by the dynamism of the external environment, to the constantly changing conditions of which the nervous system must quickly adapt.
Thus, if unconditioned reflexes provide only strictly limited orientation in the environment, then conditioned reflexes provide universal orientation.

The biological significance of conditioned reflexes in the life of humans and animals is enormous, since they ensure their adaptive behavior - they allow them to accurately navigate in space and time, find food (by sight, smell), avoid danger, and eliminate influences harmful to the body. With age, the number of conditioned reflexes increases, behavioral experience is acquired, thanks to which an adult organism turns out to be better adapted to the environment than a child’s.

The biological significance of conditioned reflexes is that they make it possible to adapt much better and more accurately to the conditions of existence and to survive in these conditions.

As a result of the formation of conditioned reflexes, the body reacts not only directly to unconditioned stimuli, but also to the possibility of their action on it; reactions appear some time before unconditional irritation. In this way, the body is prepared in advance for the actions that it has to carry out in a given situation. Conditioned reflexes contribute to finding food, avoiding danger in advance, eliminating harmful effects and so on.

The adaptive significance of conditioned reflexes is also manifested in the fact that the precedence of conditioned stimulation by an unconditioned one strengthens the unconditioned reflex and accelerates its development.

LECTURE 2. PHYSIOLOGY OF HIGHER NERVOUS ACTIVITY. INTEGRATED BRAIN ACTIVITY AND SYSTEM ORGANIZATION OF ADAPTIVE BEHAVIORAL REACTIONS. TEACHING I.P. PAVLOVA ON TYPES OF HIGHER NERVOUS ACTIVITY

Higher nervous activity and its age-related characteristics. Conditioned and unconditioned reflexes.

1. Differences between conditioned reflexes and unconditioned ones:

Unconditioned reflexes- innate reactions of the body, they were formed and consolidated in the process of evolution and are inherited.

Conditioned reflexes arise, consolidate, fade during life and are individual.

Unconditioned reflexes necessarily arise if adequate stimuli act on certain receptors.

Conditioned reflexes require special conditions for their formation; they can be formed in response to any stimuli (of optimal strength and duration) from any receptive field.

Unconditioned reflexes are relatively constant, persistent, unchanging and persist throughout life.

Conditioned reflexes are changeable and more mobile.

Unconditioned reflexes can occur at the level of the spinal cord and brain stem.

Conditioned reflexes are a function of the cerebral cortex, realized with the participation of subcortical structures.

Unconditioned reflexes can ensure the existence of an organism only at the very early stage of life.

The body's adaptation to constantly changing environmental conditions is ensured by conditioned reflexes developed throughout life.

Conditioned reflexes are changeable. In the process of life, some conditioned reflexes, losing their meaning, fade away, while others are developed.

1. Biological significance of unconditioned reflexes.

An organism is born with a certain set of unconditioned reflexes. They ensure the maintenance of the body’s vital functions in relatively constant conditions of existence. These include unconditioned reflexes:

food- chewing, sucking, swallowing, secretion of saliva, gastric juice, etc.,

defensive- withdrawing a hand from a hot object, coughing, sneezing, blinking when a stream of air hits the eye, etc.,

sexual reflexes- sexual intercourse, feeding and caring for offspring,

thermoregulatory,

respiratory,

cardiovascular,

maintaining the constancy of the internal environment of the body(homeostasis), etc.

1. Biological significance of conditioned reflexes.

Conditioned reflexes provide a more perfect adaptation of the body to changing living conditions. They help to find food by smell, timely escape from danger, and orientation in time and space.

1. Conditions for the formation of a conditioned reflex.

Conditioned reflexes are developed on the basis of unconditioned ones. For the formation of a conditioned reflex, certain conditions are required. First of all, you need a conditioned stimulus, or signal. A conditioned stimulus can be any stimulus from the external environment or internal environment of the body.

For example :

in the laboratory of I.P. Pavlov, the flashing of an electric light bulb, the ringing of a bell, the gurgling of water, skin irritation, taste and olfactory stimuli, the clinking of dishes, the sight of a burning candle, etc. were used as conditioned stimuli;

conditioned reflexes are temporarily developed in a person by observing a work schedule, eating at the same time, and a constant bedtime.

To develop a conditioned reflex, the conditioned stimulus must be reinforced with an unconditioned stimulus, that is, one that causes an unconditioned reflex. When a conditioned reflex is formed, the conditioned stimulus must precede the action of the unconditioned stimulus (usually by 1-5 s).

A conditioned reflex can be developed by combining an indifferent stimulus with a previously developed conditioned reflex - these are conditioned reflexes of the second order, then the indifferent stimulus must be reinforced with a conditioned stimulus of the first order.

For example :

The clinking of knives in the dining room will cause a person to salivate only if this clinking has been reinforced with food one or more times. The ringing of knives and forks in our case is a conditioned stimulus, and the unconditioned stimulus that causes the salivary unconditioned reflex is food.

The sight of a burning candle can become a signal for a child to withdraw his hand only if at least once the sight of a candle coincides with pain from a burn.

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1. What is the progressiveness of I.M.’s views? Sechenov on human mental activity?

In 1863, a book by I.M. was published. Sechenov "Reflexes of the brain". In this work, for the first time in the history of natural science, human behavior and “mental” - mental activity were explained by the reflex principle of the nervous system. THEM. Sechenov argued that brain reflexes include three parts. The first, initial link is stimulation in the senses caused by external influences. The second, central link is the processes of excitation and inhibition occurring in the brain. On their basis, mental phenomena arise (sensations, ideas, feelings, etc.). The third, final link is the movements and actions of a person, i.e. his behavior. All these links are interconnected and condition each other.

2. What is the significance of the works of I.M. Sechenov and I.P. Pavlov for the development of behavioral science?

The role of I.M. Sechenov and I.P. Pavlov in the creation of the doctrine of higher nervous activity. For many centuries, people have wondered about the amazing adaptability of animal behavior to environmental conditions. Purposeful, reasonable human behavior seemed even more mysterious.

The beginning of the scientific study of complex adaptive reactions of humans and animals, mental and mental activity of humans was laid by the works of the great Russian scientists I.M. Sechenov and I.P. Pavlova.

3. What reflexes are called unconditioned?

Unconditioned reflexes are hereditarily transmitted (innate) reactions of the body, inherent to the entire species. Execute protective function, as well as the function of maintaining homeostasis (adaptation to environmental conditions).

Unconditioned reflexes are an inherited, unchangeable reaction of the body to external and internal signals, regardless of the conditions for the occurrence and course of reactions. Unconditioned reflexes ensure the body's adaptation to constant environmental conditions. The main types of unconditioned reflexes: food, protective, orientation, sexual.

An example of a defensive reflex is the reflexive withdrawal of the hand from a hot object. Homeostasis is maintained, for example, by a reflex increase in breathing when there is an excess of carbon dioxide in the blood. Almost every part of the body and every organ is involved in reflex reactions.

4. What is the significance of unconditioned reflexes? Give examples of unconditioned reflexes and explain their significance for the body.

Unconditioned reflexes help a person survive in the early stages of development. That is, for example, a child at birth. His unconditioned reflex will be to scream, because... otherwise he won't be able to breathe.

Unconditioned reflexes are given from birth, and conditional person develops in the process of existence.

As already written above, unconditional helps at an early stage of development, and conditional helps at subsequent stages, i.e. when a person is already able to take a deliberate action.

5. What reflexes are called conditioned?

Conditioned reflexes are those acquired during our life. I.P. Pavlov showed that, along with hereditary ones, there are many reflexes that are acquired by the body during life. Such reflexes arise under certain conditions, which is why they were called conditioned.

6. What is the biological significance of conditioned reflexes?

Conditioned reflexes are developed on the basis of unconditioned reflexes; they help us adapt to life. For example, learn to walk, talk, read books, etc. When we see food, we produce saliva, for example, this is their biological significance.

7. What is Pavlov’s method of forming conditioned reflexes in animals?

I.P. Pavlov studied conditioned reflexes in experiments on animals (dogs). To do this, the dog was secured in a special pen to limit its movements. When the dog was given food (an unconditioned stimulus), it reflexively salivated - an unconditioned salivary reflex arose. To develop a conditioned reflex, half a minute before feeding they turned on an electric light bulb or another stimulus that was indifferent to the salivary reflex. After several combinations of turning on the light bulb and feeding, a single flash of light caused salivation even if there was no food in the feeder. Thus, the flash of light became a signal of the appearance of food - a conditioned stimulus. The dog has developed a conditioned salivary reflex.

8. What is the biological significance of inhibition of conditioned reflexes?

Conditional = internal inhibition:

a) ensures the gradual extinction of conditioned reflexes in the absence of reinforcement of the conditioned stimulus by the unconditioned. Thanks to the internal inhibition of biologically inappropriate reactions of the body, it is possible to develop new conditioned reflexes and change behavior in the process of adaptation to the external environment. For example, when a reservoir from which animals drank dries up, they stop coming to it and find a new reservoir.

b) contributes to the emergence - the ability to distinguish one signal from other, similar ones. If one stimulus is reinforced, and another, close to it, is not reinforced, then a conditioned reflex reaction occurs only to the reinforced stimulus, and the reaction to the other stimulus is inhibited. For example, by the nature of a conditioned knock on the door, a dog can determine who has come - one of their own or someone else's, and react accordingly.

9. How do conditioned reflexes differ from unconditioned ones?

Unconditioned reflexes are innate, hereditary reactions of the body. Conditioned reflexes are reactions acquired by the body in the process individual development based on life experience.

Unconditioned reflexes are relatively constant; conditioned reflexes are unstable and this property is reflected in their very name. Unconditioned reflexes are carried out in response to adequate stimulation applied to a specific receptive field. Conditioned reflexes can be formed to any irritation of any receptive field perceived by the body. Conditioned reflexes are primarily a function of the cerebral cortex. Unconditioned reflexes can occur at the level of the spinal cord and brain stem.

10. What is the significance of unconditioned and conditioned reflexes?

The orienting reflex occupies a special place among the unconditioned reflexes in ensuring safety. It appears in response to a new stimulus: a person becomes alert, listens, turns his head, squints his eyes, and thinks. The orienting reflex ensures the perception of an unfamiliar stimulus.

Conditioned reflexes formed during the learning process allow the body to adapt more flexibly to specific environmental conditions and form the basis for the development of a person’s habits and entire lifestyle. The adaptive significance of conditioned reflexes is enormous. Thanks to them, a person can take the necessary actions in advance to protect himself, focusing on signs of possible danger, without seeing the danger itself. Conditioned stimuli have a signaling character. They warn of danger.

All immediate sensations, perceptions and corresponding human reactions are carried out on the basis of unconditioned and conditioned reflexes. However, under specific conditions social environment a person orients and reacts not only to immediate stimuli. For a person, the signal of any stimulus is the word denoting it, and its semantic content. Words spoken, heard and visible are signals, symbols of specific objects and environmental phenomena. The word man denotes everything that he perceives with the help of his senses.

Each person, as well as all living organisms, has a number of vital needs: food, water, comfortable conditions. Everyone has instincts of self-preservation and continuation of their kind. All mechanisms aimed at satisfying these needs are laid down at the genetic level and appear simultaneously with the birth of the organism. These are innate reflexes that help to survive.

The concept of an unconditioned reflex

The word reflex itself is not something new and unfamiliar for each of us. Everyone has heard it in their life, and quite many times. This term was introduced into biology by I.P. Pavlov, who devoted a lot of time to studying the nervous system.

According to the scientist, unconditioned reflexes arise under the influence of irritating factors on the receptors (for example, withdrawing a hand from a hot object). They contribute to the body’s adaptation to those conditions that remain practically unchanged.

This is the so-called product of the historical experience of previous generations, therefore it is also called a species reflex.

We live in a changing environment; it requires constant adaptations, which cannot in any way be provided for by genetic experience. Unconditioned reflexes of a person are constantly either inhibited, then modified or arise again, under the influence of those stimuli that surround us everywhere.

Thus, already familiar stimuli acquire the qualities of biologically significant signals, and the formation of conditioned reflexes occurs, which form the basis of our individual experience. This is what Pavlov called higher nervous activity.

Properties of unconditioned reflexes

The characteristics of unconditioned reflexes include several mandatory points:

1. Congenital reflexes are inherited.
2. They appear equally in all individuals of a given species.
3. For a response to occur, the influence of a certain factor is necessary, for example, for the sucking reflex it is irritation of the lips of a newborn.
4. The area of ​​perception of the stimulus always remains constant.
5. Unconditioned reflexes have a constant reflex arc.
6. They persist throughout life, with some exceptions in newborns.

The meaning of reflexes

All our interactions with environment built on the level of reflex responses. Unconditioned and conditioned reflexes play an important role in the existence of the organism.

In the process of evolution, a division occurred between those aimed at the survival of the species and those responsible for adaptability to constantly changing conditions.

Congenital reflexes begin to appear in utero, and their role boils down to the following:

• Maintaining internal environment indicators at a constant level.
• Preserving the integrity of the body.
• Preservation of a species through reproduction.

The role of innate reactions immediately after birth is great; they ensure the survival of the baby in completely new conditions.

The body lives surrounded external factors, which are constantly changing and need to be adapted to. This is where higher nervous activity in the form of conditioned reflexes comes to the fore.

For the body they have the following meaning:

• We will improve the mechanisms of its interaction with the environment.
• The processes of contact between the body and the external environment are clarified and complicated.
• Conditioned reflexes are an indispensable basis for the processes of learning, education and behavior.

Thus, unconditioned and conditioned reflexes are aimed at maintaining the integrity of a living organism and the constancy of the internal environment, as well as effective interaction with the outside world. Between themselves they can be combined into complex reflex acts that have a certain biological orientation.

Classification of unconditioned reflexes

Hereditary reactions of the body, despite their innateness, can differ greatly from each other. It is not at all surprising that the classification can be different, depending on the approach.

Pavlov also divided all unconditioned reflexes into:

• Simple (the scientist included the sucking reflex among them).
• Complex (sweating).
• The most complex unconditioned reflexes. A variety of examples can be given: food reactions, defensive reactions, sexual reactions.

Currently, many adhere to a classification based on the meaning of reflexes. Depending on this, they are divided into several groups:

The first group of reactions has two characteristics:

1. If they are not satisfied, this will lead to the death of the body.
2. Satisfaction does not require the presence of another individual of the same species.

The third group also has its own characteristic features:

1. Self-development reflexes have nothing to do with the body’s adaptation to a given situation. They are aimed at the future.
2. They are completely independent and do not stem from other needs.

We can also divide them according to their level of complexity, then the following groups will appear before us:

1. Simple reflexes. These are the body's normal responses to external stimuli. For example, withdrawing your hand from a hot object or blinking when a speck gets into your eye.
2. Reflex acts.
3. Behavioral reactions.
4. Instincts.
5. Imprinting.

Each group has its own characteristics and differences.

Reflex acts

Almost all reflex acts are aimed at ensuring the vital functions of the body, so they are always reliable in their manifestation and cannot be corrected.

These include:

• Breath.
• Swallowing.
• Vomiting.

In order to stop a reflex act, you simply need to remove the stimulus that causes it. This can be practiced when training animals. If you want natural needs not to distract from training, then you need to walk the dog before this, this will eliminate the irritant that can provoke a reflex act.

Behavioral reactions

This type of unconditioned reflex can be well demonstrated in animals. Behavioral reactions include:

• The dog's desire to carry and pick up objects. Retrieval reaction.
• Showing aggression when seen stranger. Active defensive reaction.
• Finding objects by smell. Olfactory-search reaction.

It is worth noting that a behavioral reaction does not mean that the animal will certainly behave this way. What is meant? For example, a dog that has a strong active-defensive reaction from birth, but is physically weak, most likely will not show such aggression.

These reflexes can determine the animal's actions, but they can be controlled. They should also be taken into account when training: if an animal completely lacks an olfactory-search reaction, then it is unlikely that it will be possible to train it as a search dog.

Instincts

There are also more complex forms in which unconditioned reflexes appear. Instincts come into play here. This is a whole chain of reflex acts that follow each other and are inextricably interconnected.

All instincts are associated with changing internal needs.

When a child is just born, his lungs practically do not function. The connection between him and his mother is interrupted by cutting the umbilical cord, and carbon dioxide accumulates in the blood. It begins its humoral effect on the respiratory center, and instinctive inhalation occurs. The child begins to breathe independently, and the first cry of the baby is a sign of this.

Instincts are a powerful stimulant in human life. They may well motivate success in a certain field of activity. When we stop controlling ourselves, instincts begin to guide us. As you yourself understand, there are several of them.

Most scientists are of the opinion that there are three basic instincts:

1. Self-preservation and survival.
2. Continuation of the family.
3. Leadership instinct.

All of them can generate new needs:

• In safety.
• In material prosperity.
• Looking for a sexual partner.
• In caring for children.
• In influencing others.

We could go on and on about the types of human instincts, but, unlike animals, we can control them. For this purpose, nature has endowed us with reason. Animals survive only due to instincts, but for this we are also given knowledge.

Don't let your instincts get the better of you, learn to manage them and become the master of your life.

Imprint

This form of unconditioned reflex is also called imprinting. There are periods in the life of every individual when the entire surrounding environment is imprinted on the brain. For each species, this time period may be different: for some it lasts several hours, and for others it lasts several years.

Remember how easily young children master foreign speech skills. While schoolchildren put a lot of effort into this.

It is thanks to imprinting that all babies recognize their parents and distinguish individuals of their species. For example, after the birth of a baby, a zebra spends several hours alone with it in a secluded place. This is exactly the time that is necessary for the cub to learn to recognize its mother and not confuse her with other females in the herd.

This phenomenon was discovered by Konrad Lorenz. He conducted an experiment with newborn ducklings. Immediately after the hatching of the latter, he presented them with various objects, which they followed like a mother. They even perceived him as a mother, and followed him around.

Everyone knows the example of hatchery chickens. Compared to their relatives, they are practically tame and are not afraid of humans, because from birth they see him in front of them.

Congenital reflexes of an infant

After birth, the baby goes through a complex developmental path that consists of several stages. The degree and speed of mastery of various skills will directly depend on the state of the nervous system. The main indicator of its maturity is the unconditioned reflexes of the newborn.

The presence of them in the baby is checked immediately after birth, and the doctor makes a conclusion about the degree of development of the nervous system.

From the huge number of hereditary reactions, the following can be distinguished:

1. Kussmaul search reflex. When the area around the mouth is irritated, the child turns his head towards the irritant. The reflex usually fades by 3 months.
2. Sucking. If you place your finger in the baby's mouth, he begins to perform sucking movements. Immediately after feeding, this reflex fades away and becomes more active after some time.
3. Palmo-oral. If you press on the child's palm, he opens his mouth slightly.
4. Grasping reflex. If you put your finger in the baby’s palm and lightly press it, a reflexive squeezing and holding occurs.
5. The inferior grasp reflex is caused by light pressure on the front of the sole. The toes flex.
6. Crawling reflex. When lying on the stomach, pressure on the soles of the feet causes a crawling movement forward.
7. Protective. If you lay a newborn on his stomach, he tries to raise his head and turns it to the side.
8. Support reflex. If you take the baby under the armpits and place him on something, he will reflexively straighten his legs and rest on his entire foot.

The unconditioned reflexes of a newborn can go on for a long time. Each of them symbolizes the degree of development of certain parts of the nervous system. After an examination by a neurologist in the maternity hospital, a preliminary diagnosis of some diseases can be made.

From the point of view of their significance for the baby, the mentioned reflexes can be divided into two groups:

1. Segmental motor automatisms. They are provided by segments of the brain stem and spinal cord.
2. Posotonic automatisms. Provide regulation of muscle tone. The centers are located in the midbrain and medulla oblongata.

Oral segmental reflexes

This type of reflexes includes:

• Sucking. Appears during the first year of life.
• Search. Extinction occurs at 3-4 months.
• Proboscis reflex. If you hit a baby on the lips with your finger, he pulls them out into his proboscis. After 3 months, extinction occurs.
• The hand-mouth reflex is a good indicator of the development of the nervous system. If it does not appear or is very weak, then we can talk about damage to the central nervous system.

Spinal motor automatisms

Many unconditioned reflexes belong to this group. Examples include the following:

• Moro reflex. When a reaction is caused, for example, by hitting the table near the baby's head, the latter's arms are spread to the sides. Appears up to 4-5 months.
• Automatic gait reflex. When supported and slightly tilted forward, the baby makes stepping movements. After 1.5 months it begins to fade.
• Galant reflex. If you run your finger along the paravertebral line from the shoulder to the buttocks, the body bends towards the stimulus.

Unconditioned reflexes are assessed on a scale: satisfactory, increased, decreased, absent.

Differences between conditioned and unconditioned reflexes

Sechenov also argued that in the conditions in which the body lives, innate reactions are completely insufficient for survival; the development of new reflexes is required. They will help the body adapt to changing conditions.

How do unconditioned reflexes differ from conditioned reflexes? The table demonstrates this well.

Despite the obvious difference between conditioned reflexes and unconditioned ones, together these reactions ensure the survival and preservation of the species in nature.