What conditioned and unconditioned reflexes do you know? Conditioned reflexes, their general characteristics and significance for the organism’s adaptation to the environment

The outstanding Russian physiologist I.M. Sechenov was the first to express the idea of ​​the connection between human consciousness and thinking and reflex activity his brain. This idea was developed and convincingly confirmed in numerous experiments by I.P. Pavlova. Therefore I.P. Pavlov is considered the creator of the doctrine of higher nervous activity.

Higher nervous activity- these are the functions of the cortex cerebral hemispheres brain and the nearest subcortical formations, where temporary nerve connections (conditioned reflexes) are developed anew, ensuring the most subtle and perfect individual adaptation of the body to changing conditions external environment.

UNCONDITIONED AND CONDITIONED REFLEXES

Higher nervous activity is reflexive in nature. Higher animals and humans have unconditioned and conditioned reflexes. Their specificity is as follows.

Unconditioned reflexes ensuring the maintenance of vital functions in relatively constant environmental conditions, are inherent in a person from birth. These include food (sucking, swallowing, salivation, etc.), defensive (coughing, blinking, withdrawing a hand, etc.), reproduction (feeding and caring for offspring), respiratory, etc.

Conditioned reflexes are developed on the basis of unconditioned ones under the influence of a conditioned stimulus. They provide a more perfect adaptation of the body to changing environmental conditions. They help to find food by smell, avoid danger, navigate, etc.

Meaning of the word. In humans, conditioned reflexes can be formed not only as in animals, on the basis of the first signaling system, when the conditioned stimuli are directly objects of the external world, but also on the basis of the second (speech) signaling system, when the conditioned stimuli are words expressing concepts about objects and phenomena. Conditioned reflexes are physiological basis technical processes, the basis of thinking. The word is a kind of irritant for many conditioned reflexes. For example, just talking about food or describing it can cause a person to salivate.

Human consciousness is associated with the activity of the cerebral cortex. This has been convincingly proven by numerous experiments by I.P. Pavlov, as well as by the study of diseases and dysfunctions of the brain.

The teachings of I. P. Pavlov on the higher nervous activity of man convincingly proved the inconsistency and anti-scientific nature of religious ideas about the “soul”.

Inhibition of conditioned reflexes. When environmental conditions change, previously developed conditioned reflexes fade away and new ones are formed. I.P. Pavlov distinguished two types of inhibition of conditioned reflexes.

External braking occurs when the body is exposed to an irritant that is stronger than the previous one. At the same time, a new focus of excitation is formed in the cerebral cortex. For example, in a dog, the conditioned salivary reflex developed in response to light (see “Digestion”) is inhibited under experimental conditions by a stronger stimulus - the sound of a bell. The latter calls in auditory zone cerebral cortex strong excitement. Initially, it generates inhibition of neighboring areas, and then spreads to the visual area. Therefore, excitation cannot be carried out through the neurons located in it and the arc of the previous conditioned reflex is interrupted.

Internal inhibition occurs in the arc of a conditioned reflex when the conditioned stimulus ceases to receive reinforcement from the unconditioned stimulus and the temporary connections formed in the cortex are gradually inhibited. When conditioned reflexes are repeated in the same sequence, dynamic stereotypes are formed that make up habits and skills.

Hygiene of physical and mental work. The activity of the body depends on the state of the central nervous system. Her overwork leads to vital distress important functions the body, reduces perception, attention, memory and performance.

With monotonous physical labor Only one group of muscles works and only one part of the central nervous system is excited, which leads to its fatigue.

To avoid overwork, it is useful to perform industrial exercises during breaks, which involve other muscles. This, in turn, leads to the excitation of new areas of the cerebral cortex, inhibition of previously working areas, their rest and restoration of performance.

Mental work also causes fatigue in the central nervous system. The best vacation this involves gymnastics or other physical activity.

The daily routine is of great importance in the formation of conditioned reflexes. When followed, a person develops many important conditioned reflexes that stimulate better functioning. various systems organs and preventing their fatigue.

Alternation of physical and mental labor, rationalization of work, adherence to the daily routine, leisure are of paramount importance for protecting the central nervous system from fatigue.

Sleep gives the most complete rest to the central nervous system. Alternation of sleep and wakefulness - necessary condition human existence. I.P. Pavlov experimentally proved that sleep is an inhibition that involves the cerebral cortex and other parts of the brain. During sleep, metabolism, hearing, smell, and the intensity of activity of a number of organ systems decrease, muscle tone decreases, and thinking turns off. Sleep is a protective device against overwork of the nervous system. Infants sleep 20-22 hours, schoolchildren - 9-11 hours, adults - 7-8 hours. With lack of sleep, a person loses his ability to work. In order for the body to receive the most complete rest during sleep, it is necessary to go to bed at the same time, eliminate bright light, noise, ventilate the room, etc.

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 basic principle of the nervous system is 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) - a stimulus that previously did not cause a corresponding reaction, but under certain conditions of formation, begins to cause it), reproducing 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(signs):

• All conditioned reflexes represent one of the forms of adaptive reactions of the body to changing environmental conditions.
• UR are acquired and canceled during individual life each specific 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

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- reaction to the properties (signs) of a stimulus (food, 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.

A reflex is the body's response to internal or external stimulation, carried out and controlled by the central nervous system. The first scientists who developed ideas about what was previously a mystery were our compatriots I.P. Pavlov and I.M. Sechenov.

What are unconditioned reflexes?

An unconditioned reflex is an innate, stereotypical reaction of the body to the influence of the internal or environmental environment, inherited by the offspring from the parents. It remains in a person throughout his life. Reflex arcs pass through the brain and the cerebral cortex does not take part in their formation. The significance of the unconditioned reflex is that it provides adaptation human body directly to those environmental changes that often accompanied many generations of his ancestors.

What reflexes are unconditioned?

An unconditioned reflex is the main form of activity of the nervous system, an automatic reaction to a stimulus. And since a person is influenced various factors, then there are different reflexes: food, defensive, orientation, sexual... Food ones include salivation, swallowing and sucking. Defensive actions include coughing, blinking, sneezing, and jerking limbs away from hot objects. Approximate reactions include turning the head and squinting the eyes. Sexual instincts include those associated with reproduction, as well as caring for offspring. The significance of the unconditioned reflex is that it ensures the preservation of the integrity of the body and maintains the constancy of the internal environment. Thanks to him, reproduction occurs. Even in newborn children, one can observe an elementary unconditioned reflex - this is sucking. By the way, it is the most important. Irritant in in this case touching the lips of any object (pacifier, mother's breast, toy or finger). Another important unconditioned reflex is blinking, which occurs when a foreign body approaches the eye or touches the cornea. This reaction belongs to the protective or defensive group. Also observed in children, for example, when exposed to strong light. However, the signs of unconditioned reflexes are most clearly manifested in various animals.

What are conditioned reflexes?

Conditioned reflexes are those acquired by the body during life. They are formed on the basis of inherited ones, subject to exposure to an external stimulus (time, knocking, light, and so on). A striking example are experiments conducted on dogs by academician I.P. Pavlov. He studied the formation of this type of reflexes in animals and was the developer unique technique receiving them. So, to develop such reactions, the presence of a regular stimulus - a signal - is necessary. It triggers the mechanism, and repeated repetition of the stimulus allows it to develop. In this case, a so-called temporary connection arises between the arcs of the unconditioned reflex and the centers of the analyzers. Now the basic instinct awakens under the influence of fundamentally new external signals. These stimuli from the surrounding world, to which the body was previously indifferent, begin to acquire exceptional, vital importance. Each living creature can develop many different conditioned reflexes during its life, which form the basis of its experience. However, this applies only to this particular individual, by inheritance this life experience will not be transmitted.

An independent category of conditioned reflexes

It is customary to classify into a separate category conditioned reflexes of a motor nature developed throughout life, that is, skills or automated actions. Their meaning is to master new skills, as well as develop new motor forms. For example, over the entire period of his life a person masters many special motor skills that are associated with his profession. They are the basis of our behavior. Thinking, attention, consciousness are freed when performing operations that have reached automaticity and become a reality Everyday life. Most in a successful way mastering skills is the systematic execution of exercises, timely correction of noticed errors, as well as knowledge of the ultimate goal of any task. If the conditioned stimulus is not reinforced by the unconditioned stimulus for some time, it is inhibited. However, it does not disappear completely. If you repeat the action after some time, the reflex will be restored fairly quickly. Inhibition can also occur when a stimulus of even greater strength appears.

Compare unconditioned and conditioned reflexes

As mentioned above, these reactions differ in the nature of their occurrence and have different formation mechanisms. In order to understand what the difference is, just compare unconditioned and conditioned reflexes. Thus, the first ones are present in a living creature from birth; throughout life they do not change or disappear. In addition, unconditioned reflexes are the same in all organisms of a particular species. Their significance lies in preparing a living being for constant conditions. The reflex arc of this reaction passes through the brain stem or spinal cord. As an example, here are some (congenital): active secretion of saliva when a lemon enters the mouth; sucking movement of the newborn; coughing, sneezing, withdrawing hands from a hot object. Now let's look at the characteristics of conditioned reactions. They are acquired throughout life, can change or disappear, and, no less important, each organism has its own individual (its own). Their main function is to adapt a living creature to changing conditions. Their temporary connection (reflex centers) is created in the cerebral cortex. An example of a conditioned reflex is the reaction of an animal to a nickname or the reaction of a six-month-old child to a bottle of milk.

Unconditioned reflex diagram

According to the research of academician I.P. Pavlova, general scheme unconditioned reflexes is as follows. Certain receptor nerve devices are affected by certain stimuli from the internal or external world of the body. As a result, the resulting irritation transforms the entire process into the so-called phenomenon nervous excitement. It is transmitted via nerve fibers(as if by wire) to the central nervous system, and from there it goes to a specific working organ, already turning into a specific process on cellular level this part of the body. It turns out that certain stimuli are naturally connected with this or that activity in the same way as cause and effect.

Features of unconditioned reflexes

The characteristics of unconditioned reflexes presented below systematize the material presented above; it will help to finally understand the phenomenon we are considering. So, what are the features of inherited reactions?

Unconditioned instinct and reflex of animals

Exceptional constancy of the underlying neural connection unconditional instinct, is explained by the fact that all animals are born with a nervous system. She is already able to respond appropriately to specific environmental stimuli. For example, a creature may flinch at a sharp sound; he will secrete digestive juice and saliva when food enters his mouth or stomach; it will blink when visually stimulated, and so on. Innate in animals and humans are not only individual unconditioned reflexes, but also much more complex forms of reactions. They are called instincts.

An unconditioned reflex, in fact, is not a completely monotonous, template, transfer reaction of an animal to an external stimulus. It is characterized, although elementary, primitive, but still by variability, variability, depending on external conditions (strength, peculiarities of the situation, position of the stimulus). In addition, it is influenced by internal states animal (decreased or increased activity, posture, etc.). So, also I.M. Sechenov, in his experiments with decapitated (spinal) frogs, showed that when exposed to the fingers hind legs In this amphibian, the opposite motor reaction occurs. From this we can conclude that the unconditioned reflex still has adaptive variability, but within insignificant limits. As a result, we find that the balancing of the organism and the external environment achieved with the help of these reactions can be relatively perfect only in relation to slightly changing factors of the surrounding world. The unconditioned reflex is not able to ensure the animal’s adaptation to new or sharply changing conditions.

As for instincts, sometimes they are expressed in the form simple actions. For example, the rider, thanks to his sense of smell, finds the larvae of another insect under the bark. It pierces the bark and lays its egg in the found victim. This ends all of its actions that ensure continuation of the family. There are also complex unconditioned reflexes. Instincts of this kind consist of a chain of actions, the totality of which ensures procreation. Examples include birds, ants, bees and other animals.

Species specificity

Unconditioned reflexes (specific) are present in both humans and animals. It should be understood that such reactions will be the same in all representatives of the same species. An example is a turtle. All species of these amphibians retract their heads and limbs into their shell when danger arises. And all the hedgehogs jump and make a hissing sound. In addition, you should know that not all unconditioned reflexes occur at the same time. These reactions vary with age and season. For example, the breeding season or the motor and sucking actions that appear in an 18-week fetus. Thus, unconditioned reactions are a kind of development for conditioned reflexes in humans and animals. For example, as cubs grow older, they transition into the category of synthetic complexes. They increase the body's adaptability to external environmental conditions.

Unconditional inhibition

In the process of life, each organism is regularly exposed - both from the outside and from the inside - to various stimuli. Each of them is capable of causing appropriate reaction- reflex. If all of them could be realized, then the life activity of such an organism would become chaotic. However, this does not happen. On the contrary, reactionary activity is characterized by consistency and orderliness. This is explained by the fact that unconditioned reflexes are inhibited in the body. This means that the most important reflex at a particular moment in time delays the secondary ones. Typically, external inhibition can occur at the moment of starting another activity. The new pathogen, being stronger, leads to the attenuation of the old one. And as a result, the previous activity will automatically stop. For example, a dog is eating, and at that moment the doorbell rings. The animal immediately stops eating and runs to meet the newcomer. There is a sharp change in activity, and the dog’s salivation stops at this moment. TO unconditional inhibition reflexes also include some innate reactions. In them, certain pathogens cause the complete cessation of certain actions. For example, the anxious clucking of a hen makes the chicks freeze and hug the ground, and the onset of darkness forces the canary to stop singing.

In addition, there is also a protective It arises as a response to a very strong stimulus that requires the body to take actions that exceed its capabilities. The level of such influence is determined by the frequency of impulses of the nervous system. The more excited a neuron is, the higher the frequency of the stream of nerve impulses it generates. However, if this stream exceeds certain limits, a process will arise that will begin to interfere with the passage of excitation along the neural circuit. The flow of impulses along the reflex arc of the spinal cord and brain is interrupted, resulting in inhibition that preserves executive bodies from complete exhaustion. What conclusion follows from this? Thanks to the inhibition of unconditioned reflexes, the body secretes from all possible options the most adequate, capable of protecting against excessive activity. This process also contributes to the exercise of so-called biological precautions.

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

The concept of “reflex” was introduced by Sechenov, he believed that “reflexes form the basis of the nervous activity of humans and animals.” Pavlov divided reflexes into conditioned and unconditioned.

Comparison of conditioned and unconditioned reflexes

Development of a conditioned reflex

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

Inhibition of conditioned reflexes

Conditional (non-reinforcement): the lamp lights up, but the dog is not given meat. Gradually, salivation when the lamp is turned on stops (the conditioned reflex fades).

Unconditional: During the action of a conditioned stimulus, a powerful unconditioned stimulus arises. For example, when the lamp is turned on, the bell rings loudly. No saliva is produced.

Choose one, the most correct option. The centers of conditioned reflexes, in contrast to unconditioned ones, are located in humans in
1) cerebral cortex
2) medulla oblongata
3) cerebellum
4) midbrain

Answer

Choose one, the most correct option. Salivation in a person at the sight of a lemon is a reflex
1) conditional
2) unconditional
3) protective
4) approximate

Answer

Choose three options. The peculiarity of unconditioned reflexes is that they




5) are congenital
6) are not inherited

Answer

Choose three correct answers out of six and write down the numbers under which they are indicated. Unconditioned reflexes that ensure the vital functions of the human body,
1) are developed in the process of individual development
2) formed in the process of historical development
3) are present in all individuals of the species
4) strictly individual
5) formed under relatively constant environmental conditions
6) are not congenital

Answer

Choose three correct answers out of six and write down the numbers under which they are indicated. The peculiarity of unconditioned reflexes is that they
1) arise as a result of repeated repetition
2) are a characteristic characteristic of an individual individual of the species
3) are genetically programmed
4) are characteristic of all individuals of the species
5) are congenital
6) build skills

Answer

Choose one, the most correct option. What are the features of spinal reflexes in humans and mammals?
1) acquired during life
2) are inherited
3) are different in different individuals
4) allow the organism to survive in changing environmental conditions

Answer

Choose one, the most correct option. The extinction of a conditioned reflex when it is not reinforced by an unconditioned stimulus is
1) unconditional inhibition
2) conditioned inhibition
3) rational action
4) conscious action

Answer

Choose one, the most correct option. Conditioned reflexes of humans and animals provide
1) adaptation of the body to constant environmental conditions
2) adaptation of the body to the changing external world
3) development of new motor skills by organisms
4) discrimination by animals of the trainer’s commands

Answer

Choose one, the most correct option. A baby's reaction to a bottle of milk is a reflex that
1) inherited
2) is formed without the participation of the cerebral cortex
3) acquired during life
4) persists throughout life

Answer

Choose one, the most correct option. When developing a conditioned reflex, the conditioned stimulus must
1) act 2 hours after unconditional
2) come immediately after the unconditional
3) precede the unconditional
4) gradually weaken

Answer

1. Establish a correspondence between the meaning of the reflex and its type: 1) unconditional, 2) conditional. Write numbers 1 and 2 in the correct order.
A) provides instinctive behavior
B) ensures the adaptation of the organism to the environmental conditions in which many generations of this species lived
C) allows you to gain new experience
D) determines the behavior of the organism in changed conditions

Answer

2. Establish a correspondence between the types of reflexes and their characteristics: 1) conditional, 2) unconditional. Write numbers 1 and 2 in the order corresponding to the letters.
A) are congenital
B) adaptation to new emerging factors
C) reflex arcs are formed in the process of life
D) are the same in all representatives of the same species
D) are the basis of learning
E) are constant, practically do not fade during life

Answer

Choose one, the most correct option. Conditioned (internal) inhibition
1) depends on the type of higher nervous activity
2) appears when a stronger stimulus occurs
3) causes the formation of unconditioned reflexes
4) occurs when the conditioned reflex fades

Answer

Choose one, the most correct option. The basis of nervous activity in humans and animals is
1) thinking
2) instinct
3) excitement
4) reflex

Answer

1. Establish a correspondence between the examples and types of reflexes: 1) unconditional, 2) conditional. Write numbers 1 and 2 in the correct order.
A) withdrawing a hand from the fire of a burning match
B) a child crying at the sight of a man in a white coat
C) a five-year-old child reaching out to the sweets he saw
D) swallowing pieces of cake after chewing them
D) salivation at the sight of a beautifully set table
E) downhill skiing

Answer

2. Establish a correspondence between the examples and the types of reflexes that they illustrate: 1) unconditional, 2) conditioned. Write numbers 1 and 2 in the order corresponding to the letters.
A) sucking movements of the child in response to touching his lips
B) constriction of the pupil illuminated by the bright sun
C) performing hygiene procedures before bed
D) sneezing when dust enters the nasal cavity
D) secretion of saliva to the clink of dishes when setting the table
E) roller skating

Answer

© D.V. Pozdnyakov, 2009-2019

Our nervous system- this is a complex mechanism of interaction between neurons that send impulses to the brain, and it, in turn, controls all organs and ensures their functioning. This process of interaction is possible due to the presence in humans of basic, inseparable acquired and innate forms of adaptation - conditioned and unconditional reactions. A reflex is a conscious response of the body to certain conditions or stimuli. Such a team effort nerve endings helps us interact with the world around us. A person is born with a set of simple skills - this is called an example of such behavior: the ability of a baby to suckle at the mother's breast, swallow food, blink.

and animal

As soon as Living being is born, he needs certain skills that will help ensure his life. The body actively adapts to the surrounding world, that is, it develops a whole complex of targeted motor skills. It is this mechanism that is called species behavior. Each living organism has its own set of reactions and innate reflexes, which is inherited and does not change throughout life. But behavior itself is distinguished by the method of its implementation and application in life: congenital and acquired forms.

Unconditioned reflexes

Scientists say that congenital form behavior is an unconditioned reflex. An example of such manifestations is observed from the moment a person is born: sneezing, coughing, swallowing saliva, blinking. The transfer of such information is carried out by inheriting the parent program by the centers that are responsible for reactions to stimuli. These centers are located in the brain stem or spinal cord. Unconditioned reflexes help a person to quickly and accurately respond to changes in the external environment and homeostasis. Such reactions have a clear demarcation depending on biological needs.

• Food.
• Approximate.
• Protective.
• Sexual

Depending on the species, living beings have different reactions to the world, but all mammals, including humans, have a sucking habit. If you put a baby or young animal on the mother's nipple, a reaction will immediately occur in the brain and the feeding process will begin. This is an unconditioned reflex. Examples of feeding behavior are inherited in all creatures that receive nutrients from their mother's milk.

Defensive reactions

These types of reactions to external stimuli are inherited and are called natural instincts. Evolution has given us the need to protect ourselves and take care of our safety in order to survive. Therefore, we have learned to instinctively react to danger; this is an unconditioned reflex. Example: Have you ever noticed how your head tilts when someone raises a fist over it? When you touch a hot surface, your hand jerks back. This behavior is also called unlikely that a person in his right mind would try to jump from a height or eat unfamiliar berries in the forest. The brain immediately starts the process of processing information that will make it clear whether it is worth risking your life. And even if it seems to you that you are not thinking about it, instinct immediately kicks in.

Try to bring your finger to the baby’s palm, and he will immediately try to grab it. Such reflexes have been developed over centuries, however, now a child does not really need such a skill. Still have primitive people the baby clung to his mother, and that’s how she carried him. There are also unconscious innate reactions that are explained by the connection of several groups of neurons. For example, if you hit your knee with a hammer, it will jerk - an example of a two-neuron reflex. In this case, two neurons come into contact and send a signal to the brain, forcing it to respond to an external stimulus.

Delayed reactions

However, not all unconditioned reflexes appear immediately after birth. Some arise as needed. For example, a newborn baby practically does not know how to navigate in space, but after about a couple of weeks he begins to respond to external stimuli - this is an unconditioned reflex. Example: the child begins to distinguish the mother’s voice, loud sounds, bright colors. All these factors attract his attention - an orientation skill begins to form. Involuntary attention is the starting point in the formation of an assessment of stimuli: the baby begins to understand that when the mother talks to him and approaches him, most likely she will pick him up or feed him. That is, a person forms complex shape behavior. His crying will attract attention to him, and he consciously uses this reaction.

Sexual reflex

But this reflex is unconscious and unconditional, it is aimed at procreation. It occurs during puberty, that is, only when the body is ready for procreation. Scientists say that this reflex is one of the strongest, it determines challenging behavior living organism and subsequently triggers the instinct to protect its offspring. Despite the fact that all these reactions are initially characteristic of humans, they are triggered in a certain order.

Conditioned reflexes

In addition to the instinctive reactions that we have at birth, a person needs many other skills to better adapt to the world around him. Acquired behavior is formed in both animals and people throughout life; this phenomenon is called “conditioned reflexes”. Examples: salivation occurs at the sight of food; when following a diet, a feeling of hunger arises in certain time days. This phenomenon is formed by a temporary connection between the center or vision) and the center of the unconditioned reflex. An external stimulus becomes a signal to specific action. Visual images, sounds, smells can form lasting connections and give rise to new reflexes. When someone sees a lemon, salivation may begin, and when a strong smell or contemplation of an unpleasant picture occurs, nausea may occur - these are examples of conditioned reflexes in humans. Note that these reactions can be individual for each living organism; temporary connections are formed in the cerebral cortex and send a signal when an external stimulus occurs.

Throughout life, conditioned reactions can arise and also disappear. It all depends on For example, in childhood a child reacts to the sight of a bottle of milk, realizing that it is food. But when the baby grows up, this object will not form an image of food for him; he will react to a spoon and a plate.

Heredity

As we have already found out, unconditioned reflexes are inherited in every species of living beings. But conditioned reactions only affect complex human behavior, but are not passed on to descendants. Each organism “adapts” to a particular situation and the reality surrounding it. Examples of innate reflexes that do not disappear throughout life: eating, swallowing, reaction to taste qualities product. Conditioned stimuli change constantly depending on our preferences and age: in childhood, when a child sees a toy, he experiences joyful emotions; in the process of growing up, a reaction is caused, for example, by visual images of a film.

Animal reactions

Animals, like humans, have both unconditioned innate reactions and acquired reflexes throughout life. In addition to the instinct of self-preservation and obtaining food, living beings also adapt to their environment. They develop a reaction to the nickname (pets), and with repeated repetition, an attention reflex appears.

Numerous experiments have shown that it is possible to instill in a pet many reactions to external stimuli. For example, if you call your dog with a bell or a certain signal at each feeding, he will have a strong perception of the situation and he will immediately react. During the training process, rewarding a pet for following a command with a favorite treat forms a conditioned reaction; walking the dog and the sight of a leash signals an imminent walk, where he must relieve himself - examples of reflexes in animals.

Summary

The nervous system constantly sends many signals to our brain, and they shape the behavior of humans and animals. The constant activity of neurons allows us to perform habitual actions and respond to external stimuli, helping us better adapt to the world around us.