An unconditioned reflex is ... the value of an unconditioned reflex. Unconditional and conditioned reflexes

Reflex refers to the response of the body to internal or external stimulation, which is carried out and controlled by the central nervous system. The first scientists who developed ideas about human behavior, which before that were a mystery, were our compatriots I.P. Pavlov and I.M. Sechenov.

What are unconditioned reflexes?

An unconditioned reflex is a congenital, inherited by the offspring of the parents, a stereotyped reaction of the organism to the effect of the internal or the environment. It persists in a person throughout his life. Reflex arcs pass through the brain and spinal cord, the cortex of the large hemispheres does not participate in their formation. The value of the unconditioned reflex is that it provides the adaptation of the human body directly to those changes in the environment that often accompanied many generations of its ancestors.

Which reflexes are unconditioned?

An unconditioned reflex is the basic form of activity of the nervous system, an automatic reaction to the stimulus. And since various factors affect a person, reflexes can also be different: food, defensive, indicative, sexual ... Foods include salivation, swallowing and sucking. Defensive cough, blinking, sneezing, pulling limbs away from hot objects. Approximate reactions can be called head turns, mowing of eyes. By sexuality are the instincts associated with reproduction, as well as care for the offspring. The value of the unconditioned reflex is that it ensures the preservation of the integrity of the organism, maintains the constancy of the internal environment. Thanks to it, reproduction occurs. Even in newborn babies one can observe an elementary unconditioned reflex - this is sucking. By the way, it is the most important. The irritant in this case is the touch to the lips of an object (nipples, mother's breast, toy or finger). Another important unconditioned reflex is blinking, which occurs when an extraneous body approaches the eye or touches the cornea. Such a reaction refers to a defensive or defensive group. Also in children, there is a narrowing of the pupils, for example, when exposed to strong light. However, the most clearly signs of unconditioned reflexes are manifested in various animals.

What are conditioned reflexes?

Conditional are called reflexes, acquired by the body during life. They are formed on the basis of the heritable ones, under the condition of the action of an external stimulus (time, knock, light, and so on). A vivid example are the experiments carried out on dogs by Academician I.P. Pavlov. He studied the formation of this type of reflexes in animals, he was the developer of a unique technique for obtaining them. Thus, the development of such reactions requires the presence of a regular stimulus-signal. It triggers the mechanism, and repeated repetition of the stimulus's effect makes it possible to develop a conditioned reflex. Thus there is a so-called temporary connection between the arcs of the unconditioned reflex and the centers of the analyzers. Now the basic instinct is awakened by the action of fundamentally new signals of an external character. These stimuli of the surrounding world, to which the organism was previously indifferent, begin to acquire an exceptional, vital importance. For every living creature, during the course of life, many different conditioned reflexes can form, which form the basis of his experience. However, this applies only to this particular individual, by inheritance this life experience will not be transmitted.

Independent category of conditioned reflexes

In an independent category, it is customary to isolate the conditioned reflexes of the motor character, that is, skills or automated actions developed during the course of life. Their meaning lies in the development of new skills, as well as the development of new motor forms. For example, during the whole period of his life a person takes possession of a lot of special motor skills that are related to his profession. They are the basis of our behavior. Thinking, attention, and consciousness are released when performing operations that have reached automatism and become the reality of everyday life. The most successful way of mastering skills is the systematic execution of the exercise, the timely correction of noticed errors, as well as knowledge of the ultimate goal of any task. In the event that the conditioned stimulus is not reinforced for some time unconditionally, its inhibition occurs. However, it does not disappear at all. If after a while to repeat the action, then the reflex will recover fairly quickly. Deceleration can also occur if the stimulus is even more powerful.

Compare unconditioned and conditioned reflexes

As already mentioned above, these reactions differ in the nature of their origin and have a different mechanism of formation. In order to understand what is the difference, just compare unconditioned and conditioned reflexes. So, the first are available to a living being from the very birth, throughout the life they do not change and do not disappear. In addition, unconditioned reflexes are the same for all organisms of a particular species. Their meaning lies in the preparation of a living being for permanent conditions. The reflex arc of such a reaction passes through the trunk of the brain or spinal cord. As an example, we give some unconditioned reflexes (congenital): active salivation, when a lemon enters the mouth; Sucking motion of the newborn; Coughing, sneezing, pulling your hands away from a hot object. And now let us consider the characteristics of conditioned reactions. They are acquired throughout life, they can change or disappear, and, not least, each organism has its own (individual). Their main function is to adapt the living being to changing conditions. Their temporal connection (centers of reflexes) is created in the cerebral cortex of the brain. As an example of a conditioned reflex, one can cite the animal's reaction to the nickname or the reaction of a six-month-old child to a bottle of milk.

The unconditioned reflex scheme

According to the researches of Academician I.P. Pavlov, the general scheme of unconditioned reflexes is as follows. These or other receptor nerve devices are affected by various stimuli of the internal or external world of the organism. As a result, the resulting stimulation transforms the entire process into a so-called phenomenon of nervous excitation. It is transmitted along nerve fibers (as by wires) to the central nervous system, and from there it comes to a specific working organ, already turning into a specific process at the cellular level of this part of the body. It turns out that these or other stimuli are naturally associated with one or another activity as well as the cause with the effect.

Features of unconditioned reflexes

The characteristic of unconditioned reflexes presented below, as it were, systematizes the material presented above, it will help us to finally deal with the phenomenon we are considering. So, what are the features of inherited reactions?

1. Congenital nature of the body's response to stimuli.
2. The constancy of the neural connections between certain types of stimuli and responses.
3. Species character: similar reflexes occur identically in all representatives of a particular species of living organisms, they differ only in the characteristic features of animals that belong to different species. For example, the instinctive care for the offspring of all bees in the swarm is exactly the same, but it differs from the same instincts of wasps or ants.
4. Congenital unconditioned reflexes generally do not depend on personal experience, they practically do not change during the life of the animal.
5. In higher organisms this type of reactions is usually carried out by the lower parts of the nervous system, the involvement of the cerebral cortex is not fixed.

Unconditional instinct and reflex of animals

The exceptional consistency of the neural connection underlying the unconditioned instinct is due to the fact that all animals are born with a nervous system. It is already able to react properly to specific environmental stimuli. For example, a creature can shudder with a sharp sound; He will have digestive juice and saliva when food gets into the mouth or into the stomach; It will blink with visual irritation and so on. Congenital in animals and humans are not only individual unconditioned reflexes, but also much more complex forms of reactions. They were called instincts.

Unconditioned reflex, in fact, is not completely monotonous, template, transfer reaction of the animal to an external stimulus. It is characterized, albeit by elementary, primitive, but still variable, variability, depending on external conditions (strength, peculiarities of the situation, position of the stimulus). In addition, it affects the internal state of the animal (decreased or increased activity, posture and others). So, still I.M. Sechenov in his experiments with decapitated (spinal) frogs showed that when the fingers of the hind legs of this amphibian are subjected to an opposite motor reaction. From this we can conclude that the unconditioned reflex still possesses adaptive variability, but in insignificant limits. As a result, we can see that the balancing of the organism and the external environment achieved with the help of these reactions can be relatively perfect only with respect to the slightly changing factors of the surrounding world. Unconditioned reflex is not able to provide adaptation of the animal to new or sharply changing conditions.

As for instincts, sometimes they are expressed in the form of simple actions. For example, a rider, thanks to the sense of smell, searches for larvae of another insect under the bark. He pierces the bark and lays his egg in the victim found. This ends all of its action, ensuring the continuation of the genus. There are also complex unconditioned reflexes. Instincts of this kind consist of a chain of actions, the totality of which ensures the continuation of the genus. As an example, you can bring birds, ants, bees and other animals.

Species specificity

Unconditioned reflexes (species) are present in both humans and animals. It should be understood that such reactions will be the same for all representatives of the same species. An example is the turtle. All kinds of these amphibians drag the head and limbs into the shell in the event of danger. And all the hedgehogs jump and make a hissing sound. In addition, one should know that not all unconditioned reflexes occur at the same time. These reactions vary according to age and season. For example, the period of reproduction or motor and sucking actions that appear in an 18-week-old fetus. Thus, unconditioned reactions are a kind of experience for conditioned reflexes in humans and animals. For example, in the course of growing up, the cubs transition to the category of synthetic complexes. They increase the adaptability of the organism to external environmental conditions.

Unconditional braking

In the process of vital activity, each organism is regularly exposed - both from the outside and from the inside - to various stimuli. Each of them is able to cause a corresponding reaction - a reflex. If all of them could be realized, the vital 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 the inhibition of unconditioned reflexes occurs in the body. This means that the most important reflex at the particular moment of time detains the secondary reflex. Usually external braking can occur at the time of the beginning of other activities. A new causative agent, like the stronger one, leads to the attenuation of the old one. And as a result, the previous activity will automatically stop. For example, a dog eats, and at that moment they ring the doorbell. The animal immediately stops eating and runs to meet the newcomer. There is a sharp change in activity, and the salivation in the dog at this point stops. Certain congenital reactions also include unconditional inhibition of reflexes. In them, certain pathogens cause complete cessation of certain actions. For example, the alarming cackling of a chicken causes chickens to freeze and cuddle to the ground, and the onset of darkness forces the kenar to stop singing.

In addition, there is also protective (transcendental) inhibition. It arises as a response to a very strong stimulus, requiring the body of actions that exceed its capabilities. The level of such an impact is determined by the frequency of the impulses of the nervous system. The more strongly a neuron is excited, the higher will be the frequency of the flow of nerve impulses that it generates. However, if this flow exceeds certain limits, then there will be a process that will begin to prevent the passage of excitation along the neural circuit. The flow of impulses along the reflex arc of the spinal cord and brain is interrupted, as a result, inhibition will occur, preserving the executive organs from complete exhaustion. Which of these is the conclusion? Due to the inhibition of unconditioned reflexes, the organism identifies among all possible variants the most adequate, capable of protecting against unbearable activity. This process also contributes to the manifestation of so-called biological caution.