CONDITIONAL REFLEXES AND THEIR CHARACTERISTICS

The main elementary act of higher nervous activity is the formation of a conditioned reflex.

There are countless conditioned reflexes. Subject to the appropriate rules, any perceived stimulus can be made a stimulus that triggers a conditioned reflex (signal), and any activity of the body can be its basis (reinforcement). By the nature of signals and reinforcements, as well as by the relationship between them, different classifications conditioned reflexes. As for studying physiological mechanism temporal connections, then researchers have a lot of work to do here.

The classification of conditioned reflexes was determined according to the following particular features: 1) the circumstances of formation, 2) the type of signal, 3) the composition of the signal, 4) the type of reinforcement, 5) the relationship in time of the conditioned stimulus and reinforcement.

General signs of conditioned reflexes. Conditioned reflex a) is an individual higher adaptation to changing conditions of life; b) carried out by the highest departments of the central nervous system; c) is acquired through temporary neural connections and is lost if the environmental conditions that caused it have changed; d) is a warning signal reaction.

So, a conditioned reflex is an adaptive activity carried out by the higher parts of the central nervous system through the formation of temporary connections between the signal stimulation and the signaled reaction.

natural and artificial conditioned reflexes . Depending on the nature of the signal stimulus, conditioned reflexes are divided into natural and artificial.

Conditioned reflexes are called natural, which are formed in response to the influence of agents that are natural signs of a signaled unconditioned irritation.

An example of a natural conditioned food reflex is the salivation of a dog to the smell of meat. This reflex inevitably develops naturally over the course of a dog's life.

Conditioned reflexes are called artificial, which are formed in response to the influence of agents that are not natural signs of signaled unconditioned irritation. An example of an artificial conditioned reflex is the salivation of a dog to a sound, a metronome. In life, this sound has nothing to do with food. The experimenter artificially made it a food intake signal.

Nature develops natural conditioned reflexes from generation to generation in all animals according to their way of life. As a result, natural conditioned reflexes are more easily formed, more likely to be strengthened and more durable than artificial ones.

Exteroceptive, interoceptive and proprioceptive conditioned reflexes. Conditioned reflexes to external stimuli are called exteroceptive, to stimuli from internal organs - interoceptive, to stimuli of the musculoskeletal system - proprioceptive.

Exteroceptive reflexes are divided into reflexes caused by distant (acting at a distance) and contact (acting by direct contact) stimuli. Further, they are divided into groups according to the main types of sensory perception; visual, auditory, etc.

Interoceptive conditioned reflexes can also be grouped according to organs and systems that are sources of signaling: gastric, intestinal, cardiac, vascular, pulmonary, renal, uterine, etc. A special position is occupied by the so-called time reflex. It manifests itself in various vital functions of the body, for example, in the daily periodicity of metabolic functions, in the release of gastric juice at the onset of dinner time, in the ability to wake up at the appointed hour. Apparently, the body "counts time" mainly by interoceptive signals. The subjective experience of interoceptive reflexes does not have the figurative objectivity of exteroceptive ones. It gives only vague feelings that make up the overall well-being, which is reflected in mood and performance.

Proprioceptive conditioned reflexes underlie all motor skills. They begin to develop from the first flapping of the wings of the chick, from the first steps of the child. Associated with them is the mastery of all types of locomotion. The coherence and accuracy of movement depends on them. The proprioceptive reflexes of the hand and the vocal apparatus in humans are being used in a completely new way in connection with labor and speech. The subjective "experience" of proprioceptive reflexes consists mainly in the "muscular feeling" of the position of the body in space and its members relative to each other. At the same time, for example, signals from the accommodative and oculomotor muscles have a visual nature of perception: they provide information about the distance of the object under consideration and its movements; signals from the muscles of the hand and fingers make it possible to assess the shape of objects. With the help of proprioceptive signaling, a person reproduces the events taking place around him with his movements.

Conditioned reflexes to simple and complex stimuli. A conditioned reflex can be developed to any one of the listed extero-, intero- or proprioceptive stimuli, for example, to turn on a light or to a simple sound. But in real life this rarely happens. More often, a complex of several stimuli becomes a signal, for example, the smell, warmth, soft fur of the mother cat become an irritant of the conditioned sucking reflex for the kitten. Accordingly, conditioned reflexes are divided into simple and complex, or complex, stimuli.

Natural signals always consist of many components, in other words, they are complex stimuli. Conditioned reflexes are formed to such signals that are more complex and variable than to simple signals. In a complex signal, each of its components has a different physiological strength and corresponds to the effect caused by each stimulus.

Simultaneous complex stimuli consist of several components acting simultaneously. Conditioned reflexes to successive complexes of stimuli are formed if individual stimuli follow each other in a certain sequence (such a signal is reinforced by food). Numerous studies have established that as a result of a more or less prolonged training of a conditioned reflex to a complex stimulus, a fusion occurs, the synthesis of the individual components of the complex into a single stimulus. So, with repeated use of a sequential complex of stimuli, consisting of four sounds, they merge into a single stimulus. As a result, each of the four sounds loses its signal value, i.e. applied alone does not cause a conditioned response.

Conditioned reflexes to a chain of stimuli. If indifferent stimuli, from which a complex signal is formed, act sequentially, i.e. do not coincide with each other, and the unconditioned reinforcement joins the last of them, then a conditioned reflex to a chain of stimuli can be formed on such a signal. The signal value of an individual member of the chain turns out to be the greater, the closer it is to the reinforcement, i.e. to the end of the chain. The formation of conditioned reflexes to a chain of stimuli underlies the development of various so-called motor skills by reinforcing random or forced movements. For example, after saying “Give me a paw!” to a dog, we “raise” its paw ourselves, “rewarding” the dog with a piece of biscuit. Soon the dog, having heard these words, “gives a paw” on its own. An analysis of the mechanism for the formation of this type of reflex showed that at first a temporary connection is formed between the three foci of excitation: the auditory, motor and food centers. Then the sequence of action of the chain members is fixed. Finally, the position of its main members of the “give paw” sound signal, proprioceptive (limb movement) and natural food (feeding) is clarified.

An important concept in the physiology of higher nervous activity is integrity in conditioned reflex activity. It manifests itself primarily in systemicity, stereotypy, "settings" and "switching" of reactions according to the signals of the situation. As a result, animal behavior is determined not by single signals, but by the entire picture of the environment. Conditioned reflex activity covers many aspects of the present and connects it with the experience of the past, and this, in turn, leads to a subtle adaptation to future events.

The real stimuli that the organism deals with form a dynamic stereotype of stimuli. The existing stereotype of stimuli directs the formation of new reflexes in a certain direction. For example, when assimilating new objects of hunting, the predator uses the most reliable hunting techniques already familiar to him. The stereotype allows you to adequately respond, despite some changes in the environment. So, for example, having developed a stereotype of driving a car, you can drive a car, somewhat varying the control depending on the nature pavement, and at the same time talk with a passenger sitting next to you. An analysis of human activity shows that each of us continuously forms an innumerable number of household, work, sports and other stereotypes throughout our lives. In particular, this is manifested in the appearance of appetite at certain times of the day, the stereotypical performance of work or sports movements, etc. As we age, stereotypes become stronger and harder to change. Alteration of the prevailing stereotypes is always a great difficulty.

Conditioned reflex setting. The formation of successive complexes from situational and main conditioned stimuli in the form of a chain with far-spaced links is the physiological mechanism of the so-called conditioned reflex tuning. The name "configuration" itself indicates that we are talking not about the performance of some activity, but only about the state of readiness for this activity caused by the mechanism of temporary connection.

Conditioned reflex switching. The formation of complexes of different signal values ​​from the same basic signals with the addition of different environmental stimuli is a physiological mechanism of conditioned reflex switching. When considering the physiological mechanisms of a conditioned reflex of any complexity, it should be borne in mind that the process of developing even the most elementary temporal connection is associated with the formation of a conditioned reflex to the experimental situation. Now it is obvious that during the development of any conditioned reflex, several types of temporary connections are formed - a situational reflex (the type of a given experimental chamber, smells, lighting, etc.), a reflex for time, a reflex for a given stimulus, etc. Each conditioned reaction consists of a number of somatic and vegetative ingredients.

To understand the physiological mechanism of situational conditioned reflexes, E.A. Asratyan introduced the concept of "conditioned reflex switching". It consists in the fact that the same stimulus can become a conditioned signal for various conditioned reactions. So, for example, a beep in one experimental chamber can be a signal of a food reaction, and in another chamber it can be a signal of a defensive reflex. The same signal in the first half of the day can serve as a defensive conditioned stimulus, and in the second half as a food signal. It is obvious that in both examples the conditioned signal is not the signal in itself, but a complex of stimuli consisting of the given signal and the entire setting of the experiment. While maintaining the experimental environment, any sound or other stimuli can be used, which, like the experimental environment, can serve, according to the terminology of E.A. Hasratyan, switches.

Conditioned reflexes of the nth order. The dog has developed a strong food conditioned reflex, for example, to turn on a light bulb. If after 10 - 15 s after an indifferent agent, for example, a sound, the inclusion of a light bulb (a conditioned stimulus of a previously developed food conditioned reflex) is applied without subsequent unconditional reinforcement, then a conditioned connection is formed between the foci of excitation caused by the actions of sound and light. Reactions developed in this way are called a 2nd order conditioned reflex.

Let's take another example. The dog developed a strong salivary reflex to the metronome. Then they began to show her a black square, but instead of feeding, they presented the sound of a metronome, to which a conditioned reflex had previously been developed. After several combinations of these stimuli without food reinforcement, a second-order conditioned reflex was formed, i.e. the black square began to induce salivation, although it was never presented by itself in combination with food. Conditioned reflexes of the 2nd order in dogs, as a rule, are unstable and soon disappear. Usually they manage to develop conditioned reflexes no higher than the 3rd order. Conditioned reflexes of the nth order are formed more easily with a general increase in the excitability of the cerebral cortex. For example, in children with increased excitability, conditioned reflexes up to the 6th order are quite easily developed, while in balanced healthy children - usually not higher than the 3rd order. In adults healthy people conditioned reflexes up to the 20th order are easily developed, but they are also unstable.

imitative conditioned reflexes. These reflexes are especially easily developed in animals leading a group lifestyle. For example, if a conditioned reflex (for example, food) is developed in one monkey from the herd in front of the whole herd, then this conditioned reflex is also formed in other members (L.G. Voronin). Imitative reflexes as one of the types of adaptive reactions of animals are widespread in nature. In its simplest form, this reflex is found in the form of a following reflex. For example, schooling fish follow their relatives or even fish silhouettes. Another example was given by Charles Darwin. It is well known that crows do not let a person with a gun or any long object in their hands come close. It is quite obvious that this “saving fear” (according to Charles Darwin) developed mainly not as a result of personal experience with a person, but due to the imitation of the behavior of individuals of the same species or even other species. For example, the call of a jay serves as a danger signal for many forest animals.

Of great importance is imitation in the ontogeny of the behavior of primates, including humans. For example, "blind" imitation in children gradually turns into purely human abilities.

According to their physiological mechanism, imitative conditioned reflexes are obviously similar to conditioned reflexes of the nth order. This is easily seen in the example of the development of a conditioned motor food reflex. The spectator monkey perceives the conditioned stimulus and, although it does not receive food reinforcement, it also perceives natural conditioned stimuli accompanying food intake (type of food, its smell, etc.). So, on the basis of a natural conditioned reflex, a new conditioned reflex is developed. And if we take into account that natural conditioned reflexes, due to their inextricable and long-term connection with unconditioned reflex activity, are very strong, it becomes clear why conditioned reflex reactions are formed on their basis so easily and quickly.

Associations. Associations are formed when indifferent stimuli are combined without reinforcement. For the first time, such conditioned relationships were studied in dogs in the laboratory of I.P. Pavlova. In the experiments, combinations of tone and light were made without food reinforcement. Already after 20 combinations, the first signs of the formation of a temporary connection between these stimuli appeared: under the action of light, the dog turned to the sound source (which was inactive at that time), and when the tone sounded, it looked at the light bulb (which was not lit), as if waiting for it to be turned on. Studies have shown that a temporary connection between indifferent stimuli (exteroceptive) is formed in mammals after 10-40 combinations, and between stimuli of the same modality it is formed faster than to signals of different modality.

Conditioned reflexes on attitude. These conditioned reflexes are developed not for absolute, but for relative signs of stimuli. For example, if an animal is simultaneously presented with a small and a large triangle, and only a small triangle is reinforced with food, then, according to the rules for the formation of a conditioned reflex, a positive conditioned reflex is formed on the small triangle, and a negative conditioned reflex (differentiation) on the large triangle. If now a new pair of triangles is presented, in which the small triangle is equal in absolute size to the large triangle, then the animal “from the spot” will manifest a conditioned food reflex to the smaller triangle in this pair.

Let's take another example. The dolphins were able to learn to choose the middle one from three presented objects, since in preliminary experiments they received reinforcement (fish) only when they chose the middle one. It is important that the animals caught the sign " middle subject” in conditions when, with each new experiment, different objects were presented (balls, cylinders, etc.) and in different parts of space in order to avoid the formation of a conditioned reflex “to the place”.

The biological significance of the conditioned reflex to an attitude, as well as the temporal connection between indifferent stimuli, as a reflex of the nth order, is that if the agents that cause them subsequently coincide with the unconditioned reflex, then they immediately (“from the spot”) become conditioned reflexes - there is a "transfer" of the developed conditioned reflex to a similar situation. There is every reason to believe that the reflex to attitude, the temporal connection between indifferent stimuli, as well as conditioned reflexes of a higher order, underlie the physiological mechanism of such phenomena as "transfer of experience", "foresight", "insight", etc., arising, as it were, without the preliminary development of a conditioned reflex.

chain conditioned reflex. The possibility of obtaining a conditioned reflex to a chain of stimuli depends on the phylogenetic level of development of the nervous system of a given animal species. So, in monkeys (macaques, baboons, capuchins), after 40-200 applications of a chain stimulus, its components, tested separately, in most cases do not cause a conditioned reflex. In lower vertebrates (fish, reptiles), even after 700 - 1300 applications of the chain of stimuli, its components retain their signal value. In these animals, a conditioned reflex to a chain of stimuli is developed quite easily, but a complex stimulus does not become a single one: each of its components retains its signal value.

There are four methods of formation of chain conditioned reflexes in animals. The first way is to combine single exteroceptive stimuli of single motor reactions into a chain. The second way is to build up the chain of movements from the reinforced end. For example, first an animal (pigeon, rat, etc.) is trained to peck (press) the first shelf in the experimental chamber by a prearranged signal (turning on a light bulb). Then, after letting a sufficiently hungry animal into the chamber, the conditioned signal is not given, forcing the animal to perform search reactions. The bait is placed on the second shelf. As soon as the animal touches the second shelf, the lamp is immediately turned on (conditional signal), and after pecking (pressing) the second shelf, the animal receives food reinforcement.

As a result of several such combinations, the pecking (pressing) of the second shelf is fixed in the animal. After that, another exteroceptive signal is introduced - turning on the bell, preceding the pecking (pressing) of the second shelf. Thus, a two-membered, three-membered, etc. is formed. chain of motion. In contrast to this method, in the third method of forming a chain of motor reflexes, new movements and stimuli are "wedged" in a similar way, but between the last link in the chain and reinforcement. Finally, in the fourth way of forming a chain of movements, the animal is not restricted in its movements, but only those chains that are “correct” are reinforced. It turned out that under such conditions, for example, the monkeys quickly learned to perform the necessary chain of movements, and all unnecessary actions gradually disappeared from them.

In animals, chains of movements are developed with varying degrees of difficulty, depending on the phylogenetic level of development of the nervous system. In turtles, for example, for a long time with great difficulty it is possible to develop a very unstable three-term chain of movements, in pigeons it is possible to form a fairly strong chain of 8-9 movements, and in mammals - from more more movements. It was concluded that there is a dependence of the rate of formation of individual links and the entire chain of movements as a whole on the level of phylogenesis of the animal.

Automation of conditioned reflexes. Very many conditioned reflexes in animals and humans are automated after prolonged training, becoming, as it were, independent of other manifestations of higher nervous activity. Automation tends to evolve gradually. Initially, it can be expressed in the fact that individual movements are ahead of the corresponding signals. Then there comes a period when the chain of movements is completely carried out in response to the first, "starting" component of the chain of stimuli. At first glance at the result of training a conditioned reflex, one may get the impression that at first the reflex is “attached” to something that controls it, and then after a long exercise it becomes independent to some extent.

Conditioned reflexes developed with different correspondence in time of the signal and reinforcement. By the way the signal is located in time relative to the reinforcing reaction, there are present and trace conditioned reflexes.

Conditioned reflexes are called cash, in the development of which reinforcement is used during the action of a signal stimulus. Available reflexes are divided depending on the term of reinforcement attachment into coinciding, delayed and delayed. A coinciding reflex is produced when, immediately after the signal is turned on, a reinforcement is attached to it.

A delayed reflex is developed in cases where a reinforcing reaction is added only after a certain time has elapsed (up to 30 s). This is the most common way to develop conditioned reflexes, although it requires more combinations than the coincidence method.

A delayed reflex is developed when a reinforcing reaction is attached after a long isolated action of the signal. Typically, such an isolated action lasts 1-3 minutes. This method of developing a conditioned reflex is even more difficult than both of the previous ones.

Trace reflexes are called conditioned reflexes, during the development of which a reinforcing reaction is presented only some time after the signal is turned off. In this case, the reflex is developed on a trace from the action of a signal stimulus; short intervals (15-20 s) or long intervals (1-5 min) are used. The formation of a conditioned reflex according to the trace method requires largest number combinations. On the other hand, trace conditioned reflexes provide very complex acts of adaptive behavior in animals. An example would be hunting for lurking prey.

Conditions for the development of temporary links. Combination of signal stimulus with reinforcement. This condition for the development of temporary connections was revealed from the very first experiments with salivary conditioned reflexes. The footsteps of an attendant carrying food only produced "psychic salivation" when they were combined with food.

This is not contradicted by the formation of trace conditioned reflexes. Reinforcement is combined in this case with a trace of excitation nerve cells from a previously turned on and already turned off signal. But if the reinforcement begins to get ahead of the indifferent stimulus, then the conditioned reflex can be worked out with great difficulty, only by taking a number of special measures.

Indifference of the signal stimulus. The agent chosen as the conditioned stimulus of the food reflex must not in itself have anything to do with food. He must be indifferent, i.e. indifferent, for the salivary glands. The signal stimulus should not cause a significant orienting reaction that interferes with the formation of a conditioned reflex. However, each new stimulus causes an orienting reaction. Therefore, in order to lose its novelty, it must be applied repeatedly. Only after the orienting reaction is practically extinguished or reduced to an insignificant value, the formation of a conditioned reflex begins.

The predominance of the strength of excitation caused by reinforcement. The combination of the click of a metronome and feeding the dog leads to a quick and easy formation of a conditioned salivary reflex to this sound. But if you try to combine the deafening sound of a mechanical rattle with food, then such a reflex is extremely difficult to form. For the development of a temporary connection, the ratio of signal strength and reinforcing reaction is of great importance. In order for a temporary connection to form between them, the focus of excitation created by the latter must be stronger than the focus of excitation created by the conditioned stimulus, i.e. there must be a dominant. Only then will the excitation spread from the focus of the indifferent stimulus to the focus of excitation from the reinforcing reflex.

The need for significant intensity of arousal. A conditioned reflex is a warning reaction to a signal about upcoming significant events. But if the stimulus that they want to make a signal turns out to be an event even more significant than those that follow it, then this stimulus itself causes the corresponding reaction of the organism.

Absence of extraneous stimuli. Each extraneous irritation, for example, an unexpected noise, causes an orienting reaction.

Normal functioning of the nervous system. A full-fledged closing function is possible provided that the higher parts of the nervous system are in a normal working condition. The performance of the nerve cells of the brain is sharply reduced with insufficient nutrition, with the action of toxic substances, for example, bacterial toxins in diseases, etc. Therefore, overall health is important condition normal activity of the higher parts of the brain. Everyone knows how this condition affects the mental work of a person.

The state of the organism has a significant influence on the formation of conditioned reflexes. So, physical and mental work, nutritional conditions, hormone activity, the action of pharmacological substances, breathing at elevated or reduced pressure, mechanical overload and ionizing radiation, depending on the intensity and timing of exposure, can modify, enhance or weaken conditioned reflex activity up to its complete suppression.

The study of the final, behavioral manifestations of higher nervous activity has significantly outstripped the study of its internal mechanisms. Until now, both the structural foundations of the temporal connection and its physiological nature have not yet been sufficiently studied. Different views are expressed on this issue, but the issue has not yet been resolved. However, at the current level of research, it is becoming more and more certain that, along with the structural, it is necessary to take into account the neurochemical organization of the brain.

CLASSIFICATION OF CONDITIONED REFLEXES

Conditioned reflexes are divided according to various criteria:

• according to biological significance: food, sexual, defensive, etc.;
• by the type of receptors that perceive the conditioned stimulus: exteroceptive, interoceptive and proprioceptive;
• by the nature of the response: motor, vascular, respiratory, indicative, cardiac, statokinetic, etc.;
• by complexity: simple and complex;
• in order of development of conditioned reflexes: first order, second, third, etc.

TYPES OF INHIBITION OF CONDITIONAL REFLEXES

The manifestation of complex conditioned reflex reactions that ensure the vital activity and adaptation of the organism to changing environmental conditions is possible only with a strictly balanced coordination of conditioned reflex mechanisms of regulation. This coordination is based on the simultaneous and coordinated excitation of some cortical nerve centers and the inhibition of others.

The biological significance of inhibition lies in the improvement of the necessary conditioned reflexes and in the disappearance of reflexes that have lost their necessity. Inhibition also protects the body from overexertion (protective inhibition).

All types of inhibition of conditioned reflexes are divided into two types: unconditioned (innate) and conditioned (acquired) inhibition. By finding the source of inhibition, unconditioned inhibition can be external, when the cause of inhibition is located outside the arc of the conditioned reflex, and internal. With internal inhibition, the source of inhibition is located inside the arc of the conditioned reflex.

Conditional inhibition can only be internal.

External unconditional inhibition of conditioned reflexes is manifested by a slowdown or complete cessation of conditioned reflex activity when a new stimulus arises that causes an orienting reaction. For example, if a dog has developed a conditioned salivary reflex to turn on a light bulb, then giving a sound signal when the light is turned on inhibits the previously developed salivation reflex.

There are two types of external braking - permanent brake and damping brake. Permanent brake - inhibition of the conditioned reflex by a one-time or reusable strong biological stimulus. So, if a dog has begun a conditioned reflex salivation at the sight of food, then a sudden strong sound irritation (thunder) causes a cessation of salivation. Burning brake - inhibition of the conditioned reflex by a repeatedly repeated stimulus with low biological significance. For example, if a fox's hole is not far from railway, then after a repeated sound stimulus (train noise), her orienting reaction to this sound fades.

Conditioned inhibition of conditioned reflexes is due to the development of an inhibitory reaction that suppresses a positive conditioned reflex. This type of inhibition is also called acquired.

Conditional inhibition is subdivided into four types: extinction, differential, conditional and retarded.

If a conditioned stimulus is not reinforced by an unconditioned stimulus for a long time, it loses its biological significance; fading inhibition and the conditioned reflex disappears.

Differential braking due to the ability of the animal to distinguish between similar stimuli and respond to only one of them. So, if a dog develops a salivary reflex to the light of a 100 W light bulb and reinforces it with food, and uses other similar stimuli (light bulbs with a power of 80 or 120 W) without reinforcement, then after a certain time the reflexes to them fade away and only the reflex to the reinforced one appears. signal (100 W). This type of inhibition allows animals to develop new vital skills.

If the action of a certain conditioned stimulus with an already formed conditioned reflex is accompanied by the action of some other stimulus and this combination is not reinforced by the action of the unconditioned stimulus, then the conditioned reflex to the action of the conditioned stimulus also disappears. This extinction of the conditioned reflex is called conditional brake. For example, an animal has a reflex to the light of a light bulb. In the case of the simultaneous use of light and sound of the metronome for a certain time and not reinforcing it with giving food, after some time already one sound signal will inhibit the manifestation of a conditioned reflex to the light of a light bulb.

delayed braking develops when the reinforcement of the conditioned stimulus by the unconditioned stimulus is carried out with a large delay (by several minutes) in relation to the action of the conditioned stimulus.

important in animal life beyond, or protective, inhibition, which occupies an intermediate position between conditional and unconditional inhibition. This type of inhibition occurs when the conditioned or unconditioned stimulus is too strong, which contributes to the weakening or disappearance of conditioned reflex reactions.

- a set of neurophysiological processes that provide consciousness, subconscious assimilation of incoming information and individual adaptive behavior of the organism in the environment.

mental activity

– it is an ideal subjectively realized activity of the organism, carried out with the help of neurophysiological processes.

Thus, mental activity is carried out with the help of GNI. Mental activity takes place only during the period of wakefulness and is realized, and GNI - both during sleep as unconscious processing of information, and during wakefulness as conscious and subconscious processing.

All reflexes are divided into 2 groups - unconditioned and conditional.

Unconditioned reflexes are called innate reflexes. These reflexes are of a species nature. Conditioned reflexes are acquired, individual.

Types of conditioned reflexes

In relation to the signal stimulus to the unconditioned stimulus, all conditioned reflexes are divided into natural and artificial (laboratory).

1. I. natural conditioned reflexes are formed to signals that are natural signs of a reinforcing stimulus. For example, the smell, color of meat can be conditioned signals of meat reinforcement. Conditioned reflexes easily arise without special development for a while. So, eating at the same time leads to the release of digestive juices and other reactions of the body (for example, leukocytosis at the time of eating).
2. II. Artificial (laboratory) called conditioned reflexes to such signal stimuli, which in nature are not related to the unconditioned (reinforcing) stimulus.
3. 1. Difficulty is classified as:

a) simple conditioned reflexes developed to single stimuli (classical conditioned reflexes by I.P. Pavlov);

b) complex conditioned reflexes, i.e. on several signals acting simultaneously or sequentially; c) chain reflexes - to a chain of stimuli, each of which causes its own conditioned reflex (dynamic stereotype).

1. By developing a conditioned reflex based on another conditioned reflex distinguish conditioned reflexes of the second, third and other orders. Reflexes of the first order are conditioned reflexes developed on the basis of unconditioned reflexes (classical conditioned reflexes). Second-order reflexes are developed on the basis of first-order conditioned reflexes, in which there is no unconditioned stimulus. The third-order reflex is formed on the basis of the second-order conditioned reflex. The higher the order of conditioned reflexes, the more difficult it is to develop them. Dogs manage to form conditioned reflexes only up to the third order.

Depending on the signal system distinguish conditioned reflexes to the signals of the first and second signal systems, i.e. on word. The latter are developed only in humans: for example, after the formation of a conditioned pupillary reflex to light (pupil constriction), pronouncing the word “light” also causes pupil constriction in the subject.

The biological significance of conditioned reflexes lies in their preventive role, they have an adaptive value for the body, preparing the body for future useful behavioral activity and helping it to avoid harmful effects adapt to the natural and social environment. Conditioned reflexes are formed due to the plasticity of the nervous system.

The main conditions for the development of conditioned reflexes

1. The presence of two stimuli, one of which is unconditioned (food, pain stimulus, etc.), causing an unconditioned reflex reaction, and the other is conditioned (signal), signaling the upcoming unconditioned stimulus (light, sound, type of food, etc.) ;
2. Multiple combination of conditioned and unconditioned stimuli;
3. The conditioned stimulus must precede the action of the unconditioned one and accompany it for a certain time;
4. According to its biological expediency, the unconditioned stimulus must be stronger than the conditioned one.
5. The active state of the central nervous system.

Mechanisms for the formation of conditioned reflexes

The physiological basis for the emergence of conditioned reflexes is the formation of functional temporary connections in the higher parts of the central nervous system. Temporary connection is a set of neurophysiological, biochemical and ultrastructural changes in the brain that occur during the combined action of conditioned and unconditioned stimuli. According to I.P. Pavlov, a temporary connection is formed between the cortical center of the unconditioned reflex and the cortical center of the analyzer, on the receptors of which the conditioned stimulus acts, i.e. the connection closes in the cerebral cortex (Fig. 50). The closure of a temporary connection is based on dominant interaction process between excited centers. Impulses caused by a conditioned signal from any part of the skin and other sensory organs (eye, ear) enter the cerebral cortex and provide the formation of a focus of excitation there. If, after the conditioned signal stimulus, food reinforcement (feeding) is given, then a more powerful second focus of excitation arises in the cerebral cortex, to which the excitation that has arisen and radiates through the cortex is directed. The repeated combination in the experiments of the conditioned signal and the unconditioned stimulus facilitates the passage of impulses from the cortical center of the conditioned signal to the cortical representation of the unconditioned reflex - synaptic facilitation - dominant.

It should be noted that the focus of excitation from an unconditioned stimulus is always stronger than from a conditioned one, since the unconditioned stimulus is always biologically more significant for the animal. This focus of excitation is dominant, therefore, it attracts excitation from the focus of conditioned irritation.

It should be noted that the resulting temporal relationship is two-way. In the process of developing a conditioned reflex, a two-way connection is formed between two centers - the cortical end of the analyzer, on the receptors of which the conditioned stimulus acts, and the center of the unconditioned reflex, on the basis of which the conditioned reflex is developed. This was shown in experiments where two unconditioned reflexes were taken: a blinking reflex, caused by a stream of air near the eyes, and an unconditioned food reflex. When they were combined, a conditioned reflex developed, and if an air stream was supplied, then a food reflex arose, and when a food stimulus was given, blinking was noted.

Conditioned reflexes of the second, third and higher orders. If you develop a strong conditioned food reflex, for example, to light, then such a reflex is a first-order conditioned reflex. On its basis, a second-order conditioned reflex can be developed; for this, a new, previous signal is additionally used, for example, a sound, reinforcing it with a first-order conditioned stimulus (light).

As a result of several combinations of sound and light, the sound stimulus also begins to cause salivation. Thus, a new, more complex mediated temporal connection arises. It should be emphasized that the reinforcement for the second-order conditioned reflex is precisely the first-order conditioned stimulus, and not the unconditioned stimulus (food), since if both light and sound are reinforced with food, then two separate first-order conditioned reflexes will arise. With a sufficiently strong second-order conditioned reflex, a third-order conditioned reflex can be developed.

For this, a new stimulus is used, for example, touching the skin. In this case, the touch is reinforced only by a second-order conditioned stimulus (sound), the sound excites the visual center, and the latter excites the food center. An even more complex temporal connection emerges. Reflexes of a higher order (4, 5, 6, etc.) are produced only in primates and humans.

Inhibition of conditioned reflexes

There are two types of inhibition of conditioned reflexes that are fundamentally different from each other: congenital and acquired, each of which has its own variants.

Unconditional (innate) inhibition conditioned reflexes is divided into external and transboundary inhibition.

1. External braking- manifests itself in the weakening or termination of the current conditioned reflex under the action of some extraneous stimulus. For example, the inclusion of sound, light during the current conditioned reflex causes the appearance of a reaction that weakens or stops the existing conditioned reflex activity. This reaction, which arose to a change in the external environment (a reflex to novelty), I.P. Pavlov called the “what is it?” reflex. It consists in alerting and preparing the body for action in case of a sudden need (attack, flight, etc.).

External braking mechanism. According to the theory of I.P. Pavlov, an extraneous signal is accompanied by the appearance in the cerebral cortex of a new focus of excitation, which has a depressing effect on the current conditioned reflex by the mechanism dominants. External inhibition is unconditioned reflex. Since in these cases the excitation of the cells of the orienting reflex arising from an extraneous stimulus is outside the arc of the present conditioned reflex, this inhibition was called external. External braking promotes emergency adaptation of the body to changing conditions of the external and internal environment and makes it possible, if necessary, to switch to another activity in accordance with the situation.

1. Extreme braking occurs if force or frequency the action of the stimulus lies beyond the limits of the efficiency of the cells of the cerebral cortex. For example, if you develop a conditioned reflex to the light of a light bulb and turn on the spotlight, the conditioned reflex activity will stop. Many researchers refer to the limiting inhibition mechanism as pessimal. Since the appearance of this inhibition does not require special development, it, like external inhibitions, is unconditioned reflex and plays a protective role.

Conditional (acquired, internal) inhibition conditioned reflexes is an active nervous process that requires its development, like the reflex itself. Therefore, it is called conditioned reflex inhibition: it is acquired, individual. According to the theory of IP Pavlov, it is localized within ("inside") the nerve center of a given conditioned reflex. There are the following types of conditional inhibition: extinction, retardation, differential and conditional inhibition.

1. Fading braking occurs when the conditioned signal is repeatedly applied and not reinforced. In this case, at first the conditioned reflex weakens, and then completely disappears, after a while it can be restored. The rate of extinction depends on the intensity of the conditioned signal and the biological significance of the reinforcement: the more significant they are, the more difficult the extinction of the conditioned reflex is. This process is associated with forgetting previously received information if it is not repeated for a long time. The extinct conditioned reflex is quickly restored when it is reinforced.
2. delayed braking occurs when the reinforcement is delayed for 1–2 minutes relative to the onset of the action of the conditioned stimulus. Gradually, the manifestation of the conditioned reaction decreases and then stops altogether. This inhibition is also characterized by the phenomenon of disinhibition.
3. Differential braking is produced with the additional inclusion of a stimulus close to the conditioned one, and its non-reinforcement. For example, if in a dog a 500 Hz tone is reinforced with food, and a 1000 Hz tone is not reinforced and alternated during each experiment, then after a while the animal begins to distinguish both signals. This means that: at a tone of 500 Hz, a conditioned reflex will occur in the form of movement to the feeder, eating food, salivation, and at a tone of 1000 Hz, the animal will turn away from the feeder with food, there will be no salivation. The smaller the differences between the signals, the more difficult it is to develop differential inhibition. Conditioned differential inhibition under the action of extraneous signals of medium strength weakens and

accompanied by the phenomenon of disinhibition, i.e. it's the same active process, as in other types of conditional inhibition.

1. Conditional brake occurs when another stimulus is added to the conditioned signal and this combination is not reinforced. So, if you develop a conditioned salivary reflex to light, then connect an additional stimulus to the conditioned signal “light”, for example, “bell”, and do not reinforce this combination, then the conditioned reflex gradually fades away. The “light” signal must continue to be reinforced with food. After that, the addition of the "bell" signal to any conditioned reflex weakens it, i.e. "bell" has become a conditioned brake for any conditioned reflex. This type of inhibition is also disinhibited if another stimulus is connected.

The value of all types of conditional (internal) inhibition conditioned reflexes is to eliminate unnecessary activity at a given time - a subtle adaptation of the body to the environment.

dynamic stereotype

Separate conditioned reflexes in a certain situation can be linked together into complexes. If a number of conditioned reflexes are carried out in a strictly defined order with approximately the same time intervals and this whole complex of combinations is repeated many times, then a single system will be formed in the brain that has a specific sequence of reflex reactions, i.e. previously disparate reflections are connected into a single complex.

Thus, in the cerebral cortex, with prolonged use of the same sequence of conditioned signals (external stereotype), a certain system of connections (internal stereotype) is created. A dynamic stereotype arises, which is expressed in the fact that a constant and strong system of responses is developed to a system of various conditioned signals that always act one after another after a certain time. In the future, if only the first stimulus is used, then all other reactions will develop in response. Dynamic stereotype - salient feature mental activity of a person.

The reproduction of a stereotype is, as a rule, automatic. A dynamic stereotype prevents the creation of a new one (it is easier to teach a person than to retrain). The elimination of a stereotype and the creation of a new one are often accompanied by significant nervous tension(stress). A stereotype plays a significant role in a person's life: professional skills are associated with the formation of a certain stereotype, a sequence of gymnastic elements, memorizing poetry, playing musical instruments, practicing a certain sequence of movements in ballet, dancing, etc. are all examples of dynamic stereotypes, and their role is obvious. There are relatively stable forms of behavior in society, in relationships with other people, in assessing current events and responding to them. Such stereotypes are of great importance in human life, as they allow you to perform many activities with less stress on the nervous system. The biological meaning of dynamic stereotypes is to free the cortical centers from solving standard tasks in order to ensure the performance of more complex ones.

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

Reflexes unconditioned and conditional.

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

To include:

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

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

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

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

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

The development of the child's higher nervous activity is in close connection with the formation of the structure of the cerebral cortex and the system of analyzers as a whole.

In higher animals and humans in the postnatal period, the main regulating role in behavior is played by the cerebral cortex, which is an organ of individual adaptation of the organism to the external environment. I.P. Pavlov pointed out that the balancing of the organism with the environment cannot be ensured by unconditioned reflexes alone. “The balancing achieved by these reflexes would be perfect only with the absolute constancy of the external environment. And since external environment despite its extreme diversity, at the same time, it is in constant fluctuation, then unconditional connections, as constant connections, are not enough and it is necessary to supplement them with conditioned reflexes, temporary connections.

A. Neonatal period. The formation of conditioned reflexes begins from the first days or weeks after birth, those. during the period when the most intensive development of cortical structures occurs and separate cortical fields associated with the corresponding receptors are formed.

The earlier formation of conditioned food reflexes in a developing organism compared to defensive reflexes is of great adaptive importance. In the first period of the life of the organism, the main vital functions are reduced to food intake. The appearance during this period of conditioned food reflexes provides him with a more complete implementation of the act of nutrition.

The possibility of earlier development of conditioned food reflexes from phylogenetically older analyzers (olfactory, skin, vestibular) than from phylogenetically newer ones (auditory, visual) indicates that corticolization of phylogenetically old analyzer systems associated with the food center occurs in more early dates than phylogenetically young analyzer systems.

Age features the formation of conditioned reflexes are clearly revealed in the nature of the development of the conditioned reaction itself. The defensive conditioned reflex in various animal species in the process of development, first of all, manifests itself in the form of a general motor reaction and its accompanying vegetative components (changes in respiration and cardiac activity), and then much later its specialized form is formed in the form of a local reflex. Thus, at the early stages of ontogenesis, there is a wide generalization of excitation processes in the effector and afferent parts of the conditioned reflex arc, followed by the appearance at the later stages of cortical inhibition processes, which determines the locality and specialization of the conditioned reaction. Age-related differences in higher nervous activity are revealed mainly in the ability to develop the process of internal inhibition, without which complex forms of conditioned reactions cannot be formed. This ability is found only at a later age, with a certain degree of morphological maturity and activity of the biochemical processes of the cerebral cortex.

The earliest conditioned reflexes in a child are natural food reflexes in the form of sucking movements that occur on the position of the child during feeding. They are formed for the first time at the age of 8-15 days to a complex complex of tactile, proprioceptive and labyrinth stimuli. At the 2-4th week of life, artificial protective and food conditioned reflexes to vestibular stimuli begin to form. From the 3-4th week, conditioned reflexes to proprioceptive stimuli are developed. At the end of the 1st month, conditioned reflexes to odor stimuli are developed, and reflexes are formed somewhat later on odors that act mainly on the olfactory apparatus. In the same period, conditioned food and defensive reflexes to sound signals are formed.

B. Breast age. At the beginning of the 2nd month, conditioned reflexes are formed to light stimuli, conditioned "food and protective reflexes to skin-tactile stimuli, as well as conditioned protective reflexes to taste substances are formed. Thus, there is a certain sequence in the appearance of reflexes from various analyzers: first of all they are formed from the vestibular and auditory receptors, and later - from the visual and skin-tactile.However, during the second half of the 1st month and the first half of the 2nd month, conditioned reflexes

sy in a child are formed from all analyzers. This indicates that it is at this age that the cortex of the cerebral hemispheres of the child gets the opportunity to establish diverse conditioned connections.

Early conditioned reflexes in children are unstable and mild. The receptor from which the reflex is produced is also of decisive importance in the emergence and stability of the conditioned reflex. Ceteris paribus, the vestibular and auditory conditioned reflexes are strengthened before others, then the visual, olfactory and gustatory reflexes, and last of all - the skin-tactile and proprioceptive ones. However, along with the general regularities in the formation of conditioned reflexes, which are characteristic of all children, already at an early age individual features of the child's cortical functions are revealed, depending on the type of his nervous system. The individual characteristics of the child are most clearly manifested during the period when the cerebral cortex, in addition to the formation of positive conditioned reflex connections, begins to perform another function, closely related to the first, the function of analyzing external stimuli. This last function is based on the development of cortical inhibition.

The ability to analyze external stimuli is revealed by the example of the formation of differentiations. In the 2nd month of a child's life, almost all analyzers differentiate stimuli that differ significantly from each other. At the 3-4th month, the analyzer function of the cerebral cortex is rapidly improving and allows you to develop stronger and more subtle differentiations. The development of mechanisms for closing conditioned reflex connections and differentiating external stimuli quickly complicates and fundamentally changes the entire behavior of the child in the sense of his vigorous activity n knowledge of the surrounding world.

Thus, the essential feature of the conditioned reflex activity of the child in the first six months of life must be considered complex stimuli that are effective for him. For example, the “feeding position”, in which tactile, proprioceptive and vestibular receptors are irritated and naturally excited at the same time. Are starting to show different kinds conditioned (internal) inhibition: differential inhibition is formed (3-4th month), a conditioned brake at the 5th month, delayed inhibition at the 6th month, i.e., by the end of the first year of life, all types of internal inhibition are developed (conditioned inhibition of conditioned reflexes - see section 6.8).

C. In the nursery period (from 1 year to 3 years), conditioned reflex activity is characterized not only by the development of individual conditioned reflexes, but also by the formation of dynamic stereotypes, and often in more a short time than in adults.

D. A 2-year-old child develops a huge number of conditioned reflexes to the ratio of the size, severity, distance, color of objects. These types of conditioned reflexes determine the integrated reflection of phenomena outside world; they are considered the basis of concepts formed on the basis of the first signal system. An example of a dynamic stereotype of this age can be changes in the characteristics of the child's GNI according to the daily routine: sleep - wakefulness, nutrition, walks, requiring a sequence of behavioral elements that make up the procedures for washing, feeding, playing.

The systems of conditional connections developed at this time are especially strong, and most of them retain their significance throughout the entire subsequent life of a person. Therefore, one can think that during this period, in a number of cases, imprinting still continues to operate. Raising children in a sensory enriched environment accelerates their mental development. The interaction of the projection and non-projection sections of the cerebral cortex provides a deeper perception environment. Of particular importance in this case is the interaction of excitations that ensure the emergence of sensations and motor activity, for example, visual perception of an object and grasping it with a hand.

E. At the age of 3-5 years, the improvement of conditioned reflex activity is expressed in an increase in the number of dynamic stereotypes (for more details, see section 6.14).

torii develop a conditioned defensive reflex to the same call in another laboratory. In this case, the call is reinforced by a slight irritation of the limb. electric shock. Soon, the dog reacts to the call not by salivation, but by withdrawing the limb - a defensive conditioned reflex. In this case, the conditioned signal is essentially a set of stimuli - a call and the environment of the laboratory. Such situations often occur in life. For example, a bell before the start of the lesson informs students about the need to start classes, at the end of the lesson - about the beginning of the break.

D. A consistent set of a number of conditioned reflexes is a dynamic stereotype, illustrating the consistency in the activity of the cerebral cortex, analytical and synthetic activity (E.A. Asratyan). In the experiments of E.A. Asratyan, conditioned reflexes were developed in dogs in a certain sequence, for example, a bell, a metronome (60 beats / min), hissing, metronome differentiation (120 beats / min), light, a wheelchair (Fig. 6.5).

conditioned reflexes to each of the stimuli, instead of each conditioned signal, one conditioned signal "light" was used in the experiment. At the same time, various conditioned reflexes were received on one stimulus - light, as with the sequential action of all the listed signals. In the cortex, there was a connection between all the points of the conditioned signals, and it was enough to turn on the “light” stereotype in the first place, as conditions were created for turning on the subsequent ones.

Thus, in the cerebral cortex, with prolonged use of the same sequence of conditioned signals (external stereotype), a certain system of connections (internal stereotype) is created. The reproduction of a stereotype is, as a rule, automatic. A dynamic stereotype prevents the creation of a new one (it is easier to teach a person than to retrain). The elimination of a stereotype and the creation of a new one are often accompanied by significant nervous tension (stress). A stereotype plays a significant role in a person's life: professional skills are associated with the formation of a certain stereotype; a sequence of gymnastic elements, memorizing poetry, playing musical instruments, practicing a certain sequence of movements in ballet, dancing, etc. - all these are examples of dynamic stereotypes, the role of which is obvious.

D. Conditioned reflexes have several components. During the development of a conditioned reflex, for example, a defensive reflex, to a bell with irritation of a limb by an electric current, in addition to a motor reaction, the cardiovascular and respiratory systems react to electrocutaneous stimulation; possible increase in heart rate, increased blood pressure due to the excitation of the sympathoadrenal system and the release of adrenaline into the blood, a change in the frequency and depth of breathing, metabolic changes. Firstly, they are associated with the action of stimuli, and secondly, with the provision of motor responses by vegetative shifts. Subsequently, vegetative shifts, although to a lesser extent, persist under the action of only a conditioned signal, in this case a bell, and accompany the conditioned defensive reflex.