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

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

Differences conditioned reflexes from unconditional:

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

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

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

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

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

Conditioned reflexes are changeable and more mobile.

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

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

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

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

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

Biological significance of unconditioned reflexes.

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

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

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

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

thermoregulatory,

respiratory,

cardiovascular,

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

Biological significance of conditioned reflexes.

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

Conditions for the formation of a conditioned reflex.

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

For example :

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

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

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

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

For example :

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

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

on the topic: “Higher nervous activity”

The concept of higher nervous activity 3
Characteristics of conditioned reflexes in comparison with unconditioned 5
The procedure for developing a conditioned reflex 6
The meaning of conditioned reflexes 8
The importance of conditioned reflexes in the development of diseases in humans 8
Inhibition of conditioned reflexes and the meaning of inhibition 9
Types of higher nervous activity (HNA) 10
Temperament 11
The importance and knowledge of temperament in working with patients 12

The concept of higher nervous activity

Higher nervous activity is the processes occurring in the higher parts of the central nervous system. nervous system animals and humans. These processes include a set of conditioned and unconditioned reflexes, as well as “higher” mental functions that ensure adequate behavior of animals and humans in changing natural and social conditions. Higher nervous activity should be distinguished from the work of the central nervous system in synchronizing work various parts organisms with each other. Higher nervous activity is associated with neurophysiological processes taking place in the cerebral cortex and the subcortex closest to it.

Divisions of the brain

Continuous Improvement mental processes higher nervous activity occurs in two ways - empirical and theoretical. Theoretical is carried out in the process of learning (learning other people's experience). The empirical is carried out in the process of life - by obtaining direct experience and verification, formed as a result of theoretical training of stereotypes in personal practice.

Higher nervous activity (HNA) is the activity of the cerebral cortex and the subcortical formations closest to it, ensuring the most perfect adaptation (behavior) of highly organized animals and humans to the environment. The higher nervous activity of the central nervous system should be distinguished from the work of the central nervous system in synchronizing the work of various parts of the body with each other.

The term “higher nervous activity” was first introduced into science by I.P. Pavlov, who considered it equivalent to the concept of mental activity. I.P. Pavlov identified two main sections in the physiology of higher nervous activity: the physiology of analyzers and the physiology of the conditioned reflex. Subsequently, these sections were supplemented by the doctrine of the second human signaling system.

Thanks to the works of I.P. Pavlov's physiology of higher nervous activity becomes a science about the neurophysiological mechanisms of the psyche and behavior, based on the principle of reflex reflection of the external world.

The foundation of GNI is conditioned reflexes. They arise on the basis of a combination of the action of unconditioned reflexes and conditioned stimuli, which include signals reaching a person through vision, hearing, smell, and touch. In humans, the activity of the cerebral cortex has the most developed ability to analyze and synthesize signals coming from the environment and internal environment of the body.

Thinking and consciousness I.P. Pavlov also considered GNI to be an element. Continuous improvement of higher nervous activity occurs in the process of learning (learning other people's experience).

First experimental studies on animals is associated with the name of the Roman physician Galen (129-201 AD), according to whom mental activity is carried out by the brain and is its function. Galen tested the effect of various medicinal substances on animal organisms and observed their behavior after cutting the nerves leading from the sensory organs to the brain.

Galen described some brain centers that control limb movements, facial expressions, chewing and swallowing. He distinguished different types brain activity and for the first time put forward provisions on innate and acquired forms of behavior, on voluntary and involuntary muscle reactions. However, due to poor development experimental sciences For many centuries, the study of mental processes took place without connection with the morphology and physiology of the brain.

2. Characteristics of conditioned reflexes in comparison with unconditioned ones

The term “conditioned reflex” was used by I. P. Pavlov to describe a reflex reaction that occurs in response to an initially indifferent stimulus if it is combined several times in time with an unconditioned stimulus. The formation of a conditioned reflex is based on either the modification of existing neural connections or the formation of new ones.

The conditioned reflex is characterized by the following features:

Flexibility, the ability to change depending on conditions;

Purchasability and cancellation;

Signal character (an indifferent stimulus turns into a signal, i.e. becomes a significant conditioned stimulus);

Implementation of the conditioned reflex by the higher parts of the central nervous system.

Biological role conditioned reflexes is to expand the range of adaptive capabilities of a living organism. Conditioned reflexes complement unconditioned ones and allow subtle and flexible

adapt to a variety of environmental conditions (Table 1).

Table 1

The difference between conditioned reflexes and unconditioned ones

Unconditioned reflexes	Conditioned reflexes
Congenital, reflect the specific characteristics of the organism	Acquired throughout life and reflect the individual characteristics of the body
Relatively constant individuals throughout life	Formed, changed and can be canceled when they become inadequate to living conditions
Implemented along anatomical pathways determined genetically	Implemented through functionally organized temporary connections
Characteristic of all levels of the central nervous system and carried out mainly by its lower parts (spinal cord, brainstem, subcortical nuclei)	They are realized with the obligatory participation of the cerebral cortex, and therefore its integrity and safety are required, especially in higher mammals
Each reflex has a specific receptive field and its own specific stimuli	Reflexes can be formed from any receptive field to a wide variety of stimuli
React to a present stimulus that can no longer be avoided	They adapt the body to the action of a stimulus that does not yet exist, it has yet to be experienced, i.e. they have a warning, signal value

3. The procedure for developing a conditioned reflex

The conditioned reflex connection is not innate, but is formed as a result of learning. A newborn baby has only a set of nerve elements for the formation of conditioned reflexes: receptors, ascending and descending nerve pathways, which are in the process of formation central departments sensory analyzers and the brain, which has unlimited possibilities for combining all these elements.

The formation of conditioned reflexes requires certain conditions:

1) the presence of two stimuli - an unconditional (food, painful stimulus, etc.), “triggering” an unconditional reflex reaction, and a conditioned (signal) one that precedes the unconditional;

2) repeated exposure to a conditioned stimulus preceding the unconditional one;

3) the indifferent nature of the conditioned stimulus (should not be excessive, cause a defensive or any other unconditioned reaction);

4) the unconditioned stimulus must be sufficiently significant and strong, the excitement from it must be more pronounced than from the conditioned stimulus;

5) the formation of a conditioned reflex is prevented by extraneous (distracting) stimuli;

6) the tone of the cerebral cortex must be sufficient for the formation of a temporary connection - a state of fatigue or ill health prevents the formation of a conditioned reflex.

The process of formation of a classical conditioned reflex consists of three stages:

The first stage is the pregeneralization stage. It is characterized by a pronounced concentration of excitation, primarily in the zones of projections of conditioned and unconditioned stimuli. This stage of concentration of excitation is short-lived, and is followed by the second stage - the stage of generalization of the conditioned reflex. The generalization stage is based on the process of diffuse spread of excitation (irradiation). During this period, conditioned reactions arise both to the signal and to other stimuli (the phenomenon of afferent generalization). Also, reactions occur in the intervals between presentations of a conditioned stimulus - these are intersignal reactions. At the third stage, as only the conditioned stimulus is reinforced, intersignal reactions fade, and the conditioned response arises only to the conditioned stimulus. This stage is called the stage of specialization, during which the bioelectrical activity of the brain becomes more limited and is associated primarily with the action of a conditioned stimulus. This process provides differentiation (fine discrimination) of stimuli and automation of the conditioned reflex.

4. The meaning of conditioned reflexes

Conditioned reflexes ensure the body's perfect adaptation to changing living conditions and make behavior plastic. When a conditioned signal is applied (a signal that causes a corresponding conditioned reflex), the cerebral cortex provides the body with preliminary preparation of a response to those environmental stimuli that will subsequently have an impact.

The conditioned stimulus must somewhat precede the unconditioned stimulus, i.e., signal about it. When a conditioned reflex is formed, a temporary connection arises between the centers of the conditioned stimulus analyzer and the center of the unconditioned reflex. Pavlov called the conditioned reflex a temporary connection, because this reflex appears only while the conditions under which it was formed are in effect. Conditioned reflexes are the basis of skills, habits, training, education, development of speech and thinking in a child, labor, social and creative activity.

Conditioned reflexes may arise or disappear if the signal is incorrect. However, if the need for the reflex does not disappear, it can exist throughout life.

The importance of conditioned reflexes in the development of diseases in humans

Such famous scientists as C. Sherrington and R. Magnus have proven that reflexes can be quite complex, involving entire organ systems in their implementation. Examples of such reflexes are walking, positioning the head, eyes and torso in space.

It has been shown that the reflex principle underlies all

processes in the body associated with maintaining vital functions (breathing, blood circulation, digestion, etc.), motor

activity, perception processes, etc.

Individual characteristics manifestations of higher nervous activity depend on character, temperament, intelligence, attention, memory and other properties of the body and psyche. A disorder of human higher nervous activity (neurosis) is caused by unfavorable environmental conditions (biological and social), physical and mental overstrain and is accompanied by dysfunction of various organs and systems.

6. Inhibition of conditioned reflexes and the meaning of inhibition

Inhibition is the activation of inhibitory neurons, which leads to a decrease in excitation in the centers of an already developed conditioned reflex. Inhibition of conditioned reflex activity manifests itself in the form of external, or unconditional, inhibition and in the form of internal, or conditioned, inhibition.

External unconditional inhibition conditioned reflexes are an innate, genetically programmed inhibition of one conditioned reflex by other conditioned or unconditioned ones. There are two types of external braking: transient and inductive.

1. Transcendental inhibition of conditioned reflexes (CR) develops either with high stimulus strength or with weak functioning of the nervous system. Extreme inhibition has a protective value.

2. Inductive inhibition of the SD is observed in the case of application of a new stimulus after the development of the SD or together with a known stimulus.

The biological significance of external inhibition is that the body delays its reaction to minor events and focuses its activity on the most important ones at the moment.

Internal, or conditioned, inhibition is inhibition that occurs within the reflex arc in the event of non-reinforcement of the conditioned reflex. The biological significance of internal inhibition is that if conditioned reflex reactions to generated signals cannot provide the adaptive behavior necessary in a given situation, especially when the situation changes, then such signals are gradually canceled while maintaining those that turn out to be more valuable.

There are three types of internal inhibition of the conditioned reflex: differentiation, extinction and delayed inhibition.

1. As a result of differential inhibition, a person begins to distinguish between stimuli that are similar in their parameters and reacts only to biologically significant ones.

2. Extinction inhibition occurs when, with a conditioned reflex developed, the effect on the body of a conditioned stimulus is not reinforced by the influence of an unconditioned stimulus. Thanks to extinction, the body stops responding to signals that have lost their meaning. Fading helps to free yourself from unnecessary unnecessary movements.

3. Delayed inhibition occurs if the developed conditioned reflex is moved away in time from the unconditioned stimulus that reinforces it. Delay in children is developed with great difficulty under the influence of upbringing and training. Delay is the basis of endurance, willpower, and the ability to restrain one’s desires.

7. Types of higher nervous activity (HNA)

The balance of nervous processes is the balance of the processes of excitation and inhibition, creating the basis for more balanced behavior.

Additional properties of nervous processes were highlighted.

Dynamism is the ability of brain structures to quickly generate nervous processes during the formation of conditioned reactions. The dynamism of nervous processes underlies learning.

Lability is the rate of emergence and cessation of nervous processes. This property allows you to make movements with high frequency, quickly and clearly starting and finishing the movement.

Activation - characterizes the individual level of activation of nervous processes and underlies the processes of memorization and reproduction.

Based on various combinations of the three main properties of nervous processes, various types of GNI are formed. In I. P. Pavlov’s classification, there are four main types of GNI, differing in adaptability to external conditions:

1) a strong, unbalanced (“unrestrained”) type is characterized by a high strength of excitation processes that predominate over inhibition. This is a man with high level active, quick-tempered, energetic, irritable, addicted, with strong, quickly arising emotions that are clearly reflected in speech, gestures and facial expressions;

2) a strong, balanced, mobile (labile or “living”) type is characterized by strong, balanced processes of excitation and inhibition with the ability to easily replace one process with another. These are energetic people, with great self-control, decisive, able to quickly navigate a new environment, agile, impressionable, clearly expressing their emotions;

3) a strong, balanced, inert (calm) type is distinguished by the presence of strong processes of excitation and inhibition, their balance, but at the same time low mobility of nervous processes. These are very efficient, able to restrain themselves, calm people, but slow, with weak expression of feelings, difficult to switch from one type of activity to another, committed to their habits;

4) weak type is characterized by weak excitation processes and easily occurring inhibitory reactions. These are weak-willed, sad, sad people, with high emotional vulnerability, suspicious, prone to gloomy thoughts, to a depressed mood, they are timid, and often succumb to the influence of others.

8. Temperament

These types of GNI correspond to classical description temperaments, created by Hippocrates, an ancient Greek doctor who lived almost 2.5 millennia before I.P. Pavlov (Table 2).

table 2

Correlation of types of higher nervous activity and temperaments according to Hippocrates

Temperaments according to Hippocrates	Equilibrium	Mobility
	Unbalanced, with a predominance of the excitation process
Sanguine	Balanced	Mobile
Phlegmatic person	Balanced	Inert
Melancholic

However, usually the combination of properties of the nervous system is more diverse, and therefore in life it is rarely possible to see such “pure” types of GNI. I. P. Pavlov also noted that between the main types there are “intermediate, transitional types, and they must be known in order to navigate human behavior.”

Any work with people is inextricably linked with the process and problems of communication; it permeates professional activity health workers at any level. The individual characteristics of the patient’s psyche in the conditions of therapeutic relationships and interactions come into contact with the psychological properties of the medical worker. The purpose of such contact is to provide assistance to the patient.

Conflicts of interests are the source of conflicts, but the factors that provoke conflict are extremely diverse. These may include the character-logical characteristics of a person: reduced self-criticism, prejudice and envy, self-interest, selfishness, the desire to subordinate others to oneself; his mood, well-being, intelligence, knowledge and ignorance of human psychology, psychology of communication, etc.

As a result, everything that constitutes an interpersonal communication situation can act as a conflict factor, a barrier to communication, and create a difficult psychological situation.

The likelihood of conflicts increases when:

Incompatibility of characters and psychological types;

The presence of a choleric temperament;

The absence of three qualities: the ability to be critical of oneself, tolerance of others and trust in others.

Calmness and understanding, restraint and tolerance, responsiveness and culture of behavior of a medical worker will positively affect the established relationship with the patient, and will form his trust in doctors and medicine.

List of used literature:

1. Batuev A.S. Higher nervous activity: Textbook. for universities for special purposes "Biology", "Psychology". - M.: Higher. school, 1991.—256 p.

2. Human anatomy: tutorial for students of institutions providing education in the specialty “Nursing” / E.S. Okolokulak, K.M. Kovalevich, Yu.M. Kiselevsky. Edited by E.S. Around the fist. - Grodno: GrSMU, 2008. - 424 p.

3. Smirnov V.M., Budylina S.M. Physiology of sensory systems and higher nervous activity./ Moscow, “Academa”, 2003.

4. Physiology of higher nervous activity / H.H. Danilova, A.L. Krylova. - Rostov n/d: “Phoenix”, 2005. - 478, p.

5. Physiology of higher nervous activity: a textbook for students. institutions of higher education prof. education / V.V. Shulgovsky. — 3rd ed., revised. - M.: Publishing Center "Academy", 2014. - 384 p.

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

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

1. Differences between conditioned reflexes and unconditioned ones:

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

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

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

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

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

· Conditioned reflexes are changeable and more mobile.

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

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

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

· Adaptation of the body to constantly changing environmental conditions is ensured by conditioned reflexes developed throughout life.

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

Biological significance of unconditioned reflexes.

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

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

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

· thermoregulatory,

· respiratory,

· cardiovascular,

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

Biological significance of conditioned reflexes.

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

The concept of an unconditioned reflex

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

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

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

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

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

Properties of unconditioned reflexes

The characteristics of unconditioned reflexes include several mandatory points:

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

The meaning of reflexes

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

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

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

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

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

The body lives surrounded by external factors that are constantly changing, and it is necessary to adapt to them. This is where higher nervous activity in the form of conditioned reflexes comes to the fore.

For the body they have the following meaning:

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

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

Classification of unconditioned reflexes

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

Pavlov also divided all unconditioned reflexes into:

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

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

The first group of reactions has two characteristics:

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

The third group also has its own characteristic features:

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

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

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

Each group has its own characteristics and differences.

Reflex acts

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

These include:

Breath.
Swallowing.
Vomiting.

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

Behavioral reactions

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

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

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

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

Instincts

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

All instincts are associated with changing internal needs.

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

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

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

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

All of them can generate new needs:

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

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

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

Imprint

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

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

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

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

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

Congenital reflexes of an infant

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

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

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

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

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

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

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

Oral segmental reflexes

This type of reflexes includes:

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

Spinal motor automatisms

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

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

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

Differences between conditioned and unconditioned reflexes

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

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

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

The mechanisms of higher nervous activity in higher animals and humans are associated with the activity of a number of parts of the brain. The main role in these mechanisms belongs to the cerebral cortex. It has been experimentally shown that in higher representatives of the animal world, after complete surgical removal of the cortex, higher nervous activity sharply deteriorates.

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Reflex is the basis of nervous activity. Unconditioned and conditioned reflexes and their role in the life of humans and animals

Introduction

Relevance of the work. Higher nervous activity ensures the individual adaptation of the body to changing conditions of the external and internal environment.

Reflexes are reactions of the body that occur with the obligatory participation of the nervous system in response to irritation of perceptive nerve endings - receptors.

I.P. Pavlov divided all reflex reactions into two groups: unconditioned and conditioned. They also underlie human behavior.

Unconditioned and conditioned reflexes form the basis of the most complex forms of activity of the organism as a whole - its behavior in the external environment.

Conditioned reflexes are highest form adaptation of the body to external conditions.

The study of reflex reactions is relevant in our time.

Goal of the work : study unconditioned and conditioned reflexes and their role in the life of humans and animals.

Job objectives:

Consider the reflex as the basis of nervous activity;

Study unconditioned and conditioned reflexes;

Study the differences between conditioned and unconditioned reflexes;

Study the role of the unconditioned and conditioned reflex in the life of humans and animals.

1 Reflex as the basis of nervous activity

The main form of nervous activity is reflexes. Reflex is the body’s response to irritation from the external or internal environment, carried out through the central nervous system.

Irritation of the skin of the plantar part of the foot in humans causes reflex flexion of the foot and toes. This is the plantar reflex. When the quadriceps tendon is struck under the patella, the leg is extended at the knee. It's a knee-jerk reaction. Touching the lips of an infant causes sucking movements in him - the sucking reflex. Illumination of the eye with bright light causes constriction of the pupil - the pupillary reflex. Thanks to reflex activity, the body is able to quickly respond to various changes in the external or internal environment. Reflex reactions are very diverse. They can be conditional or unconditional.

All organs of the body contain nerve endings that are sensitive to stimuli. These are receptors. Receptors vary in structure, location and function. Some receptors look like relatively simply arranged nerve endings, or they are separate elements of complex sensory organs, such as the retina of the eye. 1

Based on their location, receptors are divided into exteroceptors, proprioceptors and interoceptors. Exteroreceptors perceive stimuli from the external environment. These include the receptive cells of the retina of the eye, ear, skin receptors, olfactory and taste organs. Interoreceptors are located in tissues internal organs(heart, liver, kidneys, blood vessels etc.) and perceive changes in the internal environment of the body. Proprioceptors are located in the muscles and perceive muscle contractions and stretches, i.e. signal the position and movements of the body.

In the receptors, under the action of appropriate stimuli of a certain strength and duration of action, an excitation process occurs. The resulting excitation from the receptors is transmitted to the central nervous system along centripetal nerve fibers. In the central nervous system, due to intercalary neurons, the reflex turns from a narrow-local act into a holistic activity of the nervous system. In the central nervous system, incoming signals are processed and impulses are transmitted to centrifugal nerve fibers.

The executive organ whose activity changes as a result of the reflex is called an effector. The path along which nerve impulses travel from the receptor to the executive organ is called a reflex arc. This is the material basis of the reflex.

Speaking about the reflex arc, we must keep in mind that any reflex act is carried out with the participation large quantity neurons. The two- or three-neuron reflex arc is just a diagram. In fact, the reflex occurs when not one, but many receptors located in one or another area of the body are irritated. Nerve impulses during any reflex act, arriving in the central nervous system, spread widely in it, reaching its different parts. Therefore, it is more correct to say that the structural basis of reflex reactions is made up of neural chains of centripetal, central, or intercalary, and centrifugal neurons. Due to the fact that in any reflex act groups of neurons take part, transmitting impulses to various parts of the brain, the whole organism is involved in the reflex reaction. And indeed, if you were unexpectedly pricked in the hand by a pin, you would immediately pull it away. This is a reflex reaction. But this will not only reduce the arm muscles. Breathing and the activity of the cardiovascular system will change. You will react with words to an unexpected injection. Almost the entire body was involved in the response. A reflex act is a coordinated reaction of the entire organism. 2

There are both direct and feedback connections between the central nervous system and the working and executive organs. When a stimulus acts on the receptors, a motor reaction occurs. As a result of this reaction, nerve impulses from the effector organs - the muscles - enter the central nervous system. These secondary afferent (centripetal) impulses constantly signal the nerve centers about the state of the motor system, and in response to these signals, new impulses are received from the central nervous system to the muscles, including the next phase of movement or changing movement in accordance with the conditions of activity. This means that there is a circular interaction between regulators (nerve centers) and regulated processes, which gives grounds to speak not of a reflex arc, but of a reflex ring, or reflex chain.

The structure of the reflex ring differs significantly from the structure of the reflex arc, which is essentially open at the periphery. The reflex ring has additional links in the form of receptors of the executive organ, an afferent neuron and a system of interneurons that transmit secondary afferent impulses to the centrifugal neurons of the reflex ring.

Secondary afferent impulses (feedback) are very important in the coordination mechanisms carried out by the nervous system. In patients with impaired muscle sensitivity, movements, especially walking, lose their smoothness and become uncoordinated. The central nervous system in such patients loses control over movements.

Thanks to feedback, we can not only judge the results of actions, but also make amendments to our activities and correct mistakes. Therefore, in order for the body’s activity to be coordinated and provide the desired effect, only direct connections from the brain to the working organ are not enough; feedback connections (working organs - brain), through which impulses travel, signaling the correctness or error of the action being performed, are also important. Physiologists know many examples of self-regulation of functions in the body using feedback: this is the maintenance of blood pressure at a constant level due to impulses entering the central nervous system from receptors of blood vessels, or the importance of impulses from receptors of the lungs and respiratory muscles in the regulation of breathing, etc.

The doctrine of the reflex activity of the central nervous system led to the idea of a nerve center. A nerve center is a collection of neurons in the central nervous system that participate in the implementation of a certain reflex action or the regulation of a particular function.

The nerve center is a complex functional association, “ensembles” of neurons located in various parts of the central nervous system, coordinately involved in the regulation of functions and reflex reactions.

Nerve centers have a number of characteristic properties determined by the characteristics of the conduction of excitation through the synapses of the central nervous system and the structure of the neural circuits that form them.

In the central nervous system, unilateral conduction of excitation is noted. This is due to the characteristics of synapses; transmission of excitation in them is possible only in one direction - from the nerve ending, where the transmitter is released upon excitation, to the postsynaptic membrane. In the opposite direction, the excitatory postsynaptic potential does not propagate. 3

In the synapses of the central nervous system, there is a slow conduction of excitation. It is known that excitation along nerve fibers is carried out quickly. In synapses, the speed of excitation is approximately 200 times lower than the speed of excitation in the nerve fiber. This is due to the fact that when transmitting an impulse through a synapse, time is spent on the release of the transmitter by the nerve ending in response to the incoming impulse; on the diffusion of the transmitter through the synoptic cleft to the postsynaptic membrane; on the appearance of an excitatory postsynaptic potential under the influence of this mediator.

In the central nervous system, the rhythm of impulses entering it is transformed into its own rhythm. In this case, both a decrease in the frequency of impulses entering it and an increase in their frequency may occur. In response to a single stimulation of a centripetal neuron, the central nervous system sends a series of impulses along the centrifugal neuron, following each other at a certain interval. Rhythm transformation is associated with the characteristics of the transmission of excitation through synapses. Nerve centers are characterized by the phenomenon of summation of excitation. This property was first described by I.M. Sechenov in 1863. It was found that weak stimulations do not cause a visible reflex reaction of the central nervous system. A reflex response can only be caused by a stimulus that has reached a threshold strength. But if a weak stimulus acts simultaneously on several receptor areas (for example, several areas of the skin) or a weak stimulus acts on the receptor repeatedly (for a long time), then the reflex response will arise due to folding, i.e. summation, excitement.

This phenomenon is based on the process of summation of excitatory postsynaptic potentials on the body of neurons. As a rule, the portion of the transmitter released by the nerve ending in response to a single impulse is too small to cause an excitatory postsynaptic potential sufficient to depolarize the nerve cell membrane. Such depolarization is possible either in the case of simultaneous excitation of several synapses located on the neuron body, or when a series of nerve impulses arrive at the same synapse, following each other with a short interval. In this case, postsynaptic potentials are summed with each other, and at the moment when the total potential reaches a threshold value, a propagating action potential arises. The reflex reaction does not stop immediately after the cessation of the stimulus, and for some period of time, exciting impulses continue to flow to the working organ (effector) from the central nervous system. This is an aftereffect. The aftereffect is usually longer than more irritation and the longer it acted on the receptors. Unlike isolated nerve fibers, nerve centers are easily fatigued. Fatigue of the nerve centers manifests itself in a gradual decrease and ultimately complete cessation of the reflex response with prolonged stimulation of the receptor. It is believed that fatigue of the nerve centers is associated with a disruption in the transmission of excitation in interneuron synapses. In this case, there is a decrease in the reserves of the synthesized transmitter in the nerve endings and a decrease in the sensitivity of the postsynaptic membrane to the transmitter. 4

After excitation of the central nervous system by rhythmic stimulation, the next stimulation causes a greater effect, or a smaller force of subsequent stimulation is required to maintain the previous level of response. This property of nerve centers is called prototyping. The facilitating effect during penetration is explained by the fact that with the first stimuli of irritation, the transmitter vesicles move closer to the presynaptic membrane and with subsequent irritation, the transmitter is more quickly released into the synaptic cleft.

2 Unconditioned reflexes

Unconditioned reflexes are innate reactions to certain influences of external agents, carried out with the help of the nervous system. The term “unconditioned reflex” was introduced by I.P. Pavlov.

Characteristics unconditioned reflexes are their relative constancy, innateness and species specificity, as well as the fact that they serve as the basis and reinforcing factor for the formation of conditioned reflexes. The totality of B. r. constitutes the so-called lower nervous activity of animals, conditioned higher nervous activity.

Unconditioned reflexes are divided into simple (food, defensive, sexual, visceral, tendon) and complex reflexes (instincts, emotions). Some researchers to B. r. also include indicative (orientative-exploratory) reflexes. The instinctive activity of animals (instincts) includes several stages of animal behavior, and the individual stages of its implementation are sequentially connected with each other like a chain reflex.

The question of the mechanisms of closure of unconditioned reflexes has not been studied enough. According to the teachings of I.P. Pavlov about the cortical representation of B. r., each unconditional stimulation, along with the inclusion of subcortical structures, causes excitation of nerve cells in the cerebral cortex. Studies of cortical processes using electrophysiological methods have shown that an unconditioned stimulus comes to the cerebral cortex in the form of a generalized flow of ascending excitations. 5

Based on the provisions of I.P. Pavlov about the nerve center as a morphofunctional set of nerve formations located in various parts of the central nervous system, the concept of the structural and functional architecture of unconditioned reflexes was developed. The central part of the unconditioned reflex arc does not pass through any one part of the central nervous system, but is multi-story and multi-branched. Each branch passes through an important part of the nervous system: the spinal cord, medulla oblongata, midbrain, and cerebral cortex. The higher branch, in the form of the cortical representation of one or another unconditioned reflex, serves as the basis for the formation of conditioned reflexes. Evolutionarily more primitive species of animals are characterized by simple unconditioned reflexes and instincts, for example, in animals in which the role of acquired, individually developed reactions is still relatively small and innate, albeit complex forms of behavior predominate, dominance of tendon and labyrinthine reflexes is observed. With complication structural organization the central nervous system and the progressive development of the cerebral cortex, complex unconditioned reflexes and, in particular, emotions acquire a significant role.

The study of unconditioned reflexes is important for the clinic. Thus, in conditions of pathology of the central nervous system, unconditioned reflexes may appear, characteristic of the early stages of onto- and phylogenesis (sucking, grasping, Babinsky, Bekhterev, etc. reflexes), which can be considered as rudimentary functions, i.e. functions that existed previously, but were suppressed during the process of phylogenesis by the higher parts of the central nervous system. When the pyramidal tracts are damaged, these functions are restored due to the resulting disconnection between the phylogenetically ancient and later developed parts of the central nervous system.

The set of unconditioned reflexes that provide complex forms of animal behavior is called instinct. For example, bird migration, caring for offspring, construction of dams by beavers. However, unconditioned reflexes alone are not enough for the body to adapt to changing environmental conditions. Such adaptations are carried out thanks to reflexes, which I. P. Pavlov called conditioned in 1903. 6

Instincts are very strong. Complex forms of behavior associated with their manifestation often indicate their high adaptive significance. For example, puppies from the hunting dog breed, without prior training in hunting conditions, exhibit many nuances in behavior that are characteristic of trained animals.

During the growth and development of the organism, the system of unconditioned reflex connections still turns out to be limited, inert, and unable to provide sufficiently mobile adaptation reactions corresponding to fluctuations in the external and internal environment. More perfect adaptation of the body to constantly changing conditions of existence occurs thanks to conditioned reflex, i.e., individually acquired, reactions. Conditioned reflex mechanisms of the brain are related to all types of activity of the body (to somatic and vegetative functions, to behavior), providing adaptive reactions aimed at maintaining the integrity and stability of the “organism-environment” system. IP Pavlov called a conditioned reflex a temporary connection between a stimulus and a response activity that occurs in the body under certain conditions. Therefore, in the literature, instead of the term “conditioned reflex,” the term “temporary connection” is often used, which also includes more complex manifestations of animal and human activity, representing entire systems of reflexes and behavioral acts.

3 Conditioned reflexes

Conditioned reflexes are individually acquired complex adaptive reactions of the animal and human body that arise under certain conditions (hence the name) based on the formation of a temporary connection between a conditioned (signal) stimulus and an unconditioned reflex act that reinforces this stimulus. They are carried out by the higher parts of the central nervous system - the cerebral cortex and subcortical formations; are formed in the process of ontogenesis on the basis of unconditioned reflexes. 7

Conditioned reflexes can be formed to any stimulation of any receptor fields. (A conditioned food reflex can be developed to stimulate visual, auditory, skin and other receptors).

There are natural and artificial conditioned reflexes. Natural ones are produced in response to natural signals that accompany an unconditioned stimulus (the sight and smell of food; the sight and sounds made by a predator; a start command for an athlete). Natural conditioned reflexes are developed in natural conditions and, as a rule, remain throughout life. In the experiment, artificial conditioned reflexes are developed in response to signals not related to the stimulus (light, bell, etc.). 8

Certain conditions are necessary for the formation of conditioned reflexes. It is important that the indifferent stimulus, which then becomes conditioned, precedes (by 15 s) or coincides with the action of the unconditioned. If an indifferent stimulus acts long before the unconditioned one, or if the unconditioned stimulus is given first and then the conditioned stimulus, then the conditioned reflex is not developed. Conditioned reflexes are formed and reinforced only after a sufficient number of repeated combinations. The rate of formation and stability of a conditioned reflex depend on the intensity of the unconditioned reaction (food conditioned reflexes are developed faster in a hungry animal). The formation of conditioned reflexes is also influenced by the strength of the conditioned stimulus: reflexes are more difficult to develop to weak signals than to stronger ones. Under natural conditions, reflexes are most often formed in response to signals that simultaneously or sequentially irritate various receptors. Such conditioned reflexes are called complex. In an experiment, with the sequential presentation of several signals, conditioned reflexes of the first, second and subsequent orders are developed.

A conditioned reflex is formed due to the emergence of a functional temporary connection between the center in the cerebral cortex that perceives the conditioned signal and the center of the cortical representation of the unconditioned reflex. Cortical representation of the unconditioned reflex these are the nerve cells in the cortex that are involved in its execution. For example, the arc of the unconditioned salivary reflex passes through the center in the medulla oblongata. When the neurons of the medulla oblongata are excited, the impulses propagate along the ascending pathways, reach the neurons of the cortical representation in the frontal lobe, activate them and return along the reverse pathways to the center of the unconditioned reflex. If the functioning of the cortical representation is disrupted, salivation becomes weak, less accurate and quickly stops. With simultaneous irritation of the hearing organ, signals arrive at the hearing center of the temporal lobe and activate it. Thus, two groups of excited neurons appear simultaneously in the cerebral cortex: neurons of the cortical representation of the salivary reflex and the hearing center. Thanks to this, a new functional connection is formed between them, which is reinforced as it is repeated.

4 Differences between conditioned and unconditioned reflexes

Unconditioned reflexes are innate reactions of the body, they were formed and consolidated in the process of evolution and are inherited. Conditioned reflexes arise, become consolidated, and fade away throughout life and are individual. Unconditioned reflexes are specific, i.e. they are found in all individuals of a given species. Conditioned reflexes can be developed in some individuals of a given species, while in others they may be absent. Unconditioned reflexes do not require special conditions for their occurrence; they certainly occur if certain receptors are acted upon by adequate stimuli. Conditioned reflexes require special conditions for their formation; they can be formed in response to any stimuli (of optimal strength and duration) from any receptive field.

Unconditioned reflexes are relatively constant, stoic, unchanging and persist throughout life. Conditioned reflexes are changeable and more mobile. 9

The implementation of unconditioned reflexes involves mainly the subcortical parts of the central nervous system. These reflexes can be carried out in higher animals even after the removal of their cerebral cortex. Although it was possible to show that after removal of the cerebral cortex the nature and course of unconditioned reflex reactions changes, this gave grounds to talk about the cortical representation of the unconditioned reflex. Conditioned reflexes in higher animals are a function of the cerebral cortex.

The change of unconditioned reflexes for each person, depending on age, is just as programmed as the replacement of baby teeth with permanent ones. This is due to several reasons.

By the time of birth, not all parts of the nervous system are functioning. Some nerve centers are formed later. Thus, more ancient systems (for example, the extrapyramidal) mature earlier than the pyramidal system, with which voluntary movements and actions are associated. The reflexes of the extrapyramidal system include the Babinski reflex and the Robinson reflex. If an adult draws a dashed line along the sole of the foot, he will bend his toes, and a child will straighten them - they form a figure reminiscent of a fan. Any touch to the child’s palm causes the hand to be clenched into a fist. In premature babies it can be so severe that some babies can support their weight if they are allowed to grab a stick with their hands and then lift the stick with the baby.

The second reason for the change in reflexes is related to the ecological adaptability of organisms to the capabilities that a child has at a given age. When the child begins to hold his head up, then when it “falls” (and this happens whenever the child gets tired), the head turns to the side, and he does not bury his mouth and nose in the bed. Otherwise, the child could suffocate. After voluntary movements become available to the child, this reflex fades away.

Sexual reflexes also do not appear immediately; they largely depend on age.

At the birth of a person or any land mammal, a certain chain of reflexes follows, constituting instinct: birth accumulation carbon dioxide in the blood of a newborn inhalation.

In hippopotamuses, which usually give birth to their young in water, the chain of reflexes is somewhat different: birth accumulation of carbon dioxide in the blood ascent to the surface inhalation. Ignorance of this caused the death of a baby hippopotamus born in captivity. The staff of this zoo were very concerned that the newborn cub did not appear from the water for a long time. They decided to release the water to save him, but in doing so they killed the cub. He was not allowed to float up and breathing became impossible. In other words, the chain of reflexes was broken and the middle link was crossed out.

In one row there are images of the heads of adult animals, and in the second - the heads of their young. Students must answer the question which row is their favorite.

Practice has shown that cubs evoke more sympathy.

Signal stimuli of pups that evoke parental reflexes. On the right are adult forms of the same animal species and humans.

5 The role of unconditioned and conditioned reflexes in the life of humans and animals

Unconditioned reflexes, together with conditioned ones, ensure the adaptability of organisms to living conditions.

Examples of unconditioned reflexes are: food, defensive, sexual, self-regulation of the functions of organs and systems, pain, swallowing, vomiting, sneezing, coughing, blinking, etc. In the first moments after birth, the child is able to breathe, feed by sucking, etc. 10

The ability to use predominantly the right or left hand is also an unconditioned reflex. The so-called instincts are nothing more than complex complexes of various reflexes. Some unconditioned reflexes are used in medicine to determine the state of people's health: knee, Achilles, abdominal, blinking, plantar, sucking, etc. Of these, the knee reflex is probably known to everyone who has been to a neurologist. The doctor hits the muscle tendon below the patella with a special hammer. At the same time, the lower leg is extended at the knee joint. The Achilles reflex is induced in the same way: a blow to the Achilles tendon causes plantar flexion of the foot. Abdominal reflexes manifest themselves in the form of displacements of the abdominal wall in response to line irritations of the abdominal skin. The blink reflex is manifested by contraction of the orbicularis oculi muscles when illuminated or the sudden appearance of an object in the field of vision. Based on these and other reflexes, the doctor judges the state of the nervous system.

During life, innate reflexes can change and become difficult to recognize. It should be noted that in humans, unlike animals, unconditioned reflexes manifest themselves with the participation of the cerebral cortex.

The reflex activity of the nervous system, consisting of unconditioned and conditioned reflexes, determines the entire variety of body functions, including memory, thinking and behavior.

The perfect adaptation of the organism to the environment is carried out through the formation and disappearance of various conditioned reflexes. Variability, conditioning by factors of the external and internal environment of the body and the temporariness of conditioned reflexes are extremely important. biological significance, providing flexibility and precision in adapting the body to a changing environment. The signaling nature of conditioned reflex activity allows the body, based on one, often distant precursors - conditioned stimuli, to strive in advance for favorable conditions for its existence and avoid unfavorable ones, and also immeasurably expands the perception of objects and events of the surrounding world and the range of activity. The role of unconditioned reflexes in V. n. d. lies not only in the fact that on their basis all conditioned reflexes are ultimately developed, but also in the fact that unconditioned reflexes, especially their complex forms, act as a concentrated expression of the hereditarily fixed experience of previous generations, as a manifestation of genetic memory. 11

The relative importance of conditioned and unconditioned reflexes in V. n. d. changes during the process historical development animal world. In the behavior of invertebrates and lower vertebrates, innate forms of nervous activity prevail over acquired ones; During the evolution of animals, acquired forms of nervous activity gradually gain predominance, becoming the dominant forms of nervous activity. e. Moreover, these forms themselves undergo significant changes: conditioned reflexes continuously become more complex and improved, their composition is constantly enriched, conditioned reflex activity as a whole becomes an increasingly more advanced and active means of adaptation to the environment, i.e., it ensures the possibility of the organism’s existence in all a wider range of environmental conditions.

conclusions

Changing environmental conditions require constant adaptation of the body to them. Such reactions in humans are ensured by the reflex activity of the nervous system. In the process of evolution, firmly fixed, inherited reflexes arose that provide the adaptive capabilities of the organism, unite and coordinate its functions. I. P. Pavlov called these reflexes unconditional. Unconditioned reflexes are innate reactions of the body, fixed and carried out with the help of the nervous system. They are fully formed by the time of birth, carried out by a reflex arc ready at the time of birth, and are characteristic of all representatives of this species. Unconditioned reflexes are constant and stable throughout life, carried out with the participation of the spinal cord, brain stem and subcortical nuclei. The biological role of these reflexes is that they ensure the functioning of the body immediately after birth, and subsequently are the main one for the development of conditioned reflexes. Examples of unconditioned reflexes include sucking in newborns, blinking, salivation when food enters the mouth, etc.

Conditioned reflexes are acquired in the process individual development organism throughout life based on interaction with the environment. Conditioned reflexes are changeable; they can arise, become stronger, or be lost if the need for them disappears. Conditioned reflexes are individual; a reflex may be present in some individuals of a species and absent in others. These reflexes are mobile; they can be formed, if necessary, when any receptor apparatus is irritated. Conditioned reflexes are developed with the participation of the cerebral cortex.

The biological role of the conditioned reflex is to expand the range of adaptive capabilities of the body to a wide variety of conditions. Conditioned reflexes form the basis of training, education, development of speech and thinking in a child, skills in labor, social and creative activities of a person.

List of used literature

Asratyan E. A., Essays on the physiology of conditioned reflexes, M., 2006.
Belenkov N. Yu., Conditioned reflex and subcortical formations of the brain, M., 2005.
Beritov I. S., Structure and functions of the cerebral cortex, M., 2005.
Kogan A. B., Electrophysiological study of the central mechanisms of some complex reflexes, M., 2004.
Konorski Yu., Integrative brain activity, trans. from English, M., 2004.
Livanov M. N., Spatial organization of brain processes, M., 2002.
Milner P., Physiological Psychology, trans. With. English, M., 2003.
Pavlov I. P., Complete. collection tr., vol. 3, M. L., 2006.
Electrical activity of the brain during the formation of simple forms of temporary connection, M., 2006.

1 Anokhin P.K., Biology and neurophysiology of the conditioned reflex, M., 2006.

2 Dmitriev A. S., Physiology of higher nervous activity, M., 2006.

3 Voronin L.G., Course of lectures on the physiology of higher nervous activity. M. 2006.

4 Physiology of higher nervous activity, part 12, L., 2004.

5 Voronin L.G., Course of lectures on the physiology of higher nervous activity. M. 2006.

6 Physiology of higher nervous activity, part 12, L., 2004.

7 Rudenko L. P., Functional organization elementary and complex forms of conditioned reflex activity, M., 2004.

8 Dmitriev A. S., Physiology of higher nervous activity, M., 2006.

9 Voronin L.G., Course of lectures on the physiology of higher nervous activity. M. 2006.

10 Physiology of higher nervous activity, part 12, L., 2004.

11 Anokhin P.K., Biology and neurophysiology of the conditioned reflex, M., 2006.

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