The rapid development of physiology and biology, discoveries in psychophysics and psychophysiology also stimulated the development of an anatomical and morphological model of the reflex, which filled sufficient

246 Part II. Psychology

but the speculative concepts of Descartes and Hartley have real content.

In the works of the psychophysiologist and physician I. Prochazka, the “general sensory” was discovered - the area of ​​​​the brain where the nerves originate, when irritated, a transition from sensation to the motor response of the body to an external impulse occurs, i.e. from sensory (sensory, centripetal) nerves to motor (motor, centrifugal). More low levels innervations of behavior, which Kabanie wrote about, are associated with the work not of the brain, but spinal cord, which participates in the organization of elementary forms of behavior, a kind of automatisms, which, however, do not act purely mechanically, but according to the biological needs of the body.

The study of the reflex system was continued in the works of the English anatomist and physiologist C. Bell and the French scientist F. Magendie, who identified fibers running from the roots through the spinal cord to the fibers that activate the muscular apparatus. Thus, the model of the reflex was defined as a kind of automaton, consisting of three blocks: centripetal, central and centrifugal. This anatomical and morphological model of the central nervous system was called the Bell-Magendie law. This law describes the pattern of distribution of nerve fibers in the roots of the spinal cord: sensory fibers enter the spinal cord as part of the dorsal roots, and motor fibers enter the anterior roots.

Research by I.M. Sechenov systematized previous concepts, transforming the reflex system in accordance with experimental data of physiology. In the structure of the analyzer, he identified three parts - centripetal, i.e. sensing receptor central part, processing information, and centrifugal, transmitting signals to the muscle. An important point for modern understanding The reflex has the idea put forward by Sechenov of an image - a signal that not only “triggers” the reflex, but also regulates its course. In other words, it is not the external stimulus, but its reflection in the sense organ that is the signal that triggers the reflex act. In this case, the signal (i.e., the image of an object or situation), which allows one to distinguish the properties of objects in the external environment, directs and corrects the course of the reflex, optimizing its course.

Chapter 3. Mind and body 247

In the central part, several information processing centers are distinguished, the main of which are: the center of inhibition (volitional regulation), information storage (memory), warning (thinking) and signal amplification (emotions).

Having introduced the principle of “coordinating movement with feeling,” Sechenov fundamentally revised the role of muscle efforts in the reflex act. His idea that the muscular sense contains a system of signals about the spatiotemporal parameters of the external world has been proven by a significant number of works by modern psychologists and physiologists. Thus, a muscle is not only an organ of movement, but also an organ of cognition, since objective actions are external analogues of certain mental operations (analysis, synthesis, classification, etc.), helping the formation of internal, actually mental operations.

Sechenov’s thoughts about feedback (i.e., signals from muscles to sensory organs) necessary for self-regulation of behavior were developed by NA Bernstein, who studied the mechanisms of movement construction.

Bernstein showed that automatic execution muscle commands sent by nerve centers cannot form the basis of a complex movement, since it is continuously adjusted during execution. This occurs due to the fact that there is a cyclic connection between the muscle and the center. From the centers, signals are sent to the periphery in advance (Bernstein called them sensory corrections), which reflect the final result, according to the changing situation.

That is, the body, while working, solves a motor problem. Moreover, there are five different levels building movement. Each level has its own, in its language, “afferent syntheses.” This means that in the nerve centers there is, as it were, encoded information that carries information in advance about the external world, in the space of which one or another class of movements is to be performed - “advanced reflection”. Thanks to this, the body is able to anticipate and predict the conditions in which it will have to act in the future, and not just store information about the past and respond to stimuli that affect its nervous apparatus at the moment.

The organism encounters the world already having a supply of projects for possible movements. The creation of these projects shows active

248 Part 11. Psychology

the ability of the organism, the ability to be creative, to create something new, to build, as Bernstein wrote, a model of the “needed result.” Thus, the reflex model was finally formulated, and the most important reason for the activity was not the direct effect of the stimulus on the organs of its perception, but the preparation of a model of a possible future action.

In addition to the structure of the reflex act, scientists were also interested in the ways of its transformation, changes under the influence of training and education. Great value for psychological research of this problem there were works by I.P. Pavlova and V.M. Bekhterev.

Having studied the patterns of dynamics of nervous processes (inhibition, irradiation, concentration, etc.), which determine external manifestations behavior, scientists have identified two levels reflex behavior- unconditioned (simple) and conditioned (or combination) reflexes. Having a biological basis, conditioned reflex is formed on the basis of an innate, unconditional (certain need, for example, for food, protection from harmful influences, etc.), and the body constantly learns to distinguish and differentiate signals. If the signal leads to success, i.e. is reinforced, a connection is formed between it and the body’s response, which becomes stronger with repetition. This is how a conditioned reflex arises and is reinforced.

The orienting reflex discovered by Pavlov, or, as he called it, the “What is it?” reflex was also of great importance. It lies in the fact that the body continually asks this question to the world around it, trying to find out the meaning of the situation in which it finds itself, and in the best possible way“calculate” what is of greatest value to him. Orienting reflex not only helps adaptation in an unfamiliar environment, but is also the biological basis of any cognitive motivation, stimulating interest in unfamiliar, new stimuli.

By studying the biological mechanisms of reflex activity, Bekhterev proved that the flexibility and plasticity of the nervous system makes it possible to change reflexes of any degree of complexity in the desired direction. That is, in the behavior of living beings, inherited reflexes play a minimal role, while the leading one belongs to acquired, conditioned ones.

Chapter 3. Psyche and body 249

QUESTIONS

1. What is the evidence of the connection between individual qualities and the organism of the creature?
Vali in antiquity?

2. How ideas about organic bases changed individually
sti?

3. What is the role of Darwin’s evolutionary theory in the development of psychology?

4. What data on the functioning of the senses were obtained in Muhl’s studies
Lehr and Helmholtz?

5. What is the sensation threshold?

6. What are the differences between absolute and relative thresholds?

7. What is a dominant?

8. What mental processes can be explained by the activity of the dominant?

9. What is the structure of the analyzer in Sechenov’s concept?

10. How Bernstein will be explained complex character behavior?

11.What is a conditioned reflex?

SAMPLE ABSTRACT TOPICS

1. Comparative analysis of the approach to the problem of reflex in the history of psychology.

2. The importance of psychophysiology for psychological science.

3. The organic basis of individuality - from Hippocrates to Eysenck.

4. The theory of dominance, its significance for psychology.

5. The role of reflex theory in development psychological concepts education
and training.

LITERATURE

1.Bernstein N.A. Essay on the physiology of movements and physiology of activity.
M., 1966.

2. Bekhterev V.M. Objective psychology. M., 1991.

3. Galperin P.Ya. Introduction to Psychology. M., 1976.

4. Ibn Son. Canon of medical science. Tashkent, 1954. Book 1.

5. Pavlov I.P. Poly. collection Op.: In 6 vols. M.; L., 1951. T. 3.

6. Rubinshtein S.L. Basics general psychology. M., 1989. T. 1, 2.

7. Sechenov IM. Selected works.: In 2 vols. M., 1958. T. 2.

8. Ukhtomsky A.A. Dominant. L., 1966.

In the article we will talk about the founder of the reflex theory. It is generally accepted that its creators are several people at once, but this is not at all true. The fact is that many scientists made a certain contribution, but today we will look at the specific contribution of Rene Descartes. We will also learn in detail about the provisions of his theory and get acquainted with the biography of the scientist himself.

A little about the topic

The name of Rene Descartes is associated with a very important and difficult period in the development of psychological science. The scientist’s statements served to create a new concept that allowed us to look at the world differently psychological problems. The psyche began to be viewed as the inner world of a person, which is completely amenable to introspection, but at the same time is an absolutely independent substance, separate from the external world.

The essence of Descartes' entire teaching is precisely to prove the complete opposition of the concepts of material and spiritual worlds. The scientist introduced the concept of reflex into use without naming it, and this gave impetus to the fact that people and animals began to be considered from the natural scientific and psychological side, taking into account their relationship.

About the author

Now let’s learn a little about the founder of the reflex theory. Descartes was born in 1596 in France. From his parents he received a small but still significant fortune, which allowed him not to worry about his food and devote himself entirely to science. At the Jesuit college he received a decent education in the humanities and mathematics. Later he excelled in studying psychology, philosophy and physics.

Due to poor health, the college director allowed the young man to skip morning services. Thanks to this, the scientist developed a habit that he retained for the rest of his life - staying in bed until almost noon. At the same time morning hours were the most productive for the thinker.

After training

After René Descartes completed his studies, he hurried to Paris, where he indulged in the amusements of his youth. However, all this superficial fuss quickly became boring. young man, whose thoughts went very far from the present day. That is why very soon he began to lead a more secluded and quiet lifestyle in order to devote free time studying mathematics.

At the age of 21 he became a soldier and spent several years on the front lines in Hungary, Holland and Bavaria. He learned to handle weapons and matured, becoming a bit of an adventurer. The guy really liked to attend various balls and had fun gambling. He was incredibly lucky, largely due to the fact that he was an excellent mathematician. Soon Rene Descartes met his beloved woman, who bore him a beautiful daughter. By for unknown reasons at the age of 5, the baby died, and this greatly shocked Descartes. After that, he always said that the death of his daughter was the most tragic event in his life.

It must be said that the development of reflex theory was directly related to events in the life of the scientist himself. Almost everything he talked about, one way or another, found manifestation in his own life. He was always interested in how all theoretical knowledge could be applied in practice, so he did not lose heart and regularly conducted a wide variety of experiments.

It is known that the man was trying to find a way to prevent his hair from turning gray. He also experimented with a rocking chair. Later, the founder of the reflex theory talked about his dream, which became a real revelation for him. This happened during his military service. He was in a large Bavarian house, which was heated by a powerful stove. The man dozed off and had an amazing dream. He supposedly saw the spirit of truth accusing him of laziness. The Spirit said that the life task of a scientist is to prove the principles of mathematics and their usefulness in the study of nature. Thus, Descartes had a serious mission ahead of him.

Dedication to one thing

After this dream, the scientist served for some time and returned to Paris, but he was again tired of youth life, and he decided to retire to study mathematics. Rene sold his father's estate and bought a small house in Holland. By the way, in just 20 years, Descartes changed about 24 houses, and all because he strived for complete solitude. At the same time, he visited 13 cities, and carefully hid his residential address from his closest friends, with whom he regularly corresponded.

He really disliked unexpected guests and meaningless gatherings. When buying a new house, I always took into account two main points - that there should be a Catholic cathedral nearby, and that a university should be located nearby.

Descartes: reflex theory

The theory of reflexes became the most important discovery XVII century. The concept of a reflex first began to appear in Descartes's writings on physics. It was necessary in order to completely complete the picture of the mechanistic world created by the scientist. And all that was missing from it were the behavioral characteristics of living beings. In this case, it is necessary to take into account the general background of events against which Descartes’ discovery took place. At this time, the body and its functions began to be viewed from a new angle, which gradually led to a complete revolution in the study of the anatomical and physiological nature of man. The final blow to the basic medieval concepts of essence and form was dealt by the discovery of Harvey's blood circulation. That is why it is worth understanding the basic principles of Descartes’ reflex theory as total product of that time, which matured under the most suitable conditions. At the same time, due to the lack of knowledge about the activity of the central nervous system, the reflex theory still did not have such a basic basis. scientific basis, as a theory of blood circulation.

Many compare these two discoveries, and it must be said that Descartes’ contribution is much more significant, since it concerned not any function of the body, but the very process of interaction of living beings with each other.

Beautiful metaphor

The founder of the reflex theory made his discovery precisely thanks to the above-mentioned discovery of Harvey. The fact is that Descartes imagined the interaction of living beings in the form of the reaction of nervous “machines” to each other. He created an association of the nervous system that was similar to the circulatory system.

The heart was the brain, from which various “tubes” branched off, that is, blood vessels. They transmit nerve impulses, which provide a person with information from the outside world. At the same time, according to the movement of blood in the vessels, that is, according to the transmission nerve impulse To nervous system, one can judge a living being and many of its features.

Descartes called impulses “animal spirits” - a very ancient and mystical term that actually meant nothing more than tiny particles, which move quickly in the human body.

Basic provisions

The study of reflexes led the scientist to the fact that he was able to form some basic principles. Firstly, it should be noted that a reflex according to Descartes is an act of the nervous system. At the same time, it must be clearly understood that the scientist did not use the term “reflex” itself, but he outlined it incredibly clearly, and the followers only had to come up with a suitable word, which is what they did. Secondly, the man still considered the activity of animals to be machine-like, while human activity was presented in the form huge amount acts of the nervous system, that is, a complete set of certain reflexes. To explain his thoughts more clearly, Rene compared the nervous process with thermal and light phenomena, and such comparisons have been encountered since ancient times.

Reflex theory and physiology turned out to be very connected, because knowledge about the soul and its properties, as it later became clear, was largely based on new discoveries in physics, especially in the field of optics. The studies of Ibn al-Haytham and R. Bacon showed how much the sphere of sensations depends not only on the soul, but also on the laws of physics. Based on this, we can conclude that the founder of the reflex theory created his discovery on the basis of modern knowledge of physics and mechanics. The isolated understanding of the soul disappeared, but a clear understanding of its inseparability from physiology appeared.

Descartes considered the first cause of a motor act to be a certain nerve impulse, the cause of which lay outside himself. Thus, the body receives a signal from the outside world, which is transmitted via nerve fibers into the brain. At the same time, the scientist did not deny the disposition of organs and even recognized it as a basic necessity.

Despite the fact that a fixed system of nerves and muscles was recognized, it was still subject to change. Descartes believed that with each new impulse the nerve “threads” do not acquire their old uniform, but stretch and change their configuration.

And what after?

The followers of Descartes, studying examples of conditioned reflexes, no longer doubted that explaining the activity of the soul, that is, the nervous system, in terms of some invisible forces, is as pointless as explaining the work mechanical forces the action of superpowers.

Rene formed a methodological rule, which is that what a person experiences applies only to himself and directly to his body. This means that everyone can feel and see the whole picture of the world in their own way, and in many ways it is based on physiology, that is, on how impulses are transmitted and interpreted by the nervous system.

Conditioned reflexes, examples of which are still remembered in schools, are nothing more than an individual and acquired over time basic set of the person himself, that is, it is not applicable to other people and their model of the world. And conditioned reflexes are pure physiology, which at the same time has a decisive influence on the nervous system.

Behavior modeling

Having come to his conclusions, the scientist realized that human behavior can be controlled and modeled. Almost all body systems lend themselves to creating reflexes. Descartes emphasized that only speech and intelligence can not be modeled. Thus, the researcher tried to explain the process of learning, which is why he is considered one of the predecessors of associationism.

Descartes believed that the importance of this knowledge lies in the fact that it enables a person to control his passions. After all, if you can teach this to animals that have a brain but no mind, then even more so can people, who can program themselves and change their attitudes, succumb to this.

Sechenov

Below we will consider the principles of the reflex theory of Sechenov and Pavlov. The views of I. Sechenov were formed by the middle of the last century. He studied the functioning of the brain and came to the conclusion that nervous activity is provoked not by the soul, but by environmental factors. The scientist was able to show that the psyche is not something original and given, but only a property of the brain that can be consciously changed.

Ivan Pavlov

The views of I. Pavlov were formed under the influence of I. Sechenov. Man for a long time studied the functioning of the brain, and later became the discoverer of conditioned reflexes. Brain activity was considered as a result of the functionality of the cortex. Thanks to a series of experiments on people and animals, he was able to show that the basis of any mental processes is reflexes. The scientist’s research later made it possible to create a classification of people by character, but initially it was a classification by the type of activity of the nervous system. I. Pavlov identified an unbalanced type, a balanced type with active nervous processes, a balanced type with low activity of nervous processes, and a weak type, in which excitatory and inhibitory processes were equally weak. Based on this knowledge, each person can now determine his strengths and weaknesses, learn to manage his reactions and, thus, decisively change his entire life.

By the way, everyone modern theories about attracting the Universe to fulfill desires, the power of positive thinking, etc. are based, as you already guessed, on reflexes.

It is almost impossible to unequivocally answer the question of who is the founder of the reflex theory. Descartes undoubtedly laid its foundations, but further development took place thanks to a number of outstanding scientists.

Introduction

Human interaction with reality is carried out through the nervous system.

The human nervous system consists of three sections: the central, peripheral and autonomic nervous systems. The nervous system functions as a single and integral system.

The complex, self-regulating activity of the human nervous system is carried out due to the reflex nature of this activity.

This work will reveal the concept of “reflex”, its role and significance in the body.

Reflex theory and its basic principles

The provisions of the reflex theory developed by I.M. Sechenov. I. P. Pavlov and developed by N. E. Vvedensky. A. A. Ukhtomsky. V. M. Bekhterev, P. K. Anokhin and other physiologists are the scientific and theoretical basis of Soviet physiology and psychology. These provisions find their creative development in the research of Soviet physiologists and psychologists.

The reflex theory, which recognizes the reflex nature of the activity of the nervous system, is based on three main principles:

1) the principle of materialistic determinism;

2) the principle of structure;

3) the principle of analysis and synthesis.

The principle of materialistic determinism means that each nervous process in the brain is determined (caused) by the action of certain stimuli.

The principle of structure is that the differences in the functions of different parts of the nervous system depend on the characteristics of their structure, and changes in the structure of parts of the nervous system during development are determined by changes in functions. Thus, in animals that do not have a brain, the higher nervous activity is much more primitive compared to the higher nervous activity of animals that have a brain. In a person during historical development the brain has reached especially complex structure and perfection that is associated with it labor activity and social living conditions that require constant verbal communication.

Principle of analysis and synthesis is expressed as follows. When centripetal impulses enter the central nervous system, excitation occurs in some neurons, and inhibition occurs in others, i.e., physiological analysis occurs. The result is the distinction between specific objects and phenomena of reality and processes occurring inside the body.

At the same time, during the formation of a conditioned reflex, a temporary nervous connection (closure) is established between two foci of excitation, which physiologically expresses synthesis. The conditioned reflex is the unity of analysis and synthesis.

Reflex - concept, its role and significance in the body

Reflexes (from the Latin slot reflexus - reflected) are the body's responses to receptor irritation. Nerve impulses arise in the receptors, which enter the central nervous system via sensory (centripetal) neurons. There, the received information is processed by intercalary neurons, after which motor (centrifugal) neurons are excited and nerve impulses activate the executive organs - muscles or glands. Intercalary neurons are those whose bodies and processes do not extend beyond the central nervous system. The path along which nerve impulses travel from the receptor to the executive organ is called a reflex arc.

Reflex actions are holistic actions aimed at satisfying a specific need for food, water, safety, etc. They contribute to the survival of an individual or species as a whole. They are classified into food, water-producing, defensive, sexual, orientation, nest-building, etc. There are reflexes that establish a certain order (hierarchy) in a herd or flock, and territorial ones, which determine the territory captured by a particular individual or flock.

There are positive reflexes, when a stimulus causes a certain activity, and negative, inhibitory reflexes, when the activity stops. The latter, for example, includes the passive defensive reflex in animals, when they freeze when a predator appears or an unfamiliar sound.

Reflexes play an exceptional role in maintaining constancy internal environment body, its homeostasis. So, for example, when increasing blood pressure a reflex slowdown of cardiac activity occurs and the lumen of the arteries expands, so the pressure decreases. When it drops strongly, opposite reflexes arise, strengthening and speeding up the contractions of the heart and narrowing the lumen of the arteries, as a result of which the pressure increases. It continuously fluctuates around a certain constant value, which is called the physiological constant. This value is determined genetically.

The famous Soviet physiologist P.K. Anokhin showed that the actions of animals and humans are determined by their needs. For example, the lack of water in the body is first replenished from internal reserves. Reflexes arise that delay the loss of water in the kidneys, the absorption of water from the intestines increases, etc. If this does not lead to the desired result, in the centers of the brain that regulate the flow of water, excitement arises and a feeling of thirst appears. This arousal causes goal-directed behavior, the search for water. Thanks to direct connections, nerve impulses going from the brain to the executive organs are provided necessary actions(the animal finds and drinks water), and thanks to feedback connections, nerve impulses going in the opposite direction - from peripheral organs: oral cavity and the stomach - to the brain, informing the latter about the results of the action. Thus, during drinking, the center of water saturation is excited, and when thirst is satisfied, the corresponding center is inhibited. This is how the controlling function of the central nervous system is carried out.

A great achievement in physiology was the discovery of conditioned reflexes by I. P. Pavlov.

Unconditioned reflexes are innate, inherited reactions by the body to environmental influences. Unconditioned reflexes are characterized by constancy and do not depend on learning and special conditions for their occurrence. For example, the body responds to painful stimulation with a defensive reaction. There is great diversity unconditioned reflexes: defensive, food, orientation, sexual, etc.

The reactions underlying unconditioned reflexes in animals have been developed over thousands of years in the course of adaptation various types animals to environment, in the process of struggle for existence. Gradually, under the conditions of long-term evolution, the unconditional reflex reactions necessary to satisfy biological needs and preserve the vital functions of the organism were consolidated and passed on by inheritance, and those of the unconditional reflex reactions that lost their value for the life of the organism, lost their expediency, on the contrary, disappeared, without recovering.

Under the influence of constant changes in the environment, stronger and more advanced forms of animal response were required, ensuring the organism’s adaptation to changed living conditions. In the process of individual development, highly organized animals develop special kind reflexes, which I. P. Pavlov called conditioned.

Conditioned reflexes acquired by an organism during life provide an appropriate response of a living organism to changes in the environment and, on this basis, balance the organism with the environment. Unlike unconditioned reflexes, which are usually carried out by the lower parts of the central nervous system (dorsal, medulla oblongata, subcortical nodes), conditioned reflexes in highly organized animals and in humans are carried out mainly by the higher department of the central nervous system (cortex cerebral hemispheres brain).

Observing the phenomenon of “psychic secretion” in a dog helped I.P. Pavlov discover a conditioned reflex. The animal, seeing food from a distance, began to salivate intensively even before the food was served. This fact has been interpreted in different ways. The essence of “psychic secretion” was explained by I. P. Pavlov. He found that, firstly, in order for a dog to start salivating at the sight of meat, it had to have seen and eaten it at least once before. And, secondly, any irritant (for example, the type of food, a bell, the blinking of a light bulb, etc.) can cause salivation, provided that the time of action of this irritant coincides with the time of feeding. If, for example, feeding was constantly preceded by the knocking of a cup containing food, then there always came a moment when the dog began to salivate just by knocking. Reactions that are caused by stimuli that were previously indifferent. I. P. Pavlov called them conditioned reflex. The conditioned reflex, noted I.P. Pavlov, is a physiological phenomenon, since it is associated with the activity of the central nervous system, and at the same time, psychological, since it is a reflection in the brain of specific properties of stimuli from the outside world.

Conditioned reflexes in animals in the experiments of I.P. Pavlov were most often developed on the basis of an unconditioned food reflex, when food served as an unconditioned stimulus, and the function of a conditioned stimulus was performed by one of the stimuli that were indifferent (indifferent) to food (light, sound, etc. .).

There are natural conditioned stimuli, which serve as one of the signs of unconditioned stimuli (the smell of food, the squeak of a chicken for a hen, causing a parental conditioned reflex in her, the squeak of a mouse for a cat, etc.), and artificial conditioned stimuli, which are completely unrelated to unconditioned reflex stimuli (for example, a light bulb, the light of which caused a dog to develop a salivary reflex, the ringing of a gong, to which moose gather for feeding, etc.). However, any conditioned reflex has a signal value, and if the conditioned stimulus loses it, then the conditioned reflex gradually fades away.

The main mechanism of the central nervous system activity is the reflex. Reflex is response the body to the action of a stimulus, carried out with the participation of the central nervous system and aimed at achieving a useful result.

Reflex translated from Latin language means "reflection". The term “reflection” or “reflection” was first used by R. Descartes (1595-1650) to characterize the body’s reactions in response to irritation of the senses. He was the first to express the idea that all manifestations of the effector activity of the body are caused by very real physical factors. After R. Descartes, the idea of ​​reflex was developed by the Czech researcher T. Prochazka, who developed the doctrine of reflective actions. At this time, it was already noted that in spinal animals, movements occur in response to irritation of certain areas of the skin, and destruction of the spinal cord leads to their disappearance.

Further development reflex theory is associated with the name of I.M. Sechenov. In the book “Reflexes of the Brain,” he argued that all acts of unconscious and conscious life are reflexes by nature of origin. This was a brilliant attempt to introduce physiological analysis into mental processes. But at that time there were no methods for objectively assessing brain activity that could confirm this assumption of I.M. Sechenov. This objective method was developed by I.P. Pavlov - conditioned reflex method, with with the help of which he proved that the higher nervous activity of the body, like the lower, is reflex.

The structural basis of the reflex, its material substrate ( morphological basis) is reflex arc - a set of morphological structures that ensures the implementation of a reflex (the path along which excitation passes during the implementation of a reflex).

The basis of the modern idea of reflex activity lies the concept useful adaptive result, for the sake of which any reflex is performed. Information about the achievement of a useful adaptive result enters the central nervous system through the feedback link in the form reverse afferentation, which is an obligatory component of reflex activity. The principle of reverse afferentation was introduced into the reflex theory by P.K. Anokhin. Thus, according to modern ideas the structural basis of the reflex is not the reflex arc, but reflex ring, consisting of the following components (links):

Receptor;

Afferent neural pathway;

Nerve center;

Efferent nerve pathway;

Working body (effector);

Reverse afferentation (Fig. 8).

Rice. 8. Diagram of the morphological structures of somatic (left) and vegetative (right) reflexes. 1 - receptor; 2 - afferent nerve pathway; 3 - nerve center; 4 - efferent nerve pathway; 5 - working body (effector); 6 - reverse afferentation

Analysis of the structural basis of the reflex is carried out by sequentially turning off individual links of the reflex ring (receptor, afferent and efferent pathways, nerve center). When any link of the reflex ring is turned off, the reflex disappears. Consequently, for the reflex to occur, the integrity of all links of its morphological basis is necessary.

The cells of the central nervous system have numerous connections with each other, so the human nervous system can be represented as a system of neural circuits (neural networks) that transmit excitation and form inhibition. In this neural network, excitation can spread from one neuron to many other neurons. The process of excitation spreading from one neuron to many other neurons is called irradiation of excitation or the divergent principle of excitation propagation. There are two types of excitation irradiation:

directed or systemic irradiation, when excitation spreads through a certain system of neurons and forms the coordinated adaptive activity of the body;

unsystematic or diffuse(non-directional) irradiation, chaotic spread of excitation, in which coordinated activity is impossible (Fig. 9).

Rice. 9. Scheme of the phenomenon of convergence (A) and divergence (irradiation) (B) of excitation in the central nervous system.

In the central nervous system, excitations from various sources can converge on one neuron. This ability of excitations to converge to the same intermediate and final neurons is called convergence of excitations(Fig.9).

Belarusian State Pedagogical University named after Maxim Tank

Faculty of Psychology

USRS№3
in behavioral physiology
topic: Reflex theory. The concept of reflex.

Completed:
Mishulkova Anastasia
Pavlovna
1st year, 15th group
Checked:
Pokrovskaya S.E.

Minsk 2010

Reflex theory. The concept of reflex.
Psychophysiological concept of reflex (I.M. Sechenov).
The doctrine of conditioned reflexes (I.P. Pavlov).

5. The doctrine of the dominant as the leading factor in the organization of behavior

1. Reflex theory. The concept of reflex.
Reflex translated from Latin means turned back reflected. Reflexes are reactions of the body carried out by the nervous system in response to the influence of external or internal stimuli (Biological Encyclopedic Dictionary 1989).
The concept of a reflex arose in the 17th century in the teachings of the French philosopher and naturalist Rene Descartes (1596-1650), although the term “reflex” itself was introduced later by the Czech anatomist and physiologist Jiri Prochazka (1749-1820).
The concept of reflex developed by Rene Descartes was called mechanical. R. Descartes modeled nervous processes on the circulatory system, using the principles of optics and mechanics that existed at that time. By reflex, he understood the movement of “animal spirits” from the brain to the muscles according to the type of reflection of a light beam. “Animal spirits” Descartes designated the flows of the lightest and most mobile particles of blood, which, filtered from the rest, rise to the brain. According to the scheme of nerve impulse transmission proposed by Descartes, external objects act on the peripheral endings of the nerve “threads” located inside the “nerve tubes.” By stretching, the “threads” open the valves of the holes leading from the brain to the nerves. Through the channels of these nerves, “animal spirits move into the corresponding muscles, which as a result swell, and thus movement occurs.
The behavior of animals and the involuntary movements of humans were natural according to Descartes, i.e. a reflex response to some event in the outside world. The body was freed from the soul for the first time. This allowed Descartes to call animals soulless mechanisms, machines. In contrast, only man has the capacity for conscious voluntary behavior, for which the soul is responsible. And here R. Descartes remained in the position of idealism. He considered human consciousness as a substantial principle capable of interacting with the body and influencing through the cerebral pineal gland (in modern anatomy - the pineal gland) on bodily processes subject to reflex laws. Body and consciousness (“rational soul”) for Descartes are independent substances (Batuev, 1991. Sokolova, 1995 Yaroshevsky 1998).
Further development of the reflex foundations of a behavioral act is reflected in the following concepts:

1. The doctrine of nervous vibrations by D. Hartley
Biological concept of the reflex I Prohaska.
Anatomical concept of the reflex (C Bell and F Magendie, M Hall and I Muller).
Psychophysiological concept of reflex IM Sechenov.
The concept of the conditioned reflex I P Pavlov
Reflexology V M Bekhterev
Dialectical concept of A A Ukhtomsky

2. Psychophysiological concept of the reflex by I. MSechenov
Russian physiologist and psychologist Ivan Mikhailovich Sechenov (1829-1905) developed a natural science theory of mental regulation of behavior. The concept of the reflex nature of nervous activity underwent significant changes in him. Reflex was defined as “a holistic act with its average intracerebral link and extracerebral somatic periphery connecting the body with object" (Sechenov, 1952) Reflex, therefore, was understood by him as a universal and unique form of interaction of the organism with the environment. For the first time, the inseparability of mental processes from the brain and at the same time the conditioning of the psyche by the external world was shown. All mental acts, according to I.M. Sechenov, according to the method origin and mechanism of execution are reflexes.
The main provisions of the reflex concept are as follows:
The reflex principle covers the functions of all hierarchical levels of the psyche. The psychophysiological basis of mental phenomena is formed by processes that, in their origin and method of implementation, represent a particular form of reflex acts. An integral reflex act with its peripheral beginning, center and peripheral final link further constitutes an indivisible functional unit of the substrate of mental processes. In the structure of a reflex act as an integral unit, nervous and neuropsychic components are united by a common functional principle. They play the role of regulatory signals in relation to the executive level. Reflexes of different levels of complexity correspond to regulatory signals that are different in structure and subject content (Sechenov. 1952).Opening by I.M. Sechenov in 1862, central inhibition was the first step towards his creation of a new physiology of the brain. Activity nerve centers is now thought of as a continuous dynamics of excitation and inhibition. According to M.G. Yaroshevsky, the most important achievement of Russian scientific thought was the transition to a new strategy for explaining psychophysiological correlations. The meaning of the transition, he notes, determined the refusal to localize “immaterial” consciousness in the material substance of the brain and the transfer of the analysis of a psychophysiological problem to a fundamentally new plan, namely, to a research plan behavior of an entire organism in the natural and social environment “in relation to humans” The pioneer of such reorientation was I.M. Sechenov (Yaroshevsky, 1998).
3. The doctrine of conditioned reflexes (I.P. Pavlov)
I. P. Pavlov, studying conditioned reflexes and their relationships, observed inhibition (suppression) of conditioned reflexes under the influence of extraneous or strong stimuli, as well as weak ones - during a painful state of the body. He believed that the balance between excitation and inhibition determines the external manifestation of the behavior of animals and humans, and put forward his own scheme classification of types of braking during conditioned reflex activity.
External (unconditional) inhibition. Under external braking understand the urgent suppression of current conditioned reflex activity under the influence of stimuli foreign to it, causing an indicative or some other unconditioned reflex. According to the mechanism of its occurrence, this type of inhibition is classified as congenital, which are carried out due to the phenomena of negative induction (induction braking, according to Pavlov). A. A. Ukhtomsky called him associated inhibition and saw in it the physiological basis for performing the dominant form of activity of the body. Unconditioned inhibition is called external because the reason for its occurrence lies outside the structure of the inhibitory reflex itself.
Orienting reflex- the most common factor of unconditional inhibition. However, the inhibitory effect of the orienting reflex, when the same signal is repeated, gradually weakens and may disappear completely. At the same time, the orientation reflex itself ceases to be observed. Orienting reflex (what's happened?) arises for a more complete perception of information contained in an unexpected and extraneous stimulus.
In everyday life, it is constantly observed how a person stops his current activity as a result of switching his attention to a new, suddenly appeared stimulus. At the moment of occurrence of this reflex, conjugate inhibition of competing reflexes appears. It can be more or less deep, short-term or longer, which depends on the physiological strength of the orienting and inhibitory reflexes. With repeated stimulation, due to habituation, the orienting reflex disappears, and the effect of external inhibition also decreases. This type of braking was called fading brake.
Another type of unconditioned inhibition is distinguished by the constancy of its effect on a particular inhibited reflex and is therefore called permanent brake. The stability of external inhibition is determined, in particular, by the physiological strength of the inhibitory reflex act. Reflexes that are vital for the body include defensive unconditioned reflexes to various harmful stimuli, including pain. As in the case of a fading brake, the duration of a permanent brake on the defensive reflex is determined by its strength and the nature of the reflex being inhibited and, in particular, the degree of its strengthening.
“Young” conditioned reflexes are inhibited more easily and by more long term, the more “old”, under the same conditions. Unstable behavioral skills or knowledge disappear more easily under strong unpleasant outside influences than more firmly learned life stereotypes. Painful effects from internal organs have a longer inhibitory effect on conditioned reflex activity. And sometimes their power is so great that it distorts the normal flow of even unconditioned reflexes.
Consequently, two antagonistic reflexes - food and defensive - cannot coexist the weaker one is inhibited by the influence of the stronger one.
In this regard, Pavlovian external inhibition acts as a subtle tool capable of highlighting the most biologically significant form of behavior, subordinating all other types of activity to it. From the standpoint of the doctrine of the dominant, this can be considered as a conjugate inhibition under the dominant, which plays a decisive role in its formation. And this inhibition must be timely, i.e., have a coordinating significance for the work of other organs and the body as a whole.
It is well known that if you increase the intensity of any irritation, the effect it causes increases (law of force). However, further increase in irritation will lead to a decrease or complete disappearance of the effect. The basis for this result is not fatigue, but extreme braking, which I.P. Pavlov called protective, since it protects brain cells from excessive consumption of energy resources. This type of inhibition depends on the functional state of the nervous system, age, typological characteristics, hormonal conditions, etc.
The endurance limit of a cell against stimuli of varying intensity is called the limit of its performance, and the higher this limit, the easier the cell tolerates the action of super-strong stimuli. Moreover, we are talking not only about the physical, but also about the informational power (significance) of conditioned signals.
An extreme case of extreme inhibition is numbness, which occurs in animals and humans under the influence of extreme stimulation. A person may fall into a state stupor - full immobility. Such conditions arise not only as a result of the action of a physically strong stimulus (a bomb explosion, for example), but also as a result of severe moral shocks (for example, an unexpected message about a serious illness or death of a loved one).
Internal (conditioned) inhibition. To the form internal braking conditioned reflex activity includes those cases when the conditioned stimulus ceases to be reinforced by the unconditioned, i.e., gradually loses its triggering signal value. Such inhibition does not occur urgently, not immediately, but develops slowly according to the general laws of the conditioned reflex and is equally changeable and dynamic. That's why I. P. Pavlov named him conditioned inhibition. He believed that such developed inhibition occurs within the central nervous structures of the conditioned reflexes themselves, and hence its name - internal(i.e. not externally induced, not inductive).
Let's highlight main features conditioned inhibition. 1. It develops when stimuli are not reinforced, which gradually acquire the properties of a conditioned inhibitory or negative signal. 2. Conditioned inhibition can be trained. An inhibited conditioned reflex can spontaneously recover, and this property is extremely important when developing behavioral skills at an early age. 3. The ability for various manifestations of conditioned inhibition depends on the individual properties of the nervous system: in excitable individuals it is more difficult and slower to develop. 4. Conditioned inhibition depends on the physiological strength of the unconditioned reflex, which reinforces the positive conditioned signal. 5. Conditioned inhibition depends on the strength of the previously developed conditioned reflex. 6. Conditioned inhibition can interact with unconditioned inhibition, in these cases the phenomenon occurs disinhibition, and sometimes, as a result of the summation of conditioned and unconditioned inhibition, their overall effect may increase. I. P. Pavlov divided conditioned inhibition into four types: extinction, differentiation, conditioned inhibition, delay inhibition.
Extinction inhibition develops in the absence of reinforcement of the conditioned signal by the unconditioned. Conditioned reflexes are temporary precisely because when unconditional reinforcement is canceled, the corresponding brain connection loses its strength, is sometimes inhibited for a long time, and sometimes ceases to exist altogether.
Let us imagine that the appearance of a certain area is constantly combined in an animal with the receipt of food. But if food resources have disappeared here, the animal eventually, having not found food, stops visiting the previously familiar area due to the development of extinctive inhibition. The magnitude and speed of development of extinction inhibition depend on the strength of the conditioned reflex (stable reflexes are extinguished more slowly), on the physiological strength and type of the unconditioned reflex (extinction in a hungry dog ​​is more difficult than in a well-fed one; food conditioned reflexes are extinguished faster than defensive ones), on the frequency of non-reinforcement ( regular non-reinforcement contributes to the rapid development of inhibition). It develops in waves and depends on individual typological differences.
Differential braking develops when stimuli that are similar in properties to the reinforced signal are not reinforced. This type of inhibition underlies the discrimination of stimuli. With the help of differential inhibition, from the mass of similar stimuli, one is singled out that will respond to one reinforced, i.e., biologically important for it, and to other similar stimuli the conditioned reaction will be less pronounced or absent completely.
Property generalization(primary generalization) conditioned reflexes are an inevitable attribute of behavioral adaptations of animals in their natural habitat. Considering that the variability of the environment occurs according to a probabilistic law and fluctuations of certain biologically significant signs cannot be predicted with high probability, significant sensory generalization of conditioned reflexes as a stage of an active search for vital objects becomes biologically justified.
At the stage of generalization of conditioned reflexes, it is revealed dominant mechanism, one of the characteristic features of which is the ability of the reflex system to diffusely respond to a wide repertoire of external stimuli. In the process of repeated implementation of this reflex act, diffuse responsiveness is replaced by a selective response only to those irritations that primarily created this dominant. The stage of specialization of the dominant occurs due to the mechanisms of differential inhibition.
The latter has the following basic properties: 1) the closer the differentiated stimuli are, the more difficult it is to develop differential inhibition in response to one of them; 2) the degree of inhibition is determined by the strength of excitation developed by the positive conditioned reflex; 3) the development of this inhibition occurs in waves; 4) differential inhibition is trainable, which underlies the subtle recognition of sensory environmental factors.
I. P. Pavlov identified as an independent type of conditioned inhibition conditional brake, which is formed when a combination of a positive conditioned signal and an indifferent stimulus is not reinforced. For example, a dog has formed a conditioned food reflex to sound. If the light of a light bulb is added to this signal and their combined action is not reinforced with food, then after several uses this combination will cease to cause a food reaction, although the isolated use of the bell will still cause profuse salivation. Essentially, this is a variant of differential braking.
The incremental stimulus at the first moment of its application in combination with a positive signal causes an orienting reflex and inhibition of the conditioned reaction (external inhibition), then turns into an indifferent stimulus (fading brake), and finally, in place of unconditioned inhibition, a conditioned inhibition develops. If the additional stimulus has acquired these properties, then, being attached to any other positive signal, it will inhibit the conditioned reflex corresponding to this signal.
During production braking lag reinforcement by the corresponding unconditioned reflex is not canceled, as in previous types of inhibition, but is significantly delayed from the beginning of the action of the conditioned stimulus. Only the last period of action of the conditioned signal is reinforced, and the significant period of its action preceding it is deprived of reinforcement. It is this period that is accompanied by inhibition of retardation and is called inactive phase of a delayed conditioned reflex. After its expiration, inhibition stops and is replaced by excitation - the so-called active phase of the reflex. In this case, two stimuli act in combination and the second component is time.
In experiments with food conditioned reflexes, the delay of reinforcement from the beginning of the conditioned signal can reach 2-3 minutes. and for electrical defense - 30-60 s. The adaptive value of inhibition of delay consists in a subtle analysis of the time of delay of the stimulus; the positive phase of the reflex is timed to coincide with the launch of the unconditioned reflex. For example, a cat waiting for prey at a mouse hole does not show salivation until the mouse is in its teeth.
Close interaction different types conditioned inhibition, especially conditioned and unconditioned inhibition, as well as the possibility of developing conditioned inhibition on the basis of unconditional inhibition are convincing grounds for the assumption of their common physiological nature.

Dialectical concept of reflex (A.A. Ukhtomsky).

Dialectical concept of reflex. A. A. Ukhtomsky (1875-1942) owes the theoretical and physiological merit, which consists in the in-depth further development of the principle of determinism in the reflex theory.
The dialectical nature of A. A. Ukhtomsky’s thinking was clearly demonstrated in his understanding of the essence of the reflex. Seeing in the reflex a mechanism of activity, he saw in the reflex act the unity of internal and external determinants, and the internal determinants are ultimately also given and determined by external conditions.
A. A. Ukhtomsky emphasized that “... a reflex is a reaction that is motivated quite clearly by the current situation or environment. This, however, does not destroy the spontaneous action of the substrate, it only puts it within certain boundaries in its opposition to environmental factors, and from this it becomes more defined in content and meaning. The reflex is not depicted as a purely passive movement of a bone ball under the influence of an external blow it receives; This is how the reflex could be depicted while it was necessary to emphasize in particular its motivation from the environment. But in its entirety, it seems to be a meeting in time of two conditions: on the one hand, the activity prepared or formed in the substrate (cell) itself during its previous history, and, on the other hand, the external impulses of the currentmoment."
Consequently, internal determinants are the accumulated history of the interaction of a reacting substrate with an environmental factor (the principle of historicism).
Both in origin and in the conditions of manifestation, internal determinants are ultimately determined by environmental factors, that is, they have only relative independence. The external acts as a complex of conditions for the existence of the internal. This means that the environment of an organism is not the entire physical world surrounding it, but only that small part of it, the elements of which are biologically significant for the organism. But for an organism, only such external things are of biological interest that can become part of life experience, that is, part of the internal ones, or contribute to the transformation of certain external factors into internal ones.
Modern theory of behavior has moved far from simple Cartesian schemes. The introduction of the principle of historicism allows us to understand biological adequacy, that is, the appropriateness of the body's reactions to environmental influences. The Cartesian worldview is based on rigid unambiguous causality (hard determinism of Laplace); the recognition of real contradictions is alien to it. A. A. Ukhtomsky shows that real behavior requires recognition of the existence of contradictions as a continuous attribute of the development process, as the driving forces for constructing behavior.
The historical approach allowed A. A. Ukhtomsky to identify the actual role and evaluate the significance of the conditioned reflex in the evolution of the animal world, as well as to reveal one of the cardinal properties of the conditioned stimulus - its transformation from indifferent to an “obligatory” component of the environment. Such a learned stimulus begins to evoke a new reaction. As a result of such assimilation, the body determined and recorded its attitude to this stimulus - determined its biological significance for itself.
Considering the system of reflexes in the evolutionary series, A. A. Ukhtomsky writes: “... a simple reflex of classical physiology is not initial and fundamentally general type reflex activity of centers, over which a special area of ​​conditioned reflexes specializes, but on the contrary, is a particular special and late product of reduction and simplification of the conditioned reflex, which now becomes a general type of activity of the central nervous apparatus.”
The individual adaptation of an individual with the help of conditioned reflexes serves as a kind of compass - a guideline for solving the problems of the species. Natural selection fixes those mutational acquisitions that correspond to the findings of the individual. Thus, individual adaptation comes ahead of evolutionary genetic rearrangements. The principles of historicism and the relationship between reactivity and activity in holistic behavior as a way of resolving contradictions, brought into physiology by A. A. Ukhtomsky, significantly enriched the reflex theory, which finally got rid of the dualism and mechanism of the Cartesian sense, taking a solid dialectical position
5. The doctrine of the dominant as the leading factor in the organization of behavior
A. A. Ukhtomsky put forward the principle of dominance as the basis for the emerging coordination relationships. He actively relied on the ideas of C. Sherrington about the convergence of afferent influences to the devices that form common pathways in the central nervous system. But only N. E. Vvedensky’s ideas about the dynamism of relationships in the nervous system, conditioned by the nature of the influence, the functional state of the nerve centers and the characteristics of the working organ, made it possible to formulate the doctrine of the dominant - the working principle of nervous activity and the vector of behavior.
The dominant, as the hidden pre-preparedness of the organism to perform a specific behavior, determines the likelihood of a particular reflex reaction (conditioned or unconditioned) in response to the current irritation.
Even I.M. Sechenov drew attention to the fact that irradiation of excitation occurs towards foci of increased excitability. The determining role in the formation of such a focus, according to Ukhtomsky, is played by the state of the developing in it stationary excitation. If this level of excitation is low, then the nervous influences coming here can raise it to a state characteristic of the dominant, that is, create increased excitability in it. If the level of excitation in the center is already high, then when a new wave of excitation arrives, an inhibition effect occurs.
Important features of the dominant focus are increased excitability, i.e. responsiveness to incoming waves of excitation, and the ability of the center to summarize these excitations. In the dominant focus, a certain level of stationary excitation is established, which contributes to the summation of previously subthreshold excitations and the transfer to a rhythm of work that is optimal for the given conditions, when this focus becomes the most responsive.
Consequently, the dominant, before becoming dominant, must go through the stage of the summation reflex. At the same time, the conditioned reflex, before becoming such, goes through the dominant stage (II stage of generalized, diffuse responsiveness).
An important role in the process of dominant formation is played by the process coupled inhibition. The state of excitation in the center, reinforced by excitations from the most distant sources, being quite stable, i.e. inert, in turn reduces the ability of some other centers to respond to impulses that are directly related to them. Conjugate inhibition must be timely, i.e., have a coordinating significance for the work of other organs and the organism as a whole. This is the most energy-intensive process, the most subtle, developed later and at the same time the most vulnerable.
The process of inhibition not only formalizes and supports the dominant, but can also lead to the cessation of its functioning, that is, the dominant itself can be inhibited. A. A. Ukhtomsky identified four cases inhibition of the dominant: 1) if the dominant is a chain reflex, then the resolving act will be the end of the dominant (for example, sexual behavior); 2) the emergence in the centers of a new dominant, incompatible with the first, leads to its inhibition (defensive behavior inhibits feeding); 3) direct inhibition of the dominant is possible through volitional means, i.e., from the cerebral cortex (suppression of natural physiological needs in inadequate conditions); 4) persistent reinforcement of the dominant by extraneous impulses can in itself prepare for its inhibition (the dominant carries its end within itself, having the ability to disinhibit).
Plays an important role in the existence of a dominant time factor. It is on the duration of functional shifts in the centers that such properties of the dominant as stability, inertia, and the ability to summarize are based. The dominant relies on the presence of a certain set of optimal stimuli, but mainly on trace processes, which distinguish it from conditioned and unconditioned reflexes (private short reflexes, according to Ukhtomsky).
Complex reflex acts are carried out not by one anatomical center, but by several, which seem to form a kind of functional constellation of centers in the work of the entire brain. Each participant in this constellation, being connected with its neighbors and stimulating them, in turn receives stimulation from them. This condition was called symptom complex of the dominant.
The primary focus of excitation during the formation of natural biological dominants (hunger, thirst) occurs in the structures of the hypothalamus, which contain a large number of specific chemoreceptor neurons. This focus acts as the most important system-forming factor in the formation of a dominant constellation, which includes many secondary foci in those parts of the brain where there are prerequisites for long-term retention of trace processes (hippocampus, cerebral cortex).
To understand the mechanisms of transformation of a dominant from a symptom complex, A. A. Ukhtomsky used the concept functional center, or organ. This emphasized the following: the point is not so much that in the nervous system there are certain constellations of interconnected centers, morphologically widely scattered throughout the brain mass, but also that they are functionally united by the unity of actions, their vector orientation towards a certain result.
Unlike a technical mechanism, such a functional organ is formed during the course of the reaction itself and has many degrees of freedom, giving it the opportunity to carry out many variable operations. The unity of their action is achieved by the ability of a given set of brain structures to influence each other from the point of view mastering the rhythm, i.e. synchronizing their activity. Each of the potential components of the constellation initially has its own specific tempo and rhythm of excitations, but in the formation of a single constellation as a constellation of consonantly working ganglion areas that co-excite each other, the determining role is played by the timing, speed and rhythm of the action, i.e. in the timing of the execution of individual moments of reaction. The dominance of a given constellation will depend both on the synchronization of the activity of its constituent components and on the associated inhibition of other reflexes.
In its formation, the working constellation
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