The physiological basis of sensations is activity. III

State budgetary educational institution

Higher professional education

"Yaroslavl State Medical Academy"

Ministry of Health of the Russian Federation

Department of Pedagogy and Psychology with EITI course

COGNITIVE MENTAL PROCESSES

(SENSATION, PERCEPTION, ATTENTION, MEMORY, THINKING, IMAGINATION)

Textbook for 1st year students of medical, pediatric, dental, pharmaceutical faculties

Yaroslavl

UDC 15

Vasilyeva L.N., senior teacher of the department of pedagogy and psychology with the EITI course of the Yaroslavl State Medical Academy, candidate of psychological sciences, Misiyuk Yu.V., senior teacher of the department of pedagogy and psychology with the EITI course of the Yaroslavl State Medical Academy, Odintsova O.Yu., Lecturer at the Department of Pedagogy and Psychology with the EITI course at the Yaroslavl State Medical Academy.

Reviewer:

Baraboshin Alexander Timofeevich, head of the course of the Department of Pedagogy and Psychology with the EITI course of the Yaroslavl State Medical Academy, associate professor, candidate of medical sciences.

Cognitive mental processes (sensation, perception, attention, memory, imagination). Yaroslavl, Yaroslavl State Medical Academy, 2013, 60 p.

Mental processes: sensation, perception, attention, memory, imagination in real life are inseparable and inextricably linked and influence successful activity. It is cognitive mental processes that provide a person with knowledge about the world around him and about himself. The textbook reveals the concept, properties, types and main characteristics of cognitive mental processes, their development in ontogenesis.

Addressed to 1st year students of medical, pediatric, dental, pharmaceutical faculties.

Authorized for publication by the Central Coordination Methodological Council (protocol No. 7 of June 18, 2013).

INTRODUCTION	4 s.
§ 1. SENSATIONS	7 p.
1.1. Physiological basis of sensations	8 p.
1.2. Classification of sensations	8 p.
1.3. Properties of sensations	9 p.
1.4. Phenomena of sensations	11 p.
1.5. Development of sensations in ontogenesis	14 p.
§ 2. PERCEPTION	15 s.
2.1. Physiological basis of perception	16 p.
2.2. Classification of perception	16 p.
2.3. Properties of perception	20 s.
2.4. Phenomena of perception	22 p.
2.5. Development of perception in ontogenesis	22 p.
§ 3. ATTENTION	23 p.
3.1. Physiological basis of attention	24 s.
3.2. Classification of types of attention	25 s.
3.3. Properties of attention	25 s.
3.4. Distraction of attention	27 p.
3.5. Development of attention in ontogenesis	27 p.
§ 4. MEMORY	29 p.
4.1. Classification of types of memory	30 s.
4.2. Main memory characteristics	32 pp.
4.3. Factors influencing memorization	33 p.
4.4. Basic laws of memory	34 p.
4.5. Development of memory in ontogenesis	35 s.
§ 5. THINKING	36 pp.
5.1.Operations and forms of thinking	37 p.
5.2. Types of thinking	39 p.
5.3. Individual characteristics of thinking	40 s.
5.4. Diagnostic thinking of a doctor	42 pp.
5.5. Speech and language	43 p.
5.6. Modern ideas about the structure of intelligence	45 pp.
§ 6. IMAGINATION	47 p.
6.1. Physiological basis of imagination	47 p.
6.2. Types of imagination	48 p.
6.3. Functions of the imagination	50 s.
6.4. Imagination and creativity	51 p.
6.5. Individual characteristics of imagination	53 p.
TEST CONTROL OF KNOWLEDGE	55 pp.
BIBLIOGRAPHY	60 s.

INTRODUCTION

The unprecedented growth of science and technology, the complication of professional activity have increased the dependence of a specialist’s success in work on the professionalization of his cognitive processes: thinking, speech, imagination, attention, memory, thinking. The reason for the incorrect actions of a medical specialist can be inaccuracy of perception, inattention, inertia of his thinking, etc. The professional preparedness of a specialist is formed along with the improvement of the sensitivity of his senses, attention, ideas, memory, imagination and other mental processes. For example, the more accurately a specialist distinguishes between similar influences, identifies subtle changes in perceived phenomena, remembers and reproduces the necessary data, the better he performs his duties. Conversely, insufficiently sharp vision, inertia of attention (inability to switch and distribute it), too strong a tendency towards automaticity of actions, and poor memory can lead to mistakes and inaccurate task completion.

The direction of development of sensations, perceptions and attention in students must correspond to the requirements that their future profession places on them. Sensations, perceptions and attention develop in active and personally significant activities. The future doctor needs evenly developed basic properties of attention. He will not be able to correctly diagnose or carry out treatment without being attentive to the objective and subjective indicators of the disease, to the condition and personality of the patient. The formation of attention and its properties in students involves influencing the direction of their personality, will, and attitude to work. To do this, you need to explain to them their upcoming professional responsibilities, exercise them in solving problems that require correct perception and quick comprehension of future work situations (identifying the main and secondary in these situations). Attention and attentiveness are formed in students in the process of active learning activities, thanks to maintaining discipline and organization in all classes.

There is not a single profession in which a specialist could do without imagination. It is especially important in the medical profession. One of the main functions of the imagination is penetration into the inner world of another person, which forms the basis of such a professionally important quality of a doctor as empathy. Imagination is not an innate and permanent quality of a person, like other mental processes and properties, it develops and improves.

The medical profession places high demands on the thinking of a specialist. It must be purposeful, flexible, deep, mobile, fast and accurate. To develop professional clinical thinking in students, it is necessary, first of all, to equip them with a system of concepts and knowledge necessary to perform the tasks of future work. But this weapon must be special: simply memorizing concepts and knowledge is not enough, since thinking presupposes a targeted relationship between existing knowledge and information perceived at the moment.

The formation of thinking includes the ability to compare, analyze, carry out operations of synthesis, abstraction, concretization, classification, systematization, widely mobilize knowledge, avoid templates, creatively take into account specific data. To form thinking means, on the basis of certain knowledge, scientific facts with the help of a certain form of their assimilation and application, which ensures the active activity of students, to improve operations, processes, types and forms of thinking, as well as the qualities of the mind in accordance with the tasks and conditions of professional medical practice.

The development of independent thinking is one of the most important tasks of higher education. When solving it, it is necessary to take into account the various manifestations of a person’s independent thinking, in particular, not only the ability to solve some new problems, but also the ability to see these problems on their own. The inability to see problems is the result of formalism in the assimilation of educational information, which consists in the fact that the student only remembers the specific content of the problem of various sciences, but does not see what they are. If a problem discovered by the student himself is solved, then this is associated with a high level of mental activity; knowledge is acquired in a creative way and ensures a higher quality.

Professional speech development helps a student acquire knowledge, improve his thinking, memory and other qualities. A specialist without a sufficiently high level of professional speech will not be able to successfully perform his duties. It is very important that students expand their general and professional vocabulary, develop the skills of fluent and correct proficiency in professional language, learn to express their thoughts briefly, clearly and logically in class, and develop fast reading skills.

A person’s choice of one of many decisions and actions at each moment in time is determined by his needs and picture of the world, i.e. his knowledge and ideas about the world in general and about a specific situation in particular. All knowledge about the clearly observable and hidden from direct view structure of things, the patterns of relationships between them, about people and their qualities, about oneself and, finally, knowledge about the general structure of the world is the result of the integration of knowledge obtained through cognitive processes of different levels of complexity.

Each of these processes has its own characteristics and structure and makes its own special contribution to the formation of an internally connected, dynamic, but at the same time holistic image of the world. Taking place simultaneously, mental processes interact with each other so smoothly and imperceptibly for us that at any given moment in time we perceive and understand the world not as a pile of colors, shades, shapes, sounds, smells that need to be understood, but precisely as a world located outside of us, filled with light, sounds, smells, objects, inhabited by people. Thanks to these processes, the world does not appear to us frozen, but in a temporal perspective, as something that develops and exists not only in the present, but also has a past and a future. The mental processes by which ideas about the world around us, as well as about the organism itself and its internal environment, are formed are called cognitive mental processes.

Images of the surrounding world are complex mental formations; various mental processes take part in their formation, the significance of which in the structure of the whole picture can be revealed by artificially (experimentally or logically) dividing this image into its component parts, as well as in the event of disturbances in the course of these processes. The division of a single mental process into separate cognitive processes (sensation, perception, attention, memory, imagination), accepted in psychology, is thus conditional. At the same time, this division is based on the objective specific features of each of these processes, distinguishing them from each other by the contribution they make to the construction of a holistic image.

Let us consider in more detail those basic cognitive mental processes that are involved in constructing images of the surrounding world.

FEEL

The simplest cognitive process is sensation, which represents a certain primary source of a completed image of the world. In the course of practical activity, a person equally relies on both the data of sensory experience and thinking; they are intimately intertwined. The primacy of sensations does not mean that the entire image is a simple sum of them. Sensations provide only the raw material on the basis of which a holistic image is built. At the same time, sensation as a reflection in a person’s consciousness of individual aspects and properties of an object, perception as a holistic image of an object created on the basis of a complex of sensations, and representation as a sensory-visual image of an object are traditionally referred to as forms of sensory cognition.

Feeling –This is a mental cognitive process of sensory reflection of individual properties of objects and phenomena of objective reality with their direct impact on the senses. The need for constant sensation is clearly demonstrated when the sense organs are completely deprived of external influence. As experiments have shown, if a person is placed in an environment isolated from any sensations, the psyche ceases to function normally. Similar results were observed in the 1950s. John Lill, neuroscientist who developed the hyperbaric chamber . It looked like a dark, soundproof tank, isolated from sounds, light and smells. The reservoir was filled with a high-density solution, the temperature of which corresponded to the temperature of the human body. The person placed in the tank seemed to be in weightlessness. However, the subject quite soon asked to end the experiment due to the occurrence of hallucinations, thinking disorders, distorted perception of time, space, his body, etc. Specific problems of a psychological nature arise during sensory deprivation, that is, when the influx of external influences is limited, which is well known from the example of the development of people who are blind or deaf, as well as those with poor vision and hearing. Numerous observations have shown that disruption of the flow of information in early childhood, associated with deafness and blindness, causes sharp delays in mental development. If children born blind-deaf or deprived of hearing and vision at an early age are not taught special techniques that compensate for these defects through the sense of touch, their mental development will become impossible and they will not develop independently. Thus, sensations are necessary for normal human functioning. They are the main source of knowledge about the outside world. To this, perhaps, we can only add that sensations also reflect the state of the human body with the help of receptors located in his body.

Physiological basis of sensations

Phenomena of the external world and the state of the body that affect our senses (for example, sound waves, photons of light, temperature, etc.) are called irritants. The process of exposure of stimuli to the sense organs is called irritation. Irritation, in turn, causes in the nervous tissue excitation. The sensation occurs as a reaction of the nervous system to a particular stimulus. and, like any mental phenomenon, has a reflex character. Sensations are provided by the activity of special nervous apparatuses called analyzers. Each analyzer consists of three parts:

1) Peripheral department, called a receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process);

2)Afferent or sensitive nerves (centripetal), conducting excitation to the nerve centers;

3) Central section of the analyzer- these are the sections of the analyzer in which nerve impulses are processed.

For sensation to arise, the entire analyzer as a whole must work.

Physiological research shows that sensation is not a passive process. As a result of the sensation, motor reactions arise, sometimes in the form of a vegetative reaction (vasoconstriction, galvanic skin reflex), sometimes in the form of muscle reactions (turning the eyes, tensing the neck muscles, motor reactions of the hand, etc.). Motor reactions are provided by efferent neurons that carry nerve impulses to the executive organs.

Human sensations are a product of historical development, qualitatively different from the sensations of animals. In animals, the development of sensations is entirely limited by their biological, instinctive needs. A person is able to sense a much larger number of properties of the objects around him. This is due to the fact that in the process of historical development, a person has formed an incomparably wider range of needs.

Classification of sensations

There are different approaches to classifying sensations:

1. According to the main modalities there are:

- sense of smell;

- taste;

- touch

- vision;

- hearing.

2. Systematic classification of Ch. Sherrington sensations are divided into 3 types:

- interoceptive– these are sensations that signal the state of the internal processes of the body. They arise due to receptors located on the walls of the stomach and intestines, heart and circulatory system and other internal organs. This is the most ancient and elementary group of sensations. They are little realized and have the most diffuse form, most often close to emotional states.

- proprioceptive- these are sensations that transmit signals about the position of the body in space and form the basis of human movements. They play a decisive role in their regulation. These are a sense of balance (static) and a motor (kinesthetic) sensation. Receptors for proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and are called Paccini corpuscles. Excitation occurs in these receptors when muscles are stretched and the position of joints changes. Proprioceptive sensations also include a specific type of sensitivity called the sense of balance, or static sensation. Receptors for the sense of balance are located in the semicircular canals of the inner ear.

- exteroceptive- these are sensations that ensure the receipt of signals from the outside world. Exteroceptive sensations are the main group of sensations that connect a person with the external environment. Exteroceptive sensations are usually divided into two subgroups:

a) contact sensations are caused by a stimulus directly applied to the surface of the corresponding receptor. Examples of contact sensation are taste and touch.

b) distant sensations are caused by stimuli acting on the sense organs at some distance. These senses include smell, hearing and vision.

3. Genetic classification by H. Head allows us to distinguish two types of sensitivity:

- protopathic sensitivity - more primitive, less differentiated and localized, which includes organic feelings (hunger, thirst, etc.);

- epicritic sensitivity - finely differentiated, rational, genetically younger. This type of sensitivity includes the main types of human sensations.

Properties of sensations

The main properties of sensations include: quality, intensity, duration, spatial localization, absolute and relative thresholds.

1. Quality - this is the main feature of this sensation, distinguishing it from other types of sensations (visual sensation is qualitatively different from auditory sensation, etc.).

2. Intensity – this is a quantitative characteristic that depends on the strength of the current stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions.

3. Duration(or duration) Feel - This is a temporary characteristic of the sensation that has arisen. It is determined by the functional state of the sensory organ, the time and intensity of the stimulus. When a stimulus acts on a sense organ, the sensation does not arise immediately, but after some time - the so-called latent (hidden) period Feel. The latent period of different types of sensations is not the same: for example, for tactile sensations it is 130 ms, for pain - 370, and for taste - only 50 ms. Likewise, the sensation does not disappear simultaneously with the cessation of the stimulus. This inertia of sensations manifests itself in the so-called aftereffect. For example, a visual sensation is stored as a sequential image. So, for example, if in complete darkness we light a bright lamp for a while and then turn it off, then after that for some time we “see” the bright light of the lamp against a dark background. The aftereffect also explains why we do not notice breaks between successive frames of an animated film: they are filled with traces of the frames that were in effect before - successive images from them.

4. Spatial localization stimulus allows you to localize it in space. Contact sensations correspond to the part of the body that is affected by the stimulus.

So far we have been talking about the qualitative difference in types of sensations. However, no less important is the quantitative analysis of the intensity of sensations. Not every irritation causes a sensation. For a sensation to arise, the stimulus must reach a certain magnitude. The minimum magnitude of the stimulus at which sensation first occurs is called absolute lower threshold of sensation (or the threshold for the appearance of sensation). Stimuli that do not reach it lie below the threshold of sensation. For example, we do not feel individual specks of dust and small particles falling on our skin. Light stimuli below a certain brightness limit do not cause visual sensations in us. The value of the lower absolute threshold characterizes absolute sensitivity sense organs. The weaker the stimuli that cause sensations (i.e., the lower the absolute threshold), the higher the absolute sensitivity of the senses.

Different analyzers have different sensitivities. The threshold of one human olfactory cell for some odorous substances does not exceed 8 molecules. It takes at least 25,000 times more molecules to produce the sensation of taste than to produce the sensation of smell. A person has a very high sensitivity of visual and auditory analyzers.

The absolute sensitivity of the analyzer is limited not only by the lower, but also by the upper threshold of sensation. Upper absolute threshold Feel is called the maximum strength of the stimulus, at which a sensation adequate to the current stimulus still arises. A further increase in the strength of stimuli acting on our receptors causes a painful sensation (for example, with an extremely loud sound, blinding brightness of light, etc.).

The value of absolute thresholds, both lower and upper, varies depending on various conditions: the age of the person, the functional state of the receptor, the strength and duration of the stimulus, etc.

It is necessary to distinguish from absolute sensitivity relative, or difference, sensitivity, i.e. . sensitivity to change in stimulus, discovered by the German scientist M. Weber. Difference sensitivity is a relative value, not an absolute one. This means that the greater the magnitude of the initial stimulus, the greater must be the addition to it in order for a change in sensation to occur. For example, we notice changes in the illumination of a room depending on the initial illumination level. If the initial illumination is 100 lux (lux), then the increase in illumination that we first notice should be at least 1 lux. The same applies to auditory, motor, and other sensations. The minimal difference between two stimuli, causing barely h noticeable difference in sensations is called threshold of discrimination , or difference threshold. The discrimination threshold is characterized by a relative value that is constant for a given analyzer. For a visual analyzer, this ratio is approximately 1/100 of the intensity of the initial stimulus, for an auditory one - 1/10, for a tactile one - 1/30.

Phenomena of sensations

1. Sensory adaptation. Both the absolute and relative sensitivity of our sense organs can vary within very large limits. For example, in the dark our vision becomes sharper, and in strong light its sensitivity decreases. This can be observed when a person moves from a dark room to a brightly lit one. In this case, the person’s eyes begin to experience pain; it takes some time for the analyzer to adapt to the bright lighting. In the opposite case, when a person moves from a brightly lit room to a dark room, he also does not see anything at first (he temporarily “goes blind”), and it takes 20-30 minutes for him to be able to navigate well enough in the dark. Studies have shown that the sensitivity of the eye increases 200,000 times when moving from bright light to darkness. The described changes in sensitivity are called adaptation sense organs to environmental conditions. Adaptation is a change in the absolute and relative sensitivity of the senses under the influence of external influences. Adaptation phenomena are characteristic of both the auditory sphere and the sense of smell, touch, and taste. The change in sensitivity that occurs according to the type of adaptation does not occur immediately; it has its own temporary characteristics. These temporal characteristics are different for different sense organs. So, in order for vision in a dark room to acquire the required sensitivity, about 30 minutes should pass. Adaptation of the auditory organs occurs much faster. Human hearing adapts to the surrounding background within 15 s. There is also a rapid change in sensitivity in the sense of touch (weak contact with the skin of our clothing ceases to be perceived after just a few seconds). The phenomena of thermal adaptation (getting used to temperature changes) are well known. However, these phenomena are clearly expressed only in the average range, and adaptation to extreme cold or extreme heat, as well as to painful stimuli, almost does not take place. The phenomena of adaptation to odors are also known. Thus, there are three types of adaptation phenomena:

1. Adaptation as the complete disappearance of sensation during prolonged exposure to the stimulus;

2. Adaptation as a dulling of sensation under the influence of a strong stimulus. (These two types of adaptation refer to negative adaptation, since as a result it reduces the sensitivity of the analyzers.)

3. Adaptation is also called an increase in sensitivity under the influence of a weak stimulus. This type of adaptation is defined as positive adaptation. For example, in the visual analyzer, dark adaptation of the eye, when its sensitivity increases under the influence of darkness, is a positive adaptation. A similar form of auditory adaptation is adaptation to silence.

The physiological mechanism of the adaptation phenomenon consists of changes in the functioning of receptors. For example, it is known that under the influence of light, visual purple, located in the rods of the retina, decomposes. In the dark, on the contrary, visual purple is restored, which leads to increased sensitivity. The phenomenon of adaptation is also explained by the processes occurring in the central sections of the analyzers. With prolonged stimulation, the cerebral cortex responds with internal protective inhibition, reducing sensitivity.

2. Interaction and mutual influence of sensations Each other . A change in the sensitivity of the analyzer under the influence of irritation of other sense organs is called interaction of sensations. All our analyzing systems are capable of influencing each other. At the same time, the interaction of sensations, like adaptation, manifests itself in two opposite processes - an increase and decrease in sensitivity. The general pattern is that weak stimuli increase, and strong stimuli decrease, the sensitivity of analyzers when they interact. An increase in sensitivity as a result of the interaction of analyzers is called sensitization. A.R. Luria identified two options for increasing sensitivity (sensitization):

Based on sustainable changes occurring in the body;

Based on temporary physiological and psychological changes in the state of the body (for example, under the influence of psychoactive substances, mental disorders, etc.).

Sensitization of the senses is easy to notice in the following cases: when compensating for sensory defects (blindness, deafness) and the specific requirements of certain professions. Thus, the loss of vision or hearing is to a certain extent compensated by the development of other types of sensitivity. Blindness causes increased tactile sensitivity, and people can read books with a special Broglie alphabet using their fingers. There are cases when people with limited vision engaged in sculpture, which indicates a highly developed sense of touch. Deafness causes the development of vibration sensations. Some people who are deaf develop vibration sensitivity so strongly that they can even hear music - to do this, they put their hand on the instrument. Deaf-blind people, holding their hand at the throat of the speaking interlocutor, can thus recognize him by his voice and understand what he is talking about.

The phenomena of sensitization of the sense organs are also observed in persons of certain professions. Dyers can distinguish up to 50-60 shades of black. The ability of musicians to detect differences in tones that are not perceived by an ordinary listener, or the sensitivity of the taste analyzer of tasters is known.

The interaction of sensations is also manifested in a phenomenon called synesthesia- the occurrence, under the influence of irritation of one analyzer, of a sensation characteristic of other analyzers. In psychology, the facts of “colored hearing” are well known, which occurs in many people, and especially in many musicians (for example, Scriabin). For example, it is widely known that we evaluate high-pitched sounds as “light” and low-pitched sounds as “dark”. It is characteristic that the phenomenon of synesthesia is not distributed equally in all people.

All these facts show that the acuity of absolute and differential sensitivity can vary significantly and that human participation in various forms of conscious activity can change the acuity of this sensitivity.

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PHYSIOLOGICAL BASES OF SENSATIONS. CONCEPT OF ANALYZER.

All living beings that have a nervous system have the ability to sense sensations. As for conscious sensations (about, the source and quality of which a report is given), only humans have them. In the evolution of living beings, sensations arose on the basis of the primary irritability, which is the property of living matter to respond to biologically significant environmental influences by changing its internal state and external behavior.

By their origin, from the very beginning, sensations were associated with the activity of the body, with the need to satisfy its biological needs. The vital role of sensations is to promptly convey to the central nervous system (as the main organ of control of human activity and behavior) information about the state of the external and internal environment, the presence of biologically significant factors in it. Sensation, unlike irritability, carries information about certain qualities of external influence.

A person’s sensations, in their quality and diversity, reflect the variety of environmental properties that are significant to him. Human sense organs, or analyzers, from the moment of birth are adapted to perceive and process various types of energy in the form of stimuli-irritants (physical, mechanical, chemical and others). Stimulus- any factor that affects the body and can cause any reaction in it.

It is necessary to distinguish between stimuli that are adequate for a given sense organ and those that are not adequate for it. This fact indicates a subtle specialization of the senses to reflect one or another type of energy, certain properties of objects and phenomena of reality. The specialization of the sense organs is a product of long-term evolution, and the sense organs themselves are products of adaptation to the influences of the external environment, therefore, in their structure and properties they are adequate to these influences.

In humans, subtle differentiation in the field of sensations is associated with the historical development of human society and with social and labor practice. “Serving” the processes of adaptation of the organism to the environment, the senses can successfully perform their function only if they correctly reflect its objective properties. Thus, the nonspecificity of the sense organs gives rise to the specificity of sensations, and the specific qualities of the external world gave rise to the specificity of the senses. Sensations are not symbols, hieroglyphs, but reflect the actual properties of objects and phenomena of the material world that affect the subject’s senses, but exist independently of him.

The sensation arises as a reaction of the nervous system to a particular stimulus and, like any mental phenomenon, has a reflex character. Reaction– the body’s response to a specific stimulus.

The physiological basis of sensation is a nervous process that occurs when a stimulus acts on an analyzer adequate to it. Analyzer– a concept (according to Pavlov) denoting a set of afferent and efferent nervous structures involved in the perception, processing and response to stimuli.

Efferent is a process directed from the inside out, from the central nervous system to the periphery of the body.

Afferent– a concept that characterizes the course of the process of nervous excitation through the nervous system in the direction from the periphery of the body to the brain.

The analyzer consists of three parts:

1. Peripheral department ( or receptor), which is a special transformer of external energy into the nervous process. There are two types of receptors: contact receptors- receptors that transmit irritation upon direct contact with objects affecting them, and distant receptors– receptors that respond to stimuli emanating from a distant object.

2. Afferent (centripetal) and efferent (centrifugal) nerves, conducting pathways connecting the peripheral part of the analyzer with the central one.

3. Subcortical and cortical sections (brain end) of the analyzer, where the processing of nerve impulses coming from peripheral sections occurs (see Fig. 1).

In the cortical section of each analyzer there is analyzer core, i.e. the central part, where the bulk of the receptor cells is concentrated, and the periphery, consisting of scattered cellular elements, which are located in varying quantities in various areas of the cortex.

The nuclear part of the analyzer consists of a large mass of cells that are located in the area of the cerebral cortex where the centripetal nerves from the receptor enter. The scattered (peripheral) elements of this analyzer are included in areas adjacent to the cores of other analyzers. This ensures the participation of a large part of the entire cerebral cortex in a separate act of sensation. The analyzer core performs the function of fine analysis and synthesis, for example, it differentiates sounds by height. Scattered elements are associated with coarse analysis functions, such as distinguishing between musical sounds and noise.

Certain cells of the peripheral parts of the analyzer correspond to certain areas of cortical cells. Thus, spatially different points in the cortex represent, for example, different points of the retina; The spatially different arrangement of cells is represented in the cortex and the organ of hearing. The same applies to other senses.

Numerous experiments carried out using artificial stimulation methods now make it possible to quite definitely establish the localization in the cortex of certain types of sensitivity. Thus, the representation of visual sensitivity is concentrated mainly in the occipital lobes of the cerebral cortex. Auditory sensitivity is localized in the middle part of the superior temporal gyrus. Touch-motor sensitivity is represented in the posterior central gyrus, etc.

For sensation to arise, the entire analyzer must work as a single whole. The impact of an irritant on the receptor causes irritation. The beginning of this irritation is the transformation of external energy into a nervous process, which is produced by the receptor. From the receptor, this process travels along the centripetal nerve to the nuclear part of the analyzer, located in the spinal cord or brain. When excitation reaches the cortical cells of the analyzer, we feel the qualities of the stimuli, and after this the body’s response to the irritation occurs.

If the signal is caused by a stimulus that threatens to cause damage to the body, or is addressed to the autonomic nervous system, then it is very likely that it will immediately cause a reflex reaction emanating from the spinal cord or other lower center, and this will happen before we are aware of this effect ( reflex- automatic response of the body to the action of any internal or external stimulus).

Our hand withdraws when burned by a cigarette, our pupil constricts in bright light, our salivary glands begin to secrete saliva when we put a piece of candy in our mouth, and all this happens before our brain deciphers the signal and gives the appropriate order. The survival of an organism often depends on the short neural circuits that make up the reflex arc.

If the signal continues its path along the spinal cord, then it follows two different paths: one leads to the cerebral cortex through thalamus, and the other, more diffuse, passes through reticular formation filter, which keeps the cortex awake and decides whether the signal transmitted in a direct way is important enough for the cortex to “get busy” decoding it. If the signal is considered important, a complex process will begin that will lead to a sensation in the truest sense of the word. This process involves changing the activity of many thousands of cortical neurons, which will have to structure and organize the sensory signal to give it meaning. ( Sensory- associated with the functioning of the sense organs).

First, the cortex's attention to the stimulus will now entail a series of movements of the eyes, head, or torso. This will allow you to become more deeply and in detail familiar with the information coming from the sensory organ - the primary source of this signal, and also, possibly, connect other senses. As new information becomes available, it will be associated with traces of similar events stored in memory.

Between the receptor and the brain there is not only a direct (centripetal) connection, but also a feedback (centrifugal) connection. The feedback principle discovered by I.M. Sechenov, requires recognition that the sense organ is alternately both a receptor and an effector.

Thus, sensation is not only the result of a centripetal process, it is based on a complete and complex reflex act, subject in its formation and course to the general laws of reflex activity. In this case, the analyzer constitutes the initial and most important part of the entire path of nervous processes, or reflex arc.

Reflex arc– a concept denoting a set of nerve structures that conduct nerve impulses from stimuli located on the periphery of the body to the center , processing them in the central nervous system and causing a reaction to appropriate stimuli.

The reflex arc consists of a receptor, pathways, a central part and an effector. The interconnection of the elements of the reflex arc provides the basis for the orientation of a complex organism in the surrounding world, the activity of the organism depending on the conditions of its existence.

Figure 2 shows a variant of the action of the human reflex arc in the event of a mosquito bite (according to J. Godefroy).

The signal from the receptor (1) is sent to the spinal cord (2) and the activated reflex arc can cause the hand to be withdrawn (3). Meanwhile, the signal travels further to the brain (4), going along a direct path to the thalamus and cortex (5) and along an indirect path to the reticular formation (6). The latter activates the cortex (7) and prompts it to pay attention to the signal, the presence of which it has just learned. Attention to the signal is manifested in head and eye movements (8), which leads to recognition of the stimulus (9), and then to programming the reaction of the other hand in order to “drive away the unwanted guest” (10).

The dynamics of the processes occurring in the reflex arc is a kind of similarity to the properties of external influence. For example, touch is precisely such a process in which hand movements repeat the outlines of a given object, as if becoming similar to its structure. The eye operates on the same principle due to the combination of the activity of its optical “device” with oculomotor reactions. The movements of the vocal cords also reproduce the objective pitch nature. When the vocal-motor unit was turned off in the experiments, the phenomenon of a kind of pitch deafness inevitably arose. Thus, thanks to the combination of sensory and motor components, the sensory (analyzer) apparatus reproduces the objective properties of the stimuli acting on the receptor and is likened to their nature.

Numerous and diverse studies on the participation of effector processes in the occurrence of sensation have led to the conclusion that sensation as a mental phenomenon in the absence of a response from the body or in its inadequacy is impossible. In this sense, a motionless eye is as blind as a motionless hand ceases to be an instrument of knowledge. The sense organs are closely connected with the organs of movement, which perform not only adaptive and executive functions, but are also directly involved in the processes of obtaining information.

Thus, the connection between touch and movement is obvious. Both functions are merged in one organ - the hand. At the same time, the difference between executive and palpating movements of the hand is also obvious (Russian physiologist, author of the doctrine of higher nervous activity) I.P. Pavlov called the latter orienting-exploratory reactions, relating to a special type of behavior - perceptual behavior, not executive behavior. Such perceptual regulation is aimed at strengthening the input of information and optimizing the process of sensation. All this suggests that for sensation to arise, it is not enough for the body to be subjected to the appropriate influence of a material stimulus, but some work of the organism itself is also necessary. This work can be expressed both in internal processes and in external movements.

In addition to the fact that the senses are a kind of “window” for a person into the world around them, they also represent, in fact, energy filters through which corresponding changes in the environment pass. By what principle is the selection of useful information in sensations carried out? We have already touched on this issue in part. To date, several hypotheses have been formulated.

According to the first hypothesis,mechanisms exist to detect and pass limited classes of ,signals, and messages that do not match those classes are ,rejected. The task of such selection is performed by comparison mechanisms. For example, in insects these mechanisms are included in solving the difficult task of finding a partner of their own species. “Winking” of fireflies, “ritual dances” of butterflies, etc. - all these are genetically fixed chains of reflexes, following one after another. Each stage of such a chain is sequentially solved by insects in a binary system: “yes” - “no”. The female’s movement is wrong, the color spot is wrong, the pattern on the wings is wrong, she “responded” wrong in the dance - that means the female is alien, of a different species. The stages form a hierarchical sequence: the start of a new stage is possible only after the answer to the previous question is “yes”.

Second hypothesis suggests that the acceptance or non-acceptance of messages can be regulated on the basis of special criteria, which, in particular, represent the needs of a living being. All animals are usually surrounded by a “sea” of stimuli to which they are sensitive. However, most living organisms respond only to those stimuli that are directly related to the needs of the organism. Hunger, thirst, readiness to mate, or some other internal drive may be the regulators, the criteria by which the selection of stimulus energy is carried out.

According to the third hypothesis, the selection of information in sensations occurs on the basis of the criterion of novelty. Under the influence of a constant stimulus, sensitivity seems to dull and signals from the receptors cease to enter the central nervous system ( sensitivity- the body’s ability to respond to environmental influences that have no direct biological significance, but cause a psychological reaction in the form of sensations). Thus, the sensation of touch tends to fade. It may disappear completely if the irritant suddenly stops moving across the skin. Sensory nerve endings signal the brain about the presence of irritation only when the strength of the irritation changes, even if the time during which it presses harder or less on the skin is very short.

The situation is similar with hearing. It was discovered that a singer needs vibrato - a slight fluctuation in pitch - to control his own voice and maintain it at the desired pitch. Without the stimulation of these deliberate variations, the singer's brain does not notice the gradual changes in pitch.

The visual analyzer is also characterized by the extinction of the indicative reaction to a constant stimulus. The visual sensory field would seem to be free of the obligatory connection with the reflection of movement. Meanwhile, data from the genetic psychophysiology of vision show that the initial stage of visual sensations was precisely the display of the movement of objects. The compound eyes of insects work effectively only when exposed to moving stimuli.

This is the case not only in invertebrates, but also in vertebrates. It is known, for example, that the retina of a frog, described as an “insect detector,” reacts precisely to the movement of insects. If there is no moving object in the frog's field of vision, its eyes do not send significant information to the brain. Therefore, even if surrounded by many motionless insects, a frog can die of starvation.

Facts indicating the extinction of the orienting reaction to a constant stimulus were obtained in the experiments of E.N. Sokolova. The nervous system subtly models the properties of external objects acting on the sense organs, creating their neural models. These models perform the function of a selective filter. If the stimulus currently acting on the receptor does not coincide with the previously established neural model, mismatch impulses appear, causing an indicative reaction. And vice versa, the orienting reaction fades to the stimulus that was previously used in the experiments.

Thus, the process of sensation is carried out as a system of sensory actions aimed at selecting and transforming the specific energy of external influence and providing an adequate reflection of the surrounding world.

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The physiological basis of sensations is the activity of complex complexes of anatomical structures, called analyzers by I. P. Pavlov. Each analyzer consists of three parts: 1) a peripheral section called a receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process); 2) nerve pathways; 3) the cortical sections of the analyzer (they are also called the central sections of the analyzers), in which the processing of nerve impulses coming from the peripheral sections occurs. For sensation to occur, all components of the analyzer must be used. If any part of the analyzer is destroyed, the occurrence of the corresponding sensations becomes impossible. Thus, visual sensations cease when the eyes are damaged, when the integrity of the optic nerves is damaged, and when the occipital lobes of both hemispheres are destroyed.

Basic properties and patterns of sensation. The main properties of sensations include quality, intensity, duration, spatial localization.

Quality — this is a property that characterizes the basic information displayed by a given sensation, distinguishing it from other types of sensations, as well as the shades of this type of sensation. For example, taste sensations provide information O some chemical characteristics of an object: sweet or sour, bitter or salty. The sense of smell also provides us with information about the chemical characteristics of an object, but of a different kind: flower smell, almond smell, hydrogen sulfide smell, etc.

Intensity sensation is its quantitative characteristic and depends on the strength of the current stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, if you have a runny nose, the intensity of perceived odors may be distorted.

Duration sensations are a temporary characteristic of the sensation that has arisen. It is also determined by the functional state of the sensory organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called latent (hidden) period. When a stimulus acts on a sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same.

And finally, sensations are characterized by spatial localization irritant. The analysis carried out by the receptors gives us information about the localization of the stimulus in space, that is, we can tell where the light comes from, the heat comes from, or what part of the body the stimulus affects.

Of greatest interest are such properties of sensations as adaptation, sensitization and synesthesia.

Adaptation characterizes a change in sensitivity and indicates the great plasticity of the organism and its adaptation to environmental conditions. A distinction is made between complete and incomplete adaptation. With complete adaptation, certain stimuli become habitual and cease to influence the activity of the higher parts of the brain. An example of complete adaptation could be that a person does not feel the weight of clothes, watches, jewelry, or that after a long winter the greenery of the meadows seems bright and conspicuous to us, but after a few days we get used to it and then stop noticing it. The same thing happens with the smells of soap and toilet water, which we strongly feel at first and hardly notice in the future. Full adaptation protects our consciousness from unnecessary information and thereby allows us to focus on more important information. An example of incomplete information might be that when we leave a movie theater, we perceive objects and people in the foyer, but strong sunlight prevents us from seeing the designs on the curtains or other elements in the decorative design of the foyer. Adaptation depends on temporal characteristics. For example, in order for vision in a cinema, when the lights went out, to become fully sharp and we could perceive not only the glowing screen, but also the people sitting in the hall, the details of the design of the screening room, a certain amount of time must pass. In addition, adaptation depends on the strength of the stimulus. The stronger it is, the more difficult the adaptation process. It is just as difficult to get used to extreme cold as it is to extreme heat, and adaptation to pain is almost impossible.

Sensitization characterizes, in contrast to adaptation, in which sensitivity both decreases and increases, only an increase in sensitivity. Another distinctive feature of sensitization is that if during adaptation sensitivity depends on environmental conditions, then during sensitization sensitivity depends on psychological and physiological changes occurring in the body itself. The increase in sensitivity may be more or less long lasting. Long-term, constant changes in sensitivity towards its increase are associated with changes occurring in the body and with the age-related characteristics of a person. For example, it is known that the severity of sensitivity increases with age, reaching its maximum by 20 - 30 years. Sensitization is also associated with the type of higher nervous activity. People with a weak type of nervous system are more sensitive than people with a strong nervous system. Sensitivity depends on the general condition of the body, its fatigue.

Sensitivity can also change due to a person’s attitudes and changes in his interests. In addition, the temporary nature of the sensations may be due to the effect of medicinal substances on the subject’s condition.

Synesthesia characterizes the phenomenon of transfer of qualities of one modality to another. In synesthesia, under the influence of a stimulus characteristic of a given sense organ, sensations characteristic of another sense organ arise. An example of synesthesia is the so-called color hearing. It is known that A. N. Scriabin and N. A. Rimsky-Korsakov had such hearing. The features of “colored hearing” also appear in ordinary people. For example, it is known that we associate high-pitched sounds with light tones, and low-pitched sounds with darker tones. This feature also manifests itself in humans in relation to smell. A. R. Luria drew attention to the fact that the interaction of sensations is reflected in speech. In the Russian language, there are certain phrases that jointly characterize the manifestation of sensations, for example: a warm word, flashy clothes, a cold look, a bitter reproach, a sweet lie, a sharp sound, etc.

The interaction of sensations can manifest itself not only in the joint work of sense organs, but also in the influence of one sense organ on another. For example, whistling can heighten visual sensations. It should be taken into account that the weaker the strength of the stimulus, the more pronounced the sensation, and, conversely, the action of strong stimuli leads to a decrease in sensitivity. Loud music makes it difficult to clearly distinguish the individual sounds of the melody and the words of the song text, and strong light in the theater hall makes it difficult to perceive the actions taking place on stage, making it difficult to perceive and understand the speech of the characters.

The main patterns of sensations include: 1) absolute thresholds and sensitivity; 2) difference thresholds and sensitivity.

The minimum magnitude of the stimulus at which sensation first occurs is called lower absolute threshold Feel . Stimuli whose strength lies below the absolute threshold of sensation do not produce sensations, but this does not mean that they do not have any effect on the body. The lower absolute threshold of sensation is also absolute sensitivity. That is, absolute sensitivity is the ability to respond to minimal influences.

Upper absolute threshold- this is the maximum magnitude of the stimulus that can still be felt. The upper absolute threshold is sometimes called the pain threshold , because with corresponding magnitudes of stimuli we experience pain - pain in the eyes when the light is too bright, pain in the ears when the sound is too loud.

Absolute thresholds - upper and lower - determine the boundaries of the surrounding world accessible to our perception.

Difference thresholds and sensitivity show how sensitive a person is to a minimal change in the strength of the stimulus (for example, a minimal change in air temperature or sound volume). Moreover, sensitivity to these changes depends on the initial strength of the stimulus. Imagine that you are holding a weight of several hundred grams in your hands. A change in weight of a few tens of grams will be quite sensitive to you. If you maintain a weight of several kilograms, then the minimal change in weight that you feel will be more significant.

The properties under consideration indicate the flexibility of the sensory system, its interaction with the environment and the entire human psyche as a whole.

Feeling- the simplest mental process, consisting of reflecting individual properties of objects and phenomena during their direct impact on the corresponding receptors.

Receptors- these are sensitive nerve formations that perceive the influence of the external or internal environment and encode it in the form of a set of electrical signals. The latter then enter the brain, which deciphers them. This process is accompanied by the emergence of the simplest mental phenomena - sensations. The psychophysics of sensations is shown in Fig. 5.1.

Rice. 5.1. Psychophysical mechanism of sensation formation

Some human receptors are combined into more complex formations - sense organs.

A person has an organ of vision - the eye, an organ of hearing - the ear, an organ of balance - the vestibular apparatus, an organ of smell - the nose, an organ of taste - the tongue. At the same time, some receptors are not united into one organ, but are scattered over the surface of the entire body. These are receptors for temperature, pain and tactile sensitivity. 2

Tactile sensitivity is provided by touch and pressure receptors.

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A large number of receptors are located inside the body: pressure receptors, chemical senses, etc. For example, receptors sensitive to the content of glucose in the blood provide a feeling of hunger. Receptors and sensory organs are the only channels through which the brain can receive information for subsequent processing.

“We constantly experience new worlds, our body and mind constantly perceive external and internal changes. Our very life depends on how successfully we perceive the world in which we move, and how accurately these sensations guide our movements. We use our senses to avoid threatening stimuli—extreme heat, the sight, sound, or smell of a predator—and strive for comfort and well-being.” 3

Bloom F, Leiserson A, Hofstadter L. Brain, mind, behavior. – M.: Mir, 1998. – P. 138.

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All receptors can be divided into distant, which can perceive irritation at a distance (visual, auditory, olfactory), and contact(taste, tactile, pain), which can perceive irritation upon direct contact with them.

The density of information flow entering through receptors has its optimal limits. When this flow intensifies, a information overload(for example, air traffic controllers, stock brokers, managers of large enterprises), and when it decreases - sensory isolation(for example, submariners and astronauts).

5.2. ANALYZER – THE MATERIAL BASIS OF SENSATIONS

Sensations are the product of activity analyzers person. An analyzer is an interconnected complex of nerve formations that receives signals, transforms them, configures the receptor apparatus, transmits information to nerve centers, processes it and deciphers it. I. P. Pavlov believed that the analyzer consists of three elements: sensory organ conducting pathways And cortical section. According to modern concepts, the analyzer includes at least five departments:

1) receptor;

2) conductive;

3) setting block;

4) filtration unit;

5) analysis block.

Since the conductor section is essentially just an “electrical cable” that conducts electrical impulses, the most important role is played by the four sections of the analyzer (Fig. 5.2). The feedback system allows you to make adjustments to the operation of the receptor section when external conditions change (for example, fine-tuning the analyzer with different impact forces).

Rice. 5.2. Analyzer structure diagram

If we take the human visual analyzer as an example, through which most of the information is received, then these five sections are represented by specific nerve centers (Table 5.1).

Table 5.1. Structural and functional characteristics of the constituent elements of the visual analyzer

In addition to the visual analyzer, with the help of which a person receives a significant amount of information about the world around him, other analyzers that perceive chemical, mechanical, temperature and other changes in the external and internal environment are also important for compiling a holistic picture of the world (Fig. 5.3).

Rice. 5.3. Basic human analyzers

In this case, contact and distant effects are analyzed by various analyzers. Thus, in humans there are a distant chemical analyzer (olfactory) and a contact analyzer (taste), a distant mechanical analyzer (auditory) and a contact (tactile) analyzer.

Diagram of the structure of the auditory analyzer

The human auditory analyzer is located deep in the temporal bone and actually includes two analyzers: auditory and vestibular. Both of them work on the same principle (they record fluid vibrations in the membranous canals using sensitive hair cells), but they allow one to obtain different types of information.

One is about air vibrations, and the second is about the movement of one’s own body in space (Fig. 5.4).

Rice. 5.4. Diagram of the structure of the inner ear - the main section of the receptor part of the auditory analyzer

The work of the auditory analyzer itself is a good illustration of the phenomenon of the transition of physical phenomena to mental ones through the stage of physiological processes (Fig. 5.5).

Rice. 5.5. Scheme of the occurrence of auditory sensations

At the input of the auditory analyzer we have a purely physical fact - air vibrations of a certain frequency, then in the cells of the organ of Corti we can register a physiological process (the emergence of a receptor potential and the formation of an action potential), and finally, at the level of the temporal cortex, mental phenomena such as sound occur Feel.

THRESHOLDS OF SENSATIONS

In psychology, there are several concepts of sensitivity threshold (Fig. 5.6).

Rice. 5.6. Thresholds of sensations

Lower absolute sensitivity threshold defined as the lowest strength of stimulus that can cause sensation.

Human receptors are distinguished by very high sensitivity to an adequate stimulus. For example, the lower visual threshold is only 2–4 quanta of light, and the olfactory threshold is equal to 6 molecules of an odorous substance.

Stimuli with a strength less than the threshold do not cause sensations. They're called subliminal and are not realized, but can penetrate the subconscious, determining human behavior, as well as forming the basis for it dreams, intuition, unconscious desires. Research by psychologists shows that the human subconscious can react to very weak or very short stimuli that are not perceived by consciousness.

Upper absolute sensitivity threshold changes the very nature of the sensations (most often to pain). For example, with a gradual increase in water temperature, a person begins to perceive not heat, but pain. The same thing happens with strong sound or pressure on the skin.

Relative threshold(discrimination threshold) is the minimum change in the intensity of the stimulus that causes changes in sensations. According to the Bouguer–Weber law, the relative threshold of sensation is constant when measured as a percentage of the initial value of stimulation.

Bouguer–Weber law: “The discrimination threshold for each analyzer has a constant relative value: DI/I= const, where I- the strength of the stimulus."

Weber's constants for different senses are: 2% for the visual analyzer, 10% for the auditory (in intensity) and 20% for the taste analyzer. This means that a person can notice a change in illumination of about 2%, while a change in auditory sensation requires a change in sound intensity of 10%.

The Weber-Fechner law determines how the intensity of sensations changes with changes in the intensity of stimulation. It shows that this dependence is not linear, but logarithmic.

Weber–Fechner law:“The intensity of the sensation is proportional to the logarithm of the strength of stimulation: S = K lgI + C, where S is the intensity of sensation; I – stimulus strength; K And C- constants."

CLASSIFICATION OF SENSATIONS

Depending on the source of stimulation acting on the receptors, sensations are divided into three groups. Each of these groups, in turn, consists of various specific sensations (Fig. 5.7).

1. Exteroceptive sensations reflect the properties of objects and phenomena of the external environment (“five senses”). These include visual, auditory, taste, temperature and tactile sensations. In fact, there are more than five receptors that provide these sensations, 4

Touch, pressure, cold, heat, pain, sound, smell, taste (sweet, salty, bitter and sour), black and white and color, linear and rotational movement, etc.

[Close] and the so-called “sixth sense” has nothing to do with it.

Rice. 5.7. Varieties of human sensations

For example, visual sensations arise when excited chopsticks(“twilight, black and white vision”) and cones(“daytime, color vision”).

Temperature sensations in humans occur during separate excitation cold and heat receptors. Tactile sensations reflect the impact on the surface of the body, and they arise when excited or sensitive touch receptors in the upper layer of the skin, or with stronger exposure to pressure receptors in the deep layers of the skin.

2. Interoreceptive sensations reflect the state of the internal organs. These include sensations of pain, hunger, thirst, nausea, suffocation, etc. Painful sensations signal damage and irritation of human organs and are a unique manifestation of the body’s protective functions. The intensity of pain varies, reaching great strength in some cases, which can even lead to a state of shock.

3. Proprioceptive sensations(muscular-motor). These are sensations that reflect the position and movements of our body. With the help of muscular-motor sensations, a person receives information about the position of the body in space, the relative position of all its parts, the movement of the body and its parts, the contraction, stretching and relaxation of muscles, the condition of joints and ligaments, etc. Muscular-motor sensations are complex. Simultaneous stimulation of receptors of different quality gives sensations of a unique quality:

♦ irritation of receptor endings in muscles creates a feeling of muscle tone when performing a movement;

♦ sensations of muscle tension and effort are associated with irritation of the nerve endings of the tendons;

♦ irritation of the receptors of the articular surfaces gives a sense of direction, shape and speed of movements.

The physiological basis of sensations is the activity of complex complexes of anatomical structures, named by I.P. Pavlov analyzers . Each analyzer consists of three parts:

1) a peripheral section called the receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process);

2) nerve pathways;

3) the cortical sections of the analyzer (they are also called the central sections of the analyzers), in which the processing of nerve impulses coming from the peripheral sections occurs.

The cortical part of each analyzer includes an area that represents a projection of the periphery (i.e., a projection of the sensory organ) in the cerebral cortex, since certain receptors correspond to certain areas of the cortex. For sensation to occur, all components of the analyzer must be used. If any part of the analyzer is destroyed, the occurrence of the corresponding sensations becomes impossible. Thus, visual sensations cease when the eyes are damaged, when the integrity of the optic nerves is damaged, and when the occipital lobes of both hemispheres are destroyed.

Analyzer - this is an active organ, reflexively rearranged under the influence of stimuli, therefore sensation is not a passive process, it always includes motor components. Thus, the American psychologist D. Neff, observing an area of skin with a microscope, became convinced that when it is irritated by a needle, the moment the sensation occurs is accompanied by reflexive motor reactions of this area of the skin. Subsequently, numerous studies have established that sensation is closely related to movement, which sometimes manifests itself in the form of a vegetative reaction (vasoconstriction, galvanic skin reflex), sometimes in the form of muscle reactions (turning the eyes, tension in the neck muscles, motor reactions of the hand, etc.) .d.). Thus, sensations are not at all passive processes - they are active, or reflexive, in nature.

3. Classification of types of sensations.

There are different approaches to classifying sensations. It has long been customary to distinguish between five (based on the number of sense organs) main types of sensations: smell, taste, touch, vision and hearing. This classification of sensations according to the main modalities is correct, although not exhaustive. B. G. Ananyev spoke about eleven types of sensations. A. R. Luria believes that the classification of sensations can be carried out according to at least two basic principles - systematic And genetic (in other words, according to the principle of modality, with one sides, andBy principle difficulties or the level of their construction - on the other).

Let's consider systematic classification sensations (Fig. 1). This classification was proposed by the English physiologist C. Sherrington. Considering the largest and most significant groups of sensations, he divided them into three main types: interoceptive, proprioceptive and exteroceptive Feel. The first combine signals reaching us from the internal environment of the body; the latter transmit information about the position of the body in space and the position of the musculoskeletal system, and ensure the regulation of our movements; finally, still others provide signals from the external world and create the basis for our conscious behavior. Let's consider the main types of sensations separately.

Interoceptive sensations signaling the state of the internal processes of the body arise due to receptors located on the walls of the stomach and intestines, the heart and circulatory system and other internal organs. This is the most ancient and most elementary group of sensations. Receptors that perceive information about the state of internal organs, muscles, etc. are called internal receptors. Interoceptive sensations are among the least conscious and most diffuse forms of sensations and always retain their proximity to emotional states. It should also be noted that interoceptive sensations are often called organic.

Proprioceptive sensations transmit signals about the position of the body in space and form the afferent basis of human movements, playing a decisive role in their regulation. The described group of sensations includes a sense of balance, or static sensation, as well as a motor, or kinesthetic, sensation.

Peripheral receptors of proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and are called Paccini corpuscles.

In modern physiology and psychophysiology, the role of proprioception as the afferent basis of movements in animals was studied in detail by A.A. Orbeli, P.K. Anokhin, and in humans - by N.A. Bernstein.

Peripheral receptors for the sensation of balance are located in the semicircular canals of the inner ear.

The third and largest group of sensations are exteroceptive Feel. They bring information from the outside world to a person and are the main group of sensations that connect a person with the external environment. The entire group of exteroceptive sensations is conventionally divided into two subgroups: contact and distant sensations.

Rice. 1. Systematic classification of the main types of sensations

Contact sensations are caused by the direct impact of an object on the senses. Examples of contact sensation are taste and touch. Distant Feel reflect the qualities of objects located at some distance from the senses. Such sensations include hearing and vision. It should be noted that the sense of smell, according to many authors, occupies an intermediate position between contact and distant sensations, since formally olfactory sensations occur at a distance from the object, but, at the same time, the molecules characterizing the smell of the object, with which the olfactory receptor contacts, undoubtedly belong to this subject. This is the duality of the position occupied by the sense of smell in the classification of sensations.

Since sensation arises as a result of the action of a certain physical stimulus on the corresponding receptor, the primary classification of sensations considered by us proceeds, naturally, from the type of receptor that gives the sensation of a given quality, or “modality”. However, there are sensations that cannot be associated with any specific modality. Such sensations are called intermodal. These include, for example, vibration sensitivity, which connects the tactile-motor sphere with the auditory sphere.

The sensation of vibration is the sensitivity to vibrations caused by a moving body. According to most researchers, the vibration sense is an intermediate, transitional form between tactile and auditory sensitivity. In particular, the school of L. E. Komendantov believes that tactile-vibration sensitivity is one of the forms of sound perception. With normal hearing, it does not appear particularly prominent, but with damage to the auditory organ, this function is clearly manifested. The main position of the “auditory” theory is that tactile perception of sound vibration is understood as diffuse sound sensitivity.

Vibration sensitivity acquires particular practical significance in cases of damage to vision and hearing. It plays a big role in the lives of deaf and deaf-blind people. Deaf-blind people, thanks to the high development of vibration sensitivity, learned about the approach of a truck and other types of transport at a great distance. In the same way, through the vibrational sense, deaf-blind people know when someone enters their room. Consequently, sensations, being the simplest type of mental processes, are actually very complex and have not been fully studied.

It should be noted that there are other approaches to the classification of sensations. For example, the genetic approach proposed by the English neurologist H. Head. Genetic classification allows us to distinguish two types of sensitivity: 1) protopathic (more primitive, affective, less differentiated and localized), which includes organic feelings (hunger, thirst, etc.); 2) epicritic (more subtly differentiating, objectified and rational), which includes the main types of human sensations. Epicritic sensitivity is younger in genetic terms, and it controls protopathic sensitivity.

The famous Russian psychologist B.M. Teplov, considering the types of sensations, divided all receptors into two large groups: exteroceptors (external receptors), located on the surface of the body or close to it and accessible to external stimuli, and interoceptors (internal receptors), located deep within tissues such as muscles, or on surfaces of internal organs. The group of sensations that we called “proprioceptive sensations” was considered by B.M. Teplov as internal sensations.

All sensations can be characterized in terms of their properties. Moreover, the properties can be not only specific, but also common to all types of sensation. The main properties of sensations include: quality, intensity, duration, spatial localization, absolute and relative thresholds of sensations.

Quality - this is a property that characterizes the basic information displayed by a given sensation, distinguishes it from other types of sensations and varies within a given type of sensation. For example, taste sensations provide information about certain chemical characteristics of an object: sweet or sour, bitter or salty. The sense of smell also provides us with information about the chemical characteristics of an object, but of a different kind: flower smell, almond smell, hydrogen sulfide smell, etc.

It should be borne in mind that very often, when they talk about the quality of sensations, they mean the modality of sensations, since it is the modality that reflects the main quality of the corresponding sensation.

Intensity sensation is its quantitative characteristic and depends on the strength of the current stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, if you have a runny nose, the intensity of perceived odors may be distorted.

Duration Feel - this is a temporary characteristic of the sensation that has arisen. It is also determined by the functional state of the sensory organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called latent (hidden) period. When a stimulus acts on a sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same. For example, for tactile sensations it is 130 ms, for pain - 370 ms, and for taste - only 50 ms.

The sensation does not appear simultaneously with the onset of the stimulus and does not disappear simultaneously with the cessation of its effect. This inertia of sensations manifests itself in the so-called aftereffect. A visual sensation, for example, has some inertia and does not disappear immediately after the cessation of the action of the stimulus that caused it. The trace of the stimulus remains in the form of a consistent image. There are positive and negative sequential images. Positive consistent image corresponds to the initial irritation, consists in maintaining a trace of irritation of the same quality as the actual stimulus.

Negative sequential image consists in the emergence of a quality of sensation opposite to the quality of the stimulus that acts. For example, light-darkness, heaviness-lightness, warmth-cold, etc. The emergence of negative sequential images is explained by a decrease in the sensitivity of a given receptor to a certain influence.

And finally, sensations are characterized by spatial localization irritant. The analysis carried out by the receptors gives us information about the localization of the stimulus in space, that is, we can tell where the light comes from, the heat comes from, or what part of the body the stimulus affects.

All the properties described above, to one degree or another, reflect the qualitative characteristics of sensations. However, no less important are the quantitative parameters of the main characteristics of sensations, in other words, the degree sensitivity .

4. Patterns of sensations.

So far we have been talking about the qualitative difference in types of sensations. However, quantitative research, in other words, their measurement, is no less important.

Sensitivity and its measurement. Various sense organs that give us information about the state of the external world around us may be more or less sensitive to the phenomena they display, i.e. can reflect these phenomena with greater or less accuracy. Sensitivity The sensory organ is determined by the minimum stimulus that, under given conditions, is capable of causing sensation. The minimum strength of the stimulus that causes a barely noticeable sensation is called lower absolute threshold of sensitivity .

Stimuli of lesser strength, so-called subthreshold, do not cause sensations, and signals about them are not transmitted to the cerebral cortex. At each individual moment, from an infinite number of impulses, the cortex perceives only vitally relevant ones, delaying all others, including impulses from internal organs. This position is biologically expedient. It is impossible to imagine the life of an organism in which the cerebral cortex would equally perceive all impulses and provide reactions to them. This would lead the body to inevitable death. It is the cerebral cortex that guards the vital interests of the body and, raising the threshold of its excitability, transforms irrelevant impulses into subthreshold ones, thereby relieving the body of unnecessary reactions.

However, subthreshold impulses are not indifferent to the body. This is confirmed by numerous facts obtained in the clinic of nervous diseases, when it is weak, subcortical stimuli from the external environment that create a dominant focus in the cerebral cortex and contribute to the occurrence of hallucinations and “deception of the senses.” Subthreshold sounds can be perceived by the patient as a host of intrusive voices with simultaneous complete indifference to real human speech; a weak, barely noticeable ray of light can cause hallucinatory visual sensations of various contents; barely noticeable tactile sensations - from contact of skin with clothing - a series of perverted acute skin sensations.

The lower threshold of sensations determines the level of absolute sensitivity of this analyzer. There is an inverse relationship between absolute sensitivity and the threshold value: the lower the threshold value, the higher the sensitivity of a given analyzer. This relationship can be expressed by the formula:

where E is sensitivity, and P is the threshold value of the stimulus.

Our analyzers have different sensitivities. The threshold of one human olfactory cell for the corresponding odorous substances does not exceed 8 molecules. It takes at least 25,000 times more molecules to produce the sensation of taste than to create the sensation of smell.

The sensitivity of the visual and auditory analyzer is very high. The human eye, as shown by the experiments of S.I. Vavilov (1891-1951), is capable of seeing light when only 2-8 quanta of radiant energy hit the retina. This means that we would be able to see a burning candle in complete darkness at a distance of up to 27 kilometers. At the same time, in order for us to feel touch, we need 100-10,000,000 times more energy than for visual or auditory sensations.

The absolute sensitivity of the analyzer is not limited only to the lower, but also upper threshold of sensation . The upper absolute threshold of sensitivity is the maximum strength of the stimulus at which a sensation adequate to the current stimulus still occurs. A further increase in the strength of stimuli acting on our receptors causes only a painful sensation in them (for example, an extremely loud sound, blinding brightness).

The value of absolute thresholds, both lower and upper, varies depending on various conditions: the nature of the person’s activity and age, the functional state of the receptor, the strength and duration of stimulation, etc.

With the help of our senses, we can not only ascertain the presence or absence of a particular stimulus, but also distinguish between stimuli by their strength and quality. The minimum difference between two stimuli that causes a barely noticeable difference in sensation is called discrimination threshold or difference threshold . The German physiologist E. Weber (1795-1878), testing a person’s ability to determine the heavier of two objects in the right and left hand, established that difference sensitivity is relative, not absolute. This means that the ratio of the additional stimulus to the main one must be a constant value. So, if there is a load of 100 grams on your hand, then for a barely noticeable sensation of weight gain to occur, you need to add about 3.4 grams. If the weight of the load is 1000 grams, then to create the feeling of a barely noticeable difference you need to add about 33.3 grams. Thus, the greater the magnitude of the initial stimulus, the greater the increase should be to it.

The discrimination threshold is characterized by a relative value that is constant for a given analyzer. For a visual analyzer this ratio is approximately 1/100, for an auditory analyzer - 1/10, for a tactile analyzer - 1/30. Experimental testing of this position showed that it is valid only for stimuli of medium strength.

Based on Weber's experimental data, the German physicist G. Fechner (1801-1887) expressed the dependence of the intensity of sensations on the strength of the stimulus with the following formula:

where S is the intensity of sensations, J is the strength of the stimulus, K and C are constants. According to this position, which is called the basic psychophysical law, the intensity of sensation is proportional to the logarithm of the strength of the stimulus. In other words, as the strength of the stimulus increases in geometric progression, the intensity of the sensation increases in arithmetic progression (Weber-Fechner law).

Difference sensitivity, or sensitivity to discrimination, is also inversely related to the value of the discrimination threshold: the greater the discrimination threshold, the lower the difference sensitivity.

The concept of difference sensitivity is used not only to characterize the discrimination of stimuli by intensity, but also in relation to other features of certain types of sensitivity. For example, they talk about sensitivity to distinguishing shapes, sizes and colors of visually perceived objects or to sound-pitch sensitivity.

Adaptation . The sensitivity of analyzers, determined by the value of absolute thresholds, is not constant and changes under the influence of a number of physiological and psychological conditions, among which the phenomenon of adaptation occupies a special place.

Adaptation, or adaptation, is a change in the sensitivity of the senses under the influence of a stimulus.

Three types of this phenomenon can be distinguished.

1. Adaptation as the complete disappearance of sensation during the prolonged action of a stimulus. We mentioned this phenomenon at the beginning of this chapter, talking about the peculiar mood of the analyzers to changes in stimuli. In the case of constant stimuli, the sensation tends to fade. For example, a light weight resting on the skin soon ceases to be felt. A common fact is the distinct disappearance of olfactory sensations soon after we enter an atmosphere with an unpleasant odor. The intensity of the taste sensation weakens if the corresponding substance is kept in the mouth for some time and, finally, the sensation may fade away completely.

Full adaptation of the visual analyzer does not occur under the influence of a constant and motionless stimulus. This is explained by compensation for the immobility of the stimulus due to movements of the receptor apparatus itself. Constant voluntary and involuntary eye movements ensure continuity of visual sensation. Experiments in which conditions were artificially created to stabilize the image relative to the retina showed that the visual sensation disappears 2-3 seconds after its occurrence, i.e. complete adaptation occurs.

2. Adaptation is also called another phenomenon, close to the one described, which is expressed in a dulling of sensation under the influence of a strong stimulus. For example, when you immerse your hand in cold water, the intensity of the sensation caused by the cold stimulus decreases. When we move from a dimly lit room into a brightly lit space, we are initially blinded and unable to discern any details around us. After some time, the sensitivity of the visual analyzer decreases sharply, and we begin to see normally. This decrease in eye sensitivity under intense light stimulation is called light adaptation.

The two types of adaptation described can be combined with the term negative adaptation, since as a result they reduce the sensitivity of the analyzers.

3. Finally, adaptation is an increase in sensitivity under the influence of a weak stimulus. This type of adaptation, characteristic of certain types of sensations, can be defined as positive adaptation.

In the visual analyzer, this is a dark adaptation, when the sensitivity of the eye increases under the influence of being in the dark. A similar form of auditory adaptation is adaptation to silence. In temperature sensations, positive adaptation is detected when a pre-cooled hand feels warm, and a pre-heated hand feels cold when immersed in water of the same temperature. The existence of negative pain adaptation has long been controversial. It is known that repeated application of a painful stimulus does not reveal negative adaptation, but, on the contrary, has an increasingly stronger effect over time. However, new facts indicate the presence of complete negative adaptation to needle pricks and intense hot irradiation.

Studies have shown that some analyzers detect fast adaptation, while others detect slow adaptation. For example, tactile receptors adapt very quickly. When any prolonged stimulation is applied, only a small volley of impulses runs along their sensory nerve at the beginning of the action of the stimulus. The visual receptor adapts relatively slowly (dark adaptation time reaches several tens of minutes), olfactory and gustatory.

Adaptive regulation of the level of sensitivity depending on what stimuli (weak or strong) affects the receptors is of great biological importance. Adaptation helps the sensory organs to detect weak stimuli and protects the sensory organs from excessive irritation in the event of unusually strong influences.

The phenomenon of adaptation can be explained by those peripheral changes that occur in the functioning of the receptor during prolonged exposure to a stimulus. Thus, it is known that under the influence of light, the visual purple located in the rods of the retina decomposes (fades). In the dark, on the contrary, visual purple is restored, which leads to increased sensitivity. In relation to other sense organs, it has not yet been proven that their receptor apparatus contains any substances that chemically decompose when exposed to a stimulus and are restored in the absence of such exposure. The phenomenon of adaptation is also explained by the processes occurring in the central sections of the analyzers. With prolonged stimulation, the cerebral cortex responds with internal protective inhibition, reducing sensitivity. The development of inhibition causes increased excitation of other foci, which contributes to increased sensitivity in new conditions (the phenomenon of sequential mutual induction).

Interaction of sensations . The intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptor, but also on the stimuli currently affecting other sense organs. A change in the sensitivity of the analyzer under the influence of irritation of other senses is called the interaction of sensations.

The literature describes numerous facts of changes in sensitivity caused by the interaction of sensations. Thus, the sensitivity of the visual analyzer changes under the influence of auditory stimulation. S.V. Kravkov (1893-1951) showed that this change depends on the volume of auditory stimuli. Weak sound stimuli increase the color sensitivity of the visual analyzer. At the same time, there is a sharp deterioration in the distinctive sensitivity of the eye when, for example, the loud noise of an aircraft engine is used as an auditory stimulus.

Visual sensitivity also increases under the influence of certain olfactory stimuli. However, with a pronounced negative emotional connotation of the smell, a decrease in visual sensitivity is observed. Similarly, with weak light stimuli, auditory sensations increase, and exposure to intense light stimuli worsens auditory sensitivity. There are known facts of increased visual, auditory, tactile and olfactory sensitivity under the influence of weak painful stimuli.

A change in the sensitivity of any analyzer is also observed with subthreshold stimulation of other analyzers. Thus, P.I. Lazarev (1878-1942) obtained evidence of a decrease in visual sensitivity under the influence of skin irradiation with ultraviolet rays.

Thus, all our analyzing systems are capable of influencing each other to a greater or lesser extent. In this case, the interaction of sensations, like adaptation, manifests itself in two opposite processes: an increase and decrease in sensitivity. The general pattern here is that weak stimuli increase, and strong ones decrease, the sensitivity of the analyzers during their interaction.

Sensitization . Increased sensitivity as a result of the interaction of analyzers and exercise is called sensitization.

The physiological mechanism for the interaction of sensations is the processes of irradiation and concentration of excitation in the cerebral cortex, where the central sections of the analyzers are represented. According to I.P. Pavlov, a weak stimulus causes an excitation process in the cerebral cortex, which easily irradiates (spreads). As a result of the irradiation of the excitation process, the sensitivity of the other analyzer increases. When exposed to a strong stimulus, a process of excitation occurs, which, on the contrary, tends to concentrate. According to the law of mutual induction, this leads to inhibition in the central sections of other analyzers and a decrease in the sensitivity of the latter.

A change in the sensitivity of analyzers can be caused by exposure to second-signal stimuli. Thus, evidence was obtained of changes in the electrical sensitivity of the eyes and tongue in response to the presentation of the words “sour as lemon” to the test subjects. These changes were similar to those observed when the tongue was actually irritated with lemon juice.

Knowing the patterns of changes in the sensitivity of the sensory organs, it is possible, by using specially selected side stimuli, to sensitize one or another receptor, i.e. increase its sensitivity.

Sensitivity and exercise . Sensitization of the senses is possible not only through the use of side stimuli, but also through exercise. The possibilities for training the senses and improving them are very great. There are two areas that determine increased sensitivity of the senses:

1) sensitization, which spontaneously results from the need to compensate for sensory defects (blindness, deafness);

2) sensitization caused by the activity and specific requirements of the subject’s profession.

The loss of vision or hearing is to a certain extent compensated by the development of other types of sensitivity.

There are cases when people deprived of vision engage in sculpture; their sense of touch is highly developed. The development of vibration sensations in the deaf also belongs to this group of phenomena. Some people who are deaf develop vibration sensitivity so strongly that they can even listen to music. To do this, they place their hand on the instrument or turn their back to the orchestra. Deaf-blind O. Skorokhodova, holding her hand at the throat of the speaking interlocutor, can thus recognize him by his voice and understand what he is talking about. The deaf-blind mute Helen Keller has such a highly developed olfactory sensitivity that she can associate many friends and visitors with the smells emanating from them, and memories of acquaintances are as well associated with her sense of smell as most people are associated with the voice.

Of particular interest is the emergence in humans of sensitivity to stimuli for which there is no adequate receptor. This is, for example, remote sensitivity to obstacles in the blind.

The phenomena of sensitization of the sense organs are observed in people who have been engaged in certain special professions for a long time.

Grinders are known to have extraordinary visual acuity. They see gaps from 0.0005 millimeters, while untrained people see only up to 0.1 millimeters. Fabric dyeing specialists distinguish between 40 and 60 shades of black. To the untrained eye they appear exactly the same. Experienced steelmakers are able to quite accurately determine its temperature and the amount of impurities in it by the faint color shades of molten steel.

The olfactory and gustatory sensations of tasters of tea, cheese, wine, and tobacco reach a high degree of perfection. Tasters can pinpoint not only what type of grape a wine is made from, but also where those grapes grew.

Painting places special demands on the perception of shapes, proportions and color relationships when depicting objects. Experiments show that the artist's eye is extremely sensitive to assessing proportions. It distinguishes changes equal to 1/60-1/150 of the size of the object. The subtlety of color sensations can be judged by the mosaic workshop in Rome - it contains more than 20,000 shades of primary colors created by man.

The possibilities for developing auditory sensitivity are also quite large. Thus, playing the violin requires special development of pitch hearing, and violinists have it more developed than pianists. Experienced pilots can easily determine the number of engine revolutions by ear. They freely distinguish 1300 from 1340 rpm. Untrained people only notice the difference between 1300 and 1400 rpm.

All this is proof that our sensations develop under the influence of living conditions and the requirements of practical work activity.

Despite the large number of similar facts, the problem of exercising the senses has not yet been sufficiently studied. What underlies the exercise of the senses? It is not yet possible to give a comprehensive answer to this question. An attempt has been made to explain the increased tactile sensitivity in blind people. It was possible to isolate tactile receptors - special bodies found in the skin of the fingers of blind people. For comparison, the same study was conducted on the skin of sighted people of various professions. It turned out that blind people have an increased number of tactile receptors. Thus, if in the skin of the nail phalanx of the first finger in sighted people the number of corpuscles on average reached 186, then in those born blind it was 270.

Thus, the structure of receptors is not constant, it is plastic, mobile, constantly changing, adapting to the best performance of a given receptor function. Together with the receptors and inseparably from them, the structure of the analyzer as a whole is being rebuilt in accordance with new conditions and requirements of practical activity.

Synesthesia . The interaction of sensations manifests itself in another type of phenomenon called synesthesia. Synesthesia is the occurrence, under the influence of stimulation of one sensation analyzer, of sensations characteristic of another analyzer. Synesthesia is observed in a wide variety of sensations. The most common is visual-auditory synesthesia, when the subject experiences visual images when exposed to sound stimuli. There is no overlap in these synesthesias among different people, but they are fairly consistent across individuals. It is known that some composers (N.A. Rimsky-Korsakov, A.M. Scriabin, etc.) possessed the ability of color hearing. We find a striking manifestation of this kind of synesthesia in the work of the Lithuanian artist M.K. Churlionis - in his symphonies of colors.

The phenomenon of synesthesia is the basis for the creation in recent years of color music devices that transform sound images into light images, and intensive research into color music. Less common are cases of auditory sensations arising when exposed to visual stimuli, gustatory sensations in response to auditory stimuli, etc. Not all people have synesthesia, although it is quite widespread. No one doubts the possibility of using such expressions as “sharp taste”, “flashy color”, “sweet sounds”, etc. The phenomena of synesthesia are another evidence of the constant interconnection of the analytical systems of the human body, the integrity of the sensory reflection of the objective world.

Thus, the structure of receptors is not constant, it is plastic, mobile, constantly changing, adapting to the best performance of a given receptor function. Together with the receptors and inseparably from them, the structure of analysis as a whole is being rebuilt in accordance with the new conditions and requirements of practical activity.