Physiological bases of sensations. The physiological basis of sensations is the work of analyzers with a physiological apparatus. Sensation is the concept of the physiological basis of the conditions for its occurrence.

The physiological basis of sensations is the work of analyzers. The physiological apparatus through which sensation arises is the analyzer. An analyzer (sensory organ) is an anatomical and physiological apparatus located on the periphery of the body or in internal organs, he receives irritation from the external and internal environment. Each such device connects the brain with the outside world and provides a variety of information. In order for a person to have normal sensations, a healthy state of all three parts of the analyzer is necessary: ​​the conductive receptor; neural pathway; cortical part.

1. 3. 2. 4. 1. Neuroconducting pathways 2. Cerebral cortex 3. Sections of analyzers in the brain 4. Taste buds

Exteroceptive Interoreceptive Proprioceptive 1. Visual 2. Olfactory 3. Gustatory 4. Auditory 5. Temperature 6. Tactile 1. Sensation of pain 2. Sensation of balance 3. Sensation of acceleration Musculoskeletal

The process of irritation consists in the appearance of an action potential in the nerve tissues and its penetration into the sensitive nerve fiber. Stimuli cause excitation in nervous tissue. The specialized part of the analyzer, through which a certain type of energy is transformed into the process of nervous excitation, is called a receptor.

Physical process stimulus Sensory organ Physiological process excitation Pathways Psychological process Center in the cerebral cortex

The quality of a sensation is a property that characterizes the basic information displayed by a given sensation, distinguishing it from other sensations. We can say this: the quality of sensation is a property that cannot be measured using numbers or compared with some kind of numerical scale. For visual sensation, quality can be the color of the perceived object. For taste or smell - chemical characterization item: sweet or sour, bitter or salty, flower smell, almond smell, hydrogen sulfide smell, etc.

It is important to understand that the intensity of the sensation depends on two factors, which can be designated as objective and subjective: - the strength of the current stimulus (its physical characteristics), - the functional state of the receptor on which a given stimulus acts. The more significant the physical parameters of the stimulus, the more intense the sensation. For example, the higher the amplitude of a sound wave, the louder the sound appears to us. And the higher the sensitivity of the receptor, the more intense the sensation.

A person exists in space, and the stimuli that act on the senses are also located at certain points in space. Therefore, it is important not only to perceive the sensation, but also to spatially localize it. 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.

Duration of sensation - it indicates the duration of existence of the sensation that has arisen. The duration of the sensation is also influenced by objective and subjective factors. The main factor, of course, is objective - the longer the effect of the stimulus, the longer the sensation. However, the duration of the sensation is influenced by both the functional state of the sensory organ and some of its inertia. After the stimulus begins to influence the sense organ, the sensation does not arise immediately, but after some time. Latent period various types sensations are not the same. For tactile sensations - 130 ms, for pain - 370 ms, 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.

General patterns of sensations: absolute threshold The absolute threshold of sensation (lower threshold of sensations) is those minimal physical characteristics of the stimulus, starting from which sensation arises. Stimuli whose strength is below the absolute threshold of sensation do not produce sensation. By the way, this does not mean at all that they do not have any effect on the body.

General patterns of sensations: The upper threshold of sensations is a high stimulus, at which it ceases to be perceived adequately. Another name for the upper absolute threshold is the pain threshold, because when we overcome it we experience pain: pain in the eyes when the light is too bright, pain in the ears when the sound is too loud, etc.

General patterns of sensations: relative threshold The relative threshold (discrimination threshold) is the minimum change in the intensity of the stimulus that causes changes in sensations.

Adaptation, or adaptation, is a change in sensitivity under the influence of a constantly acting stimulus, which is manifested in a decrease or increase in thresholds. Strong stimulus - weak sensitivity Weak stimulus - high sensitivity ADAPTATION RULE: When moving from strong to weak stimuli, sensitivity increases, from weak to strong it decreases (stimulus and sensitivity are in inverse proportion)

The interaction of sensations is a change in the sensitivity of one analytical system under the influence of the activity of another system. The general pattern of interaction between sensations is as follows: weak stimuli of one analyzer system increase the sensitivity of the other system, strong ones reduce it. For example, weak taste sensations (sour) increase visual sensitivity. Weak sound stimuli increase the color sensitivity of the visual analyzer. At the same time, there is a sharp deterioration in the various sensitivity of the eye due to the strong noise of an aircraft engine. All our analyzing systems are capable of influencing each other to a greater or lesser extent.

Increasing sensitivity as a result of the interaction of analyzers, as well as systematic exercises, is called sensitization. The possibilities for training the senses and improving them are very great.

The phenomenon of sensitization of the sense organs is observed in people long time engaged in certain types professional activity. High level The olfactory and gustatory sensations of tea, cheese, and wine tasters reach perfection. Tasters can accurately indicate not only what type of grape the wine is made from, but also the place where the grapes were grown. Painting places special demands on the perception of shape, proportions and color relationships when depicting objects. Experiments show that the artist's eye is extremely sensitive to assessing proportions. Our sensations develop under the influence of living conditions and the requirements of practical activity.

– compensatory sensitization due to the need to compensate for sensory defects (blindness, deafness); Loss of vision or hearing is compensated by the development of other types of sensitivity. There are cases where people who have lost their sight have developed skin sensitivity, they have well-developed tactile sensations and vibration sensitivity. A person suffering from deafness, by holding his hand on the throat of his interlocutor, can understand who is talking about what, and also, by picking up a newspaper, he knows whether it has been read or not. ANDREA BACHELLI RAY CHARLES DIANA GURTSKAYA

Desensitization is a decrease in the sensitivity of analyzers in the process of interaction of sensations. The interaction of sensations in some cases leads to sensitization, to an increase in sensitivity, and in other cases to its decrease, i.e., to desensitization. Strong excitation of some analyzers always reduces the sensitivity of other analyzers. Thus, increased noise levels in “loud workshops” reduce visual sensitivity.

The contrast of sensations is a change in the intensity and quality of sensations under the influence of a preliminary or accompanying stimulus. In the case of the simultaneous action of two stimuli, a simultaneous contrast occurs. This contrast can be traced in visual sensations. The same figure appears lighter on a black background, and darker on a white background. A green object against a red background appears more saturated. The phenomenon of sequential contrast is also well known. After a cold one, a weak warm stimulus seems hot. The feeling of sour increases sensitivity to sweets. If you fix your eye on a light spot for 20–40 seconds, and then close your eyes or move your gaze to a poorly lighted surface, then within a few seconds you can feel a fairly clear dark spot. This will be a consistent visual image.

Synesthesia (joint sensation) is the ability of a stimulus addressed to a specific sense organ to simultaneously evoke a sensation in another sense organ (the sight of a yellow lemon causes a sour sensation). Engineer K. L. Leontiev, using the phenomenon of synesthesia, developed a device that transforms sound signals into color ones. Color music was created based on this invention.

Complete deprivation of a person's sensory impressions, carried out for experimental purposes (for example, by immersion in water in special equipment). In response to the lack of sensations, imagination processes are activated, which in a certain way affect figurative memory. Vivid eidetic ideas arise, projected externally, which are assessed as protective (compensatory) reactions. As the time spent in S. d. conditions increases, at the stage of unstable mental activity people develop emotional lability with a shift towards low mood (lethargy, depression, apathy), which are briefly replaced by euphoria and irritability. Memory impairments are observed that are directly dependent on cyclicity emotional states. The rhythm of sleep and wakefulness is disturbed, hypnotic states develop with the appearance of hypnotic ideas, which, unlike drowsy states that occur under normal conditions, last for a relatively long time, are projected outward and are accompanied by the illusion of involuntariness. The more stringent the conditions of S. d., the faster the thinking processes are disrupted, which manifests itself in the inability to concentrate on anything, consistently think through problems, and appear

Sensations arise only when objects directly impact the sense organs. A sense organ is an anatomical and physiological apparatus located on the periphery of the body or in internal organs and specialized for receiving the effects of certain stimuli from external environment and internal organs. The main part of each sense organ is the endings of nerves, which are called receptors. A receptor is a part of an analyzer whose function is to transform external energy into a nervous process. Sensory organs such as the eye and ear, which combine dozens of receptor endings. The receptor, the nerves that conduct information about subdivisions, and the area in the cerebral cortex, which represent a single morphological structure. IP. Pavlov called it an analyzer.

Each analyzer is a nervous mechanism, which consists of three parts: 1) a peripheral section - a receptor, 2) an afferent or sensory nerve (centripetal), which conducts excitation to the nerve center three (central section of the analyzer), 3) cortical sections of the analyzer, in which are being processed nerve impulses, coming from peripheral departments. The cork part of the analyzer includes a long section, which is a projection of the periphery in the cerebral cortex, since certain parts of the cortical cells correspond to certain cells of the periphery (receptors). For sensation to arise, the entire analyzer as a whole must work.

Objects and phenomena of reality that affect our senses are called stimuli. The effect of stimuli on the sense organs is called irritation. Irritation causes excitement in the nervous tissue. Viidchuttya arises as a reaction of the nervous system to a particular stimulus and is of a reflex nature. The action of the stimulus on the receptor leads to the emergence of a nerve impulse, which is transmitted along afferent nerves to certain areas of the cerebral cortex. Reaction - the response is transmitted along the efferent (motor) nerve to the organ that responds to the senses. So, when a person touches a hot object with his hand, the signal goes to the brain and through the efferent nerves to the muscles, as a result of which they contract.

23 Types of sensations

Even the ancient Greeks distinguished five sense organs and their corresponding sensations: visual, auditory, tactile, olfactory and gustatory. Modern science significantly expanded ideas about the types of sensations. OR. Luria believes that the classification of sensations can be carried out using less than two basic principles - systematic and genetic (in other words, according to the principle of modality, on the one hand, and according to the principle of complexity and level of their construction, on the other).

Systematic classification of sensations

Based on the location of receptors on the surface of the body or inside the body, the following types of sensations are distinguished:

1) exteroceptive;

2) interoceptive;

3) proprioceptive

exteroceptive sensation- this is the largest group of sensations. They provide signals from outside world and create the basis for our consciousness. Exteroceptive sensations include visual, auditory, olfactory, sensory, tactile (tactile), thermal (temperature) and pain sensations.

interoceptive sensation- these are organic sensations, they signal the state of the internal processes of the body, bring to the brain irritations from the walls of the stomach and intestines, the heart and circulatory system and other internal organs. This is the oldest and most elementary group of sensations. They are among the least conscious and most diffuse forms of sensations and are always closely related to emotional states.

proprioceptive sensations provide signals about the position of the body in space and form the basis of human movements, playing an important role in their regulation. Peripheral receptors of proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and have the form of special nerve bodies (Paccini bodies). The excitation that occurs in these bodies reflects the sensations that occur when calculating muscle tension and changing the position of joints. This group of sensations includes a specific type of sensitivity called the sense of balance, or static sensation, their peripheral receptors are located in the canals of the inner ear. Proprioceptive sensations include kinesthetic and static sensations.

exteroceptive sensations are usually divided depending on the presence or absence of direct contact of the receptor with the stimulus causing the sensation into:

1) contact;

2) sufficient

Contact sensations are caused by the impact directly applied to the surface of the body of the corresponding organ of perception. Examples of contact sensations are taste, touch

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

Genetic classification allows us to distinguish two types of sensitivity:

1) protopathic (more primitive, affective, less differentiated and localized), which includes organic sensations (hunger, thirst, etc.);

2) epicritic (more subtly differentiated, objectified and rational), to which the main human senses belong. The sensitivity of the younger one in genetic terms is epicritical, and it controls protopathic sensitivity.

Let us dwell in more detail on the characteristics of certain types of sensations

Visual sensations play big role in human interaction with the environment. The visual apparatus is the eye, a sensory organ with a complex anatomical structure. What is the physical cause of visual sensations? The human eye perceives only a small part of electromagnetic waves. Light waves that are reflected by an object are refracted as they pass through the lens and are focused on the retina in the form of an image. The retina is connected via the optic nerve to cerebral hemispheres brain. The retina has a complex structure. One of the layers included in its composition is the layer of rods and cones, which are the final formations of the optic nerve. Rods and cones perform different functions. Rods are the organ of vision in the dark, and since under such conditions a person does not feel spectral colors, they are called non-color vision organs. Cones are the organ of “daytime” vision; they are characterized by less sensitivity to light. Since during the day a person perceives different kinds of colors, the cones are called the organ of color vision.

Visual sensations include the sensation of light and color

Auditory sensations, reflecting a wide variety of properties of sounding objects and phenomena, help a person navigate environment and regulate your actions. They are caused by sounds acting on the auditory analyzer at a distance through air vibrations and sound waves. Therefore, auditory sensations belong to distant sensations.

The sensory endings of the auditory nerve are located in the inner ear. The outer ear (pinna) collects sound vibrations and transmits them to the inner ear at the cochlea. Excitation of the nerve endings of the curls occurs according to the principle of resonance, the endings of the auditory nerve, different in length and thickness, begin to move according to a certain number of oscillations per second.

Auditory sensations include the sense of language, music and noise. With the help of auditory sensations, the following sound qualities are distinguished: strength (loud - quiet), pitch (high - low), timbre (originality of voice or musical instrument), duration (sounding time), as well as a dark-rhythmic pattern of sounds, are perceived sequentially.

Auditory sensations have great importance and in perception oral speech. Phonemic hearing, or sensitivity to speech sounds, is formed in the process of acquiring and using language. Its development affects calmness writing, especially in primary school.

Hearing sensitivity is closely related to vibration sensitivity. It is believed that in the human body there are no special receptors designed to sense vibration, and all organs and tissues of the human body are capable of reflecting vibrations.

Olfactory sensations do not have the same significance in a person’s life as visual and auditory ones, since they are not associated with orientation in the environment; their role is that they signal a person about the freshness of food, cleanliness of air, etc. In those cases, when their development is stimulated by the conditions of professional activity, they achieve significant perfection (perfumers, firefighters, etc..).

The irritants that cause olfactory sensations are microscopic particles of odorous substances that enter the nasal cavity with air, dissolve in the nasal fluid and affect the receptor. Olfactory sensations are very often combined with other senses - taste, tactile, temperature, etc. and become complex. The connection of an olfactory sensation with others can be of a conditioned reflex nature (the sight of a rose can enhance our sense of its smell).

Taste sensations are closely related to olfactory sensations; they are united by a common role in nutrition processes. The organ of taste is the tongue. Taste sensations include sour, sweet, bitter and salty. Other flavors result from the mixing of basic flavors. Taste sensations increase a person’s appetite and also perform a protective function, signaling poor quality food. The dynamics of taste sensations are closely related to the body's need for food. In a state of hunger, sensitivity increases, and when satiated, it decreases.

Skin sensations include tactile, temperature and pain sensations

Tactile sensations arise due to the impact of mechanical stimuli on the surface of the skin. The condition for their occurrence is contact with an irritant that causes deformation of the skin; tactile sensitivity is unevenly distributed throughout the body. The largest concentration of tactile receptors is on the palms, fingertips and lips.

Tactile sensations are sensations of touch and pressure. They signal the presence of a particular irritant that collides with the surface of the body. Tactile sensations reflect important properties subject of the objective world: equality, roughness, hardness, softness, dryness, moisture, etc.

Temperature sensations are divided into sensations of cold and warmth. They signal changes in the temperature environment, the danger of cooling the body or overheating, and help regulate the exchange between the body and the environment. In addition, temperature sensations give a person information about the thermal properties of objects and phenomena in the environment.

The nature of temperature sensations depends on the nature of the current stimulus. If the temperature of an object is lower than body temperature, then a feeling of cold occurs, if higher, a feeling of warmth occurs. Temperature sensations have local character, since we attribute them to a specific area of ​​the skin that is affected by irritants.

Painful sensations occur when exposed to various types of irritants (mechanical, thermal, chemical, electrical, etc.), which cause damage or destruction of body tissues. They play an important role as components of protective reflexes, signal the harm of the stimulus to the body and the need to interrupt contact with it, and have a pronounced negative emotional connotation. Painful sensations carry certain information about the stimulus; they reflect its intensity, quality (stabbing, cutting, burning pain), and location. Spatial localization The pain sensation does not always have an exact character, which is explained by the irradiation of excitation processes.

Static sensations reflect the position of the body in space and its balance. Static sensation receptors are located in the vestibular apparatus of the inner ear. This type of sensation is of great importance for the vitality of the body, since it ensures that the body maintains balance. Regulation of the body's balance is reflexive in nature. The normal operation of the static analyzer is necessary to display space using other types of sensations, in particular visual and rukhovovogo.

kinesthetic sensation (from the Greek “kinesis” - movement and “aisthesis” - sensation) is the sensation of the movements and position of parts of one’s own body. Receptors for kinesthetic sensations are found in muscles and tendons. Irritation in these receptors occurs during contraction and stretching of muscles and ligaments, and friction of joints. The result of these sensations is knowledge about the force, speed, and trajectory of movement of parts of the body.

In combination with other senses, kinesthetic sensations become specific and differentiated; in combination with visual sensations, they become important in a person’s cognition of the spatial properties of things. The combination of kinesthetic sensation with tactile sensation appears in the form of touch.

During training, it is necessary to pay attention to the development of kinesthetic sensations, which is the focus of labor, drawing, physical education lessons, as well as dancing, rhythmic gymnastics and other sports. At the same time, it is important to take into account the peculiarities of the development of this type of sensation in certain age periods.

Organic sensations are sensations associated with the activity of internal organs. These sensations, merging, form the organic feeling (well-being) of a person. This is the so-called senesthesia (general sensation), which reflects the general state of the body based on signals coming from various organs of the body. An example is the feeling of general malaise that occurs in a patient. Organic sensations include feelings of hunger, thirst, satiety, nausea, changes in the activity of the heart, stomach, and pain.

Organic sensations are caused by impulses from internal states, as well as changes chemical formula blood. They are characterized by lack of clarity, vagueness and uncertainty of localization characteristic feature th organic sensations is their emotional coloring(positive or negative).

All living beings have the ability to sense sensations. nervous system. 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 primary irritability, which is the property of living matter to respond to biologically significant environmental influences by changing its internal 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.

Potential energy signals are: light, pressure, heat, chemical substances etc.

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).

An irritant is any factor that affects the body and can cause some kind of reaction in it. It is necessary to distinguish between stimuli that are adequate for a given sense organ and those that are 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 area of ​​sensations is associated with historical development human society and with social - labor practice. “Serving” the processes of adaptation of the organism to the environment, the sense organs can successfully perform their function only if they correctly reflect its objective properties. Thus, it is not the specificity of the sense organs that gives rise to the specificity of sensations, but the specific qualities of the external world that give 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 sense organs of the subject, existing independently of him. The physiological basis of sensations is the complex activity of the sensory organs, called analyzer activity.

Analyzers are a set of interacting formations of the peripheral and central nervous systems that receive and analyze information about phenomena occurring both inside and outside the body.

The entire human body can be considered as a single and complexly differentiated analyzer of environmental impacts on humans.

The differentiation of analyzers is associated with their specialization in displaying various types of influences. The analyzer consists of three parts:

• 1. The peripheral part of the analyzers consists of receptors in which the primary transformations of external influences into internal state person.
• 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. In the cortical section (central) of each analyzer there is the core of the analyzer, 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 areas of the cortex. The peripheral (receptor) section of the analyzers consists of all sense organs - the eye, ear, nose, skin, as well as special receptor devices located in the internal environment of the body (in the digestive and respiratory organs, in the cardiovascular system, in the genitourinary organs). This section of the analyzer reacts to a specific type of stimulus and processes it into a specific excitation. Receptors can be located on the surface of the body (exteroceptors) and in internal organs and tissues (interoreceptors). Receptors located on the surface of the body respond to external stimuli. Visual, auditory, skin, taste, and olfactory analyzers have such receptors. Receptors located on the surface of the internal organs of the body respond to changes occurring inside the body. Organic sensations are associated with the activity of interoceptors. An intermediate position is occupied by proprioceptors located in muscles and ligaments, which serve to sense the movement and position of body organs, and also participate in determining the properties and qualities of objects, in particular when touching them with the hand. Thus, the peripheral section of the analyzer plays the role of a specialized, perceiving apparatus. Certain cells of the peripheral parts of the analyzer correspond to certain areas of cortical cells. Thus, spatially different points in the cortex are represented by, for example, different points The retina of the eye is represented by a spatially different arrangement of cells 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. For sensation to arise, the entire analyzer must work as a whole. The impact of an irritant on a 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 if 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.

There is no clear connection between receptors and the functions they perform. A set of hierarchical mechanisms that solve perceptual tasks of varying complexity is called a perceptual system.

Questions

Lecture 1.6. Sensations and perception

1. The concept of sensations. Physiological basis of sensations.

2. Types and properties of sensations.

3. Characteristics of the main types of sensations.

4. The concept of perception.

5. Properties and types of perception.

6. Development of the child’s sensory-perceptual sphere.

The world of human mental phenomena is diverse (mental processes, mental properties, mental states). Mental processes are divided into cognitive and emotional-volitional. In this lecture we begin to talk about cognitive processes, thanks to the functioning of which a person understands the reality around him. Cognitive processes include: sensation, perception, representation, attention, memory, imagination, thinking, speech.

Human knowledge of the world begins with the accumulation of information through the senses. To describe sensory cognition in psychology, the concepts of “sensation” and “perception” are used. Do a little experiment: ask a friend to close his eyes and touch his palm with an unfamiliar object, and then ask what he can say about the object. If the subject does not know what it is, he will answer: “Something hard, smooth, cold” or “Soft, warm, rough.” These words express the feelings that a person experiences. Sensations arise as images reflecting the individual properties of objects.

Feeling – cognitive process, in which, as a result of the direct impact of stimuli on the senses, a reflection of individual properties of objects in the objective world occurs.

Sensations are considered the simplest and primary form of orientation of the body in the surrounding world. All living beings with a nervous system have the ability to sense sensations.. Lowly organized animals reflect only individual that have direct significance for their life properties of objects and phenomena. The same for a newborn. In the first weeks of life, he reacts only to individual properties of objects. These facts indicate that sensation is the initial form of development cognitive activity.

Unlike animals, human sensations are influenced by socio-historical development. People's feelings are mediated by their practical activities, consciousness, and individual characteristics. In sensation we can roughly distinguish objective And subjective side. The objective side is associated with the characteristics of the influences of the external world, with the peculiarities of the properties of reflected objects and phenomena. The subjective side of sensations is determined by the individual characteristics of the sense organs, which are determined by both genetic and factors acquired during life. It has been proven that the nature of sensations can change under the influence of the activity being performed, illness, special exercises, etc.

Sensation is not a simple reflection of the influences of the external world by the senses. An important element of sensation is the body’s response to the impact. This reaction is indirect and active. The sensation is mediated by a person’s consciousness, his life experience, formed skills, etc. The sensation is interconnected with many mental phenomena. For example, information accumulated through the senses is a necessary condition for development thinking. There is also a direct interdependence of many sensations with emotions person (spring birdsong, sea surf, music often evoke positive emotions in a person). Feelings are always emotionally charged. The fact of different psychophysiological effects of color on a person has been experimentally proven: green calms, red excites. Of two boxes of equal weight, painted white and black, the first seems lighter, the second heavier. Special sensations coming from internal organs determine a person’s well-being and emotional tone. It is no coincidence that in the language the word “sensitivity” (meaning the characteristic cognitive function sensations) and “feeling” (experience) have the same roots.

Conscious sensations are inherent only to living organisms that have a brain and cerebral cortex. In case of disturbances in brain function or temporary shutdown of the cerebral cortex naturally or with the help of biochemical drugs, a person loses the state of consciousness and with it the ability to have sensations, that is, to feel, to consciously perceive the world. This happens during sleep, during anesthesia, and during painful states of consciousness.

Organic sensations are correlated with objects of the external world, give rise to desires, and serve as a source of volitional impulse. Movements and actions aimed at achieving a goal are regulated by sensations that are necessary to construct an action. Thus, sensations ensure human life.

Sensations are not the only form of reflection of the world. Higher forms of sensory reflection ( perception, performance) cannot be reduced to a sum or combination of sensations. Each form of reflection has a qualitative originality, but without sensations as the initial form of reflection, the existence of cognitive activity is impossible.

Without sensations, human mental activity is impossible. Currently, in connection with the task of exploring space and the bottom of the World Ocean, many experiments are being carried out to reveal the effect of sensory isolation (complete or partial absence of stimuli) on the human psyche and body. Experiments have shown that in less than a day, with complete sensory isolation, disturbances of consciousness are observed: hallucinations appear, obsessions arise. Thus, the constant “conversion of the energy of an external stimulus into a fact of consciousness,” carried out in sensations, is a necessary condition for the normal functioning of the psyche.

Physiological bases of sensations. Sensation can only arise when an object impacts a sensory organ. A sense organ is an anatomical and physiological apparatus located on the periphery of the body or in internal organs and designed to receive the effects of certain stimuli from the external and internal environment.

The physiological basis of sensation has been deeply and systematically studied within the framework of the reflex concept of I. M. Sechenov and I. P. Pavlov. It is shown that in essence sensation is a holistic reflex, uniting the peripheral and central parts of the nervous system. I. P. Pavlov introduced the concept "analyzer" and showed that the activity of analyzers reveals physiological mechanism the occurrence of sensations. Analyzer– a nervous formation that carries out the perception, analysis and synthesis of external and internal stimuli acting on the body.

The analyzer consists of 3 blocks:

1). Receptor– the peripheral part of the analyzer, which performs the function of receiving information from stimuli acting on the body. The receptor is designed to perceive a certain stimulus from the external or internal environment and to convert its energy from a physical or chemical form into the form of nervous excitation (impulse).

2). Afferent(conductive) and efferent(outgoing) paths. Afferent pathways are areas of the nervous system through which the resulting excitation enters the central nervous system. Efferent pathways are areas along which the response impulse (based on information processed in the central nervous system) is transmitted to the receptors, determining their motor activity (reaction to the stimulus).

3). Cortical projection zones(central section of the analyzer) - areas of the cerebral cortex in which nerve impulses received from receptors are processed. Each analyzer in the cerebral cortex has its own “representation” (projection), where the analysis and synthesis of information of a certain sensitivity (sensory modality) occurs.

Thus, sensation is essentially a mental process that occurs when processing information received by the brain.

Depending on the type of sensitivity, there are visual, auditory, olfactory, gustatory, cutaneous, motor and others analyzers. Each analyzer singles out stimuli of only a certain type from the entire variety of influences. For example, a hearing analyzer identifies waves generated by vibrations of air particles. The taste analyzer generates an impulse as a result of " chemical analysis» molecules dissolved in saliva, and olfactory molecules in the air. The visual analyzer perceives electromagnetic vibrations, the characteristics of which give rise to this or that visual image.

The transformation of the energy of external influence into a nerve impulse, its conduction into the brain, the formation of sensation and response - all this unfolds in time. The period of time from the application of irritation to the occurrence of a response is called latent(hidden) period. It is different for different sensations. Thus, the latent period of tactile sensations is 130 milliseconds, pain – 370.

Concept of sensation

Sensation is one of the simplest cognitive mental processes. Various information about the state of the external and internal environment human body receives sensations through the senses. Sensation is the very first connection between a person and the surrounding reality. The process of sensation arises as a result of the influence on the sense organs of various material factors, which are called stimuli, and the process of this influence itself is called irritation.

Sensations arise on the basis of irritability. Sensation is a product of development in the phylogenesis of irritability. Irritability – general property all living bodies come into a state of activity under the influence of external influences (pre-psychic level), i.e. directly affecting the life of the organism. At the early stage of development of living things, the simplest organisms (for example, the slipper ciliate) do not need to distinguish between specific objects for their life activity - irritability is sufficient. At a more complex stage, when a living person needs to identify any objects that he needs for life, and, consequently, the properties of this object as necessary for life, at this stage the transformation of irritability into sensitivity occurs. Sensitivity– the ability to respond to neutral, indirect influences that do not affect the life of the organism (example with a frog reacting to a rustle). The totality of feelings creates elementary mental processes, processes of mental reflection.

Irritation causes excitation, which travels along the centripetal, or afferent, nerves to the cerebral cortex, where sensations arise. Thus, sensation is a sensory reflection of objective reality.

Feeling- the simplest mental process of reflecting a separate quality (property) of an object under the direct influence of stimuli on the perceiving part of the analyzer.

At this level there is still no synthesis of sensations into a higher quality reflection. This is the level of the most elementary reflection. Each stimulus has its own characteristics, depending on which it can be perceived by certain senses. Thanks to sensations, a person distinguishes objects and phenomena by color, smell, taste, smoothness, temperature, size, volume and other characteristics. Sensations arise from direct contact with an object. So, for example, we learn about the taste of an apple when we taste it. Or, for example, we can hear the sound of a mosquito flying or feel its bite. In this example, sound and bite are stimuli that affect the senses. In this case, you should pay attention to the fact that the process of sensation reflects in consciousness only the sound or only the bite, without in any way connecting these sensations with each other, and, consequently, with the mosquito. This is the process of reflecting individual properties of an object.

However, the sensations are main source receipt of information for a person. On the basis of this information, the entire human psyche is built - consciousness, thinking, activity. At this level, the subject directly interacts with the material world. Those., sensations underlie all human cognitive activity.

Physiological basis of sensations

The physiological basis of sensations is the activity of complex complexes of anatomical structures, called analyzers by I. P. Pavlov. Analyzer– an anatomical and physiological apparatus for receiving influences from the external and internal environment and processing them into sensations. Each analyzer consists of three parts:

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

2) nerve pathways(afferent department - transmits excitation to the central department; efferent department - it transmits a response from the center to the periphery);

3) analyzer core– 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.