8. The concept of sensation. Physiological bases of sensations. Types and basic properties, mechanisms of changes in sensitivity, the problem of measuring sensation.
Feeling is called the mental reflection in the cerebral cortex of individual properties of objects and phenomena that directly affect the senses. For sensations to arise, it is necessary, first of all, to have objects and phenomena in the real world that affect the senses, which are called stimuli. The effect of stimuli on the sense organs is called irritation. Information about the external world can enter the brain, that is, the center that processes it, only through the sensory system, which can therefore be considered the gateway of consciousness. Sensory cell - receptor- converts the stimulus (impact) into short rhythmic electrochemical impulses. Then their flow is transmitted along nerve pathways to various switching stations of the central nervous system, where these impulses, passing from one neuron to another, are synthesized and “decoded” into a system of data about the nature of the external influence.
All living beings with a nervous system have the ability to sense sensations, but only those who have a brain with a highly developed cortex can be aware of their sensations. If the cerebral cortex is temporarily turned off (with the help of anesthesia or drugs), then a person cannot consciously respond even to severe pain.
The physiological basis of sensations is the complex activity of the sense organs. I.P. Pavlov called this activity analytical, and cell systems, the most
complexly organized and being perceptive apparatuses that directly carry out the analysis of irritations - analyzers.
The analyzer is characterized by the presence of three specific sections: peripheral (receptor), transmitting (conductor) and central (brain).
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 (interoceptors). Receptors located on the surface of the body respond to external stimuli. Visual, auditory, skin, gustatory, 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 (feelings of hunger, thirst). 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 are involved in determining the properties and qualities of objects, i.e. the peripheral section of the analyzer plays the role of a specialized, perceiving apparatus.
Depending on the location of the receptor, there are external analyzers (in which the receptors are located on the surface of the body) and internal (in which the receptors are located in the internal organs and tissues). An intermediate position is occupied by the motor analyzer, the receptors of which are located in the muscles and ligaments. Common to all analyzers are pain sensations, through which the body receives information about the destructive properties of the stimulus.
types of sensations
Classification of sensations: 1) according to the presence or absence of direct contact with the stimulus causing the sensation: 2) according to the location of the receptors, 3) according to the time of occurrence during evolution; 4) by modality (type) of stimulus.
Based on the presence or absence of direct contact of the receptor with the stimulus that causes sensation, distant (vision, hearing, smell - orientation in the immediate environment) and contact (taste, pain, tactile sensations) reception are distinguished.
The most ancient is organic (primarily pain) sensitivity, then contact (tactile) forms appeared. And the youngest evolutionarily are the auditory and visual receptor systems.
According to the modality of the stimulus, sensations are divided into visual (85% of information), auditory, olfactory, gustatory, tactile, static and kinesthetic, temperature, pain, thirst, hunger.
Visual sensations arise as a result of the influence of light rays (electromagnetic waves) on the sensitive part of the eye - the retina, which is the receptor of the visual analyzer. Light affects two types of light-sensitive cells in the retina - rods and cones. Thanks to auditory sensations (distant), a person hears speech and communicates with other people. The irritants for these sensations are sound waves - longitudinal vibrations of air particles, spreading in all directions from the sound source. The human hearing organ responds to sounds ranging from 16 to 20,000 vibrations per second. Auditory sensations reflect the pitch of sound, which depends on the frequency of vibration of sound waves; volume, which depends on the amplitude of their vibrations; timbre of sound - vibrational shapes of sound waves. All auditory sensations can be reduced to three types - speech, music, noise. Vibration sensitivity is adjacent to auditory sensations. Vibration sensations reflect vibrations of an elastic medium. This type of sensitivity is called “contact hearing.” No special vibration receptors have been found in humans. All tissues of the body can reflect vibrations of the external and internal environment. In humans, vibration sensitivity is subordinated to auditory and visual. Olfactory sensations (distant) reflect the smells of objects around us. The olfactory organs are the olfactory cells located in the upper part of the nasal cavity. Taste sensations are caused by the action of substances dissolved in saliva or water on the taste buds. Taste buds—taste buds located on the surface of the tongue, pharynx, and palate—distinguish sensations of sweet, sour, salty, and bitter. Skin sensations. There are several analyzer systems in the skin; tactile (touch sensations), temperature (cold and warm sensations), pain. The tactile sensitivity system is unevenly distributed throughout the body. But most of all, the accumulation of tactile cells is observed in the palm of the hand, on the tips of the fingers and on the lips. Tactile sensations of the hand, combining with muscle-joint sensitivity, form the sense of touch. If you touch the surface of the body and then press on it, the pressure can cause pain. Tactile sensitivity provides knowledge about the qualities of an object, and painful sensations signal the body about the need to move away from the stimulus and have a strong emotional tone. The third type of skin sensitivity is temperature sensations - regulation of heat exchange between the body and environment. The distribution of heat and cold receptors on the skin is uneven. The back is most sensitive to cold, the chest is the least sensitive. The position of the body in space is signaled by static sensations. Static sensitivity receptors are located in the vestibular apparatus of the inner ear. Sudden changes in body position relative to the ground can lead to dizziness. A special place is occupied by interoceptive (organic) sensations that arise from receptors located in the internal organs and signal their functioning. These sensations form the organic feeling (well-being) of a person. These include feelings of hunger, thirst, satiety, pain and sexual sensations.
General properties of sensations
Different types of sensations are characterized not only by specificity, but also by properties common to them. These properties include: quality, intensity, duration and spatial localization.
Quality is the main feature of a given sensation, distinguishing it from other types of sensations and varying within a given type of sensation. The qualitative diversity of sensations reflects the infinite variety of forms of matter movement.
The intensity of sensation is its quantitative characteristic and is determined by the strength of the current stimulus and the functional state of the receptor.
The duration of a sensation is its temporal characteristic. 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. When a stimulus acts on a sense organ, the sensation does not arise immediately, but after some time the so-called latent (hidden) period of sensation. The sensation does not arise simultaneously with the onset of the stimulus, nor does it 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. A positive sequential image corresponds in lightness and color to the initial stimulus and consists in preserving a trace of light stimulation of the same quality as the actual stimulus. If you light a bright lamp in complete darkness 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 presence of positive sequential images explains why we do not notice breaks between successive frames of a film: they are filled with traces of the frames that acted before - sequential images from them. The consistent image changes over time, the positive image is replaced by a negative one. With colored light sources, the sequential image turns into a complementary color.
I. Goethe in his “Essay on the Doctrine of Color” wrote: “When I walked into a hotel one evening and a tall girl with a dazzling white face, black hair and a bright red bodice entered my room, I looked intently at her standing in the twilight at some distance from me. After she left there, I saw on the light wall opposite me a black face, surrounded by a light radiance, and the clothes of a completely clear figure seemed to me to be a beautiful sea green color.”
The appearance of negative sequential images is explained by a decrease in the sensitivity of a given area of the retina to a certain color. Under normal conditions, we do not notice successive images, since the eye makes continuous movements and therefore significant fatigue of any one area of the retina is not observed.
And finally, sensations are characterized by the spatial localization of the stimulus. Analysis carried out by spatial receptors gives us information about the localization of the stimulus in space. Contact sensations correspond to the part of the body that is affected by the stimulus.
Physiological basis of sensations
Introduction
2. The concept of sensation
3. Physiology of sensations
3.1 Analyzers
3.2 Properties of sensations
3.3 Classification of sensations
4. Types of sensations
4.1 Vision
4.3 Vibratory sensations
4.4 Smell
4.7 Proprioceptive sensitivity
Bibliography
Introduction
It is known that personality is realized in activities that are possible thanks to knowledge of the environment. In ensuring a person’s interaction with the outside world, the leading role is played by the properties of the individual, his motives, and attitudes. However, every mental phenomenon is both a reflection of reality and a link in the regulation of activity. Regulation of activity begins at the level of sensations and perceptions - with mental cognitive processes. Sensations, perceptions, ideas, memory are sensory forms of cognition. Sensory reflection in a person is always associated with logical cognition and thinking. The individual in human sensory cognition is reflected as a manifestation of the general. In sensory cognition, language plays an essential role, the word, which always performs the function of generalization. In turn, logical cognition (thinking) is based on the data of sensory experience, on sensations, perceptions and memory representations. In a single process of cognition, continuous interaction of all cognitive processes takes place. More complex cognitive processes are based on sensations: perceptions, ideas, memory, thinking, imagination. We cannot learn anything about any forms of movement except through sensations. Sensation is the name given to the simplest, no longer decomposable mental process. Sensations reflect the objective qualities of an object (smell, color, taste, temperature, etc.) and the intensity of the stimuli affecting us (for example, higher or lower temperature).
1. Sensory organization of personality
The sensory organization of a personality is the level of development of individual sensitivity systems and the possibility of their unification. Human sensory systems are his sense organs, like receivers of his sensations, in which the transformation of sensation into perception occurs. Any receiver has a certain sensitivity. If we turn to the animal world, we will see that the predominant level of sensitivity of any species is a generic characteristic. For example, bats have developed sensitivity to the perception of short ultrasonic pulses, and dogs have olfactory sensitivity. main feature sensory organization of a person is that it develops as a result of all his life path. A person’s sensitivity is given to him at birth, but its development depends on the circumstances, desires and efforts of the person himself.
2. The concept of sensation
Sensation is a manifestation of a general biological property of living matter - sensitivity. Through sensation there is a psychic connection with the external and inner world. Thanks to sensations, information about all phenomena of the external world is delivered to the brain. In the same way, a loop is closed through sensations to receive feedback about the current physical and partly mental state of the body. Through sensations we learn about taste, smell, color, sound, movement, the state of our internal organs, etc. These sensations make up holistic perceptions objects and the whole world. It is obvious that the primary cognitive process occurs in the human sensory systems and, on its basis, cognitive processes that are more complex in structure arise: perceptions, ideas, memory, thinking. No matter how simple the primary cognitive process may be, it is precisely it that is the basis of mental activity; only through the “inputs” of sensory systems does the surrounding world penetrate into our consciousness.
2.1 Processing sensations
After the brain receives information, the result of its processing is the development of a response action or strategy aimed, for example, at improving physical tone, focusing more attention on the current activity, or setting up an accelerated involvement in mental activity. Generally speaking, the response action or strategy developed at any given time is best choice of the options available to a person at the time of making a decision. However, it is clear that the number available options and quality of choice are different for different people and depend, for example, on: - mental properties of the individual; - strategies for relationships with others; - partly physical condition; - experience, availability of necessary information in memory and the ability to retrieve it; - the degree of development and organization of higher nervous processes, etc.
3. Physiology of sensations
3.1 Analyzers
The physiological mechanism of sensations is the activity of the nervous apparatus - analyzers, consisting of 3 parts: - receptor - the perceiving part of the analyzer (carries out the transformation of external energy into nervous process); - central section of the analyzer - afferent or sensory nerves; - cortical sections of the analyzer, in which nerve impulses are processed. Certain receptors correspond to their own areas of cortical cells. The specialization of each sense organ is based not only on the structural features of the analyzer-receptors, but also on the specialization of the neurons that are part of the central nervous apparatus, which receive signals perceived by the peripheral sense organs. The analyzer is not a passive receiver of energy; it reflexively adapts under the influence of stimuli.
According to certain principles and containing the observer himself as one of the elements under study. Unlike sensation, in perception an image of a complete object is formed by reflecting the entire set of its properties. The process of perception includes such complex mechanisms as memory and thinking. Therefore, perception is called the human perceptual system. Perception is the result...
The human body, the integrity of the sensory reflection of the objective world. 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. Pavlova, weak...
As is known, the realization of personal potential is carried out in the process of life. This, in turn, is possible due to a person’s knowledge of the surrounding conditions. Ensuring the interaction of an individual with the outside world is determined by attitudes and motives. Meanwhile, any mental phenomenon is a reflection of reality and is a link in the regulatory system. The determining element in the functioning of the latter is sensation. Concept, physiological basis feelings, in turn, are associated with thinking and logical cognition. An essential role is played by words and language as a whole, which implement the function of generalization.
The physiological foundations of sensation, in short, are the basis on which a person’s sensory experience is formed. Its data, memory representations determine logical thinking. All, what constitutes the physiological basis of sensations, acts as a link between man and the outside world. Feelings allow us to experience the world. Let us consider further how it is characterized physiological basis of sensations in psychology (briefly).
It represents the level of development of certain sensitivity systems and the possibility of combining them. Sensory structures are called They act as. Sensory structures can be called receivers. Sensations enter them and are transformed into perception. Any receiver has a certain sensitivity. If we turn to representatives of the fauna, we can note that their physiological basis of sensations is the activity of a certain type of sensors. This, in turn, acts as a generic sign of animals. Eg, the bats sensitive to short ultrasonic pulses, dogs have an excellent sense of smell. If you touch upon physiological basis of sensations and perception human, then it should be said that the sensory system exists from the first days of life. However, its development will depend on the efforts and desires of the individual.
Before considering the mechanism of functioning of the elements of the sensory system, it is necessary to define the terminology. Sensation is the manifestation of a general biological property - sensitivity. It is inherent in living matter. Through sensations a person interacts with the external and internal world. Due to them, information about ongoing phenomena enters the brain. All, what is the physiological basis of sensations, allows you to obtain various information on subjects. For example, about their taste, color, smell, movement, sound. Sensors also transmit information to the brain about the state of internal organs. From the sensations that arise, a picture of perception is formed. Physiological basis of the sensation process allows for primary data processing. They, in turn, act as the basis for more complex operations, for example, processes such as thinking, memory, perception, and representation.
It is carried out by the brain. The result of data processing is the development of a response or strategy. It can be aimed, for example, at increasing tone, greater concentration of attention on the current operation, and setting up for accelerated inclusion in the cognitive process. The number of available options, as well as the quality of the choice of a particular reaction, depends on various factors. In particular, the individual characteristics of the individual, strategies for interaction with others, the level of organization and development of higher nervous functions, and so on will be important.
Physiological basis of sensations is formed due to the functioning of special nervous apparatus. They include three components. The analyzer distinguishes:
Specific receptors correspond to certain areas of the cortical regions. Each sense organ has its own specialization. It depends not only on the structural features of the receptors. The specialization of neurons that are included in the central apparatus is also important. They receive signals passing through the peripheral sense organs. It should be noted that the analyzer is not a passive receiver of sensations. It has the ability to reflexively rearrange itself under the influence of stimuli.
Allows you to describe data received through sensors. Any information can be characterized by its inherent properties. The key ones include duration, intensity, spatial localization, and quality. For example, the latter is a specific feature of a particular sensation by which it differs from the rest. Quality varies within a given modality. Thus, in the visual spectrum, properties such as brightness, hue, and saturation are distinguished. Auditory sensations have such qualities as pitch, timbre, volume. With tactile contact, the brain receives information about the hardness, roughness of the object, and so on.
What can they be? physiological basis of sensations? Classification of sensations can be carried out according to different signs. The simplest is differentiation according to the modality of the stimulus. Accordingly, on this basis we can distinguish and. Modality is a qualitative characteristic. It reflects the specificity of sensations as the simplest mental signals. Differentiation is carried out depending on the location of the receptors. Based on this feature, three groups of sensations are distinguished. The first includes those associated with surface receptors: skin, olfactory, gustatory, auditory, visual. The sensations that arise in them are called exteroceptive. The second group includes those associated with sensors located in the internal organs. These sensations are called interoreceptive. The third group includes those that are associated with receptors located on muscles, tendons and ligaments. These are motor and static sensations - proprioceptive. Differentiation is also carried out by sensor modality. Based on this feature, sensations are distinguished into contact (gustatory, tactile) and distant (auditory, visual).
Physiological basis of sensations- complex elements of a single sensory system. These links make it possible to recognize different properties one item at a time. This is due to the fact that they react to certain stimuli. Each receptor has its own agent. In accordance with this, the following are distinguished:
The emotional connotation of pain is particularly strong. They are visible and audible to others. Temperature sensitivity varies in different parts of the body. In some cases, a person may experience pseudo-sensations. They are expressed in the form of hallucinations and appear in the absence of a stimulus.
The eye acts as a perceiving apparatus. This sense organ has a rather complex structure. Waves of light are reflected from objects, refracted when passing through the lens, and are recorded on the retina. The eye is considered a distant receptor because it gives an idea of objects located at a distance from a person. Reflection of space is ensured by the parity of the analyzer, changing the size of the image on the retina when approaching/moving away from/to an object, the ability to bring the eyes together and apart. The retina contains several tens of thousands of nerve endings. When exposed to a wave of light, they become irritated. Nerve endings are distinguished by function and shape.
Sensitive endings that allow us to perceive sound are located in the inner ear, the cochlea with a membrane and hairs. The external organ collects vibrations. The middle ear directs them to the cochlea. The sensitive endings of the latter are irritated due to resonance - nerves of different thickness and length begin to move when a certain number of vibrations are received per second. The received signals are sent to the brain. Sound has the following properties: strength, timbre, pitch, duration and tempo-rhythmic pattern. Phonemic hearing is the ability to distinguish speech. It depends on the environment and is formed throughout life. With good knowledge foreign language is being produced new system phonemic hearing. It influences writing literacy. It develops similarly to speech. Rustles and noises are of less importance for a person if they do not interfere with his activities. They can also evoke pleasant emotions. For example, many people like the sound of rain and the rustling of leaves. Moreover, such sounds can also signal danger. For example, the hiss of gas.
It is considered a type of auditory sensation. Vibration sensitivity reflects environmental vibrations. It is figuratively called contact hearing. Humans do not have special vibration receptors. Scientists believe that this sensitivity is the oldest on the planet. At the same time, all tissues in the body can reflect fluctuations in the external and internal environment. Vibration sensitivity in human life is subordinate to visual and auditory. Its practical importance increases in those areas of activity where vibrations act as signals of malfunctions or danger. Deaf-blind and deaf people have increased vibration sensitivity. It compensates for the lack of other sensations.
It refers to distant sensations. The elements of substances penetrating into the nasal cavity act as irritants that cause olfactory sensitivity. They dissolve in liquid and affect the receptor. In many animals, smell is the main sense. They navigate by smell when looking for food or escaping from danger. The human sense of smell has little to do with orientation. This is due to the presence of hearing and vision. The instability and insufficient development of olfactory sensitivity is also indicated by the absence in the vocabulary of words that accurately denote sensations and at the same time are not related to the object itself. For example, they say “the smell of lilies of the valley.” The sense of smell is related to taste. It helps to recognize the quality of food. In some cases, the sense of smell allows one to distinguish substances by their chemical composition.
It refers to contact sensations. Taste sensitivity is caused by irritation of the receptors located on the tongue with the object. They allow you to identify sour, salty, sweet, bitter foods. The combination of these qualities forms a set of taste sensations. Primary data processing is carried out in the papillae. Each of them has 50-150 receptor cells. They wear out quite quickly when in contact with food, but have a restoration function. Sensory signals are sent to the gustatory cortex through the hindbrain and thalamus. Like olfactory sensations, these sensations increase appetite. Receptors, assessing the quality of food, perform a protective function, which is very important for survival.
It contains several independent sensory structures:
Skin sensitivity belongs to the group of contact sensations. The maximum number of sensory cells is found on the palms, lips and fingertips. The transfer of information from receptors occurs in spinal cord due to their contact with motor neurons. This ensures the implementation of reflex actions. For example, a person withdraws his hand from something hot. Temperature sensitivity ensures regulation of heat exchange between the external environment and the body. It is worth saying that the distribution of cold and heat sensors is uneven. The back is more sensitive to low temperature, the chest is less sensitive. The painful sensation occurs due to strong pressure on the surface of the body. Nerve endings are located deeper than tactile receptors. The latter, in turn, allow us to form an idea of the qualities of the object.
It includes sensations of movement and staticity of individual elements of the body. Receptors are located in tendons and muscles. Irritation is caused by muscle contraction and stretching. Many motor sensors are located on the lips, tongue, and fingers. This is due to the need for these parts of the body to perform subtle and precise movements. The operation of the analyzer provides control and coordination of movement. The formation of speech kinesthesia occurs in infancy and preschool age.
Static or gravitational sensations allow a person to understand his position in space. The corresponding receptors are located in the vestibular apparatus in the inner ear. The sacs and canals transform signals about relative movement and gravity, then transmitting them to the cerebellum, as well as to the cortex in the temporal region. Sudden and frequent changes in the position of the body relative to the surface of the earth can lead to dizziness.
The physiological basis has particular practical significance. Its study makes it possible to determine the penetration paths of signals from the outside, distribute them among receptors, and trace the progress of primary information processing. The physiological basis of sensations in psychology is the key to understanding the properties of the human sensory system. The analysis allows us to identify the causes of certain sensitivity deviations and assess the degree of influence of certain stimuli on the receptors. The information obtained is used in a variety of scientific and industrial fields. Research results have a special role in medicine. Studying the properties of receptors and stimuli allows us to create new medications, develop more effective tactics for treating mental and other diseases.
The physiological basis of sensations is the activity of complex complexes of anatomical structures, called analyzers by I. P. Pavlov. An analyzer is 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) a peripheral section called the receptor (the 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) conductive nerve pathways (afferent section - transmits excitation to the central section; efferent section - it transmits a response from the center to the periphery);
3) the core of the analyzer - 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.
Thus, the organ of sensation is the central section of the analyzer.
Physiology of attention
| Experiments with the dissected hemisphere of the brain show that attentional processes are closely related to the functioning of the corpus callosum, with the left hemisphere providing selective attention and the right hemisphere providing support general level alertness. According to the ideas of I.P. Pavlov, attention reflects the presence of a focus of excitation in the cerebral cortex, which, in turn, is a manifestation of an unconditioned orienting reflex. Such a focus of excitation, due to the process of negative induction, inhibits neighboring areas of the cerebral cortex, and at the same time all the mental activity of the body is concentrated on one object. According to Ukhtomsky, attention is determined by the dominant - the dominant, stable focus of excitation in the cortex. The dominant not only inhibits other foci of excitation, but is also able to intensify due to them, switching to itself the processes of excitation that arise in other nerve centers. The intensity of attention is especially pronounced when the goal is determined by biologically significant motivation (hunger, thirst, sexual instinct). In this case, there is a kind of “pumping” of nervous energy from the area of the brain associated with satisfying the need to the area of the cortex associated with a certain object in the external world. According to modern scientific data, in the process of activating attention, in addition to the cerebral cortex, other brain structures also play an important role. For example, the thalamus serves as a kind of filter, filtering out some information and transmitting only new and important signals to the cortex. The reticular formation activates the brain and is an important energetic component of the attention process. PHYSIOLOGY OF CONSCIOUSNESS There is a wide variety of opinions expressed about what consciousness is. Consciousness can be defined as a subjectively experienced sequence of events, as opposed to unconscious processes. Consciousness is often associated with a person's awareness of what is happening to him or what he perceives. Philosophy considers consciousness as a set of certain cognitive operations associated with the subjective experience of one’s thoughts, feelings, impressions and the ability to convey them to others through speech, actions or creative products. This is shared by P.V. Simonov, who considers consciousness as shared knowledge. The physiological prerequisite for consciousness is wakefulness. During wakefulness, the activity of higher centers increases and their threshold of excitation decreases. This condition is facilitated by the activating effect of the reticular formation of the brain stem. According to Pavlov's conditioned reflex theory, signals are recognized when they acquire the character of elements of the second signal system, that is, they are expressed in words. External stimuli are not only perceived, but the subject is aware of the fact of this perception. The problem of the conscious and unconscious came into focus only thanks to the work of Freud. Freud's concept, although much of it has now been discarded, still has a significant influence on modern scientific thinking and must be seen in its proper perspective. Unconscious information processing processes, the influence of which the subject is not aware of, are usually classified as the unconscious. There are three groups of manifestations of the unconscious. The first group is preconscious. It covers our biological needs, expressed in unconditioned reflexes and innate forms of behavior (instincts), as well as in genetically specified properties of temperament. The second group of the unconscious is the subconscious. It includes everything that was previously realized and can again become conscious under certain conditions. These are various automated skills, stereotypes of automated behavior. These also include unconscious motivators of activity (motives, semantic attitudes), norms of behavior deeply internalized by a person, and motivational conflicts repressed from the sphere of consciousness. In the process of evolution, the subconscious arose as a means of protecting consciousness from unnecessary work and intolerable stress. It protects a person from unnecessary energy expenditure and protects against stress. The third group of unconscious phenomena is superconsciousness, or intuition associated with creative processes that are not controlled by consciousness. Superconsciousness is a source of new information, hypotheses, discoveries. Superconsciousness is understood as the highest stage of the creative process. Its neurophysiological basis is the transformation of memory traces and the birth of new combinations from them, the creation of new temporary connections, and the generation of analogies. We are aware of the existence of our own mental processes. This overlapping phenomenon is the basis of self-awareness. In connection with our sensations, actions and experiences, we become aware of the existence and unity of our personality. The question arises: how did this human ability to become aware of mental processes related to the environment develop? As noted, awareness involves the simultaneous reflection of events in the form of speech or thought (“inner speech”). The development of speech function simultaneously meant the emergence of consciousness. The language of primitive people was extremely specific: each natural phenomenon was called by its own name. For example, there were different words for rainy weather, clear weather and sunny weather, and the abstract concept of “weather” did not exist. In the process of increasingly differentiated labor activity and social development, from this unconscious, monosyllabic, concrete, emotional speech, our conscious, articulate, abstract and rational speech developed. The physiological basis for the generalization of secondary signals must be sought in the processes of irradiation and generalization of excitation in the cerebral cortex. When we express general qualities surrounding objects, abstraction processes lead to the fact that words become concepts. Concepts arise as a result of separating essential properties and relations from non-essential ones. In the brain this occurs in the form of a concentration of excitation. Thus, the physiological basis of abstraction is the irradiation and concentration in brain neurons of newly formed signals, expressed in verbal form. A person's thoughts can be thought of as "inner speech." Excitation related to the second signaling system occurs in this case, but it does not cause motor reactions, i.e. movements necessary to pronounce words. Consciousness is thus associated with the second signaling system. G.P. Grabovoy considers human consciousness as an element of the world in which all elements are interconnected, then a change in a person’s consciousness (or the form of an object’s reaction) entails a change in all other elements of the world, allows one to gain knowledge about the external environment and optimize the processes occurring in it. The advantage of consciousness is that the process can be monitored literally continuously. The consciousness of the cell, which is the primary element of life, is inextricably linked with the material components, which ensures the harmonization of life at all levels of existence of living things: the morphological integrity of the structures of the body is determined by the speed and usefulness of cell self-renewal; the stability of tissue functioning is ensured by optimal exchange of information between cells; the full function of the organs depends on the final result of the work, taking into account the informational influences of other organs; homeostasis of the entire organism is determined by the adequacy of the external signal and the state of the structures that perceive it. These levels are interconnected by stage-by-stage information interactions, the degree of ordering and generalization of which determines the selectivity of functioning. |
Physiological basis of perception.
The physiological basis of perception is the processes taking place in the sensory organs, nerve fibers and the central nervous system. Thus, under the influence of stimuli at the endings of the nerves present in the sensory organs, nervous excitation arises, which is transmitted along pathways to the nerve centers and, ultimately, to the cerebral cortex. Here it enters the projection (sensory) zones of the cortex, which represent, as it were, the central projection of the nerve endings present in the sense organs. Depending on which organ the projection zone is connected to, certain sensory information is generated.
The mechanism described above is the mechanism by which sensations arise. Therefore, sensations can be considered as structural element process of perception. Own physiological mechanisms of perception are included in the process of forming a holistic image at subsequent stages, when excitation from the projection zones is transferred to the integrative zones of the cerebral cortex, where the formation of images of real world phenomena is completed. Therefore, the integrative zones of the cerebral cortex, which complete the process of perception, are often called perceptual zones. Their function differs significantly from the function of projection zones.
The physiological basis of perception is further complicated by the fact that it is closely related to motor activity, emotional experiences, and various thought processes. Consequently, having begun in the sense organs, nervous excitations caused by external stimuli pass to the nerve centers, where they cover various zones of the cortex and interact with other nervous excitations. This entire network of excitations, interacting with each other and widely covering different zones of the cortex, constitutes the physiological basis of perception.
From a practical point of view main function perception is to ensure recognition of objects, i.e. assigning them to one category or another. Essentially, when we recognize objects, we make inferences about many hidden properties of the object. Any object has a certain shape, size, color, etc. All these properties are important for its recognition.
Currently, it is customary to distinguish several stages in the process of object recognition, some of which are preliminary, others are final. In the preliminary stages, the perceptual system uses information from the retina and describes the object in terms of elementary components such as lines, edges and corners. At the final stages, the system compares this description with descriptions of the shapes of various kinds of objects stored in visual memory, and selects the best match. Moreover, during recognition, most of the information processing, both at the preliminary and final stages of recognition, is inaccessible to consciousness.
THINKING ACTIVITY
Mental activity is an executive
apparatus functional systems mental level. Due to mental
activities are carried out using information
processes in the brain, a kind of “behavior” at the information level.
Nodal mechanisms of mental activity. From a general perspective
theory of functional systems, the thinking process includes universal
system node components:
Result as the leading system-forming factor of thinking
human activity;
Assessing the result of mental activity using feedback
afferentation;
The system-organizing role of the original biological and social
needs and the dominant ones formed on their basis
motivations in constructing mental activity;
Programming mental activity using the device
acceptor of the result of action based on the mechanisms of afferent
synthesis and decision making;
Effective expression of thought processes through behavior,
somatovegetative components and through specially
organized apparatus of speech.
Information equivalents of mental activity.
The operational architectonics of mental activity is built on the basis
emotional and verbal equivalents of reality. This is in
in a certain sense, it is consonant with the teachings of I.P. Pavlova about the first and second signal
systems of reality. However, if the representations of I.P. Pavlova
were based on information assessment of signals (conditioned stimuli
physical and verbal nature), then from the standpoint of the systemic organization of mental activity, the information content
functional systems of the mental level determine the corresponding adaptive
results for human activity. In case the results
activities have only physical parameters, then the corresponding
the functional systems of mental activity they organize are built
on information equivalent physical properties these
results. If the results of the activity have speech, verbal
parameters corresponding to the functional systems of the mental
activities are built on an informational verbal basis.
Only humans have the informational equivalent of functional
systems of mental activity is associated with speech function. In animals these
processes are limited to physical and emotional levels.
The emotional basis of mental activity. Thinking process
continuously accompanied by subjective emotional
a person’s experiences of his needs and subjective attitude towards
influence of factors external environment in order to meet these
needs. With the help of emotions, traces of memory are also realized. Emotions
a person evaluates his needs, the effect of environmental factors,
attitude towards objects and other individuals and, finally, satisfaction
needs. Mental needs, as well as biological ones, like
usually accompanied emotional sensations negative
character, and satisfaction of needs - diverse
positive emotions. Based on repeated satisfaction of the same type
mental needs, a positive anticipation is formed
emotions of need satisfaction due to its inclusion in the acceptor apparatus
result of the action. In a certain situation, it is foreseen and
negative emotions, which ultimately creates probabilistic forecasting
emotional states. Systemic organization of thinking on
emotional basis is genetically determined. It already appears in
newborns, deaf-blind people, as well as people in a circle
persons speaking a language foreign to them. Emotional basis
thinking, as experiments with self-irritation show, is also characteristic
for animals.
Pathological ones are built on strong emotional sensations
craving for alcohol and drugs. Emotional states
under certain circumstances can build independently
functional systems.
The verbal basis of mental activity. Verbal quantization
thinking is inherent only to man. A person's assessment of needs and their
satisfaction, as well as various external influences on the body
along with emotional sensations is carried out with the help
linguistic symbols, phrases, verbal and written concepts
character. This level of thinking requires special training, firstly
turn to the language. With the help of linguistic symbols, thoughts are realized in
discrete phrases that can constitute inner speech, as well as
transform into external speech and actions.
Mental activity that is formed in a person on verbal
basis, in comparison with emotional activity acquires
qualitatively new information properties, although its general architectonics
retains all the typical features of a functional system.
A type of verbal quantization of mental activity
is the process of singing. An emotional person can
learn a certain melody and fill this melody with appropriate
words that add up to systemic quanta - measures and couplets.
Brain asymmetry in the processes of mental activity.
The emotional and verbal basis of thinking, as shown by modern
research, is built by the functions of different hemispheres of the brain. Right
hemisphere determines predominantly sensual, emotional
component of mental activity. The left hemisphere determines functions
language and speech. The idea of
activity of the cerebral hemispheres based on their mutual complementarity. This
point of view fits well with functional systems theory. WITH
positions of the theory of functional systems in the implementation of effective
mental activity of both hemispheres on emotional and speech
basis should dynamically contribute to the achievement of the subject
adaptive results.
Structural foundations of mental activity. Processes
mental activity and human speech are associated with the activities of various
brain structures. Identify the participation of brain structures in these processes
allow clinical observations of patients with lesions in various areas
Agnosia. When the occipital parts of the cerebral cortex are damaged, a person sees
objects, walks around them without bumping into them, but does not recognize them. This
the violation of recognition is called agnosia (from the Greek gnosis - knowledge). At
In violation of the temporal parts of the cerebral cortex, auditory agnosia is observed.
A person hears sounds, but does not associate them with a specific sound
subject. Such patients lose the ability to perceive the meaning of speech
interlocutor. When the superior parietal cortex is damaged, patients experience
tactile agnosia - subjects lose the ability to recognize objects when
their feeling, although they feel the touch.
From a systemic point of view in subjects with visual, temporal
and parietal areas of the cortex, the mechanism of previously developed assessment is disrupted
results of action.
Apraksin. In case of damage to the motor cortex in humans
there is a violation of purposeful action, although he understands that
need to do. This disorder is called “apraxia” (from the Greek.
praxis - action). The patient cannot, for example, light a match, cut
apple, fasten the buttons, although his hands are not paralyzed. In this case
one can think about disruption of systemic processes of efferent synthesis and
actions.
Aphasia - speech disorder; motor aphasia develops when
dysfunction of the inferior frontal gyrus of the left hemisphere (frontal aphasia
Broca). The patient understands the speech of the interlocutor, but his own speech
extremely difficult or completely disrupted. In this case, it is lost
be saved. Patients are able to scream, make individual sounds, But
They cannot utter a single meaningful word. Patients have impaired
efferent processes of speech formation.
Sensory aphasia occurs when the posterior pole of the superior
temporal cortex (sensitive, or temporal, Wernicke's aphasia). Wherein
in patients, the processes of speech perception are disrupted: they stop
understand both audible and written language. The ability to pronounce
speech phrases in such patients are not lost, they are even excessively
They are talkative, but their speech is distorted and completely incomprehensible. Such people
music (amusia). It can be assumed that in such patients the mechanisms
acceptor of the result of action and the ability to evaluate what has been achieved
the result of mental activity.
Other disorders are observed with damage to the parietal cortex:
patients forget individual words, more often nouns, cannot
remember the necessary words and replace them with a long description. Wherein
There is also a counting disorder (acalculia). Patients are impaired
RAM mechanism.
With bilateral damage to the base of the temporal and occipital
unusual agnosia is observed in the lobes of the cortex: patients cease to recognize
people by their faces (prosoagnosia), but nevertheless recognize them by
The visual parameter for assessing familiar personalities is selectively affected.
In case of damage to the angular gyrus without damage nearby
located Wernicke's area and Broca's area in patients in the absence of violation
perception of auditory information and speech; difficulties appear in
understanding written speech and pictures (anomic aphasia). In this case
the transmission of visual information to Wernicke's area is disrupted.
Morphofunctional bases of visual object recognition.
Dynamics of subject recognition of a visual image and its reproduction
can be represented as follows. Primary identification and
evaluation of a visual object occurs in the primary visual cortex.
From here the excitation spreads to the angular gyrus and from it to
temporal zone Wernicke, where an object is valued based on previously acquired
verbal concepts and knowledge. Excitement from Wernicke's area
spreads to Broca's area and to the speech motor structures of the motor cortex,
which determine the pronunciation of the name of the object.
Functions of speech in right-handers and left-handers. Speech functions in right-handed people, like
usually associated with the activity of the left hemisphere, which determines
processes of sequential analytical activity. Right hemisphere
right-handers determine spatiotemporal relationships, for example
recognition of faces, identification of objects by their shape, recognition
musical melodies. Such a strict division of functions is relative.
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; it 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 Conducting 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 this 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 – sensitivity high RULE ADAPTATIONS: 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. General pattern The interaction of sensations is as follows: weak stimuli of one analyzing 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 senses is observed in people who engage in certain activities for a long time. 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 SD 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 the cyclical nature of 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
