The idea of the typological features of the nervous system of humans and animals is one of the determining factors in the doctrine of higher nervous activity. VND type is a complex of individual characteristics of GNI, determined by hereditary factors and the influence environment characterized by strength, mobility and balance nervous processes(excitation and inhibition) and a certain ratio of the first and second signaling systems.
Most important property VND – the strength of nervous processes. The strength of nervous processes is understood as the ability of neurons to withstand prolonged excitation without transition to extreme inhibition under the influence of a strong stimulus. According to the strength of nervous processes, all people can be divided into two types: strong and weak.
The second property that forms the basis for the classification of types of intravenous activity is the balance between the processes of excitation and inhibition. They can be balanced, but they can also dominate one over the other. Persons with a weak nervous system easily develop protective over-the-top inhibition. Therefore, it is impossible to consider the property of balanced processes in them. The strong type can be divided on this basis into balanced and unbalanced.
The third property of the nervous system is mobility, which is characterized by the speed of mutual transitions of the processes of excitation and inhibition. In accordance with this I.P. Pavlov identified four types of GNI in animals and humans (Fig. 13.4), which made it possible to give a scientific explanation for the existence of four types of Hippocratic temperament - sanguine, phlegmatic, choleric, melancholic.
1. Strong balanced mobile (living) type– the processes of excitation and inhibition are well expressed, balanced and easily transform into one another. People easily overcome difficulties (strength), are able to quickly navigate new environment(mobility), with great self-control (poise).
2. Strong balanced inert (calm) type– a person is endowed with good strength of nervous processes and balance, but low mobility, inertia of nervous processes. People are efficient (strength), but slow, do not like to change their habits (inertia).
3. Strong unbalanced (uncontrolled) type– characterized by a strong process of excitation, which prevails over inhibition. People are very enthusiastic and can do a lot (strength), but are very hot-tempered and unpredictable (imbalance).
4. Weak type– characterized weak processes excitation and easily occurring inhibitory reactions. People are weak-willed, afraid of difficulties, easily subject to the influence of others, and prone to a melancholy mood.
Rice. 13.4. Scheme of types of higher nervous activity (according to I.P. Pavlov)
Belonging to one or another type of GNI does not at all mean an assessment of the biological fitness of an animal or the social usefulness of a person. This is evidenced by the fact that all four general types of animal nervous systems have withstood the merciless test of time in evolution. There is no reason to consider people of different types of nervous systems as “different kinds” of people. Everyone is needed and can find their place in life.
Observing various forms of behavior, the peculiarities of thinking and emotional activity of people, I.P. Pavlov proposed another classification of VND types, based on the interaction of signaling systems I and II. According to Pavlov, there are three types of people: thinking, artistic and mixed.
1. For people artistic type characterized by the predominance of concrete-figurative thinking, based on the activity of the more developed first signaling system of reality. These people are most prone to synthesis. Representatives of people with a pronounced artistic type I.P. Pavlov believed L.N. Tolstoy and I.E. Repina.
2. For people thinking type characterized by the predominance of the second signaling system of reality. They are more prone to analytical, abstract, abstract thinking. To this type of VND I.P. Pavlov attributed the famous German philosopher Hegel, the creator of the theory of the origin of species to the English scientist Charles Darwin.
3. There are categories of people who have equally developed first and second signaling systems. People with specified type prone to both abstract and sensory-figurative thinking. Their I.P. Pavlov attributed to mixed type. Among the outstanding figures of science and art, Pavlov included the multi-talented Leonardo da Vinci, a brilliant artist and mathematician, anatomist and physiologist, in this category. According to the scientist, the German poet and philosopher Goethe, the creator of periodic table elements D.I. Mendeleev, outstanding chemist, talented Russian composer A.P. Borodin.
Brain asymmetry
For the vast majority of people, the motor activity of the arms, legs, left and right half of the body, and faces are not the same. The perception of objects located to the left or right of the middle plane of the body is also ambiguous. In other words, a person has inherent motor and sensory asymmetry. To perform labor operations in everyday life, most people use their right hand, i.e. are right-handed. At the same time, the right hand is superior to the left in dexterity, strength, reaction speed, and the ability to clearly perform complex coordinated actions. A significantly smaller part of humanity (left-handed people) uses their left hand for the same purposes. In addition, there are people who use both hands equally - the so-called ambidextrous people. A stable preference for one of the hands is characteristic only of a person who stands out from other groups of living beings on this basis. The proportion of left-handers, according to various authors, ranges from 1 to 30%. Motor and sensory asymmetries, i.e. the dominance of the hands (legs) and sensory organs (vision, hearing, touch) may not coincide for each individual.
In newborn children, both hands are equal. If preferences in their use arise in the first years of life, they do not last long and can change many times. Only in the fifth year of life does the right hand of future right-handers gradually begin to take on all complex activities. It is assumed that in old age the opposite process occurs, and the inequality of hands is gradually smoothed out.
In girls and women, the asymmetry of the hands is less pronounced, and among them there are 1.5 - 2 times fewer left-handers than among representatives of the “stronger” sex. Improving the brain functions of girls stretches over a longer period and occurs slowly. In boys, already at the age of six, many functions are performed separately by the right and left hemispheres of the brain, while in girls twice as old, the specialization of the brain is often just emerging.
It is especially interesting that among twins, left-handers are found much more often than among those born alone, and both twins are rarely left-handed. Usually one of the twins always becomes right-handed. If the twins are of different sexes, then the boy is more likely to be left-handed. Among Siamese twins, as a rule, one is right-handed and the other is left-handed.
In right-handed people, Broca's speech center is located in the left hemisphere of the brain. On the right side of the cerebral hemisphere there is a structurally identical area of the brain, damage to which, however, does not lead to any consequences for them. On the contrary, if the left motor area of speech fails, right-handers experience motor aphasia. In any case, in approximately 3% of the population the speech area exhibits full functional capacity in both hemispheres of the brain. It is noteworthy that the dominant speech center in left-handed people is not always the right region - in most cases, their dominant speech center is also located in the left temporal lobe of the brain. With prolonged disruption of Broca's speech center, the right hemisphere can gradually take over its functions. If in a child the process of redistribution of the functions of the cerebral hemispheres occurs relatively quickly (about a year), then with age the reserve function increasingly remains with the right hemisphere. The localization of Broca's speech area in the left hemisphere of the brain is, apparently, the most characteristic example of specialization of both hemispheres. All other functions of the brain do not have such a pronounced dominance.
As you know, between both hemispheres of the brain there is a corpus callosum, in which millions of nerve endings create an intense cross-connection. A more pronounced corpus callosum in women is one of the reasons for the less asymmetry of the cerebral hemispheres in them. If this corpus callosum is dissected, then each hemisphere of the brain will be isolated, left to its own devices. The right hemisphere can still control the movements of the left arm and left leg (in the spinal cord, nerve fibers cross so that neurons in the right hemisphere travel along nerve pathways to the left side of the body). For example, when feeling a nail with the left hand, the impressions received freely reach the brain and consciousness, but the patient is not able to name this object, since the Broca speech center located in the left hemisphere is responsible for verbal designation, the connection with which is interrupted as a result of the dismemberment of the corpus callosum. When feeling objects with the right hand, such problems do not arise. The speech center receives the necessary information. The same thing happens if an object is viewed only with the left field of vision or sound is perceived only with the left ear.
The above examples indicate that the left hemisphere of the brain plays a leading role in the implementation of speech function. But this does not mean that the right hemisphere is unnecessary or secondary. For example, in areas such as spatial orientation, shape recognition and understanding of music and voice intonation, it is superior to the left hemisphere.
The specialization of both hemispheres of the brain allows us to conclude that the human brain, to a certain extent, has the ability to “self-repair” when the functions of one or another hemisphere are impaired. When one hemisphere fails, the second may turn on without achieving the full effectiveness of the dominant hemisphere. This fact is of fundamental importance, for example, in case of damage (death) of brain tissue after a stroke; intense long-term exercise can lead to significant restoration of hemispheric function and a certain volume restore lost skills. Of course, this process occurs slowly and does not always lead to complete functional restoration, but in most cases it is possible.
It has been established that the right hemisphere is responsible for homeostasis, and therefore ensures biological adaptation, and the left hemisphere ensures social adaptation. It is no coincidence that women whose interhemispheric asymmetry is less pronounced tend to have a more advanced adaptation strategy to various conditions.
The differences between the functions of the right and left hemispheres are shown in Table 13.1.
Table 13.1.
Interhemispheric asymmetry
| Left hemisphere | Right hemisphere |
| BETTER RECOGNIZE INCENTIVES | |
| Verbal | Not verbal |
| Easily distinguishable | Difficult to see |
| Iconic | Unsigned |
| TASKS PERFORMED BETTER | |
| For a temporary relationship | On spatial relations |
| Establishing similarities | Making Differences |
| Stimulus identity by name | Identity of stimuli by physical properties |
| Creative, where imagination is needed | Don't like creative tasks |
| FEATURES OF PERCEPTION | |
| Analytical perception | Holistic Perception |
| Sequential perception | Simultaneous perception |
| Generalized recognition | Specific recognition |
| FEATURES OF BEHAVIOR AND PSYCHE | |
| Abstract logical thinking | Concrete-imaginative thinking |
| Based on reality | Based on fantasy |
| Perception native language | Perception of foreign languages |
| Have good handwriting | Have bad handwriting |
| Work is completed on time, there is a sense of time | Don't finish work on time, no sense of time |
| Leading voluntary attention | Involuntary attention lasts for a long time |
| Good concentration | High distractibility |
Our educational system, as well as our science, generally tends to ignore the non-verbal form of intelligence. Thus, modern society discriminates against the right hemisphere. In 1981, the American neurologist R. Sperry received the Nobel Prize for the discovery of functional asymmetry of the brain.
Physiology of sleep
Sleep is a periodic functional state of a person, characterized by the absence of purposeful activity and active connections with the environment. During sleep, brain activity does not decrease, but is rebuilt. A person spends a third of his life sleeping: he sleeps 25 out of 75 years.
An analysis of a number of facts led I.P. Pavlov to the conclusion that sleep and conditioned inhibition by their nature are a single process. The only difference between them is that conditioned inhibition during wakefulness covers only certain groups of neurons, while during the development of sleep, inhibition radiates through the cerebral cortex, spreading to the underlying parts of the brain.
Sleep developing in humans and animals under the influence of conditioned inhibitory stimuli, I.P. Pavlov called it active, contrasting it with passive sleep, which occurs in cases of cessation or sharp restriction of the influx of afferent signals to the cerebral cortex.
The importance of afferent signaling in maintaining a state of wakefulness was shown by I.M. Sechenov, who cites cases of the onset of prolonged sleep known from clinical practice in patients suffering from common sensory organ disorders.
The clinic observed a patient who, of all his sense organs, retained the functions of only one eye and one ear. As long as the eye could see and the ear could hear, the person was awake, but as soon as the doctors closed these only ways of communication with the outside world for the patient, the patient immediately fell asleep. HELL. Speransky and V.S. Galkin cut the dog’s visual and olfactory nerves and destroyed both cochleae of the inner ear. After such an operation, the dog fell into a sleepy state, which lasted over 23 hours a day. She woke up only briefly from hunger or when her rectum and bladder were full.
All these facts received a new explanation after the functional significance was established reticular formation and the interaction between it and the cerebral cortex was clarified.
Afferent signals passing through the reticular formation of the midbrain and nonspecific nuclei of the thalamus to the cerebral cortex have an activating effect on it and maintain an active state. Elimination of these influences (with damage to several receptor systems or as a result of destruction of the reticular formation or shutdown of its functions under the influence of certain drugs, for example, barbiturates) leads to the onset of deep sleep. In turn, the reticular formation of the brain stem is under the continuous tonic influence of the cerebral cortex.
Rice. 13.6. Scheme of interaction between “sleep centers” and “awakening” structures during wakefulness and the onset of sleep (according to P.K. Anokhin). A. Wakefulness. Cortical influences (I) inhibit the “sleep centers” (II) and the ascending activating influences of reticular structures (III) and excitations traveling along the lemniscal pathways (IV) freely reach the cortex. B. Dream. The inhibited parts of the cortex (I) cease to have a restraining influence on the “sleep centers” (II), they block the ascending activating influences (III), without affecting excitations along the lemniscal pathways (IV).
The existence of a two-way connection between the cerebral cortex and the reticular formation plays an important role in the mechanism of sleep. Indeed, the development of inhibition in areas of the cortex reduces the tone of the reticular formation, and this weakens its ascending activating influence, which entails a decrease in the activity of the entire cerebral cortex. Thus, inhibition that initially occurs in a limited area of the cortex can cause inhibition of neurons throughout the cerebral cortex.
One of the attempts to create a unified theory of sleep was made by P.K. Anokhin (Fig. 13.6). In his hypothesis, he proceeded from the fact that the hypothalamic “sleep centers” are under tonic inhibitory influence from the cerebral cortex. When this influence weakens due to a decrease in the working tone of the cortical cells (“active sleep” according to I.P. Pavlov), the hypothalamic structures seem to be “released” and determine the entire complex picture of the redistribution of vegetative components that is characteristic of the sleep state. At the same time, the hypothalamic centers have a depressing effect on the ascending activating system, stopping access to the cortex of the entire complex of activating influences (“passive sleep” according to I.P. Pavlov). These interactions appear to be cyclical, so the sleep state can be induced artificially (or through a pathological process) by affecting any part of the cycle.
Stages of sleep
During a night's sleep, a person experiences 3-5 periodic changes of slow and fast sleep.
| NREM sleep (orthodox) | REM sleep (paradoxical) |
| Physiological state of the body | |
| It occurs after falling asleep and lasts 60-90 minutes. Metabolism and activity of the cardiovascular, respiratory, digestive and excretory systems decrease, muscle tone drops, muscles relax and temperature drops. It is believed that a decrease in body temperature may be one of the reasons for the onset of sleep. Waking up is accompanied by an increase in body temperature. | It occurs after slow sleep and lasts 10-15 minutes. The activity of internal organs is activated: pulse and breathing quicken, temperature rises, oculomotor muscles contract (the eyes move quickly), facial muscles, and skeletal muscle tone is absent. |
| Mental processes of the brain | |
| Dreams reflect thinking processes and retelling of the events of the past day; they are abstract and cognitive. Conversation may occur in a dream, night terrors in children and sleepwalking (sleepwalking) may occur. | Excitation of neurons in the occipital lobes. The appearance of realistic emotional dreams with visual, sound and olfactory images. There is a classification and ordering of the information received during the day, and memory consolidation. Depriving a person of this type of sleep leads to memory disorders and mental illness. |
| Dreams of I.M. Sechenov called unprecedented combinations of experienced impressions |
Based on the electroencephalographic picture, the phase of “slow sleep” is in turn divided into several stages.
Stage I – drowsiness, the process of falling into sleep. On the EEG, α- and θ-rhythms predominate; at the end of the stage, K-complexes appear (a series of high-amplitude slow potentials lasting 3-5 s).
Stage II – superficial sleep (sleep spindle stage). The EEG shows K-complexes and sleep spindles appear (frequency approximately 15 Hz, a variant of the α rhythm). Their appearance coincides with the blackout of consciousness; The stage occupies about 50% of sleep time and increases in duration from the first to the last cycle.
Stage III – deep sleep (delta sleep), is characterized by the presence of a ∆-rhythm with a frequency of 3.0-3.5 Hz, which occupies up to 30% of the EEG.
Stage IV – the stage of “rapid” or “paradoxical sleep”, is characterized by the presence of a δ rhythm with a frequency of approximately 1 Hz, which occupies up to 30% of the EEG. Stages III and IV are present in the first sleep cycles and absent in the last (before awakening).
Night sleep usually consists of 4-5 cycles, each of which begins with the first stages of “slow” sleep and ends with “rapid” sleep. The duration of the cycle in a healthy adult is relatively stable and amounts to 90-100 minutes. In the first two cycles, “slow” sleep predominates, in the last two cycles, “fast” sleep predominates, and “delta” sleep is sharply reduced and may even be absent.
The duration of “slow” sleep is 75-85%, and “paradoxical” sleep is 15-25% of the total duration of night sleep.
Physiological role of sleep.
· Restorative function– predominance of anabolic processes.
· Anti-stress function– sleep serves as one of the mechanisms of mental protection of the individual.
· Adaptive function– synchronization with the cycle of day and night ensures optimal interaction of the body with the environment, preparing the body for activity during wakefulness.
· Role in information processing– implementation of the process of memory consolidation: transfer of information from short-term to long-term memory.
Types of sleep.
1. periodic daily sleep;
2. periodic seasonal sleep (winter or summer hibernation of animals);
3. narcotic sleep caused by various chemical or physical agents;
4. hypnotic sleep;
5. pathological sleep.
The first two types are varieties of physiological sleep, the last three types are a consequence of special non-physiological effects on the body.
Sleep disturbance. Sleep disorders are very common among the population of civilized countries. Insomnia is a chronic disease associated with impaired synchronization biological clock with circadian rhythms. Sleep disorders are noted in 45% of the urban population. Insomnia is much less common among rural residents.
Sleep disorders are divided into three main forms:
1. Difficulty falling asleep. It occurs most often. A person suffering from this type of insomnia cannot fall asleep for a long time: sleep is disturbed by disturbing memories and thoughts that constantly pile on top of each other. All efforts and painful attempts to fall asleep lead to nothing. The very anxiety about sleep, the tense anticipation of it, the fear of the upcoming sleepless night, the worry about a hard day after a sleepless night further aggravates insomnia. A person suffering from insomnia cannot stay in one position for a long time, constantly turns around in bed in search of the most comfortable position and long time can't sleep.
2. Superficial, restless sleep with frequent awakenings. Such people usually wake up 1-2 hours after falling asleep. The duration of falling asleep after waking up in the middle of the night ranges from several minutes to several hours. However, it also happens that having woken up once, a person does not fall asleep until the morning, and only then does superficial sleep occur. Typically, people who wake up frequently complain of shallow sleep that does not bring satisfaction and vigor.
3. Early final awakening. This sleep disorder is less common. After it there are no signs of drowsiness, and the person is awake. Early awakening is similar to waking up in the middle of the night, but differs only in that it is not followed by falling asleep and that it occurs from a drowsy state and light sleep (the first awakening occurs after deep sleep). People who have increased excitability of the nervous system awaken prematurely.
A reduction in sleep duration, one of the constant signs of insomnia, is relatively rarely pronounced. In partial insomnia, periods of wakefulness occur at the beginning, middle, and end of the night. With total insomnia, wakefulness predominates, only occasionally interrupted by drowsiness. This type of insomnia is much less common.
Sleep disorders include increased sleepiness, the so-called hypersomnia. Drowsiness can be observed in people with a weak nervous system: in this case, it can be considered as a protective reaction that protects nerve cells from overstrain.
In contrast to insomnia, increased pathological sleepiness leads to prolonged sleep, which is often a consequence of inflammatory diseases of the brain, for example, viral encephalitis. In these cases, sleep can last for weeks or months, and even, in rare cases, years. Such sleep is called lethargic.
Pathological drowsiness most often occurs in people who have suffered severe infectious diseases - typhus, meningitis, influenza. Drowsiness occurs with anemia and functional disorders of the nervous system.
Unlike insomnia, excessive sleepiness is less common.
Recent studies on the required duration of sleep have shown that the average sleep requirement among young people is 8.5 hours per night. A night's sleep duration of 7.2-7.4 hours is not enough, and sleeping less than 6.5 hours for a long time can undermine your health.
The effect of “accumulation of sleep deprivation” completely disappears after the first 10 hours of “restorative” sleep. Therefore, chronic lack of sleep on weekdays and oversleeping on weekend mornings are interrelated phenomena.
Artificially depriving a person of sleep is a difficult ordeal. Experiments with sleep deprivation have shown that volunteers experience emotional imbalance, increased fatigue, delusions, sleep disturbances, vestibular dysfunction, after 90 hours of sleep deprivation hallucinations appear, by 170 hours - depersonalization, by the 200th hour the subject shows mental and psychomotor disorders . During these experiments, it was found that the body especially needs slow-wave (delta) sleep and REM sleep. After prolonged sleep deprivation, the main effect is an increase in delta sleep. Thus, after 200 hours of continuous wakefulness, the percentage of delta sleep in the first 9 hours of recording restorative sleep doubles compared to the norm, and the duration of REM sleep increases by 57%.
In order to study the role of individual sleep phases, methods have been developed to selectively prevent their occurrence. When delta sleep is suppressed, subjects develop a feeling of weakness, fatigue, memory deteriorates and attention decreases. The feeling of weakness and increased fatigue, especially increasing in the second half of the day, in patients with neurosis is due to a chronic deficit of delta sleep (V.S. Rotenberg, 1984).
REM sleep deprivation changes mood, impairs performance, and affects memory.
Sleep hygiene. Adequate sleep can be ensured by following certain rules. Before going to bed, it is necessary to exclude stimulating games and mental work. The time after dinner should pass in a calm environment, excluding strong excitement. It is recommended to take a 20-30 minute walk before bed in calm weather. Dinner should be light 1.5-2 hours before bedtime. Chocolate, coffee and strong tea at night are not recommended.
1. Innate forms of behavior (instincts and innate reflexes), their significance in the adaptive activity of the body.
Unconditioned reflexes- these are congenital reflexes, carried out along constant reflex arcs existing from birth. An example of an unconditioned reflex is the activity of the salivary gland during the act of eating, blinking when a speck enters the eye, defensive movements during painful stimuli, and many other reactions of this type. Unconditioned reflexes in humans and higher animals are carried out through the subcortical sections of the central nervous system (dorsal, medulla oblongata, midbrain, diencephalon and basal ganglia). At the same time, the center of any unconditioned reflex (UR) is connected by nerve connections with certain areas of the cortex, i.e. there is a so-called cortical representation of BR. Different BRs (food, defensive, sexual, etc.) can have different complexity. In particular, BR includes such complex innate forms of animal behavior as instincts.
BR are undoubtedly playing big role in the adaptation of the organism to the environment. Thus, the presence of innate reflex sucking movements in mammals provides them with the opportunity to feed on mother’s milk in the early stages of ontogenesis. The presence of innate protective reactions (blinking, coughing, sneezing, etc.) protects the body from foreign bodies entering the respiratory tract. Even more obvious is the exceptional importance for the life of animals of various kinds of innate instinctive reactions (building nests, burrows, shelters, caring for offspring, etc.).
It should be borne in mind that BRs are not absolutely constant, as some believe. Within certain limits, the nature of the innate, unconditioned reflex can change depending on the functional state of the reflex apparatus. For example, in a spinal frog, irritation of the skin of the foot can cause an unconditional reflex reaction of a different nature depending on the initial state of the irritated paw: when the paw is extended, this irritation causes it to flex, and when it is bent, it causes it to extend.
Unconditioned reflexes ensure adaptation of the body only under relatively constant conditions. Their variability is extremely limited. Therefore, to adapt to continuously and dramatically changing conditions of existence, unconditioned reflexes alone are not enough. This is confirmed by the often encountered cases when instinctive behavior, so striking in its “reasonableness” under normal conditions, not only does not provide adaptation in a dramatically changed situation, but even becomes completely meaningless.
For a more complete and subtle adaptation of the body to constantly changing living conditions, animals in the process of evolution have developed more advanced forms of interaction with the environment in the form of the so-called. conditioned reflexes.
2. The meaning of the teachings of I.P. Pavlova on higher nervous activity for medicine, philosophy and psychology.
1 - strong unbalanced
4 - weak type.
1. Animals with strong, unbalanced
People of this type (cholerics)
2. Dogs strong, balanced, mobile
People of this type ( sanguine people
3. For dogs
People of this type (phlegmatic
4. In dog behavior weak
melancholics
1. Art
2. Thinking type
3. Medium type
3. Rules for the development of conditioned reflexes. Law of force. Classification of conditioned reflexes.
Conditioned reflexes are not innate, they are formed in the process of individual life of animals and humans on the basis of unconditional ones. A conditioned reflex is formed due to the emergence of a new nervous connection (temporary connection according to Pavlov) between the center of the unconditioned reflex and the center that perceives the accompanying conditioned stimulation. In humans and higher animals, these temporary connections are formed in the cerebral cortex, and in animals that do not have a cortex, in the corresponding higher parts of the central nervous system.
Unconditioned reflexes can be combined with a wide variety of changes in the external or internal environment of the body, and therefore, on the basis of one unconditioned reflex, many conditioned reflexes can be formed. This significantly expands the possibilities of adaptation of an animal organism to living conditions, since an adaptive reaction can be caused not only by those factors that directly cause changes in the functions of the body, and sometimes threaten its very life, but also by those that only signal the former. Thanks to this, the adaptive reaction occurs in advance.
Conditioned reflexes are characterized by extreme variability depending on the situation and the state of the nervous system.
So, in difficult conditions of interaction with the environment, the adaptive activity of the organism is carried out both by unconditional reflex and conditioned reflex ways, most often in the form of complex systems of conditioned and unconditioned reflexes. Consequently, the higher nervous activity of humans and animals represents an inextricable unity of innate and individually acquired forms of adaptation, and is the result of the joint activity of the cerebral cortex and subcortical formations. However, the leading role in this activity belongs to the cortex.
A conditioned reflex in animals or humans can be developed on the basis of any unconditioned reflex, subject to the following basic rules (conditions). Actually, this type of reflexes was called “conditional”, since it requires certain conditions for its formation.
1. It is necessary to coincide in time (combination) of two stimuli - unconditional and some indifferent (conditional).
2. It is necessary that the action of the conditioned stimulus somewhat precede the action of the unconditioned.
3. The conditioned stimulus must be physiologically weaker compared to the unconditioned one, and possibly more indifferent, i.e. not causing a significant reaction.
4. A normal, active state of the higher parts of the central nervous system is necessary.
5. During the formation of a conditioned reflex (CR), the cerebral cortex should be free from other types of activity. In other words, during the development of the UR, the animal must be protected from the action of extraneous stimuli.
6. A more or less long-term (depending on the evolutionary advancement of the animal) repetition of such combinations of a conditioned signal and an unconditioned stimulus is necessary.
If these rules are not observed, SDs are not formed at all, or are formed with difficulty and quickly fade away.
To produce UR in various animals and humans, various techniques(registration of salivation is a classic Pavlovian technique, registration of motor-defensive reactions, food-procuring reflexes, labyrinth methods, etc.). The mechanism of formation of a conditioned reflex. A conditioned reflex is formed when a BR is combined with an indifferent stimulus.
The simultaneous stimulation of two points of the central nervous system ultimately leads to the emergence of a temporary connection between them, due to which an indifferent stimulus, previously never associated with a combined unconditioned reflex, acquires the ability to cause this reflex (becomes a conditioned stimulus). Thus, the physiological mechanism of UR formation is based on the process of closing a temporary connection.
The process of formation of the UR is a complex act, characterized by certain sequential changes in the functional relationships between the cortical and subcortical nervous structures participating in this process.
At the very beginning of combinations of indifferent and unconditioned stimuli, an indicative reaction occurs in the animal under the influence of the factor of novelty. This innate, unconditioned reaction is expressed in the inhibition of general motor activity, in the rotation of the torso, head and eyes towards stimuli, in the pricking of the ears, olfactory movements, as well as in changes in breathing and cardiac activity. It plays a significant role in the process of formation of the UR, increasing the activity of cortical cells due to the tonic influences of the subcortical formations (in particular, the reticular formation). Maintaining the required level of excitability in cortical points that perceive conditioned and unconditioned stimuli creates favorable conditions for closing the connection between these points. A gradual increase in excitability in these zones is observed from the very beginning of the development of Ur. And when it reaches a certain level, reactions to the conditioned stimulus begin to appear.
When forming, SD has a lot important the emotional state of an animal caused by the action of stimuli. The emotional tone of the sensation (pain, disgust, pleasure, etc.) immediately determines the most general assessment of the operating factors - whether they are useful or harmful, and immediately activate the corresponding compensatory mechanisms, contributing to the urgent formation of an adaptive reaction.
The appearance of the first reactions to a conditioned stimulus marks only the initial stage of the formation of the UR. At this time, it is still fragile (it does not appear for every application of a conditioned signal) and is of a generalized, generalized nature (a reaction is caused not only by a specific conditioned signal, but also by stimuli similar to it). Simplification and specialization of SD occurs only after additional combinations.
In the process of developing the SD, its relationship with the indicative reaction changes. Sharply expressed at the beginning of development of the SD, as the SD becomes stronger, the indicative reaction weakens and disappears.
Based on the relationship of the conditioned stimulus to the reaction it signals, natural and artificial conditioned reflexes are distinguished.
Natural called conditioned reflexes, which are formed in response to stimuli that are natural, necessarily accompanying signs, properties of the unconditional stimulus on the basis of which they are produced (for example, the smell of meat when feeding it). Natural conditioned reflexes, compared to artificial ones, are easier to form and more durable.
Artificial called conditioned reflexes, formed in response to stimuli that are usually not directly related to the unconditional stimulus that reinforces them (for example, a light stimulus reinforced by food).
Depending on the nature of the receptor structures on which conditioned stimuli act, exteroceptive, interoceptive and proprioceptive conditioned reflexes are distinguished.
Exteroceptive conditioned reflexes, formed in response to stimuli perceived by external external receptors bodies, constitute the bulk of conditioned reflex reactions that ensure adaptive (adaptive) behavior of animals and humans in conditions of a changing external environment.
Interoceptive conditioned reflexes, produced in response to physical and chemical stimulation of interoreceptors, provide physiological processes of homeostatic regulation of the function of internal organs.
Proprioceptive conditioned reflexes, formed by irritation of the own receptors of the striated muscles of the trunk and limbs, form the basis of all motor skills of animals and humans.
Depending on the structure of the used conditioned stimulus, simple and complex (complex) conditioned reflexes are distinguished.
When simple conditioned reflex a simple stimulus (light, sound, etc.) is used as a conditioned stimulus. In real conditions of the functioning of the body, as a rule, the conditioned signals are not individual, single stimuli, but their temporal and spatial complexes.
In this case, either the entire environment surrounding the animal or parts of it in the form of a complex of signals acts as a conditioned stimulus.
One of the varieties of such a complex conditioned reflex is stereotypical conditioned reflex, formed for a certain temporal or spatial “pattern”, a complex of stimuli.
There are also conditioned reflexes produced to simultaneous and sequential complexes of stimuli, to a sequential chain of conditioned stimuli separated by a certain time interval.
Trace conditioned reflexes are formed in the case when an unconditioned reinforcing stimulus is presented only after the end of the conditioned stimulus.
Finally, conditioned reflexes of the first, second, third, etc. order are distinguished. If a conditioned stimulus (light) is reinforced by an unconditioned stimulus (food), a conditioned reflex of the first order. Conditioned reflex of the second order is formed if a conditioned stimulus (for example, light) is reinforced not by an unconditioned, but by a conditioned stimulus to which a conditioned reflex was previously formed. Conditioned reflexes of the second and more complex order are more difficult to form and are less durable.
Conditioned reflexes of the second and higher order include conditioned reflexes produced in response to a verbal signal (the word here represents a signal to which a conditioned reflex was previously formed when reinforced by an unconditioned stimulus).
4. Conditioned reflexes are a factor in the body’s adaptation to changing conditions of existence. Methodology for the formation of a conditioned reflex. Differences between conditioned reflexes and unconditioned ones. Principles of the theory of I.P. Pavlova.
One of the main elementary acts of higher nervous activity is the conditioned reflex. The biological significance of conditioned reflexes lies in a sharp expansion in the number of signal stimuli that are significant for the body, which ensures an incomparably higher level of adaptive behavior.
The conditioned reflex mechanism underlies the formation of any acquired skill, the basis of the learning process. The structural and functional basis of the conditioned reflex is the cortex and subcortical formations of the brain.
The essence of the conditioned reflex activity of the body comes down to the transformation of an indifferent stimulus into a signal, meaningful one, due to the repeated reinforcement of the irritation with an unconditioned stimulus. Due to the reinforcement of a conditioned stimulus by an unconditioned stimulus, a previously indifferent stimulus is associated in the life of the organism with a biologically important event and thereby signals the occurrence of this event. In this case, any innervated organ can act as an effector link in the reflex arc of a conditioned reflex. There is no organ in the human or animal body whose functioning could not change under the influence of a conditioned reflex. Any function of the body as a whole or of its individual physiological systems can be modified (strengthened or suppressed) as a result of the formation of a corresponding conditioned reflex.
In the zone of the cortical representation of the conditioned stimulus and the cortical (or subcortical) representation of the unconditioned stimulus, two foci of excitation are formed. The focus of excitation caused by an unconditional stimulus of the external or internal environment of the body, as a stronger (dominant) one, attracts to itself excitation from the focus of weaker excitation caused by the conditioned stimulus. After several repeated presentations of the conditioned and unconditioned stimuli, a stable path of excitation movement is “trodden” between these two zones: from the focus caused by the conditioned stimulus to the focus caused by the unconditioned stimulus. As a result, the isolated presentation of only the conditioned stimulus now leads to the response caused by the previously unconditioned stimulus.
The main cellular elements of the central mechanism for the formation of a conditioned reflex are intercalary and associative neurons of the cerebral cortex.
For the formation of a conditioned reflex, the following rules must be observed: 1) an indifferent stimulus (which must become a conditioned, signal) must have sufficient strength to excite certain receptors; 2) it is necessary that the indifferent stimulus be reinforced by an unconditioned stimulus, and the indifferent stimulus must either slightly precede or be presented simultaneously with the unconditioned one; 3) it is necessary that the stimulus used as a conditional stimulus be weaker than the unconditional one. To develop a conditioned reflex, it is also necessary to have a normal physiological state of the cortical and subcortical structures that form the central representation of the corresponding conditioned and unconditioned stimuli, the absence of strong extraneous stimuli, and the absence of significant pathological processes in the body.
If the specified conditions are met, a conditioned reflex can be developed to almost any stimulus.
I. P. Pavlov, the author of the doctrine of conditioned reflexes as the basis of higher nervous activity, initially assumed that the conditioned reflex is formed at the level of the cortex - subcortical formations (a temporary connection is made between the cortical neurons in the zone of representation of the indifferent conditioned stimulus and the subcortical nerve cells that make up the central representation unconditional stimulus). In later works, I. P. Pavlov explained the formation of a conditioned reflex connection by the formation of a connection at the level of the cortical zones of the representation of conditioned and unconditioned stimuli.
Subsequent neurophysiological studies led to the development, experimental and theoretical justification of several various hypotheses about the formation of a conditioned reflex. Data from modern neurophysiology indicate the possibility of different levels of closure, the formation of a conditioned reflex connection (cortex - cortex, cortex - subcortical formations, subcortical formations - subcortical formations) with a dominant role in this process of cortical structures. Obviously, the physiological mechanism for the formation of a conditioned reflex is a complex dynamic organization of cortical and subcortical structures of the brain (L. G. Voronin, E. A. Asratyan, P. K. Anokhin, A. B. Kogan).
Despite certain individual differences, conditioned reflexes are characterized by the following general properties (features):
1. All conditioned reflexes represent one of the forms of adaptive reactions of the body to changing environmental conditions.
2. Conditioned reflexes belong to the category of reflex reactions acquired during individual life and are distinguished by individual specificity.
3. All types of conditioned reflex activity are of a warning signal nature.
4. Conditioned reflex reactions are formed on the basis of unconditioned reflexes; Without reinforcement, conditioned reflexes are weakened and suppressed over time.
5. Active forms training. Instrumental reflexes.
6. Stages of formation of conditioned reflexes (generalization, directed irradiation and concentration).
In the formation and strengthening of a conditioned reflex, two stages are distinguished: the initial stage (generalization of conditioned excitation) and the final stage of a strengthened conditioned reflex (concentration of conditioned excitation).
Initial stage of generalized conditioned excitation in essence, it is a continuation of a more general universal reaction of the body to any new stimulus, represented by an unconditioned orienting reflex. The orienting reflex is a generalized multicomponent complex reaction the body is strong enough external stimulus, covering many of its physiological systems, including autonomic ones. The biological significance of the orientation reflex lies in the mobilization of the functional systems of the body for better perception of the stimulus, i.e. the orientation reflex is adaptive (adaptive) in nature. An externally indicative reaction, called by I.P. Pavlov the “what is this?” reflex, manifests itself in the animal in alertness, listening, sniffing, turning the eyes and head towards the stimulus. This reaction is the result of a wide spread of the excitatory process from the source of initial excitation caused by the active agent to the surrounding central nervous structures. The orientation reflex, unlike other unconditioned reflexes, is quickly inhibited and suppressed with repeated application of the stimulus.
The initial stage of the formation of a conditioned reflex consists of the formation of a temporary connection not only to this specific conditioned stimulus, but also to all stimuli related to it in nature. The neurophysiological mechanism is irradiation of excitation from the center of the projection of the conditioned stimulus onto the nerve cells of the surrounding projection zones, which are functionally close to the cells of the central representation of the conditioned stimulus to which the conditioned reflex is formed. The farther from the initial initial focus caused by the main stimulus, reinforced by the unconditioned stimulus, the zone covered by the irradiation of excitation is located, the less likely it is to activate this zone. Therefore, at the initial stages of generalization of conditioned excitation, characterized by a generalized generalized reaction, a conditioned reflex response is observed to similar, close in meaning stimuli as a result of the spread of excitation from the projection zone of the main conditioned stimulus.
As the conditioned reflex strengthens, the processes of excitation irradiation are replaced by concentration processes, limiting the focus of excitation only to the zone of representation of the main stimulus. As a result, clarification and specialization of the conditioned reflex occurs. At the final stage of a strengthened conditioned reflex, concentration of conditioned excitation: a conditioned reflex reaction is observed only to a given stimulus; to secondary stimuli that are close in meaning, it stops. At the stage of concentration of conditioned excitation, the excitatory process is localized only in the zone of the central representation of the conditioned stimulus (a reaction is realized only to the main stimulus), accompanied by inhibition of the reaction to side stimuli. The external manifestation of this stage is the differentiation of the parameters of the current conditioned stimulus - the specialization of the conditioned reflex.
7. Inhibition in the cerebral cortex. Types of inhibition: unconditional (external) and conditional (internal).
The formation of a conditioned reflex is based on the processes of interaction of excitations in the cerebral cortex. However, for the successful completion of the process of closing a temporary connection, it is necessary not only to activate the neurons involved in this process, but also to suppress the activity of those cortical and subcortical formations that interfere with this process. Such inhibition is carried out due to the participation of the inhibition process.
In its external manifestation, inhibition is the opposite of excitation. When it occurs, a weakening or cessation of neuronal activity is observed, or possible excitation is prevented.
Cortical inhibition is usually divided into unconditional and conditional, purchased. Unconditional forms of inhibition include external, arising in the center as a result of its interaction with other active centers of the cortex or subcortex, and transcendental, which occurs in cortical cells with excessively strong irritations. These types (forms) of inhibition are congenital and appear already in newborns.
8. Unconditional (external) inhibition. Fading and constant brake.
External unconditional inhibition manifests itself in the weakening or cessation of conditioned reflex reactions under the influence of any extraneous stimuli. If you call the dog's UR and then apply a strong foreign irritant (pain, smell), then the salivation that has begun will stop. Unconditioned reflexes are also inhibited (Türk’s reflex in a frog when pinching the second paw).
Cases of external inhibition of conditioned reflex activity occur at every step and in the natural life of animals and humans. This includes a constantly observed decrease in activity and hesitancy to act in a new, unusual environment, a decrease in the effect or even the complete impossibility of activity in the presence of extraneous stimuli (noise, pain, hunger, etc.).
External inhibition of conditioned reflex activity is associated with the appearance of a reaction to an extraneous stimulus. It occurs more easily and is more powerful, the stronger the extraneous stimulus and the less strong the conditioned reflex. External inhibition of the conditioned reflex occurs immediately upon the first application of an extraneous stimulus. Consequently, the ability of cortical cells to fall into a state of external inhibition is an innate property of the nervous system. This is one of the manifestations of the so-called. negative induction.
9. Conditioned (internal) inhibition, its significance (limitation of conditioned reflex activity, differentiation, timing, protective). Types of conditioned inhibition, features in children.
Conditioned (internal) inhibition develops in cortical cells under certain conditions under the influence of the same stimuli that previously caused conditioned reflex reactions. In this case, braking does not occur immediately, but after more or less long-term development. Internal inhibition, like a conditioned reflex, occurs after a series of combinations of a conditioned stimulus with the action of a certain inhibitory factor. Such a factor is the abolition of unconditional reinforcement, a change in its nature, etc. Depending on the condition of occurrence, they distinguish the following types conditioned inhibition: extinction, delayed, differentiation and signal (“conditioned brake”).
Extinction inhibition develops when the conditioned stimulus is not reinforced. It is not associated with fatigue of the cortical cells, since an equally long repetition of a conditioned reflex with reinforcement does not lead to a weakening of the conditioned reaction. Extinctional inhibition develops the easier and faster the less strong the conditioned reflex and the weaker the unconditioned reflex on the basis of which it was developed. Extinction inhibition develops the faster the shorter the interval between conditioned stimuli repeated without reinforcement. Extraneous stimuli cause a temporary weakening and even complete cessation of extinctive inhibition, i.e. temporary restoration of an extinguished reflex (disinhibition). The developed extinction inhibition causes depression of other conditioned reflexes, weak ones and those whose centers are located close to the center of the primary extinction reflexes (this phenomenon is called secondary extinction).
An extinguished conditioned reflex recovers on its own after some time, i.e. extinctive inhibition disappears. This proves that extinction is associated precisely with temporary inhibition, not with a break in the temporary connection. An extinguished conditioned reflex is restored the faster, the stronger it is and the weaker it was inhibited. Repeated extinction of the conditioned reflex occurs faster.
The development of extinction inhibition is of great biological importance, because it helps animals and humans to free themselves from previously acquired conditioned reflexes that have become useless in new, changed conditions.
Delayed braking develops in cortical cells when reinforcement is delayed in time from the onset of the conditioned stimulus. Externally, this inhibition is expressed in the absence of a conditioned reflex reaction at the beginning of the action of the conditioned stimulus and its appearance after some delay (delay), and the time of this delay corresponds to the duration of the isolated action of the conditioned stimulus. Delayed inhibition develops the faster, the smaller the lag of reinforcement from the onset of the conditioned signal. With continuous action of the conditioned stimulus, it develops faster than with intermittent action.
Extraneous stimuli cause temporary disinhibition of delayed inhibition. Thanks to its development, the conditioned reflex becomes more accurate, timing it to the right moment with a distant conditioned signal. This is its great biological significance.
Differential braking develops in cortical cells under the intermittent action of a constantly reinforced conditioned stimulus and non-reinforced stimuli similar to it.
The newly formed SD usually has a generalized, generalized character, i.e. is caused not only by a specific conditioned stimulus (for example, a 50 Hz tone), but by numerous similar stimuli addressed to the same analyzer (tones of 10-100 Hz). However, if in the future only sounds with a frequency of 50 Hz are reinforced, and others are left without reinforcement, then after some time the reaction to similar stimuli will disappear. In other words, from the mass of similar stimuli, the nervous system will react only to the reinforced one, i.e. biologically significant, and the reaction to other stimuli is inhibited. This inhibition ensures the specialization of the conditioned reflex, vital discrimination, differentiation of stimuli according to their signal value.
The greater the difference between the conditioned stimuli, the easier it is to develop differentiation. Using this inhibition, one can study the ability of animals to distinguish sounds, shapes, colors, etc. Thus, according to Gubergrits, a dog can distinguish a circle from an ellipse with a semi-axial ratio of 8:9.
Extraneous stimuli cause disinhibition of differentiation inhibition. Fasting, pregnancy, neurotic conditions, fatigue, etc. can also lead to disinhibition and distortion of previously developed differentiations.
Signal braking ("conditional brake"). Inhibition of the “conditioned inhibitor” type develops in the cortex when the conditioned stimulus is not reinforced in combination with some additional stimulus, and the conditioned stimulus is reinforced only when it is used in isolation. Under these conditions, a conditioned stimulus in combination with an extraneous one becomes, as a result of the development of differentiation, inhibitory, and the extraneous stimulus itself acquires the property of an inhibitory signal (conditioned brake), it becomes capable of inhibiting any other conditioned reflex if it is attached to a conditioned signal.
A conditioned inhibitor easily develops when a conditioned and an additional stimulus act simultaneously. The dog does not produce it if this interval is more than 10 seconds. Extraneous stimuli cause disinhibition of signal inhibition. Its biological significance lies in the fact that it refines the conditioned reflex.
10. An idea of the limit of performance of cells in the cerebral cortex. Extreme braking.
Extreme braking develops in cortical cells under the influence of a conditioned stimulus, when its intensity begins to exceed a known limit. Transcendental inhibition also develops with the simultaneous action of several individually weak stimuli, when the total effect of the stimuli begins to exceed the performance limit of cortical cells. An increase in the frequency of the conditioned stimulus also leads to the development of inhibition. The development of transcendental inhibition depends not only on the strength and nature of the action of the conditioned stimulus, but also on the state of the cortical cells and their performance. When the level of efficiency of cortical cells is low, for example, in animals with a weak nervous system, in old and sick animals, fast development extreme inhibition even with relatively weak stimuli. The same is observed in animals brought to significant nervous exhaustion by prolonged exposure to moderately strong stimuli.
Transcendental inhibition has a protective significance for cortical cells. This is a parabiotic type phenomenon. During its development, similar phases are observed: equalizing, when both strong and moderately strong conditioned stimuli cause a response of the same intensity; paradoxical, when weak stimuli cause more strong effect than strong irritants; ultraparadoxical phase, when inhibitory conditioned stimuli cause an effect, but positive ones do not; and, finally, the inhibitory phase, when no stimuli cause a conditioned response.
11. Movement of nervous processes in the cerebral cortex: irradiation and concentration of nervous processes. Phenomena of mutual induction.
Movement and interaction of excitation and inhibition processes in the cerebral cortex. Higher nervous activity is determined by the complex relationship between the processes of excitation and inhibition that occur in cortical cells under the influence of various influences from the external and internal environment. This interaction is not limited only to the framework of the corresponding reflex arcs, but also plays out far beyond their boundaries. The fact is that with any impact on the body, not only corresponding cortical foci of excitation and inhibition arise, but also various changes in various areas of the cortex. These changes are caused, firstly, by the fact that nervous processes can spread (irradiate) from the place of their origin to the surrounding nerve cells, and the irradiation is replaced after some time by the reverse movement of the nervous processes and their concentration at the starting point (concentration). Secondly, the changes are caused by the fact that nervous processes, when concentrated in certain place The cortex can cause (induce) the emergence of an opposite nervous process in surrounding neighboring points of the cortex (spatial induction), and after the cessation of the nervous process, induce the opposite nervous process in the same point (temporary, sequential induction).
The irradiation of nervous processes depends on their strength. At low or high intensity, a tendency to irradiation is clearly expressed. With medium strength - to concentration. According to Kogan, the excitation process radiates through the cortex at a speed of 2-5 m/sec, the inhibitory process is much slower (several millimeters per second).
The intensification or occurrence of the excitation process under the influence of the source of inhibition is called positive induction. The emergence or intensification of the inhibitory process around (or after) excitation is called negativeby induction. Positive induction manifests itself, for example, in the strengthening of a conditioned reflex reaction after the application of a differential stimulus or arousal before bedtime. One of the common manifestations of negative induction is inhibition of the UR under the influence of extraneous stimuli. With weak or excessively strong stimuli, there is no induction.
It can be assumed that induction phenomena are based on processes similar to electrotonic changes.
Irradiation, concentration and induction of nervous processes are closely related to each other, mutually limiting, balancing and strengthening each other, and thus determining the precise adaptation of the body’s activity to environmental conditions.
12. An lysis and synthesis in the cerebral cortex. The concept of a dynamic stereotype, features in childhood. The role of the dynamic stereotype in the work of a doctor.
Analytical and synthetic activity of the cerebral cortex. The ability to form UR and temporary connections shows that the cerebral cortex, firstly, can isolate its individual elements from the environment, distinguish them from each other, i.e. has the ability to analyze. Secondly, it has the ability to combine, merge elements into a single whole, i.e. ability to synthesize. In the process of conditioned reflex activity, constant analysis and synthesis of stimuli from the external and internal environment of the body is carried out.
The ability to analyze and synthesize stimuli is inherent in its simplest form to the peripheral parts of the analyzers - the receptors. Thanks to their specialization, high-quality separation is possible, i.e. environmental analysis. Along with this, the joint action of various stimuli, their complex perception creates the conditions for their fusion, synthesis into a single whole. Analysis and synthesis, determined by the properties and activity of receptors, are called elementary.
The analysis and synthesis carried out by the cortex are called higher analysis and synthesis. The main difference is that the cortex analyzes not so much the quality and quantity of information as its signal value.
One of the striking manifestations of the complex analytical and synthetic activity of the cerebral cortex is the formation of the so-called. dynamic stereotype. A dynamic stereotype is a fixed system of conditioned and unconditioned reflexes, combined into a single functional complex, which is formed under the influence of stereotypically repeated changes or influences of the external or internal environment of the body, and in which each previous act is a signal for the subsequent one.
The formation of a dynamic stereotype is of great importance in conditioned reflex activity. It facilitates the activity of cortical cells when performing a stereotypically repeating system of reflexes, making it more economical, and at the same time automatic and clear. In the natural life of animals and humans, stereotypy of reflexes is developed very often. We can say that the basis of the individual form of behavior characteristic of each animal and person is a dynamic stereotype. Dynamic stereotypy underlies the development of various habits in a person, automatic actions in the labor process, a certain system of behavior in connection with the established daily routine, etc.
A dynamic stereotype (DS) is developed with difficulty, but once formed, it acquires a certain inertia and, given the unchanged external conditions, becomes more and more stronger. However, when the external stereotype of stimuli changes, the previously fixed system of reflexes begins to change: the old one is destroyed and a new one is formed. Thanks to this ability, the stereotype is called dynamic. However, the alteration of a durable DS is very difficult for the nervous system. It's notoriously difficult to change a habit. Remaking a very strong stereotype can even cause a breakdown of higher nervous activity (neurosis).
Complex analytical and synthetic processes underlie this form holistic activities brain like conditioned reflex switching when the same conditioned stimulus changes its signal value with a change in the situation. In other words, the animal reacts differently to the same stimulus: for example, in the morning the bell is a signal to write, and in the evening - pain. Conditioned reflex switching manifests itself everywhere in human natural life in various reactions and different forms ah behavior on the same occasion in different environments (at home, at work, etc.) and has great adaptive significance.
13. Teachings of I.P. Pavlova on the types of higher nervous activity. Classification of types and the principles underlying it (strength of nervous processes, balance and mobility).
The higher nervous activity of humans and animals sometimes reveals quite pronounced individual differences. Individual characteristics of VND are manifested in different speeds of formation and strengthening of conditioned reflexes, different speeds of development of internal inhibition, different difficulties in altering the signal meaning of conditioned stimuli, different performance of cortical cells, etc. Each individual is characterized by a certain combination of basic properties of cortical activity. It was called the VND type.
The features of the IRR are determined by the nature of the interaction, the ratio of the main cortical processes - excitation and inhibition. Therefore, the classification of types of VND is based on differences in the basic properties of these nervous processes. These properties are:
1.Force nervous processes. Depending on the performance of cortical cells, nervous processes can be strong And weak.
2. Equilibrium nervous processes. Depending on the ratio of excitation and inhibition, they can be balanced or unbalanced.
3. Mobility nervous processes, i.e. the speed of their occurrence and cessation, the ease of transition from one process to another. Depending on this, nervous processes can be mobile or inert.
Theoretically, 36 combinations of these three properties of nervous processes are conceivable, i.e. a wide variety of types of VND. I.P. Pavlov, however, identified only 4, the most striking types of VND in dogs:
1 - strong unbalanced(with a sharp predominance of excitement);
2 - strong unbalanced mobile;
3 - strong balanced inert;
4 - weak type.
Pavlov considered the identified types to be common to both humans and animals. He showed that the four established types coincide with Hippocrates' description of the four human temperaments - choleric, sanguine, phlegmatic and melancholic.
In the formation of the type of GNI, along with genetic factors (genotype), the external environment and upbringing (phenotype) also take an active part. In the course of further individual development of a person, based on the innate typological characteristics of the nervous system, under the influence of the external environment, a certain set of properties of GNI is formed, manifested in a stable direction of behavior, i.e. what we call character. The type of GNI contributes to the formation of certain character traits.
1. Animals with strong, unbalanced These types are, as a rule, bold and aggressive, extremely excitable, difficult to train, and cannot tolerate restrictions in their activities.
People of this type (cholerics) characterized by lack of restraint and mild excitability. These are energetic, enthusiastic people, bold in their judgments, prone to decisive action, unaware of limits in their work, and often reckless in their actions. Children of this type are often academically capable, but hot-tempered and unbalanced.
2. Dogs strong, balanced, mobile type, in most cases they are sociable, agile, quickly react to every new stimulus, but at the same time they easily restrain themselves. They quickly and easily adapt to changes in the environment.
People of this type ( sanguine people) are distinguished by restraint of character, great self-control, and at the same time ebullient energy and exceptional performance. Sanguine people are lively, inquisitive people, interested in everything and quite versatile in their activities and interests. On the contrary, one-sided, monotonous activity is not in their nature. They are persistent in overcoming difficulties and easily adapt to any changes in life, quickly rebuilding their habits. Children of this type are distinguished by liveliness, mobility, curiosity, and discipline.
3. For dogs strong, balanced, inert type characteristic feature is slowness, calmness. They are unsociable and do not show excessive aggression, reacting weakly to new stimuli. They are characterized by stability of habits and developed stereotypes in behavior.
People of this type (phlegmatic) are distinguished by their slowness, exceptional balance, calmness and evenness in behavior. Despite their slowness, phlegmatic people are very energetic and persistent. They are distinguished by the constancy of their habits (sometimes to the point of pedantry and stubbornness), and the constancy of their attachments. Children of this type are distinguished by good behavior and hard work. They are characterized by a certain slowness of movements and slow, calm speech.
4. In dog behavior weak type as characteristic feature cowardice and a tendency to passive-defensive reactions are noted.
A distinctive feature in the behavior of people of this type ( melancholics) is timidity, isolation, weak will. Melancholic people often tend to exaggerate the difficulties they encounter in life. They have increased sensitivity. Their feelings are often colored in gloomy tones. Children of the melancholic type outwardly look quiet and timid.
It should be noted that there are few representatives of such pure types, no more than 10% of the human population. Other people have numerous transitional types, combining in their character features of neighboring types.
The type of IRR largely determines the nature of the course of the disease, so it must be taken into account in the clinic. The type should be taken into account at school, when raising an athlete, a warrior, when determining professional suitability, etc. To determine the type of IRR in a person, special methods have been developed, including studies of conditioned reflex activity, processes of excitation and conditioned inhibition.
After Pavlov, his students conducted numerous studies of the types of VNI in humans. It turned out that Pavlov's classification requires significant additions and changes. Thus, research has shown that in humans there are numerous variations within each Pavlovian type due to the gradation of three basic properties of nervous processes. The weak type has especially many variations. Some new combinations of basic properties of the nervous system have also been established, which do not fit the characteristics of any Pavlovian type. These include - a strong unbalanced type with a predominance of inhibition, an unbalanced type with a predominance of excitation, but unlike strong type with a very weak inhibitory process, unbalanced in mobility (with labile excitation, but inert inhibition), etc. Therefore, work is currently ongoing to clarify and supplement the classification of types of internal income.
In addition to the general types of GNI, there are also specific types in humans, characterized by different relationships between the first and second signaling systems. On this basis, three types of GNI are distinguished:
1. Art, in which the activity of the first signaling system is especially pronounced;
2. Thinking type, in which the second signaling system noticeably predominates.
3. Medium type, in which signal systems 1 and 2 are balanced.
The vast majority of people belong to the average type. This type is characterized by a harmonious combination of figurative-emotional and abstract-verbal thinking. The artistic type supplies artists, writers, musicians. Thinking - mathematicians, philosophers, scientists, etc.
14. Features of human higher nervous activity. First and second signaling systems (I.P. Pavlov).
General patterns of conditioned reflex activity established in animals are also characteristic of human GNI. However, human GNI in comparison with animals is characterized by the greatest degree of development of analytical and synthetic processes. This is due not only to the further development and improvement in the course of evolution of those mechanisms of cortical activity that are inherent in all animals, but also to the emergence of new mechanisms of this activity.
This specific feature of human GNI is the presence in him, unlike animals, of two systems of signal stimuli: one system, first, consists, like in animals, of direct impacts external and internal environmental factors body; the other consists in words, indicating the impact of these factors. I.P. Pavlov called her second alarm system since the word is " signal signal"Thanks to the second human signaling system, analysis and synthesis of the surrounding world, its adequate reflection in the cortex, can be carried out not only by operating with direct sensations and impressions, but also by operating only with words. Opportunities are created for abstraction from reality, for abstract thinking.
This significantly expands the possibilities of human adaptation to the environment. He can get a more or less correct idea of phenomena and objects outside world without direct contact with reality itself, but from the words of other people or from books. Abstract thinking allows us to develop appropriate adaptive reactions also without contact with those concrete living conditions, in which these adaptive reactions are appropriate. In other words, a person determines in advance and develops a line of behavior in a new environment that he has never seen before. Thus, when going on a trip to new unfamiliar places, a person nevertheless prepares accordingly for unusual climatic conditions, for specific conditions of communication with people, etc.
It goes without saying that the perfection of human adaptive activity with the help of verbal signals will depend on how accurately and completely the surrounding reality is reflected in the cerebral cortex with the help of words. Therefore, the only true way to verify the correctness of our ideas about reality is practice, i.e. direct interaction with the objective material world.
The second signaling system is socially conditioned. A person is not born with it, he is born only with the ability to form it in the process of communicating with his own kind. Mowgli's children do not have a human second signaling system.
15. The concept of higher mental functions of a person (sensation, perception, thinking).
The basis of the mental world is consciousness, thinking, intellectual activity humans, representing the highest form of adaptive behavior. Mental activity is a qualitatively new, higher than conditioned reflex behavior, level of higher nervous activity characteristic of humans. In the world of higher animals this level is represented only in rudimentary form.
In the development of the human mental world as an evolving form of reflection, the following 2 stages can be distinguished: 1) the stage of the elementary sensory psyche - reflection of individual properties of objects, phenomena of the surrounding world in the form sensations. Unlike sensations perception - the result of the reflection of the object as a whole and at the same time something still more or less dismembered (this is the beginning of the construction of one’s “I” as a subject of consciousness). A more perfect form of concrete sensory reflection of reality, formed in the process of individual development of the organism, is representation. Performance - a figurative reflection of an object or phenomenon, manifested in the spatio-temporal connection of its constituent features and properties. The neurophysiological basis of ideas lies in chains of associations, complex temporary connections; 2) formation stage intelligence and consciousness, realized on the basis of the emergence of holistic meaningful images, a holistic perception of the world with an understanding of one’s “I” in this world, one’s own cognitive and creative creative activity. Human mental activity, which most fully realizes this highest level of the psyche, is determined not only by the quantity and quality of impressions, meaningful images and concepts, but also by a significantly higher level of needs, going beyond purely biological needs. A person no longer desires only “bread,” but also “shows,” and builds his behavior accordingly. His actions and behavior become both a consequence of the impressions he receives and the thoughts they generate, and a means of actively obtaining them. The ratio of the volumes of cortical zones providing sensory, gnostic and logical functions in favor of the latter changes in evolution accordingly.
Human mental activity consists not only in the construction of more complex neural models of the surrounding world (the basis of the cognition process), but also in the production of new information and various forms of creativity. Despite the fact that many manifestations of the human mental world turn out to be divorced from direct stimuli, events of the external world and seem to have no real objective causes, there is no doubt that the initial factors that trigger them are completely determined phenomena and objects, reflected in the structures of the brain based on universal neurophysiological mechanism - reflex activity. This idea, expressed by I.M. Sechenov in the form of the thesis “All acts of conscious and unconscious human activity, according to the method of origin, are reflexes,” remains generally accepted.
The subjectivity of mental nervous processes lies in the fact that they are a property of the individual organism, do not exist and cannot exist outside the specific individual brain with its peripheral nerve endings and nerve centers, and are not an absolutely accurate mirror copy of the real world around us.
The simplest, or basic, mental element in the functioning of the brain is sensation. It serves as that elementary act which, on the one hand, connects our psyche directly with external influence, and on the other hand, it is an element in more complex mental processes. Sensation is conscious reception, that is, in the act of sensation there is a certain element of consciousness and self-awareness.
The sensation arises as a result of a certain spatio-temporal distribution of the excitation pattern, but for researchers the transition from knowledge of the spatio-temporal pattern of excited and inhibited neurons to the sensation itself as the neurophysiological basis of the psyche still seems insurmountable. According to L. M. Chailakhyan, the transition from amenable to complete physical and chemical analysis The neurophysiological process to sensation is the basic phenomenon of an elementary mental act, the phenomenon of consciousness.
In this regard, the concept of “mental” is presented as a conscious perception of reality, a unique mechanism for the development of the process of natural evolution, a mechanism for transforming neurophysiological mechanisms into the category of the psyche, the consciousness of the subject. Human mental activity is largely determined by the ability to be distracted from real reality and make the transition from direct sensory perceptions to imaginary reality (“virtual” reality). The human ability to imagine the possible consequences of one's actions is the highest form of abstraction, which is inaccessible to animals. A striking example is the behavior of a monkey in the laboratory of I.P. Pavlov: the animal each time extinguished the fire that was burning on the raft with water, which it brought in a mug from a tank located on the shore, although the raft was in the lake and was surrounded on all sides by water.
The high level of abstraction in the phenomena of the human mental world determines the difficulties in solving the cardinal problem of psychophysiology - finding the neurophysiological correlates of the psyche, the mechanisms for transforming the material neurophysiological process into subjective image. The main difficulty in explaining specific features mental processes based on the physiological mechanisms of the nervous system activity lies in the inaccessibility of mental processes to direct sensory observation and study. Mental processes are closely related to physiological ones, but cannot be reduced to them.
Thinking is the highest level of human cognition, the process of reflection in the brain of the surrounding real world, based on two fundamentally different psychophysiological mechanisms: the formation and continuous replenishment of the stock of concepts, ideas and the derivation of new judgments and conclusions. Thinking allows you to gain knowledge about such objects, properties and relationships of the surrounding world that cannot be directly perceived using the first signal system. The forms and laws of thinking are the subject of consideration of logic, and psychophysiological mechanisms are the subject of psychology and physiology, respectively.
Human mental activity is inextricably linked with the second signaling system. At the heart of thinking, two processes are distinguished: the transformation of thought into speech (written or oral) and the extraction of thought and content from its specific verbal form of communication. Thought is a form of the most complex generalized abstract reflection of reality, conditioned by certain motives, a specific process of integration of certain ideas, concepts in specific conditions social development. Therefore, thought as an element of higher nervous activity is the result of the socio-historical development of the individual with the coming to the fore linguistic form information processing.
Human creative thinking is associated with the formation of ever new concepts. A word as a signal of signals denotes a dynamic complex of specific stimuli, generalized in a concept expressed by a given word and having a broad context with other words, with other concepts. Throughout life, a person continuously replenishes the content of the concepts he develops by expanding the contextual connections of the words and phrases he uses. Any learning process, as a rule, is associated with expanding the meaning of old and the formation of new concepts.
The verbal basis of mental activity largely determines the nature of development and formation of thinking processes in a child, manifested in the formation and improvement of the nervous mechanism for providing a person’s conceptual apparatus based on the use of logical laws of inference and reasoning (inductive and deductive thinking). The first speech motor temporary connections appear towards the end of the child’s first year of life; at the age of 9-10 months, the word becomes one of the significant elements, components of a complex stimulus, but does not yet act as an independent stimulus. The combination of words into successive complexes, into separate semantic phrases, is observed in the second year of a child’s life.
The depth of mental activity, which determines mental characteristics and forms the basis of human intelligence, is largely due to the development of the generalizing function of the word. In the development of the generalizing function of a word in a person, the following stages, or stages, of the integrative function of the brain are distinguished. At the first stage of integration, the word replaces the sensory perception of a certain object (phenomenon, event) designated by it. At this stage, each word acts as a conventional sign of one specific object; the word does not express its generalizing function, which unites all unambiguous objects of this class. For example, the word “doll” for a child means specifically the doll that he has, but not the doll in a store window, in a nursery, etc. This stage occurs at the end of the 1st - beginning of the 2nd year of life.
At the second stage, the word replaces several sensory images that unite homogeneous objects. The word “doll” for a child becomes a general designation for the various dolls that he sees. This understanding and use of the word occurs by the end of the 2nd year of life. At the third stage, the word replaces a number of sensory images of heterogeneous objects. The child develops an understanding of the general meaning of words: for example, the word “toy” for a child means a doll, a ball, a cube, etc. This level of using words is achieved in the 3rd year of life. Finally, the fourth stage of the integrative function of the word, characterized by verbal generalizations of the second and third order, is formed in the 5th year of the child’s life (he understands that the word “thing” means integrative words of the previous level of generalization, such as “toy”, “food”, “book”, “clothes”, etc.).
Stages of development of the integrative generalizing function of a word as component element mental operations are closely related to the stages and periods of development of cognitive abilities. First initial period falls on the stage of development of sensorimotor coordination (child aged 1.5-2 years). The next period of pre-operational thinking (age 2-7 years) is determined by the development of language: the child begins to actively use sensorimotor thinking patterns. The third period is characterized by the development of coherent operations: the child develops the ability to reason logically using specific concepts (age 7-11 years). By the beginning of this period, verbal thinking and activation of the child’s inner speech begin to predominate in the child’s behavior. Finally, the last, final stage of development of cognitive abilities is the period of formation and implementation of logical operations based on the development of elements of abstract thinking, logic of reasoning and inference (11-16 years). At the age of 15-17 years, the formation of neuro- and psychophysiological mechanisms of mental activity is basically completed. Further development of the mind and intelligence is achieved through quantitative changes; all the basic mechanisms that determine the essence of human intelligence have already been formed.
To determine the level of human intelligence as a general property of the mind and talents, IQ 1 is widely used - IQ, calculated based on the results of psychological testing.
The search for unambiguous, sufficiently substantiated correlations between the level of human mental abilities, the depth thought processes and the corresponding brain structures still remain largely unsuccessful.
16. FatnkciAnd speech, localization of their sensory and motor zones in the human cerebral cortex. Development of speech function in children.
The speech function includes the ability not only to encode, but also to decode this message with the help of appropriate conventional signs, while maintaining its meaningful semantic meaning. In the absence of such information modeling isomorphism, it becomes impossible to use this form of communication in interpersonal communication. Thus, people cease to understand each other if they use different code elements (different languages that are inaccessible to all persons participating in communication). The same mutual misunderstanding occurs when different semantic contents are embedded in the same speech signals.
The symbol system used by a person reflects the most important perceptual and symbolic structures in the communication system. It should be noted that mastering a language significantly complements its ability to perceive the surrounding world on the basis of the first signal system, thereby constituting that “extraordinary increase” that I. P. Pavlov spoke about, noting the fundamental important difference in the content of higher nervous activity in humans compared to animals.
Words as a form of transmission of thought form the only truly observable basis of speech activity. While the words that make up the structure of a particular language can be seen and heard, their meaning and content remain beyond the means of direct sensory perception. The meaning of words is determined by the structure and volume of memory, the information thesaurus of the individual. The semantic (semantic) structure of the language is contained in the subject's information thesaurus in the form of a specific semantic code that converts the corresponding physical parameters of the verbal signal into its semantic code equivalent. At the same time, oral speech serves as a means of immediate direct communication, written language allows one to accumulate knowledge, information and acts as a means of communication mediated in time and space.
Neurophysiological studies of speech activity have shown that when perceiving words, syllables and their combinations in impulse activity neural populations of the human brain form specific patterns with certain spatial and temporal characteristics. The use of different words and parts of words (syllables) in special experiments makes it possible to differentiate in the electrical reactions (impulse flows) of central neurons both physical (acoustic) and semantic (semantic) components of brain codes of mental activity (N. P. Bekhtereva).
The presence of an individual’s information thesaurus and its active influence on the processes of perception and processing of sensory information are a significant factor explaining the ambiguous interpretation of input information at different points in time and in different functional states of a person. To express any semantic structure, there are many different forms of representations, for example sentences. The well-known phrase: “He met her in a clearing with flowers” allows for three different semantic concepts (flowers in his hands, in her hands, flowers in the clearing). The same words and phrases can also mean various phenomena, objects (bur, weasel, scythe, etc.).
The linguistic form of communication as the leading form of information exchange between people, the daily use of language, where only a few words have an exact, unambiguous meaning, largely contributes to the development of human intuitive ability think and operate with imprecise, vague concepts (which are words and phrases - linguistic variables). The human brain, in the process of developing its second signaling system, the elements of which allow ambiguous relationships between a phenomenon, an object and its designation (a sign - a word), has acquired a remarkable property that allows a person to act intelligently and quite rationally in conditions of a probabilistic, “fuzzy” environment, significant information uncertainty. This property is based on the ability to manipulate, operate with inaccurate quantitative data, “fuzzy” logic, as opposed to formal logic and classical mathematics, which deals only with precise, uniquely defined cause-and-effect relationships. Thus, the development of the higher parts of the brain leads not only to the emergence and development of a fundamentally new form of perception, transmission and processing of information in the form of a second signal system, but the functioning of the latter, in turn, results in the emergence and development of a fundamentally new form of mental activity, the construction of conclusions based on the use of multi-valued (probabilistic, “fuzzy”) logic, the Human brain operates with “fuzzy”, imprecise terms, concepts, qualitative assessments easier than quantitative categories, numbers. Apparently, the constant practice of using language with its probabilistic relationship between a sign and its denotation (the phenomenon or thing it denotes) has served as excellent training for the human mind in the manipulation of fuzzy concepts. It is the “fuzzy” logic of human mental activity, based on the function of the second signaling system, that provides him with the opportunity heuristic solution many complex problems that cannot be solved by conventional algorithmic methods.
The speech function is carried out by certain structures of the cerebral cortex. The motor speech center responsible for oral speech, known as Broca's area, is located at the base of the inferior frontal gyrus (Fig. 15.8). When this area of the brain is damaged, disorders of the motor reactions that provide oral speech are observed.
The acoustic speech center (Wernicke's center) is located in the posterior third of the superior temporal gyrus and in the adjacent part - the supramarginal gyrus (gyrus supramarginalis). Damage to these areas results in loss of the ability to understand the meaning of words heard. The optical center of speech is located in the angular gyrus (gyrus angularis), damage to this part of the brain makes it impossible to recognize what is written.
The left hemisphere is responsible for the development of abstract logical thinking associated with the primary processing of information at the level of the second signaling system. The right hemisphere provides the perception and processing of information, mainly at the level of the first signaling system.
Despite the indicated certain left hemisphere localization of speech centers in the structures of the cerebral cortex (and as a result - corresponding violations of oral and written speech when they are damaged), it should be noted that dysfunction of the second signaling system is usually observed with damage to many other structures of the cortex and subcortical formations. The functioning of the second signaling system is determined by the functioning of the entire brain.
Among the most common dysfunctions of the second signaling system are: agnosia - loss of the ability to recognize words (visual agnosia occurs when the occipital zone is damaged, auditory agnosia occurs when the temporal zones of the cerebral cortex are damaged), aphasia - speech impairment, agraphia - violation of writing, amnesia - forgetting words.
The word, as the main element of the second signaling system, turns into a signal signal as a result of the process of learning and communication between the child and adults. The word as a signal of signals, with the help of which the generalization and abstraction that characterize human thinking are carried out, has become the exceptional feature higher nervous activity, which provides the necessary conditions progressive development human individual. The ability to pronounce and understand words develops in a child as a result of the association of certain sounds - words of oral speech. Using language, the child changes the way of cognition: sensory (sensory and motor) experience is replaced by the use of symbols and signs. Learning no longer necessarily requires one's own sensory experience; it can occur indirectly through language; feelings and actions give way to words.
As a complex signal stimulus, the word begins to form in the second half of the child’s first year of life. As the child grows and develops and his life experience expands, the content of the words he uses expands and deepens. The main tendency in the development of the word is that it generalizes a large number of primary signals and, abstracting from their concrete diversity, makes the concept contained in it more and more abstract.
Higher forms of abstraction in the signaling systems of the brain are usually associated with the act of artistic, creative human activity, in the world of art, where the product of creativity acts as one of the types of encoding and decoding of information. Even Aristotle emphasized the ambiguous probabilistic nature of the information contained in a work of art. Like any other sign signaling system, art has its own specific code (determined by historical and national factors), a system of conventions.. In terms of communication, the information function of art allows people to exchange thoughts and experiences, allows a person to join the historical and national experience of others, far people distant (both temporally and spatially) from him. The sign or figurative thinking underlying creativity is carried out through associations, intuitive anticipations, through a “gap” in information (P. V. Simonov). Apparently connected with this is the fact that many authors of works of art, artists and writers usually begin to create a work of art in the absence of preliminary clear plans, when the final form of a creative product that is perceived by other people is far from unambiguous seems unclear to them (especially if it is a work of abstract art). The source of the versatility and ambiguity of such a work of art is the understatement, the lack of information, especially for the reader, viewer in terms of understanding and interpretation of the work of art. Hemingway spoke about this when he compared a work of art to an iceberg: only a small part of it is visible on the surface (and can be perceived more or less unambiguously by everyone), a large and significant part is hidden under water, which provides the viewer and reader with a wide field for imagination.
17. Biological role of emotions, behavioral and autonomic components. Negative emotions (sthenic and asthenic).
Emotion is a specific state of the mental sphere, one of the forms of a holistic behavioral reaction, involving many physiological systems and determined both by certain motives, the needs of the body, and the level of their possible satisfaction. The subjectivity of the category of emotion is manifested in a person’s experience of his relationship to the surrounding reality. Emotions are reflex reactions of the body to external and internal stimuli, characterized by a pronounced subjective coloring and including almost all types of sensitivity.
Emotions have no biological and physiological value if the body has sufficient information to satisfy its desires and basic needs. The breadth of needs, and therefore the variety of situations in which an individual develops and manifests an emotional reaction, varies significantly. A person with limited needs is less likely to give emotional reactions compared to people with high and diverse needs, for example, with needs related to his social status in society.
Emotional arousal as a result of a certain motivational activity is closely related to the satisfaction of three basic human needs: food, protective and sexual. Emotion like active state specialized brain structures determine changes in the behavior of the body in the direction of either minimizing or maximizing this state. Motivational arousal, associated with various emotional states (thirst, hunger, fear), mobilizes the body to quickly and optimally satisfy the need. A satisfied need is realized in a positive emotion, which acts as a reinforcing factor. Emotions arise in evolution in the form of subjective sensations that allow animals and humans to quickly assess both the needs of the body itself and the effects of various factors of the external and internal environment on it. A satisfied need causes an emotional experience of a positive nature and determines the direction of behavioral activity. Positive emotions, being fixed in memory, play an important role in the mechanisms of formation of purposeful activity of the body.
Emotions, realized by a special nervous apparatus, manifest themselves in the absence of accurate information and ways to achieve life’s needs. This idea of the nature of emotion allows us to formulate its informational nature in the following form (P. V. Simonov): E=P (N—S), Where E — emotion (a certain quantitative characteristic of the emotional state of the body, usually expressed by important functional parameters of the physiological systems of the body, for example, heart rate, blood pressure, adrenaline level in the body, etc.); P- a vital need of the body (food, defensive, sexual reflexes), aimed at the survival of the individual and procreation, in humans additionally determined by social motives; N — information necessary to achieve a goal, satisfy a given need; WITH- information that the body possesses and which can be used to organize targeted actions.
This concept was further developed in the works of G.I. Kositsky, who proposed estimating the amount of emotional stress using the formula:
CH = C (I n ∙V n ∙E n - I s ∙V s ∙E s),
Where CH - state of tension, C- target, In,Vn,En - necessary information, time and energy, I s, D s, E s — information, time and energy existing in the body.
The first stage of tension (CHI) is a state of attention, mobilization of activity, increased performance. This stage has training significance, increasing the functionality of the body.
The second stage of tension (CHII) is characterized by a maximum increase energy resources body, increasing blood pressure, increased heart rate and breathing. A sthenic negative emotional reaction occurs, which has external expression in the form of rage and anger.
The third stage (SNH) is an asthenic negative reaction, characterized by depletion of the body’s resources and finding its psychological expression in a state of horror, fear, and melancholy.
The fourth stage (CHIV) is the stage of neurosis.
Emotions should be seen as additional mechanism active adaptation, adaptation of the organism to the environment with a lack of accurate information about ways to achieve its goals. The adaptability of emotional reactions is confirmed by the fact that they involve only those organs and systems that provide better interaction organism and environment. The same circumstance is indicated by the sharp activation during emotional reactions of the sympathetic department of the autonomic nervous system, which ensures the adaptive-trophic functions of the body. In an emotional state, there is a significant increase in the intensity of oxidative and energy processes in the body.
An emotional reaction is the total result of both the magnitude of a certain need and the possibility of satisfying this need at a given moment. Ignorance of the means and ways to achieve the goal seems to be a source of strong emotional reactions, while the feeling of anxiety grows, obsessive thoughts become irresistible. This is true of all emotions. Thus, the emotional feeling of fear is characteristic of a person if he does not have the means of possible protection from danger. A feeling of rage occurs in a person when he wants to crush an enemy, this or that obstacle, but does not have the corresponding strength (rage as a manifestation of powerlessness). A person experiences grief (an appropriate emotional reaction) when he is unable to make up for a loss.
The sign of an emotional reaction can be determined using the formula of P. V. Simonov. A negative emotion occurs when H>C and, conversely, a positive emotion is expected when H < S. So, a person experiences joy when he has an excess of information necessary to achieve a goal, when the goal turns out to be closer than we thought (the source of the emotion is an unexpected pleasant message, unexpected joy).
In the theory of the functional system of P.K. Anokhin, the neurophysiological nature of emotions is associated with ideas about functional organization adaptive actions of animals and humans based on the concept of “action acceptor”. The signal for the organization and functioning of the nervous apparatus of negative emotions is the fact of mismatch between the “acceptor of action” - the afferent model of expected results with the afferentation about the real results of the adaptive act.
Emotions have a significant impact on subjective state person: in a state of emotional uplift, the intellectual sphere of the body works more actively, a person is inspired, and creative activity increases. Emotions, especially positive ones, play a big role as powerful life incentives for maintaining high performance and human health. All this gives reason to believe that emotion is a state of the highest rise in a person’s spiritual and physical powers.
18. Memory. Short-term and long-term memory. The importance of consolidation (stabilization) of memory traces.
19. Types of memory. Memory processes.
20. Neural structures of memory. Molecular theory of memory.
(combined for convenience)
In formation and implementation higher functions In the brain, the general biological property of fixing, storing and reproducing information, united by the concept of memory, is very important. Memory as the basis of learning and thinking processes includes four closely related processes: memorization, storage, recognition, reproduction. Over the course of a person’s life, his memory becomes a receptacle for a huge amount of information: over the course of 60 years of active creative activity, a person is able to perceive 10 13 - 10 bits of information, of which no more than 5-10% are actually used. This indicates significant memory redundancy and the importance of not only memory processes, but also the process of forgetting. Not everything that is perceived, experienced or done by a person is stored in memory; a significant part of the perceived information is forgotten over time. Forgetting manifests itself in the inability to recognize or remember something or in the form of erroneous recognition or recollection. Forgetting may be caused by various factors, associated both with the material itself, its perception, and with the negative influences of other stimuli acting directly after memorization (the phenomenon of retroactive inhibition, memory depression). The process of forgetting largely depends on the biological meaning of the perceived information, the type and nature of memory. Forgetting in some cases can be positive, for example, memory for negative signals, unpleasant events. This is the truth of the wise eastern saying: “Happiness is the joy of memory, grief of oblivion is a friend.”
As a result of the learning process, physical, chemical and morphological changes occur in the nervous structures, which persist for some time and have a significant impact on the reflex reactions carried out by the body. The totality of such structural and functional changes in nerve formations, known as "engram" (trace) of active stimuli becomes important factor, which determines the entire variety of adaptive adaptive behavior of the organism.
Types of memory are classified according to the form of manifestation (figurative, emotional, logical, or verbal-logical), according to the temporal characteristics or duration (instant, short-term, long-term).
Figurative memory is manifested by the formation, storage and reproduction of a previously perceived image of a real signal, its neural model. Under emotional memory understand the reproduction of some previously experienced emotional state upon repeated presentation of the signal that caused the initial occurrence of such an emotional state. Emotional memory is characterized by high speed and strength. This is obviously the main reason for a person’s easier and more stable memorization of emotionally charged signals and stimuli. On the contrary, gray, boring information is much more difficult to remember and is quickly erased from memory. Logical (verbal-logical, semantic) memory - memory for verbal signals denoting both external objects and events and the sensations and ideas caused by them.
Instantaneous (iconic) memory consists in the formation of an instant imprint, a trace of the current stimulus in the receptor structure. This imprint, or the corresponding physico-chemical engram of an external stimulus, is distinguished by its high information content, completeness of signs, properties (hence the name “iconic memory”, i.e. a reflection clearly worked out in detail) of the current signal, but also by a high rate of extinction (not stored more than 100-150 ms, unless reinforced or reinforced by a repeated or ongoing stimulus).
The neurophysiological mechanism of iconic memory obviously lies in the processes of reception of the current stimulus and the immediate aftereffect (when the real stimulus is no longer effective), expressed in trace potentials formed on the basis of the receptor electrical potential. The duration and severity of these trace potentials is determined both by the strength of the current stimulus and by the functional state, sensitivity and lability of the perceiving membranes of the receptor structures. Erasing a memory trace occurs in 100-150 ms.
The biological significance of iconic memory is to provide the analyzing structures of the brain with the ability to isolate individual signs and properties of a sensory signal and image recognition. Iconic memory stores not only the information necessary for a clear understanding of sensory signals arriving within a fraction of a second, but also contains an incomparably larger amount of information than can be used and is actually used at the subsequent stages of perception, fixation and reproduction of signals.
With sufficient strength of the current stimulus, iconic memory moves into the category of short-term (short-term) memory. Short-term memory - RAM, which ensures the execution of current behavioral and mental operations. Short-term memory is based on repeated multiple circulation of pulse discharges along circular closed chains of nerve cells (Fig. 15.3) (Lorente de No, I.S. Beritov). Ring structures can also be formed within the same neuron by return signals formed by the terminal (or lateral, lateral) branches of the axonal process on the dendrites of the same neuron (I. S. Beritov). As a result of repeated passage of impulses through these ring structures, persistent changes are gradually formed in the latter, laying the foundation for the subsequent formation of long-term memory. Not only excitatory, but also inhibitory neurons can participate in these ring structures. The duration of short-term memory is seconds, minutes after the direct action of the corresponding message, phenomenon, object. The reverberation hypothesis of the nature of short-term memory allows for the presence of closed circles of circulation of impulse excitation both within the cerebral cortex and between the cortex and subcortical formations (in particular, thalamocortical nerve circles), containing both sensory and gnostic (learning, recognizing) nerve cells. Intracortical and thalamocortical reverberation circles, as the structural basis of the neurophysiological mechanism of short-term memory, are formed by cortical pyramidal cells of layers V-VI of predominantly the frontal and parietal regions of the cerebral cortex.
The participation of the structures of the hippocampus and limbic system of the brain in short-term memory is associated with the implementation by these nervous formations of the function of distinguishing the novelty of signals and reading incoming afferent information at the input of the waking brain (O. S. Vinogradova). The implementation of the phenomenon of short-term memory practically does not require and is not really associated with significant chemical and structural changes in neurons and synapses, since the corresponding changes in the synthesis of messenger (messenger) RNA require more time.
Despite the differences in hypotheses and theories about the nature of short-term memory, their initial premise is the occurrence of short-term reversible changes in the physicochemical properties of the membrane, as well as the dynamics of transmitters in synapses. Ionic currents across the membrane, combined with transient metabolic shifts during synaptic activation, can result in changes in synaptic transmission efficiency lasting several seconds.
The transformation of short-term memory into long-term memory (memory consolidation) is generally due to the onset of persistent changes in synaptic conductivity as a result of repeated excitation of nerve cells (learning populations, ensembles of Hebbian neurons). The transition of short-term memory to long-term memory (memory consolidation) is caused by chemical and structural changes in the corresponding nerve formations. According to modern neurophysiology and neurochemistry, long-term (long-term) memory is based on complex chemical processes of the synthesis of protein molecules in brain cells. Memory consolidation is based on many factors that lead to easier transmission of impulses through synaptic structures (increased functioning of certain synapses, increased conductivity for adequate impulse flows). One of these factors may be the well-known phenomenon of post-tetanic potentiation (see Chapter 4), supported by reverberating impulse flows: irritation of afferent nerve structures leads to a fairly long-term (tens of minutes) increase in the conductivity of spinal cord motor neurons. This means that the physicochemical changes in postsynaptic membranes that occur during a persistent shift in membrane potential probably serve as the basis for the formation of memory traces, reflected in changes in the protein substrate of the nerve cell.
Of certain importance in the mechanisms of long-term memory are the changes observed in the mediator mechanisms that ensure the process of chemical transfer of excitation from one nerve cell to another. Plastic chemical changes in synaptic structures are based on the interaction of mediators, for example acetylcholine, with receptor proteins of the postsynaptic membrane and ions (Na +, K +, Ca 2+). The dynamics of transmembrane currents of these ions makes the membrane more sensitive to the action of mediators. It has been established that the learning process is accompanied by an increase in the activity of the enzyme cholinesterase, which destroys acetylcholine, and substances that suppress the action of cholinesterase cause significant memory impairment.
One of the common chemical theories memory is Hiden's hypothesis about the protein nature of memory. According to the author, the information underlying long-term memory is encoded and recorded in the structure of the polynucleotide chain of the molecule. The different structure of impulse potentials, in which certain sensory information is encoded in afferent nerve conductors, leads to different rearrangements of the RNA molecule, to movements of nucleotides in their chain that are specific for each signal. In this way, each signal is fixed in the form of a specific imprint in the structure of the RNA molecule. Based on Hiden's hypothesis, it can be assumed that glial cells, which take part in the trophic provision of neuron functions, are included in the metabolic cycle of encoding incoming signals by changing the nucleotide composition of synthesizing RNAs. The entire set of possible permutations and combinations of nucleotide elements makes it possible to record a huge amount of information in the structure of an RNA molecule: the theoretically calculated volume of this information is 10 -10 20 bits, which significantly exceeds the actual volume of human memory. The process of fixing information in a nerve cell is reflected in the synthesis of a protein, into the molecule of which the corresponding trace imprint of changes in the RNA molecule is introduced. In this case, the protein molecule becomes sensitive to the specific pattern of the pulse flow, thereby, as it were, it recognizes that afferent signal, which is encoded in this impulse pattern. As a result, the mediator is released at the corresponding synapse, leading to the transfer of information from one nerve cell to another in the system of neurons responsible for recording, storing and reproducing information.
Possible substrates for long-term memory are some hormonal peptides, simple protein substances, and the specific protein S-100. Such peptides, which stimulate, for example, the conditioned reflex learning mechanism, include some hormones (ACTH, somatotropic hormone, vasopressin, etc.).
An interesting hypothesis about the immunochemical mechanism of memory formation was proposed by I. P. Ashmarin. The hypothesis is based on the recognition important role active immune response in consolidation, formation of long-term memory. The essence of this idea is as follows: as a result of metabolic processes on synaptic membranes during the reverberation of excitation at the stage of formation of short-term memory, substances are formed that play the role of an antigen for antibodies produced in glial cells. The binding of an antibody to an antigen occurs with the participation of stimulators of the formation of mediators or an inhibitor of enzymes that destroy and break down these stimulating substances (Fig. 15.4).
A significant place in ensuring the neurophysiological mechanisms of long-term memory is given to glial cells (Galambus, A.I. Roitbak), the number of which in the central nervous formations is an order of magnitude greater than the number of nerve cells. The following mechanism of participation of glial cells in the implementation of the conditioned reflex learning mechanism is assumed. At the stage of formation and strengthening of the conditioned reflex, in the glial cells adjacent to the nerve cell, the synthesis of myelin increases, which envelops the terminal thin branches of the axonal process and thereby facilitates the conduction of nerve impulses along them, resulting in an increase in the efficiency of synaptic transmission of excitation. In turn, stimulation of myelin formation occurs as a result of depolarization of the oligodendrocyte (glial cell) membrane under the influence of an incoming nerve impulse. Thus, long-term memory may be based on conjugate changes in the neuroglial complex of the central nervous formations.
The ability to selectively disable short-term memory without impairing long-term memory and selectively affecting long-term memory in the absence of any impairment of short-term memory is usually considered evidence of the different nature of the underlying neurophysiological mechanisms. Indirect evidence of the presence of certain differences in the mechanisms of short-term and long-term memory is the characteristics of memory disorders when brain structures are damaged. Thus, with some focal lesions of the brain (damages to the temporal zones of the cortex, structures of the hippocampus), when it is concussed, memory disorders occur, expressed in the loss of the ability to remember current events or events of the recent past (occurring shortly before the impact that caused this pathology) while maintaining memory of the previous ones, events that happened long ago. However, a number of other influences have the same type of effect on both short-term and long-term memory. Apparently, despite some noticeable differences in the physiological and biochemical mechanisms responsible for the formation and manifestation of short-term and long-term memory, their nature is much more similar than different; they can be considered as successive stages of a single mechanism for fixing and strengthening trace processes occurring in nervous structures under the influence of repeating or constantly acting signals.
21. Concept of functional systems (P.K. Anokhin). Systems approach in knowledge.
The idea of self-regulation physiological functions was most fully reflected in the theory of functional systems developed by Academician P.K. Anokhin. According to this theory, the balancing of the organism with its environment is carried out by self-organizing functional systems.
Functional systems (FS) are a dynamically developing self-regulating complex of central and peripheral formations, ensuring the achievement of useful adaptive results.
The result of the action of any PS is a vital adaptive indicator necessary for the normal functioning of the body in biological and social terms. This implies the system-forming role of the result of an action. It is to achieve a certain adaptive result that FSs are formed, the complexity of the organization of which is determined by the nature of this result.
The variety of adaptive results useful for the body can be reduced to several groups: 1) metabolic results, which are a consequence of metabolic processes at the molecular (biochemical) level, creating substrates or end products necessary for life; 2) homeopathic results, which are leading indicators of body fluids: blood, lymph, interstitial fluid (osmotic pressure, pH, content of nutrients, oxygen, hormones, etc.), providing various aspects of normal metabolism; 3) the results of behavioral activity of animals and humans, satisfying basic metabolic and biological needs: food, drinking, sexual, etc.; 4) the results of human social activity that satisfy social (creation of a social product of labor, environmental protection, protection of the fatherland, improvement of everyday life) and spiritual (acquisition of knowledge, creativity) needs.
Each FS includes various organs and fabrics. The combination of the latter into a FS is carried out by the result for the sake of which the FS is created. This principle of FS organization is called the principle of selective mobilization of the activity of organs and tissues into an integral system. For example, to ensure that the blood gas composition is optimal for metabolism, selective mobilization of the activity of the lungs, heart, blood vessels, kidneys, hematopoietic organs, and blood occurs in the respiratory system.
The inclusion of individual organs and tissues in the FS is carried out according to the principle of interaction, which provides for the active participation of each element of the system in achieving a useful adaptive result.
In the given example, each element actively contributes to maintaining the gas composition of the blood: the lungs provide gas exchange, the blood binds and transports O 2 and CO 2, the heart and blood vessels provide required speed blood movement and size.
To achieve results at different levels, multi-level FSs are also formed. FS at any level of organization has a fundamentally similar structure, which includes 5 main components: 1) a useful adaptive result; 2) result acceptors (control devices); 3) reverse afferentation, supplying information from receptors to the central link of the FS; 4) central architectonics - selective association of nervous elements different levels in special node mechanisms (control devices); 5) executive components (reaction apparatuses) - somatic, autonomic, endocrine, behavioral.
22. Central mechanisms of functional systems that form behavioral acts: motivation, stage of afferent synthesis (situational afferentation, trigger afferentation, memory), stage of decision-making. Formation of an acceptor of action results, reverse afferentation.
The state of the internal environment is constantly monitored by the corresponding receptors. The source of changes in the parameters of the internal environment of the body is the metabolic process (metabolism) continuously flowing in cells, accompanied by the consumption of initial and formation of final products. Any deviation of parameters from parameters that are optimal for metabolism, as well as changes in results at a different level, are perceived by receptors. From the latter, information is transmitted by a feedback link to the corresponding nerve centers. Based on incoming information, structures of various levels of the central nervous system are selectively involved in this PS for mobilization executive bodies and systems (reaction apparatuses). The activity of the latter leads to the restoration of what is necessary for metabolism or social adaptation result.
The organization of various PS in the body is fundamentally the same. This is isomorphism principle FS.
At the same time, there are differences in their organization that are determined by the nature of the result. FS that determine various indicators of the internal environment of the body are genetically determined and often include only internal (vegetative, humoral) self-regulation mechanisms. These include PS that determine the optimal level of blood mass, formed elements, environmental reaction (pH) for tissue metabolism, blood pressure. Other PS of the homeostatic level also include an external link of self-regulation, which involves the interaction of the body with the external environment. In the work of some PS, the external link plays a relatively passive role as a source of necessary substrates (for example, oxygen for PS respiration); in others, the external link of self-regulation is active and includes purposeful human behavior in the environment, aimed at its transformation. These include PS, which provides the body with optimal levels of nutrients, osmotic pressure, and body temperature.
FS of the behavioral and social level are extremely dynamic in their organization and are formed as the corresponding needs arise. In such FS, the external link of self-regulation plays a leading role. At the same time, human behavior is determined and corrected genetically, individually acquired experience, as well as numerous disturbing influences. An example of such FS is human production activity to achieve a result that is socially significant for society and the individual: the creativity of scientists, artists, writers.
FS control devices. The central architectonics (control apparatus) of the FS, consisting of several stages, is built according to the principle of isomorphism (see Fig. 3.1). The initial stage is the stage of afferent synthesis. It is based on dominant motivation, arising on the basis of the body’s most significant needs at the moment. The excitement created by the dominant motivation mobilizes genetic and individually acquired experience (memory) to satisfy this need. Habitat status information supplied situational afferentation, allows you to assess the possibility in a specific situation and, if necessary, adjust past experience of satisfying the need. The interaction of excitations created by dominant motivation, memory mechanisms and environmental afferentation creates a state of readiness (pre-launch integration) necessary to obtain an adaptive result. Triggering afferentation transfers the system from a state of readiness to a state of activity. At the stage of afferent synthesis, the dominant motivation determines what to do, memory - how to do it, situational and trigger afferentation - when to do it in order to achieve the required result.
The stage of afferent synthesis ends with decision making. At this stage, out of many possible ones, a single path is chosen to satisfy the leading need of the body. There is a restriction in the degrees of freedom of activity of the FS.
Following the decision, an acceptor of the action result and an action program are formed. IN acceptor of action results all the main features of the future result of the action are programmed. This programming occurs on the basis of dominant motivation, which extracts from memory mechanisms the necessary information about the characteristics of the result and the ways to achieve it. Thus, the acceptor of action results is an apparatus for foresight, forecasting, modeling the results of the FS activity, where the parameters of the result are modeled and compared with the afferent model. Information about outcome parameters is provided using reverse afferentation.
The action program (efferent synthesis) is a coordinated interaction of somatic, vegetative and humoral components in order to successfully achieve a useful adaptive result. The action program forms the necessary adaptive act in the form of a certain set of excitations in the central nervous system before its implementation in the form of specific actions begins. This program determines the inclusion of efferent structures necessary to obtain a useful result.
A necessary link in the work of the FS is reverse afferentation. With its help, individual stages and the final result of systems activity are assessed. Information from the receptors arrives through afferent nerves and humoral communication channels to the structures that make up the acceptor of the result of the action. The coincidence of the parameters of the real result and the properties of its model prepared in the acceptor means the satisfaction of the initial need of the organism. The activities of the FS end here. Its components can be used in other file systems. If there is a discrepancy between the parameters of the result and the properties of the model prepared on the basis of afferent synthesis in the acceptor of the results of the action, an indicative-exploratory reaction occurs. It leads to a restructuring of afferent synthesis, the adoption of a new decision, clarification of the characteristics of the model in the acceptor of the results of action and the program for achieving them. The activities of the FS are carried out in a new direction necessary to satisfy the leading need.
Principles of FS interaction. Several functional systems operate simultaneously in the body, which provides for their interaction, which is based on certain principles.
Principle of systemogenesis involves selective maturation and involution of functional systems. Thus, the PS of blood circulation, respiration, nutrition and their individual components in the process of ontogenesis mature and develop earlier than other PS.
Multi-parameter principle (multiple connected) interactions defines the generalized activities of various FS aimed at achieving a multicomponent result. For example, the parameters of homeostasis (osmotic pressure, CBS, etc.) are provided by independent PS, which are combined into a single generalized PS of homeostasis. It determines the unity of the internal environment of the body, as well as its changes due to metabolic processes and the active activity of the body in the external environment. In this case, the deviation of one indicator of the internal environment causes a redistribution in certain ratios of other parameters of the result of the generalized FS of homeostasis.
Hierarchy principle assumes that the body's physical functions are arranged in a certain row in accordance with biological or social significance. For example, in biological terms, the dominant position is occupied by the PS, which ensures the preservation of the integrity of tissues, then by the PS of nutrition, reproduction, etc. The activity of the organism in each time period is determined by the dominant PS in terms of survival or adaptation of the organism to the conditions of existence. After satisfying one leading need, another need, the most important in terms of social or biological significance, takes a dominant position.
The principle of sequential dynamic interaction provides for a clear sequence of changes in the activities of several interconnected FS. The factor determining the beginning of the activity of each subsequent FS is the result of the activity of the previous system. Another principle for organizing the interaction of the FS is the principle of systemic quantization of life activity. For example, in the process of breathing, the following systemic “quanta” can be distinguished with their end results: inhalation and the entry of a certain amount of air into the alveoli; O 2 diffusion from the alveoli to the pulmonary capillaries and the binding of O 2 to hemoglobin; transport of O2 to tissues; diffusion of O 2 from blood into tissues and CO 2 into reverse direction; transport of CO 2 to the lungs; diffusion of CO 2 from the blood into the alveolar air; exhalation. The principle of system quantization extends to human behavior.
Thus, managing the vital activity of the organism through the organization of PS at the homeostatic and behavioral levels has a number of properties that allow the organism to adequately adapt to a changing external environment. FS allows you to respond to disturbing influences from the external environment and, based on feedback, restructure the body’s activity when the parameters of the internal environment deviate. In addition, in the central mechanisms of the FS, an apparatus for predicting future results is formed - an acceptor of the result of an action, on the basis of which the organization and initiation of adaptive acts that are ahead of actual events occur, which significantly expands the adaptive capabilities of the organism. Comparison of the parameters of the achieved result with the afferent model in the acceptor of action results serves as the basis for correcting the body’s activity in terms of obtaining exactly those results that best ensure the adaptation process.
23. Physiological nature of sleep. Theories of sleep.
Sleep is a vital, periodically occurring special functional state characterized by specific electrophysiological, somatic and vegetative manifestations.
It is known that the periodic alternation of natural sleep and wakefulness belongs to the so-called circadian rhythms and is largely determined by daily changes in illumination. A person spends about a third of his life sleeping, which has led to a long-standing and keen interest among researchers in this condition.
Theories of sleep mechanisms. According to concepts 3. Freud, sleep is a state in which a person interrupts conscious interaction with the outside world in the name of deepening into the inner world, while external irritations are blocked. According to Z. Freud, the biological purpose of sleep is rest.
Humoral concept explains the main reason for the onset of sleep by the accumulation of metabolic products during the period of wakefulness. According to modern data, specific peptides, such as delta-sleep peptide, play a major role in inducing sleep.
Information deficit theory The main reason for the onset of sleep is the restriction of sensory influx. Indeed, in observations of volunteers in the process of preparation for space flight it was revealed that sensory deprivation(sharp restriction or cessation of the influx of sensory information) leads to the onset of sleep.
According to the definition of I. P. Pavlov and many of his followers, natural sleep is a diffuse inhibition of cortical and subcortical structures, cessation of contact with the outside world, extinction of afferent and efferent activity, shutdown of conditioned and unconditioned reflexes during sleep, as well as the development of general and particular relaxation. Modern physiological studies have not confirmed the presence of diffuse inhibition. Thus, microelectrode studies revealed a high degree of neuronal activity during sleep in almost all parts of the cerebral cortex. From the analysis of the pattern of these discharges, it was concluded that the state of natural sleep represents a different organization of brain activity, different from brain activity in the waking state.
24. Sleep phases: “slow” and “fast” (paradoxical) according to EEG indicators. Brain structures involved in the regulation of sleep and wakefulness.
The most interesting results were obtained when conducting polygraphic studies during night sleep. During such studies, throughout the night, the electrical activity of the brain is continuously recorded on a multichannel recorder - an electroencephalogram (EEG) at various points (most often in the frontal, occipital and parietal lobes) synchronously with the registration of rapid (REM) and slow (MSG) eye movements and electromyograms of skeletal muscles, as well as a number of vegetative indicators - activity of the heart, digestive tract, respiration, temperature, etc.
EEG during sleep. The discovery by E. Azerinsky and N. Kleitman of the phenomenon of “rapid” or “paradoxical” sleep, during which rapid eye movements (REM) were discovered with closed eyelids and general complete muscle relaxation, served as the basis for modern research into the physiology of sleep. It turned out that sleep is a combination of two alternating phases: “slow” or “orthodox” sleep and “fast” or “paradoxical” sleep. The name of these sleep phases is due to the characteristic features of the EEG: during “slow” sleep, predominantly slow waves are recorded, and during “rapid” sleep, the fast beta rhythm, characteristic of human wakefulness, is recorded, which gives rise to calling this sleep phase “paradoxical” sleep. Based on the electroencephalographic picture, the phase of “slow” sleep is, in turn, divided into several stages. The following main stages of sleep are distinguished:
Stage I - drowsiness, the process of falling into sleep. This stage is characterized by a polymorphic EEG and the disappearance of the alpha rhythm. During night sleep, this stage is usually short-lived (1-7 minutes). Sometimes you can observe slow movements of the eyeballs (SMG), while fast movements of the eyeballs (REM) are completely absent;
stage II is characterized by the appearance on the EEG of so-called sleep spindles (12-18 per second) and vertex potentials, biphasic waves with an amplitude of about 200 μV against a general background of electrical activity with an amplitude of 50-75 μV, as well as K-complexes (vertex potential with subsequent “sleepy spindle”). This stage is the longest of all; it can take about 50 % the entire night's sleep time. No eye movements are observed;
Stage III is characterized by the presence of K-complexes and rhythmic activity (5-9 per second) and the appearance of slow or delta waves (0.5-4 per second) with an amplitude above 75 μV. The total duration of delta waves in this stage occupies from 20 to 50% of the entire III stage. There are no eye movements. Quite often this stage of sleep is called delta sleep.
Stage IV - the stage of “rapid” or “paradoxical” sleep is characterized by the presence of desynchronized mixed activity on the EEG: fast low-amplitude rhythms (in these manifestations it resembles stage I and active wakefulness - beta rhythm), which can alternate with low-amplitude slow and short bursts of alpha rhythm, sawtooth discharges, REM with closed eyelids.
Night sleep usually consists of 4-5 cycles, each of which begins with the first stages of “slow” sleep and ends with “rapid” sleep. The duration of the cycle in a healthy adult is relatively stable and amounts to 90-100 minutes. In the first two cycles, “slow” sleep predominates, in the last two cycles, “fast” sleep predominates, and “delta” sleep is sharply reduced and may even be absent.
The duration of “slow” sleep is 75-85%, and “paradoxical” sleep is 15-25. % of the total duration of night sleep.
Muscle tone during sleep. Throughout all stages of “slow” sleep, the tone of skeletal muscles progressively decreases; in “rapid” sleep there is no muscle tone.
Vegetative shifts during sleep. During “slow” sleep, the heart slows down, the breathing rate decreases, Cheyne-Stokes breathing may occur, and as “slow” sleep deepens, there may be partial obstruction of the upper respiratory tract and the appearance of snoring. The secretory and motor functions of the digestive tract decrease as slow-wave sleep deepens. Body temperature decreases before falling asleep, and as slow-wave sleep deepens, this decrease progresses. It is believed that a decrease in body temperature may be one of the reasons for the onset of sleep. Waking up is accompanied by an increase in body temperature.
In REM sleep, the heart rate may exceed the heart rate during wakefulness, various forms of arrhythmias may occur and a significant change in blood pressure may occur. It is believed that the combination of these factors may lead to sudden death during sleep.
Breathing is irregular, and prolonged apnea often occurs. Thermoregulation is impaired. Secretory and motor activity of the digestive tract is practically absent.
The REM stage of sleep is characterized by the presence of an erection of the penis and clitoris, which is observed from the moment of birth.
It is believed that the absence of an erection in adults indicates organic brain damage, and in children it will lead to disruption of normal sexual behavior in adulthood.
The functional significance of individual stages of sleep is different. Currently, sleep in general is considered as an active state, as a phase of the daily (circadian) biorhythm, performing an adaptive function. In a dream, the volume of short-term memory, emotional balance, and a disturbed system of psychological defenses are restored.
During delta sleep, information received during the waking period is organized, taking into account the degree of its significance. It is believed that during delta sleep, physical and mental performance is restored, which is accompanied by muscle relaxation and pleasant experiences; An important component of this compensatory function is the synthesis of protein macromolecules during delta sleep, including in the central nervous system, which are subsequently used during REM sleep.
Initial studies of REM sleep found that significant psychological changes occur with prolonged REM sleep deprivation. Emotional and behavioral disinhibition appears, hallucinations, paranoid ideas and other psychotic phenomena occur. Subsequently, these data were not confirmed, but the effect of REM sleep deprivation on emotional status, resistance to stress and psychological defense mechanisms was proven. Moreover, an analysis of many studies shows that REM sleep deprivation has a beneficial therapeutic effect in the case of endogenous depression. REM sleep plays a big role in reducing unproductive anxious tension.
Sleep and mental activity, dreams. When falling asleep, volitional control over thoughts is lost, contact with reality is disrupted, and so-called regressive thinking is formed. It occurs with a decrease in sensory influx and is characterized by the presence of fantastic ideas, dissociation of thoughts and images, and fragmentary scenes. Hypnagogic hallucinations occur, which are a series of visual frozen images (such as slides), while subjective time passes much faster than in the real world. In delta sleep, talking in your sleep is possible. Intense creative activity dramatically increases the duration of REM sleep.
It was initially discovered that dreams occur in REM sleep. It was later shown that dreams are also characteristic of slow-wave sleep, especially the delta stage of sleep. The causes of occurrence, the nature of the content, and the physiological significance of dreams have long attracted the attention of researchers. Among ancient peoples, dreams were surrounded by mystical ideas about the afterlife and were identified with communication with the dead. The content of dreams was attributed to the functions of interpretation, prediction, or prescription for subsequent actions or events. Many historical monuments testify to the significant influence of the content of dreams on the everyday and socio-political life of people of almost all ancient cultures.
In the ancient era of human history, dreams were also interpreted in their connection with active wakefulness and emotional needs. Sleep, as Aristotle defined, is a continuation of the mental life that a person lives in the waking state. Long before Freud's psychoanalysis, Aristotle believed that sensory function is reduced in sleep, giving way to the sensitivity of dreams to emotional subjective distortions.
I.M. Sechenov called dreams unprecedented combinations of experienced impressions.
All people see dreams, but many do not remember them. It is believed that in some cases this is due to the peculiarities of memory mechanisms in a particular person, and in other cases it is a kind of psychological defense mechanism. There is a kind of repression of dreams that are unacceptable in content, i.e. we “try to forget.”
Physiological meaning of dreams. It lies in the fact that in dreams the mechanism of figurative thinking is used to solve problems that could not be solved in wakefulness with the help of logical thinking. A striking example is the famous case of D.I. Mendeleev, who “saw” the structure of his famous periodic table of elements in a dream.
Dreams are a mechanism of a kind of psychological defense - reconciliation of unresolved conflicts in wakefulness, relieving tension and anxiety. Suffice it to remember the proverb “the morning is wiser than the evening.” When resolving a conflict during sleep, dreams are remembered, in otherwise dreams are repressed or dreams of a frightening nature arise - “I only dream about nightmares.”
Dreams differ between men and women. As a rule, in dreams men are more aggressive, while in women the content of dreams great place occupy sexual components.
Sleep and emotional stress. Research has shown that emotional stress significantly affects night sleep, changing the duration of its stages, that is, disrupting the structure of night sleep, and changes the content of dreams. Most often when emotional stress note a reduction in the period of “rapid” sleep and an extension of the latent period of falling asleep. The subjects had a reduction before the exam total duration sleep and its individual stages. For parachutists, before difficult jumps, the period of falling asleep and the first stage of “slow” sleep increase.
The study of the activity of the cerebral hemispheres together with the nearest subcortex under normal conditions (by the method of conditioned reflexes) led to the creation of a diagram of types of nervous activity or basic patterns of behavior in higher animals.
Types of the nervous system are divided into general, found in humans and animals, and private, characteristic only of humans.
The type of nervous system is an individual characteristic of the nervous system according to three main characteristics: 1) the strength of excitation and inhibition; 2) the relationship, or balance, of excitation and inhibition with each other and 3) the mobility of excitation and inhibition, which is characterized by the rates of their irradiation and concentration, the rate of formation of conditioned reflexes, etc.
The school of I.P. Pavlov established four types of nervous systems in dogs. The first type is strong (strong excitation and strong inhibition), unbalanced, with a predominance of excitation over inhibition, unrestrained. The second type is strong, completely balanced, inert, sedentary, slow. The third type is strong, quite balanced, very lively, agile. The fourth type is weak, with weak excitation and inhibition, easily inhibited. Easy inhibition of this type is due to both weak and easily radiating internal inhibition, and especially external inhibition under the influence of minor extraneous stimuli.
Only a few animals clearly display the features of a certain type of nervous system. For the majority, these features are very vague, and it is difficult to determine the type of nervous system they have.
The type of nervous system, other things being equal, determines: different rates of development of conditioned reflexes, different sizes of conditioned reflexes and their strength, differences in the rate of irradiation and concentration of excitation and inhibition, different resistance to the action of factors causing disturbances in higher nervous activity, and adaptability to various influences. external environment. The type of nervous system determines not only the behavior of an animal organism, but also the nature of the activity of its internal organs, determined by the functional state of the sympathetic and parasympathetic systems.
Dogs in which inhibition predominates react poorly to substances that excite the sympathetic centers diencephalon, and, conversely, react strongly to substances that excite the parasympathetic centers of the diencephalon. Dogs in which arousal predominates, on the contrary, react strongly to substances that excite the sympathetic centers of the diencephalon, and weakly respond to substances that excite the parasympathetic centers of the diencephalon. In balanced animals the reaction to both substances is the same. The correspondence of the types of the nervous system established by the method of conditioned reflexes with the types of the nervous system determined by the action of substances on the sympathetic and parasympathetic parts of the diencephalon allows us to believe that the type of the nervous system depends on the predominance of the tone of one of the parts of the autonomic nervous system. Consequently, the nature of the animal’s behavior largely depends on the functional state of the autonomic nervous system (S. I. Galperin, 1949, 1960).
The scheme for dividing the types of the nervous system into particular, human ones is based on the fact that in some people (the first type) the first signaling system predominates over the second signaling system and, conversely, in people of the second type the second signaling system predominates over the first. In a person with an average type of nervous system, both signaling systems have approximately the same importance. Normal thinking is possible only with the inextricable participation of both systems. The degree of correlation between both systems varies enormously among different people.
When determining the types of a person, it is necessary to take into account that a person displays the world in two forms: 1) perceiving the direct action of stimuli from the external world and 2) perceiving speech signaling these direct stimuli.
Types of nervous system and temperaments
I. P. Pavlov believed that the four types of the nervous system established in experiments on animals approximately coincide with the classical scheme of temperaments established in humans by Hippocrates.
The first type roughly corresponds to the choleric person, the second to the phlegmatic person, the third to the sanguine person and the fourth to the melancholic person. Temperament is characterized mainly by the strength of nervous and, consequently, mental processes, the relationship of excitation and inhibition and the speed of their occurrence. However, a person's temperament is not equivalent to the type of his nervous system. A person's temperament is undoubtedly associated with the properties of the nervous system that characterize the type. But forms of human behavior are determined not by individual stimuli, but by phenomena, objects and people that have a certain objective meaning and evoke on the part of a person one or another attitude towards himself, determined by his upbringing, beliefs, and worldview. Therefore, when characterizing a person’s temperament, it is necessary to take into account not only the functional characteristics of his nervous system, but first of all the conditions of his life in the society of a certain historical era and his practical activities.
It must be taken into account that only a few people have these four temperaments in a relatively pure form. Most have traits different temperaments combine.
Education of nervous system types
The types of nervous system change after birth. They develop in phylogenesis, but since the animal is exposed to a variety of environmental influences from the day it is born, its character is finally formed as an alloy of the innate traits of the nervous system (type) and changes in its properties caused by the external environment, often fixed for life. Thus, the innate properties of the nervous system can only appear at the moment of birth. The behavior of humans and animals is determined not only by the innate properties of the nervous system, but to a greater extent depends on constant upbringing and training.
The type of nervous system is changed by education and systematic training. By practicing inhibition one can, to a certain extent, change a strong unbalanced type and make it more balanced. A weak type is more difficult to change significantly. In him, normal higher nervous activity is carried out only in favorable working conditions, since he is more likely than others to have “breakdowns”.
The type of nervous system influences learning in farm animals. An excitable type of horse can be trained easily and quickly, but overexertion of inhibition should be avoided. Animals of the strong, inert type learn slowly. Horses weak type almost unfit for work. They learn with difficulty.
Types of temperament I. P. Pavlova - classification of temperaments based on types of nervous system.
I. P. Pavlov showed that the basis of higher nervous activity is three components: strength (the individual maintains a high level of performance during long and intense work, recovers quickly, does not react to weak stimuli), balance (the individual remains calm in a stimulating environment, easily suppresses his inadequate desires) and mobility (the individual quickly reacts to changes in the situation, easily acquires new skills). I.P. Pavlov correlated the types of nervous systems he identified with psychological types of temperaments and discovered their complete similarity. Thus, temperament is a manifestation of the type of nervous system in human activity and behavior. As a result, the relationship between types of nervous system and temperaments is as follows:
1) strong, balanced, active type (“lively”, according to I.P. Pavlov - sanguine temperament;
2) strong, balanced, inert type (“calm”, according to I.P. Pavlov - phlegmatic temperament;
3) strong, unbalanced, with a predominance of excitement (“uncontrollable” type, according to I.P. Pavlov - choleric temperament);
4) weak type (“weak”, according to I.P. Pavlov - melancholic temperament).
A weak type cannot in any way be considered a disabled or not entirely full-fledged type. Despite the weakness of the nervous processes, a representative of the weak type, developing his individual style, can achieve great achievements in learning, work and creative activity, especially since a weak nervous system is a highly sensitive nervous system.
Sanguine temperament. A representative of this type is a lively, inquisitive, active (but without sudden, impetuous movements) person. As a rule, he is cheerful and cheerful. Emotionally unstable, easily succumbing to feelings, but they are usually not strong or deep. He quickly forgets insults and experiences failures relatively easily. He is very team-oriented, easily establishes contacts, sociable, friendly, friendly, quickly gets along with people, and easily establishes good relationships.
Phlegmatic temperament. A representative of this type is slow, calm, unhurried. In his activities he demonstrates thoroughness, thoughtfulness, and perseverance. Tends to be orderly familiar surroundings, does not like change in anything. As a rule, he brings the job he starts to completion. All mental processes in a phlegmatic person proceed slowly. This slowness can interfere with his educational activities, especially where he needs to quickly remember, quickly understand, figure out, and do quickly. In such cases, a phlegmatic person may show helplessness, but he usually remembers for a long time, thoroughly and firmly.
In relationships with people, a phlegmatic person is always even-tempered, calm, moderately sociable, and has a stable mood. The calmness of a person of phlegmatic temperament is also manifested in his attitude towards the events and phenomena of life: a phlegmatic person is not easily enraged and emotionally hurt, he avoids quarrels, he is not unbalanced by troubles and failures.
Choleric temperament. Representatives of this type are distinguished by their speed (sometimes feverish speed) of movements and actions, impetuosity, and excitability. Their mental processes proceed quickly and intensely. The imbalance characteristic of a choleric person is clearly reflected in his activities: he gets down to business with enthusiasm and even passion, takes initiative, and works enthusiastically. But his supply of nervous energy can quickly be depleted in the process of work, especially when the work is monotonous and requires perseverance and patience, and then cooling may set in, elation and inspiration disappear, and the mood drops sharply. The predominance of excitement over inhibition, characteristic of this temperament, is clearly manifested in communication with people with whom the choleric person allows harshness, hot temper, irritability, emotional restraint (which often does not give him the opportunity to objectively evaluate people’s actions) and on this basis sometimes creates conflict situations in the team .
Melancholic temperament. In representatives of this temperament, mental processes proceed slowly, people have difficulty reacting to strong stimuli; prolonged and strong stress causes them to slow down their activity, and then stop it. They get tired quickly. But in a familiar and calm environment, people with this temperament feel calm and work productively. Emotional states in people of melancholic temperament arise slowly, but are distinguished by depth, great strength and duration; melancholic people are easily vulnerable, they have a hard time withstanding insults and grief, but outwardly these experiences are expressed weakly in them.
Representatives of a melancholic temperament tend to be withdrawn, avoid communicating with unfamiliar, new people, are often embarrassed, and show great awkwardness in a new environment. Melancholic people are often distinguished by softness, tact, delicacy, sensitivity and responsiveness: those who are vulnerable themselves usually subtly feel the pain that they themselves cause to other people.
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The type of GNI is a set of individual properties of the nervous system, determined by the hereditary characteristics of the individual and his life experience.
According to the teachings of I.P. Pavlov about the types of GNI, the main ones are three properties of nervous processes: the strength of nervous processes, balance and mobility.
1. The power of nervous processes(the strength of the processes of excitation and inhibition) is associated with the level of performance of nerve cells. Weak nervous processes are characterized by the inability of nerve cells to withstand strong or prolonged loads, therefore, these cells have a low level of performance. Strong nervous processes are associated, accordingly, with a high level of efficiency of nerve cells.
2. Balance of nervous processes is determined by their ratio. It is possible that one of the nervous processes predominates (for example, excitation over inhibition) or their balance.
3. Mobility of nervous processes- the speed with which excitation can replace inhibition or vice versa. Consequently, nervous processes can be highly mobile or inert.
Different people are characterized by different ratios of all listed properties, which ultimately determine the type of their nervous system and higher nervous activity.
1. Strong unbalanced (“uncontrolled”) type characterized by a strong nervous system and a predominance of excitation processes over inhibition (their imbalance).
2. Strong balanced mobile (labile) type characterized by high mobility of nervous processes, their strength and balance.
3. Strong balanced inert type (calm, sedentary) Despite the significant strength of the nervous processes, it has low mobility.
4. Weak type characterized by low performance of cortical cells and weakness of nervous processes.
Plasticity of types of higher nervous activity. The innate properties of the nervous system are not immutable. They can change to one degree or another under the influence of upbringing due to the plasticity of the nervous system. The type of higher nervous activity consists of the interaction of the inherited properties of the nervous system and the influences that an individual experiences during life.
I. P. Pavlov called the plasticity of the nervous system the most important pedagogical factor. The strength and mobility of nervous processes can be trained, and children of the unbalanced type, under the influence of upbringing, can acquire traits that bring them closer to representatives of the balanced type. Prolonged overexertion of the inhibitory process in children of a weak type can lead to a “breakdown” of higher nervous activity and the emergence of neuroses. Such children have difficulty getting used to the new work schedule and need special attention.