Physiological bases of psychology. Lecture topic: Physiological foundations of the human psyche
The central nervous system (CNS) consists of the brain and spinal cord. The brain consists in turn of the anterior midbrain and hindbrain. Almost all departments and structures of the central and peripheral nervous system are involved in obtaining and processing information, however, the cerebral cortex is of particular importance for the human psyche, which, together with the subcortical structures included in forebrain determines the features of the functioning of human consciousness and thinking. This connection is provided by nerves that come out of ...
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Topic 4. Physiological foundations of the psyche
- General idea of the nervous system as an organic substratum of the psyche
- Reflex theory of the mental: concepts of I.M. Sechenov, I.P. Pavlov
- The theory of systemic dynamic localization of higher mental functions AR Luria. Localizationism and anti-localizationism
1. General idea of the nervous system as an organic substratum of the psyche
The human nervous system consists of two sections: central and peripheral.The central nervous system (CNS) consists of the brain and spinal cord. The brain consists, in turn, of the forebrain, middle and hindbrain. In these main sections of the central nervous system, the most important structures that are directly related to the functioning of the human psyche are also distinguished: the thalamus, hypothalamus, bridge, cerebellum, medulla(see fig.).
Almost all departments and structures of the central and peripheral nervous system are involved in receiving and processing information, however, the cerebral cortex is of particular importance for the human psyche, which, together with the subcortical structures that make up the forebrain, determines the features of the functioning of consciousness and human thinking.
The central nervous system is connected with all organs and tissues of the human body. This connection is provided nerves, that come from the brain and spinal cord. In humans, all nerves are divided into two functional groups. To the first group include nerves that carry signals from the outside world and body structures. Nerves in this groupcalled afferent. Nerves that carry signals from the CNS to the periphery (organs, muscle tissues etc.), are included inanother group and are called efferent.
The central nervous system itself is a collection of nerve cells neurons . These nerve cellsmade up of a neuronand tree-like processes called dendrites . One of these processes is elongated and connects the neuron with the bodies or processes of other neurons. Such a branch is called axon.
Part of the axons is covered with a special sheath - the myelin sheath, which provides faster impulse conduction along the nerve. The places where one neuron connects to another is called synapses.
At the periphery, axons connect to miniature organic devices designed to sense various kinds energy (mechanical, electromagnetic, chemical, etc.) and converting it into the energy of a nerve impulse. These organic devices are called receptors. They are located throughout the human body. There are especially many receptors in the sense organs, specially designed for the perception of information about the surrounding world.
Exploring the problem of perception, storage and processing of information,I.P. Pavlov introduced the concept of an analyzer. This concept stands fora relatively autonomous organic structure that ensures the processing of specific sensory information and its passage at all levels, including the central nervous system. Hence, each analyzer consists of three structural elements: receptors, nerve fibers and the corresponding departments of the central nervous system(Fig. 4.5).
There are several groups of receptors. This division into groups is caused by the ability of receptors to perceive and process only one type of influence, therefore, receptors are divided into visual, auditory, gustatory, olfactory, skin, etc. The information received with the help of receptors is transmitted further to the corresponding section of the central nervous system, including the cerebral cortex.
It should be emphasized thatthe entire cerebral cortex can be divided into separate functional areas. In this case, it is possible to distinguish not only the zones of the analyzers, but also motor, speech, etc. Thus, in accordance with the classification of K. Brodman, the cerebral cortex can be divided into 11 regions and 52 fields.
Let us consider in more detail the structure of the cerebral cortex (Fig. 4.6, Fig. 4.7, Fig. 4.8). She represents upper layer the forebrain, formed mainly by vertically oriented neurons, their processes - dendrites and bundles of axons going down to the corresponding parts of the brain, as well as axons that transmit information from the underlying brain structures.The cerebral cortex is divided into regions: temporal, frontal, parietal, occipital, and the regions themselves are divided into even smaller sections fields. It should be noted that since the left and right hemispheres are distinguished in the brain, the areas of the cerebral cortex will be divided into left and right, respectively.
The information received by the receptors is transmitted along the nerve fibers to the accumulation of specific nuclei of the thalamus, and through them the afferent impulse enters the primaryprojection zones of the cerebral cortexbrain. These zones represent the end cortical structures of the analyzer. For example, the projective zone of the visual analyzer is located in the occipital regions hemispheres, and the projective zone auditory analyzers in the upper parts of the temporal lobes.
If any zone is destroyed, then a person may lose the ability to perceive certain kind information. For example, if you destroy the zone visual sensations then the person goes blind. Thus, a person's sensations depend not only on the level of development and integrity of the sense organ, in this case, vision, but also on the integrity of the pathways nerve fibers and the primary projective zone of the cerebral cortex.
It should be noted that in addition to the primary fields of the analyzers, there are other primary fields, for example, primary motor fields associated with the muscles of the body and responsible for certain movements. Primary fields occupy relatively large area cerebral cortex no more than one third. They occupy a much larger area secondary fields , which are often referred to asassociative or integrative.
The secondary fields of the cortex are, as it were, a "superstructure" over primary fields. Their functions are to synthesize or integrate individual elements of information into a complete picture.. So, elementary sensations in sensory integrative fields (or perceptual fields) are formed into a holistic perception, and individual movements, thanks to motor integrative fields, are formed into a holistic motor act.
Secondary fields play an extremely important role in ensuring the functioning of both the human psyche and the organism itself.
Among the integrative fields of the human cerebral cortex, it is necessary to distinguish differentiated only in humans speech centers: center auditory perception speeches(the so-called Wernicke center) and motor center of speech(the so-called Broca's center).There are other centers as well. For example, consciousness, thinking,the formation of behavior, volitional control are associated with the activity of the frontal lobes, the so-called prefrontal and premotor zones.
The representation of the speech function in humans is asymmetrical. It is located in the left hemisphere. Similar phenomenon got the namefunctional asymmetry. Asymmetry is characteristic not only for speech, but also for other mental functions. Today it is known that left hemisphere in his work acts as a leader in the implementation of speech and other speech-related functions: reading, writing, counting, logical memory, verbal-logical, or abstract, thinking, arbitrary speech regulation of other mental processes and states. The right hemisphere performs functions not related to speech, and the corresponding processes usually occur at the sensory level.
The left and right hemispheres perform various functions in the perception and formation of the image of the displayed object.The right hemisphere is characterizedhigh speed of work on identification, its accuracy and clarity. This way of identifying objects can be defined as integral-synthetic, predominantly holistic, structural-semantic, i.e. the right hemisphere is responsible for the holistic perception of the object or performs the function of global image integration.The left hemisphere is functioningbased on the analytical approach, which consists in a sequential enumeration of the elements of the image, i.e. the left hemisphere displays the object, forming separate parts of the mental image. It should be noted that both hemispheres are involved in the perception of the outside world. Violation of the activity of any of the hemispheres can lead to the impossibility of a person's contact with the surrounding reality.
When getting acquainted with the structure of the central nervous system, we must definitely dwell on the consideration of one more brain structurereticular formation, which plays a special role in the regulation of many mental processes and properties. Such a namereticular or reticularit received because of its structure, since it is a collection of sparse, resembling a thin network of neural structures, anatomically located in the spinal cord, medulla oblongata and hindbrain.
The reticular formation has a noticeable effect on the electrical activity of the brain, on the functional state of the cerebral cortex, subcortical centers, cerebellum and spinal cord. It is also directly related to the regulation of the main life processes: circulation and respiration.
The reticular formation is called the source of the body's activity., since the nerve impulses formed by this structure determine the performance of the body, the state of sleep or wakefulness. It is also necessary to note the regulatory function of this formation, since the nerve impulses formed by the reticular formation differ in their amplitude and frequency, which leads to a periodic change in the functional state of the cerebral cortex, which, in turn, determines the dominant functional state of the whole organism. Therefore, the state of wakefulness is replaced by the state of sleep and vice versa (Fig. 4.10).
Violation of the activity of the reticular formation causes a violationbody biorhythms. Thus, irritation of the ascending part of the reticular formation has a reaction of changing the electrical signal, characteristic of the state of wakefulness of the organism. Constant irritation of the ascending part of the reticular formation leads to the fact that a person’s sleep is disturbed, he cannot fall asleep, the body shows increased activity. This phenomenon is called desynchronization and manifests itself in the disappearance of slow fluctuations in the electrical activity of the brain. In turn, the predominance of waves of low frequency and large amplitude causes prolonged sleep.
Thus, the human nervous system performs the functions of a system that regulates the activity of the whole organism. Thanks to the nervous system, a person is able to receive information about the external environment, analyze it and form behavior that is adequate to the situation, i.e. successfully adapt to changing environmental conditions. (Maklakov)
2. Reflex theory of the mental: the concepts of I.M. Sechenov, I.P. Pavlov
Ivan Mikhailovich Sechenov(1829 - 1905) was a supporter of the principle of determinism in psychology. This meant that he understood mental activity as a reflex.
I.M. Sechenov outlined the results of his research in the work “Reflexes of the Brain” (1863), which gained immense popularity in Russia and abroad, and then in the work “To Whom and How to Develop Psychology” (1873).
The general objective law of the mentalreflex principle of the implementation of any mental activity.The mental is an integral part of the whole holistic process reflex activity organism, since any mental activity is built according to the scheme of any complex reflex: external influence central part movement.
In every mental act (even of the highest type - mental or volitional) there is a definite beginning, middle and end. The beginning of I. M. Sechenov called the obligatory in any mental process“excitation of the sensory nerve”, which has its source in an external influence. The fact that without external influence there are no sensations, and without sensations no mental activity is possible, was proved even before him. However, I.M. Sechenov argued that without external influence there can be no thought act, since a person’s thought always arises as an answer to a question posed by another person and, in general, to the requirements that society makes of him.
The most interesting thing here is that I.M. Sechenov also anticipates the idea of internalization, which will appear in psychology only in XX V. What seems to be an "internal" urge to action is originally external in origin:"The first reason for all human action lies outside of it.
The end of the mental act also turns out to be naturally determined - it, as a rule, is expressed by an external “muscular movement”, like any reflex process: “Does a child laugh at the sight of a toy, does Garibaldi smile when he is persecuted for excessive love for his homeland, does a girl tremble at the first thought of love, whether Newton creates the laws of the world and writes them on paper everywhere the final fact is muscular movement. I.M. Sechenov was objected: but, it seems, higher mental processes have their end, on the contrary, the absence of this “muscular movement”. I. M. Sechenov objected: it is necessary to consider this process in development. Even when we do not have a visible movement as the "end" of any mental process, it undoubtedly was earlier, at the previous stages. mental development. Thus, the thought of an object in an adult is the result of the development in ontogenesis of initially fully developed practical contacts of the child with the object, when, for example, the child learns from his own experience the properties of a bell in actions with it (it is cold to the touch, has the shape of a bottle, rings when he will be picked up, etc.). Subsequently, these reflex processes are “slowed down” in their last third and a person, looking at the bell, “simply” thinks about it (that if he takes it in his hands, it will ring, it will turn out to be cold to the touch, etc.), without expressing this thought by no visible outward movement.
It is interesting that I.M. Sechenov, considering the mental as an integral component of the entire reflex process, firstly, allowed the existence of an unconscious mental life, and secondly, did not identify the physiological and the mental. The first conclusion follows from the fact that even the most elementary reflex of a living creature with a brain is accompanied by a subjective experience (feeling), which can be very weak, not reaching consciousness. The fact that I.M. Sechenov did not identify the mental and physiological at the same time proves his recognition of psychological science as independent in relation to physiology. In the work “To whom and how to develop psychology”, he gives a clear definition of the subject of psychology as a science:"Scientific psychology, in its entirety, cannot be anything other than a series of teachings on the origin of mental activities." (Sokolova)
However, the honor of deep experimental development reflex theory psyche belongs I.P. Pavlov who created a new field of sciencethe doctrine of higher nervous activity. Higher nervous activity is a concept that generalizes both the psychology and biology of higher nervous activity, which by no means means that the latter are identical. The basis of higher nervous activity is a conditioned reflex, which is both a physiological and psychological phenomenon. Here is how I.P. Pavlov, in the article "The Conditioned Reflex", written in 1934, presented his classic experience:
"...Let's do two simple experiences that will work for everyone. Pour a moderate solution of some acid into the dog's mouth. It will evoke the usual defensive reaction of the animal: with vigorous movements of the mouth, the solution will be thrown out, out, and at the same time, saliva will pour abundantly into the mouth (and then out), diluting the introduced acid and washing it from the oral mucosa. Now another experience. Several times, by any external agent, for example certain sound, we will act on the dog just before injecting the same solution into its mouth. And what? It will be enough to repeat only one sound and the same reaction will be reproduced in the dog: the same movements of the mouth and the same outflow of saliva. Both of these facts are equally precise and constant. And both of them should be designated by the same physiological term "reflex" ...
“... It is legitimate to call the constant connection of an external agent with the activity of the organism in response to it an unconditioned reflex, and a temporary one a conditioned reflex ... A temporary nervous connection is the most universal physiological phenomenon in the animal world and in ourselves. And at the same time, it is also mental what psychologists call an association, whether it will be the formation of connections from all kinds of actions, impressions, or from letters, words and thoughts ”(Pavlov I.P. Full coll. op. T. 3, book. 2, p. 322325.).
At first, the newly formed reflex is not strong and is easily disturbed. Any external stimulus, for example, the same call, given together with or immediately after the light, causes a cessation of saliva flow inhibits the reflex. Suchreflex inhibitionunder the influence of another stimulusI.P. Pavlov namedexternal braking.
If, in experiments with a dog that already has a developed “light salivation” reflex, the lamp is turned on many times in a row without feeding, then less and less saliva will be released and the reflex will completely die out.This is the result of internal extinction inhibition. Fading inhibition occurs, for example, in the process of fading skills in shooting weapons in the absence of exercise. A peculiar form of external braking is beyond-marginal braking caused by excessive force conditioned stimulus. For example, if, in an experiment with a dog that has a reflex to light a light bulb, a very bright light is given, then salivation may not only decrease, but even disappear altogether. With such transcendent inhibition, excitation in certain centers is so intensified that it turns into its opposite - inhibition.
For a person, the strength of the stimulus is determined not only by its physical characteristics (brightness, loudness, etc.), but also by its individual significance for this person. In this regard, transcendental inhibition plays a large and very complex role in the field of emotions, and in particular in the manifestation of tension. Sometimes the “reprimanding” of a subordinate employee does not have a pedagogical effect precisely because it causes prohibitive inhibition in him. (http://www.vuzllib.su/beta3/html/1/14465/14480/)
The idea of a conditioned reflex as one of the ways of gaining experience has been preserved and received further development in the works of such psychophysiologists as E.N. Sokolov and C.I. Izmailov . They proposed the conceptconceptual reflexan arc consisting of three interconnected, but relatively independent systems of neurons: afferent (sensory analyzer), effector (executive, responsible for the organs of movement) and modulating (controlling connections between the afferent and effector systems). The first system of neurons ensures the receipt and processing of information, the second system ensures the generation of commands and their execution, the third system exchanges information between the first two.
Along with this theory, there are other developments concerning, on the one hand, the role of mental processes in the control of behavior, and, on the other hand, the construction of general models of behavior regulation with the participation of physiological and psychological phenomena in this process. So, ON THE. Bernstein believes that even the simplest acquired movement, not to mention the complex human activity and behavior in general, cannot be performed without the participation of the psyche. He argues that the formation of any motor act there is an active psychomotor reaction. At the same time, the development of movement is carried out under the influence of consciousness, which at the same time performs a certain sensory correction of the nervous system, which ensures the implementation of a new movement. The more complex the movement, the more corrective changes are required. When the movement is mastered and brought to automatism, the control process leaves the field of consciousness and turns into a background one. ( Maklakov)
3.
Theory of functional systems P.K. Anokhin
Pyotr Kuzmich Anokhin ( 1898 1974 ) proposed his concept of regulation of a behavioral act. The essence of this concept is that a person cannot exist in isolation from the outside world. He is constantly exposed to certain environmental factors. Impact external factors was named Anokhinsituational afferentation.Some influences for a person are insignificant or even unconscious, but others, as a rule, unusual cause a response in him. This response is of the natureindicative reactionand is a stimulus for the manifestation of activity.
All objects and conditions of activity affecting a person, regardless of their significance, are perceived by a person in the form of an image. This image correlates with the information stored in the memory and motivational attitudes of a person. Moreover, the process of comparison is carried out, most likely, through consciousness, which leads to the emergence of a decision and a plan of behavior.
In the central nervous system, the expected outcome of actions is presented in the form of a kind of nervous model, called by Anokhin the acceptor of the result of an action.Action result acceptoris the goal towards which the action is directed. In the presence of an action acceptor and an action program formulated by consciousness, the direct execution of the action begins. This includes the will, as well as the process of obtaining information about the fulfillment of the goal. Information about the results of an action has the nature of feedback (reverse afferentation) and is aimed at forming an attitude in relation to the action being performed. As information passes through emotional sphere, it evokes certain emotions that affect the nature of the installation. If emotions are positive character, then the action stops. If emotions are negative, then adjustments are made to the performance of the action.
Theory of functional systems P.K. Anokhina received wide use due to the fact that it allows you to get closer to solving the problem of the relationship between physiological and psychological processes. This theory suggests that mental phenomena and physiological processes play an important role in the regulation of behavior. Moreover, behavior is in principle impossible without the simultaneous participation of mental and physiological processes. (Maklakov)
4
. The theory of systemic dynamic localization of higher mental functions A.R. Luria. Localizationism and anti-localizationism
Theory of Alexander Romanovich Luria (19021977) dialecticallyresolves the conflict betweentwo opposite points of view on solving the problem of localization of mental functions in the brain, namely betweenpositions of "narrow localizationism" and "anti-localizationism».
First point view held by an Austrian physician and anatomist F. gall , whose ideas about the exact localization of individual mental "abilities" (for example, "attraction to wine", "wit", "friendship and sociability", etc.) in strictly defined areas of the brain were widely spread at the turn XVIII and XIX centuries According to this point of view, the brain represents the sum of autonomously working sections, which fully corresponded to the principle of elementarism that prevailed in psychology at that time. The concept of F.A. Gall received a seemingly powerful empirical confirmation in 1861, when a French anatomist P. Broca established a clear connection of speech impairment, called motor aphasia(the patient understood the speech of others, but was not capable of articulated speech), with damage to the posterior third of the lower frontal gyrus of the left hemisphere of the brain.
13 years later, a German psychiatrist C. Wernicke established a connection between the defeat of the posterior third of the upper temporal gyrus of the left hemisphere and impaired understanding of speech. After that, many psychiatrists and neurologists began to persistently look for "think tanks" responsible for strictly defined functions. However parallel to these searchesfacts accumulatedwho spoke About , that the brain works as a whole. French scientist J.P. Flurence , removing sections of the brain in birds, back in the first half XIX V. drew attention to the fact that the mental functions disturbed as a result of such an operation are restored (moreover, the speed and success of the restoration of functions depend not on where the part of the brain is removed, but on what volume it is), andconcluded that the cerebral cortex is a homogeneous whole.
Thanks to these and similar experiments of a later time (the German physiologist F. Goltz in the 70s. XIX in., which removed parts of the brain in dogs; American neurologist K. Lashley in the late 20s. XX V. etc.) arose andstrengthened the ideas of a holistic approach to solving the problem of localization. The idea that the brain works as a whole found support among Gestalt psychologists and representatives of other schools of psychology.This is how the position of “anti-localizationism” arose. the belief that there is no rigid localization of certain mental functions in separate parts of the brain: the whole brain is responsible for their administration.
A.R. Luria based on the ideas of his predecessors in neurology (the English neurologist H. Jackson), in physiology (P.K. Anokhin and A.A. Ukhtomsky) and in psychology (L.S. Vygotsky),comes to the conclusion that the brain really works as a "single whole", but not a homogeneous, but a systematically organized whole. When the subject solves a specific problemeach time, different parts of the cortex of his brain are "involved".
If the work of any link of this system is disrupted, the work of the entire system goes wrong, but each time in a different way, depending on the specific lesion.For example, consider some violations of the most complex activity of writing. For its implementation, the work of various parts of the brain is necessary. Some parts of the brain are responsible for the acoustic analysis of the sound composition of words (if they are damaged, phonemes that sound similar in sound will be mixed, complex sound combinations will be perceived as noise, etc.), others are responsible for “recoding” the results obtained into visual-spatial schemes (if they are damaged, it will be impossible to , for example, the correct spatial arrangement of the elements of letters), the third for the organization of the general kinetic organization of movements (if they are damaged, difficulties may be observed in the transition from one grapheme to another), etc.
Thus, the loss of the “own” function of a particular part of the brain leads to a certain disruption of the entire system as a whole, however, due to functional rearrangements, compensations can be observed(up to certain limits) of the defect that has arisen.So, for example, if the secondary cortical zones of the visual analyzer (18th and 19th fields) are affected and the patient has the impossibility of recognizing objects with the help of vision (he has visual object agnosia), this does not mean at all that the patient loses the ability to perceive the meaning of objects. The same objects can be recognized by connecting other links of the system for example, giving the subject the opportunity to identify these objects using touch.
The more complex the mental function, the more “widely” it is localized in the structures of the brain. Separate elements of this system can (up to certain limits) replace each other in solving one and the same problem. Whereincerebral localization changes in ontogeny.The brain organization of speech in an adult (right-handed person) differs significantly from that in children aged 5-6 who are not yet literate. This is due to the life-time nature of the formation of higher mental functions, changes in their structure at different age levels and, accordingly, changes in their localization in the brain. The defeat of the same brain areas in different ages can lead to different consequences in a child and an adult. So, for example, the defeat of the "lower" sensory sections of the cortex in early childhood can lead to underdevelopment of cognitive functions, while the same lesion in adults can be compensated by the influence of already established higher functional systems. At the same time, the brain structures themselves develop when they are “included” in solving various problems. It is known that with damage to the frontal lobes of the brain, voluntary and volitional regulation of mental functions, controllability and expediency of behavior as a whole are upset. However, when a child is born, he does not have voluntary behavior, not because the frontal lobes have not yet “ripened”, but because the development of voluntary behavior in a child occurs due to joint activity with an adult, processes of sign “mediation”, etc. It is thanks to the construction of the corresponding HMF systems in the child that the brain develops in ontogeny in a specifically human way and is finally formed only by the age of 1214.
A.R. Luria singled out three “blocks of the brain”,who work in concert, but each solve their own problems.
First energy block brain, or block of regulation of tone and wakefulness,is responsible for the optimal state of the cortex, which is necessary both for processing and storing information (for which the second block of the brain is responsible), and for planning and controlling the activity of the subject (which is provided by the third block of the brain). Altered states of consciousness are caused by intentional (artificial) or unintentional changes in the patterns of operation of this particular block of the brain.It includes education upper divisions brain stem(structures of the hypothalamus, visual tubercles and reticular formation, which provide a two-way connection of these subcortical formations with the cortex)and structures of the ancient, or limbic, cortex, also associated with the above sections of the trunk (hippocampus, mamillary bodies, etc.). Maintaining the tone of the cortex in an optimal state depends on information coming from the sense organs, from interoreceptors that respond to deviations from constancy internal environment organism, and from the top-down influences of the higher formations of the cortex, which provide arbitrary regulation of human behavior. For example, to a certain extent, by an effort of will, a person can maintain a waking state even when the nervous system is exhausted from hard work and the person feels that he is falling asleep.
The second block receiving, processing and storing information,physiologically provides the activity of the subject, which has as its goal the knowledge of the properties and patterns of the surrounding world.
It includes structures located inback departments brain(parietal, temporal and occipital regions). Initially, modal-specific information comes from receptors (skin, auditory and visual, respectively) inprimary (projection) zones of the cerebral cortex. They have highly specialized neurons that respond only to certain signs of external stimuli. Irritation of these areas of the brain leads to the emergence of separate sensations in a person. In this case, there is a somatotopic projection of individual receptor surfaces onto areas of the primary cortex. At the same time, the area of the territory occupied by the projection of the receptors of certain skin zones is proportional not to the size of the corresponding parts of the body, but to their significance for the activity of the subject. Thus, a significant part of the area is occupied by the projections of the receptors of the lips and tongue, as well as thumbs hands due to their special significance for human activity, while the projection of the skin receptors of the legs occupies a less significant place.
Secondary, "gnostic" areas of the cortexcarry out the function of synthesizing the information received and analyzed by the primary sections of the cortex. Somatotopic projection in these areas is no longer available. Irritation of the cells of the secondary fields of the cortex leads to the appearance of images of objects (flowers, butterflies, melodies, etc.). Violations in the work of these zones lead to disturbances in object perception, called agnosia (an example of visual object agnosia, when a patient with a similar lesion does not recognize an object, although he can describe it).
There are alsotertiary cortical zonesof the brain, which are a specifically human formation and mature very late in ontogeny. They are located on the borders of the cortical representations of the three analyzers we have considered (skin, visual and auditory), i.e. on the borders of the parietal, occipital and temporal regions, and carry out the synthesis of information from different analyzers. Damage to these zones leads to a violation of complex forms of spatial perception by the subject of the world, difficulty in determining the position of the clock hands on the dial, confusing the left and right sides, etc.
Third block brain providesprogramming, regulation and control of activities.Areas of the brain that make it worklocated in the anterior regions of the cerebral hemispheres(in their frontal lobes). Cortical structures corresponding to this block can also be considered from the point of view of identifying primary, secondary and tertiary zones, only these zones, in contrast to the block of information processing and storage considered above, are included in the tasks of their block in the reverse order: they are the first to organize work on planning and implementation of the necessary programs of behavior enter the tertiary zones of the frontal cortex specifically human formations that mature in ontogenesis as the latest and the formation of which is determined by a person’s mastery of speech, his assimilation of social experience, including moral values and rules of behavior in society. In fact, these zones constitute the material substratum of arbitrary and volitional regulation by a person of his activity. Violations of the work of this block cause corresponding behavioral disorders, which can be observed in the so-called frontal patients.
The information necessary for the implementation of the functions of this block then enters the secondary fields - the premotor area, which prepares the direct implementation of motor impulses with the help of the work of the primary motor cortex zones and plays a major role in the formation of skills (motor habits). Individual movements, in turn, are controlled by primary areas of the motor cortex.
There are alsosignificant differences between the specifics of the work of the right and left hemispheres of the brain,which in normal conditions work harmoniously and in concert, however, in some cases (when the so-called corpus callosum, which connects the hemispheres to each other, is cut), they begin to work independently of each other. At the same time, in humans (unlike animals), the left hemisphere, which is the “brain apparatus” of speech, dominates in right-handers (the right hemisphere is subordinate to them). In left-handers, the right hemisphere can play a dominant role.
It can be concluded that in the concept of A. R. Luria, the relationship between mental and physiological appears in the form of their dialectical unity - there is not a single mental process that would not be somehow (and in a very specific way) localized in brain structures, but at the same time, the mental is not reducible to the physiological. (Sokolova)
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| By definition, isometric muscle contraction is such a contraction in which the inclusion of the muscle in the work occurs without any movement of the joints. During the game of tennis, a significant part of the work that the muscles do is dynamic and consists of concentric and eccentric movements. The place of the best fixation of the muscle, which usually has big sizes and being a kind of center of power and another place of muscle attachment that can be movable move towards each other. In progress... | |||
| 18338. | Ergogenic and physiological effects of the combined use of interval hypoxic training and training sessions of a predominantly anaerobic orientation | 216.98KB | |
| Interval hypoxic training of athletes. Physiological effects of various modes of intermittent hypoxia used as an additional training tool. The dynamics of physiological parameters in athletes with combinations of training loads of various physiological orientations with selected modes of intermittent hypoxia 42 2.4 The effectiveness of various modes of intermittent hypoxia in potentiating the training effect of loads ... | |||
| 6782. | Mental processes - processes conventionally identified in the integral structure of the psyche | 3.61KB | |
| The allocation of mental processes is a purely conditional division of the psyche into its constituent elements, which appeared due to the significant influence of mechanistic ideas on scientific psychologists during the formation of scientific psychology; also, this selection can be associated with analytical trends in science in the 19th and early 20th centuries. The peculiarity of mental processes is that they are the most short-term fast. At present, integrative approaches to the psyche are being developed in science, and the classification of mental processes has rather ... | |||
| 13544. | Biomechanical foundations of IVS | 3.12MB | |
| At a temperature of 4 deg. The specific gravity of distilled water at t 4 deg. An increase or decrease in t of water leads to a change in specific gravity. The presence of salts or other impurities in water also leads to an increase in specific gravity. | |||
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The structure of the human nervous system.
The nervous system (NS) of a person consists of two sections: central and peripheral. The CNS consists of the brain and spinal cord. The brain consists of the forebrain, midbrain, and hindbrain. In these departments, structures related to the functioning of the human psyche are also distinguished: the thalamus, hypothalamus, bridge, cerebellum, medulla oblongata. All departments of the central and peripheral nervous systems are involved in receiving and processing information, but the brain is of particular importance for the human psyche, which determines the features of the functioning of consciousness and thinking. The central nervous system is connected with all organs and tissues of the human body. This connection is provided by nerves that carry signals from the CNS to the periphery. The CNS is an accumulation of nerve cells - neurons and tree-like processes called dendrites; one of the processes is elongated and connects the neuron with the bodies of other neurons, such a process is called an axon. The junction of one neuron with another is called a synapse. Axons connect through nerve channels to energy-sensing devices called receptors. There are many of them in the senses to perceive information about the world around. The concept of an analyzer.
Exploring the problem of perception, storage and processing of information, Pavlov introduced the concept of an analyzer. Denotes a relatively autonomous organic structure that provides
processing of specific sensory information and its passage at all levels, including
CNS. Each analyzer consists of receptors, nerve fibers and parts of the central nervous system. Information,
received with the help of receptors is transmitted to the central nervous system, including the cerebral cortex. The primary projective zones of the analyzer are called sensory zones, because they are associated with the formation of a certain type of sensation. There are secondary fields that play a role in ensuring the functioning of the human psyche and the organism as a whole.
Theory of conditional reflex learning I.P. Pavlova.
Sechenov studied the relationship between the work of the brain and the human body with mental phenomena and behavior. Later, his ideas were developed by Pavlov, who discovered the phenomenon of conditioned reflex learning. According to Pavlov, behavior is made up of complex reflexes formed in the process of learning. The conditioned reflex is a simple physical phenomenon. Although, after the discovery of conditioned reflex learning, other ways of acquiring skills by living beings were described. The idea of conditioned reflexes was preserved and further developed in the works of Sokolov and Izmailov. They proposed the concept of a reflex arc, consisting of 3 systems of neurons: afferent, effector (responsible for the organs of movement) and modulating (controlling connections between the afferent and effector systems).
The doctrine of N.A. Bernshtein on the participation of the psyche in the regulation of movement.
Bernstein believes that the simplest transformation of movement cannot be carried out without the participation of the psyche. The formation of any motor act is an active psychomotor reaction. In this case, the movement is carried out under the influence of consciousness, which carries out a certain sensory correction of the nervous system, which ensures the implementation of new movements. When the movement is mastered and brought to automatism, the control process leaves the field of consciousness.
Model-functional systems according to P.K. Anokhin.
Anokhin proposed his concept of the regulation of a behavioral act. This concept
called the functional system model. Man cannot exist
isolated from the outside world. The impact of external factors is called situational
afferentation. Some influences are insignificant or not conscious for a person, but others
evoke a response. This reaction has the character of an orienting reaction. All
objects affecting a person are perceived by a person in the form of an image. In the CNS total
action is presented in the form of a new model, called the acceptor of the result of the action - this is the goal to which the action is directed. In the presence of an action acceptor, formulated by the human consciousness, the execution of the action begins; information passes through the emotional sphere, causing emotions that affect the nature of the installation. But the theory says that mental phenomena and physical processes play a role in the regulation of behavior.
The theory of systemic dynamic localization of higher mental functions A.R. Luria. Luria proposed to identify anatomically autonomous blocks of the brain that ensure the functioning of mental phenomena. The primary block is designed to maintain a certain level of activity, includes the reticular formation of the brain stem, parts of the midbrain, structures of the limbic system, frontal and temporal lobes. The second block is associated with cognitive mental processes and is intended for the processes of obtaining, processing and storing information. The block consists of sections of the cerebral cortex, in the posterior and temporal regions of the hemisphere. The third block provides the functions of thinking, behavioral regulation and control. The structures are located in the anterior regions of the cerebral cortex.
Physiological foundations of the psyche
The psyche is an important factor in ensuring human health.
The psyche is the ability of the brain to perceive and evaluate the world, to recreate on the basis of this the internal subjective image of the world and the image of oneself in it (worldview) and, based on this, determine the strategy and tactics of one's behavior and activities.
The perception of the world is based on two interrelated process- unconscious (unconscious) and consciousness. Unconscious or unconscious represents habits, various automatisms (for example, walking), drives, intuition, that is, it manifests itself when consciousness is not a necessity, and the corresponding images remain in the unconscious. Consciousness - highest form the reflectivity of the brain, thanks to which a person can be aware of his thoughts, feelings, actions, etc., and, if necessary, control them.
The psyche manifests itself in the form mental processes, or functions. These include sensations and perceptions, ideas, memory, attention, thinking and speech, emotions and feelings, will. Mental processes manifest themselves in different people in different ways, they are characterized by a certain level of activity that forms the background against which the practical and mental activity of the individual takes place - these can be inspiration and passivity, self-confidence and doubt, anxiety, stress, fatigue, etc. Finally, in the behavior, activities of each person, certain characteristics inherent in it are manifested. mental properties: temperament, character, abilities, etc.
Brain and psyche
The material basis of the psyche are the processes occurring in the brain.
Brain- This great amount cells (neurons) that are connected to each other by numerous connections. functional unit brain activity is nerve center- a group of cells that perform a specific function. Among such centers there are congenital ones that have essential in the control and regulation of vital important functions: breathing, swallowing, thermoregulation, heart activity and many others. Some groups of cells acquire their functions and become centers already in the process of age development due to the establishment of new temporary connections between neurons.
Higher Functions, conscious behavior is more associated with the anterior part of the brain, the nerve cells of which are arranged in a thin (about 3 mm) layer, forming the cerebral cortex. Certain areas of the cortex receive and process information received from the senses - these are the sensory cortex zones. The most extensive areas of the brain are not associated with a specific function; these associative zones perform complex operations by the connection between different parts of the brain - they are responsible for the higher mental proper human functions. Special Role in the implementation of the psyche belongs to the frontal lobes of the forebrain, the defeat of which affects intellectual activity and the emotional sphere of a person, because they are the block of programming, regulation and control of activity. The frontal lobes (for right-handers - the left) are involved in the implementation of speech.
An important functional block of the brain, which is responsible for receiving, processing and storing information, i.e. for memory, located in the posterior regions of the cerebral cortex and includes the occipital (visual), temporal (auditory) and parietal lobes.
Another block of the brain that regulates tone and wakefulness, is formed by the so-called reticular formation, located in the central part of the brain stem - it is responsible for the tone of the cerebral cortex.
Any mental function is provided only by the joint work of the entire brain as a whole.
Arising in evolution much earlier and located below the cerebral cortex subcortical formations are more associated with innate functions and behaviors, as well as with the regulation of activity internal organs, glands internal secretion and sensory functions of the brain.
The stem structures of the brain pass into the spinal cord, which directly controls the muscles of the body, controls the activity of internal organs, transmits all brain commands to the executive links and, in turn, transmits all information from the internal organs and skeletal muscles to the higher parts of the brain.
The main, basic mechanism of the activity of the nervous system is the reflex. A reflex is the body's response to a stimulus. Reflexes can be congenital and acquired.
Innate reflexes, inherited and genetically determined, ensuring the implementation of the most important vital functions, a person has relatively little. Acquired reflexes formed during life.
A more complex mechanism of brain activity is functional system. It includes a mechanism for probabilistic forecasting of future action and uses not only past experience, but also takes into account the motivation of the corresponding activity. The functional system includes feedback mechanisms that allow you to compare what is planned with the real one and make adjustments. When (ultimately) the desired positive result is achieved, positive emotions are turned on, which fix the entire neural structure that provides a solution to the problem - this is how a functional system is formed. If the goal is not achieved, then negative emotions destroy the unsuccessful building in order to “clear” the place for a new one. If the acquired form of behavior has become unnecessary, then the corresponding reflex mechanisms gradually fade away. But the information trace about this event remains in the brain thanks to memory and can restore the entire form of behavior years later, and the restoration is easier than the initial formation.
The reflex organization of the brain is subject to a hierarchical principle. Strategic tasks are determined by the cortex, it also controls conscious behavior. Subcortical structures are responsible for automatic forms of behavior carried out without the participation of consciousness. The spinal cord, together with the muscles, carry out incoming commands.
The brain, as a rule, simultaneously has to solve several tasks. This possibility is created due, on the one hand, to the hierarchical principle of organization of the centers “along the vertical”, and on the other hand, the coordination of the activity of closely related nerve ensembles “along the horizontal”. In this case, one of the functions is the main one, associated with the basic need at a given moment in time, and therefore the center associated with this function becomes dominant, predominant: it slows down, suppresses the activity of closely related centers, which, however, impede the fulfillment of the main task. Thanks to this, the dominant subjugates the activity of the whole organism and sets the vector of behavior and activity.
Usually the brain works as a whole, although its the left and right hemispheres are functionally ambiguous and solve different tasks. In most cases left hemisphere is responsible for abstract verbal (verbal) thinking, speech, therefore it is usually associated with consciousness. If the left hemisphere dominates in a given person, then the person is “right-handed” (the left hemisphere controls right half bodies). The dominance of the left hemisphere affects certain features of mental functions: a “left hemisphere” person tends to theory, tends to analyze every phenomenon, event, has a large lexicon, it has a high physical activity, purposefulness, the ability to predict events.
Right hemisphere plays a leading role in operating with images (figurative thinking), non-verbal signals. This hemisphere gives the perceived information an emotional coloring. A “right hemispheric” person perceives the whole world, phenomena, objects as a whole, without breaking it into parts; he gravitates toward specific types of activity, is slow and taciturn, endowed with the ability to feel and experience subtly.
Both hemispheres of the brain are anatomically and functionally closely interconnected. The right hemisphere processes the incoming information faster, evaluates it, and transfers the results of the analysis to the left hemisphere, where the final higher analysis and understanding of this information.
PSYCHO-PHYSIOLOGICAL PROBLEM IN PSYCHOLOGY: how physiological and mental processes are correlated The principle of psychophysical interaction: physiological processes directly affect mental ones, and mental processes affect physiological ones. The principle of psychophysical parallelism speaks of the impossibility of a causal interaction between mental and physiological processes. The principle of dualistic parallelism speaks of the independent essence of the spiritual and material principles. The principle of monistic parallelism sees two sides of one process in mental and physiological processes.
Gippenreiter Yu.B. "... Physiological processes and mental processes are only two sides of a complex, diverse, but single process of human life ... "" ... From the fact that brain process accompanies any, even the most complex and subtle "movements of the soul", it does not follow that these "movements" can be adequately described in physiological language ... "
CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM ACTIVITIES AUTONOMIC NERVOUS SYSTEM DIFFUSE NERVOUS SYSTEM GIT HUMAN NERVOUS SYSTEM STRUCTURE OF THE HUMAN NERVOUS SYSTEM
The nervous system consists of two departments: the central nervous system - a set nerve formations in the cerebral cortex, motor centers of the brain stem, cerebellum and spinal cord; peripheral nervous system, which consists of nerve fibers (nerves), ganglions and plexuses, sensitive nerve endings connecting receptors, muscles with the spinal cord and brain.
Schematic representation of a neuron 1. Nerve cell with a nucleus; 2. Process of a nerve cell (axon); 3. Myelin (pulp) sheath that dresses the axon; 4. Terminal branching of the axon in the muscle fiber; 5. A break in the image of the axon (the length of the axon is many hundreds of times greater than the size of the nerve cell).
Neural circuit Nerve cells consist of a neuron and tree-like processes - dendrites. An axon is an elongated dendrite that connects a neuron to the bodies or processes of other neurons. A myelinated axon forms a synaptic contact with a third neuron
General structure analyzer Each analyzer consists of three parts: 1. Peripheral perceiving organ (receptor); 2. Conductive afferent, i.e. centripetal path, along which nervous excitement transmitted from the periphery to the center; 3. Cortical part of the analyzer (central link).
PROCESSES OF EXCITATION AND INHIBITION IN THE CENTRAL NERVOUS SYSTEM Irritation is the process of the influence of the external and internal environment on the nerve cells located in the human sense organs. Rest is the state of a neuron in the absence of external influences and irritation. Excitation is the process of releasing its own energy by a neuron in response to irritation, leading to the generalization of action potentials and the spread of impulse activity in the nervous system. Inhibition is an active process, as a result of which the excitation of a neuron stops or its occurrence is hindered. IRRITATION STATE OF EXCITATION NEURON AT REST STATE OF INHIBITION ACTIVE STATE OF NEURON
REGULARITIES OF THE PROCESSES OF EXCITATION AND INHIBITION Irradiation is the ability nervous processes excitation and inhibition spread in the central nervous system from one of its elements (section) to another. Dominant - a temporarily dominant focus of excitation, subordinating the activity of the nerve centers at the moment, directing it and determining the nature of the response. Concentration is the ability of the processes of excitation and inhibition to return (after irradiation) to the original focus (section), where the strength of excitation or inhibition was the highest, and therefore the preservation of their traces is most stable. Induction of nervous processes - the mutual influence of the processes of excitation and inhibition.
Lobes and areas of the cerebral cortex Main functions: occipital lobe - vision; temporal lobe - hearing and speech; parietal lobe- responses to sensory stimuli and movement control; frontal lobe - coordination of the functions of other areas of the cortex; motor cortex - control of voluntary muscles; sensory cortex - bodily sensations.
Division of the cerebral cortex into areas and fields (classification according to K. Brodman) 1, 2, 3, 5, 7, 43 (partial) representation of skin and proprioceptive sensitivity; 4 motor zone; 6, 8, 9, 10 premotor and accessory motor areas; 11 representation of olfactory reception; 17, 18, 19 representation of visual reception; 20, 21, 22, 37, 41, 42, 44 representation of auditory reception; 37, 42 auditory speech center; 41 projections of the organ of Corti; 44 motor center of speech.
Cortical projection of sensitivity and motor system (according to Penfield) The map of the motor cortex shows areas of the motor cortex, the stimulation of which leads to the contraction of certain muscle groups. Separate areas can encode the angular position of the joints, driven by the corresponding muscles.
The general structure of the reticular formation of the human brain The reticular or reticular formation is a collection of sparse, resembling a thin network of neural structures anatomically located in the spinal, medulla oblongata and hindbrain. Reticular formation: affects the electrical activity of the brain, the functional state of the cerebral cortex, subcortical centers, cerebellum and spinal cord; is directly related to the regulation of basic life processes: blood circulation and respiration.
REGULARITIES OF THE HIGHER NERVOUS ACTIVITY GENERAL ACTIVITY OF THE CEREBRAL CORTEX SIGNALING ACTIVITY OF THE CEREBRAL CORTEX
PATTERNS OF HIGHER NERVOUS ACTIVITY The patterns of the processes of excitation and inhibition are irradiation, concentration and induction of nervous processes; The analytical and synthesizing activity of the cerebral cortex is a complex activity of the cerebral cortex in the fine differentiation of stimuli and the establishment of various connections between them; Dynamic stereotypy (consistency in the work of the cerebral cortex) - provides holistic reactions of the body to external stimuli and, at the same time, the adaptation of these reactions to changing environmental conditions. Signal activity of the cerebral cortex - in the work of the human cerebral cortex there are two signal systems: the first is a system of conditional and unconditioned reflexes to the direct signals of the outside world and the second - words; Functional Systems the psyche is such a combination of nervous processes and organs of the human body that allows you to effectively perform a certain intended action; The action results acceptor is a psycho-physiological mechanism for predicting and evaluating the results of activities.
Hippocrates "... A person must fully realize the fact that it is from the brain - and only from the brain - that our feelings of joy, pleasure, fun, as well as our sadness, pain, sorrow and tears ... "... We think with the brain and with its help we can see and hear and are able to distinguish between ugliness and beauty, good and evil, what is pleasant and unpleasant ... "
Sechenov I.M. mental phenomena are included in any behavioral act and represent a kind of complex reflexes, i.e. physiological phenomena; a reflex is not a mechanical response of the nerve center to an external stimulus, but the coordination of movement with a feeling that performs a signal role; the work of the receptor is only the signal half of the integral mechanism (analyzer); the other half is the work of the muscles.
CONCEPTUAL REFLECTOR ARC ACCORDING TO SOKOLOV E.N. AND Izmailov Ch.A. FLOW DIAGRAM Three systems of neurons: afferent ( touch analyzer) - ensures the receipt and processing of information; effector (executive, responsible for the organs of movement) - ensures the development of commands and their implementation; modulating (controlling the connections between the afferent and effector systems) - exchanges information between the first two. The feedback mechanism regulates the excitability of receptors, effectors and the neurons themselves Afferent system Afferent system Modulating system Modulating system Effector system Effector system Feedback
Bernstein N.A. Even the simplest acquired movement, not to mention the complex human activity and behavior in general, cannot be performed without the participation of the psyche. The formation of any motor act is an active psychomotor reaction. At the same time, the development of movement is carried out under the influence of consciousness, which carries out a certain sensory correction of the nervous system, which ensures the implementation of a new movement. When the movement is mastered and brought to automatism, the control process leaves the field of consciousness and turns into a background one.
Clark Leonard Hull A living organism is a self-regulating system with specific mechanisms of behavioral and genetic-biological regulation. These mechanisms are mostly innate and serve to maintain optimal conditions physical and biochemical balance in the body - homeostasis - and are activated when this balance is disturbed.
Anokhin P.K. The influence of external factors of the external environment that a person experiences is called situational afferentation. The reaction to impacts unusual for a person has the character of an orienting reaction and is a stimulus for the manifestation of activity. The acceptor of the result of an action is the goal towards which the action is directed. In the presence of an action acceptor and an action program formulated by consciousness, the execution of the action begins, while the will is turned on, as well as the process of obtaining information about the fulfillment of the goal. Information about the results of an action has the character of a reverse afferentation and is aimed at forming an attitude in relation to the action being performed. Information passes through the emotional sphere and causes certain emotions that affect the nature of the installation. Luria A.R. He proposed to identify anatomically relatively autonomous blocks of the brain that ensure the functioning of mental phenomena: The first block is designed to maintain a certain level of activity (the reticular formation of the brain stem, the deep sections of the midbrain, the structures of the limbic system, the mediobasal sections of the cortex of the frontal and temporal lobes of the brain). The second block is associated with cognitive mental processes and is intended for the processes of obtaining, processing and storing information (areas of the cerebral cortex, which are located in the posterior and temporal regions of the cerebral hemispheres). The third block provides the functions of thinking, behavioral regulation and self-control (the structures are located in the anterior sections of the cerebral cortex).
Physiological foundations of the psyche
For a long time, mankind did not have at least some intelligible scientific explanation the fact that man has a soul (psyche). Gradually, with the development of natural sciences, it was possible to find out that the material basis of our psyche is the work of the nervous system, consisting of neurons - nerve cells with processes, with the help of which they are combined into a network.Perhaps the clearest confirmation of this fact comes from experiments and observations from neuropsychology. Violation of the activity of some parts of the brain leads to immediate memory lapses. Violation of others - to speech disorders. Exciting neurons in certain centers can cause an immediate euphoria in the subject. Another scientific consideration is that man is certainly endowed with highest level mental development. However, it has, in comparison with any animal, the most developed nervous system.
The human nervous system consists of two sections:
Central,
Peripheral.
The central nervous system (CNS) consists of:
Brain,
spinal cord.
The brain, in turn, consists of:
forebrain,
midbrain,
Hind brain.
In the brain, for example, such important structures are distinguished as:
thalamus,
Hypothalamus,
Cerebellum,
Medulla.
It can be said that all departments and structures of the central and peripheral nervous system are involved in receiving, processing and sending information. However, the cerebral cortex, which, together with the subcortical structures that make up the forebrain, determines the features of the functioning of consciousness and thinking of a person, has a special, most characteristic value for the human psyche.
The central nervous system is connected with all organs and tissues of the human body. This connection is provided by nerves that come out of the brain and spinal cord. All nerves (bundles of nerve fibers) are divided into two functional groups:
Nerves that carry signals from the outside world and body structures (afferent nerves)
Nerves that conduct signals from the CNS to the periphery (efferent nerves).
The CNS is, as already mentioned, a network of nerve cells. If we take into account that the number of neurons in a person is about one hundred billion (10 11), then you can imagine all its complexity and intricacies. Each nerve cell (neuron) consists of a main body and processes. Tree-like processes are called dendrites. One long process is called an axon. The junctions of processes with processes of other neurons are called synapses.
Neurons are of different types, they have a highly developed specialization. For example, neurons that conduct impulses from receptors are called "sensory neurons". The neurons responsible for transmitting impulses from the CNS to the muscles are called " motor neurons". The neurons responsible for ensuring the connection of some parts of the central nervous system with others are called "neurons of the local network."
On human skin, at the bottom eyeball and in other sense organs there are receptors - specialized organic devices, of a very small size, designed to perceive various types of energy (mechanical, electromagnetic, chemical, etc.) and convert it into the energy of a nerve impulse. Long processes (axons) of nerve cells located closer to the center cling to these receptors.
IP Pavlov introduced the concept of an analyzer - a relatively autonomous organic structure that ensures the processing of specific sensory information and its passage at all levels, including the central nervous system. Each analyzer consists of three structural elements:
receptors,
nerve fibers,
Specialized departments of the CNS.
Information from receptors is transmitted to the cerebral cortex. Information from the same receptors comes only to a certain area of the cerebral cortex. The visual analyzer closes on one part of the cortex, the auditory analyzer on another, and so on.
The entire cerebral cortex can be divided into separate functional areas. Not only analyzer zones are distinguished, but also motor, speech, etc. In accordance with the classification of K. Brodman, the cerebral cortex can be divided into 11 regions and 52 fields.
The areas in the cerebral cortex are:
Temporal,
parietal,
Occipital.
These areas themselves are divided into even smaller areas - fields. Since the cortex consists of two hemispheres, the regions are divided into left and right, and are considered different.
The information received by the receptors is transmitted along the nerve fibers to the accumulation of specific nuclei of the thalamus, and through them the afferent impulse enters the primary projection zones of the cerebral cortex. These zones are the final cortical structures of the analyzer. The projective zone of the visual analyzer, for example, is located in the occipital regions of the cerebral hemispheres, and the projective zone of the auditory analyzers is located in the upper parts of the temporal lobes.
The primary projective areas of the analyzers are sometimes called sensory areas, because they are associated with the formation of a certain type of sensation. If, for one reason or another, any zone is destroyed, then a person may lose the ability to perceive a certain type of information. If you destroy the zone of visual sensations, for example, then the person goes blind. Thus, human sensations depend not only on the level of development and integrity of the sense organ, in this case, vision, but also on the integrity of the pathways - nerve fibers - and the primary projective zone of the cortex.
In addition to the primary fields of analyzers, there are other primary fields, for example, primary motor fields associated with the muscles of the body and responsible for certain movements. Primary fields generally occupy a relatively small area of the cerebral cortex - no more than one third of it. A much larger area is occupied by secondary fields, which are most often called associative or integrative.
These secondary fields are an "intelligent superstructure" on top of the primary fields. Their functions are to synthesize or integrate individual elements of information into a complete picture. So, elementary sensations in sensory integrative fields (or perceptual fields) are formed into a holistic perception, and individual movements, thanks to motor integrative fields, are formed into a holistic motor act.
Among the integrative fields there are those that are present only in humans: the center of auditory perception of speech (Wernicke's center) and the motor center of speech (Broca's center). The presence of these differentiated centers testifies to the special role of speech for the regulation of the psyche and human behavior.
The work of other centers is also closely connected with the work of consciousness. For example, the frontal lobes of the prefrontal and premotor zones determine the work of the will, goal setting. Cutting off these lobes (lobotomy) does not lead to any immediately noticeable behavioral defects, the person continues to live as if out of habit, but the formation of new goals is very difficult for him.
The hemispheres largely duplicate each other's work. But there is also the phenomenon of the so-called functional asymmetry: the symmetrical centers of the cortex perform different activities. For example, the left hemisphere in its work acts as the leader in the implementation of speech and other speech-related functions: reading, writing, counting, logical memory, verbal-logical, or abstract, thinking, arbitrary speech regulation of other mental processes and states. The right hemisphere, in symmetrical centers, performs functions not related to speech, and the corresponding processes usually proceed at the sensory level.
Both hemispheres are involved in the mental process of perceiving the outside world. But the left and right hemispheres perform different functions in the perception and formation of the image of the displayed object. The right hemisphere is characterized by a high speed of work on identification, its accuracy and clarity. It operates big images, and integral-synthetic, holistic-figurative information processing algorithms are more important for him. The right hemisphere is responsible for the holistic perception of the object or performs the function of global integration of the image.
The left hemisphere uses analytical, sequential information processing algorithms to a greater extent. It is engaged in a sequential enumeration of the elements of the image. It is easier for him to reveal the structure of the observed object, the causal relationships of phenomena.
Interestingly, the final specialization of the hemispheres occurs in the process of human life, individual development. For example, it matters what type of writing a child learns: alphabetic or hieroglyphic. Maximum specialization is noted when a person reaches a period of maturity; by old age, specialization is again lost.
In evolutionary terms, some parts of the brain are old, some are new. But all departments contribute to mental activity. For example, the reticular formation has a noticeable effect on the electrical activity of the brain, on the functional state of the cerebral cortex, subcortical centers, cerebellum and spinal cord. It is also directly related to the regulation of basic life processes: blood circulation and respiration. Any mental condition of a person is determined by the peculiarity of the work of this reticular formation. It has a regulatory role, determining which parts of the brain should rest and which should work actively.
