Central part of the brain with numbered Brodmann fields.
Brodmann fields
- Fields 1 and 2, 3 - somatosensory area, primary zone. They are located in the postcentral gyrus. In connection with the generality of functions, the term " fields 1 and 2, 3» (front to back)
- Field 4 - primary motor cortex. Located within the precentral gyrus
- Field 5 - secondary somatosensory zone. Located within the superior parietal lobule
- Field 6 - premotor cortex and supplementary motor cortex (secondary motor area). It is located in the anterior sections of the precentral and posterior sections of the superior and middle frontal gyri.
- Field 7 - tertiary zone. Located in the upper parietal lobe between the postcentral gyrus and the occipital lobe
- Field 8 - located in the posterior sections of the upper and middle frontal gyri. Includes the center of voluntary eye movements
- Field 9 - dorsolateral prefrontal cortex
- Field 10 - anterior prefrontal cortex
- Field 11 - olfactory area
- Field 12 -
- Field 13 -
- Field 14 -
- Field 15 -
- Field 16 -
- Field 17 - nuclear zone of the visual analyzer - visual area, primary zone
- Field 18 - the nuclear zone of the visual analyzer - the center of perception of written speech, the secondary zone
- Field 19 - nuclear zone of the visual analyzer, secondary zone (assessment of the value of what was seen)
- Field 20 - inferior temporal gyrus (center of the vestibular analyzer, complex pattern recognition)
- Field 21 - middle temporal gyrus (center of the vestibular analyzer)
- Field 22 - sound analyzer nuclear zone
- Field 23 -
- Field 24 - anterior cingulate cortex
- Field 25 -
- Field 26 -
- Field 27 -
- Field 28 - projection fields and associative zone
Many scientists participated in the analysis of the structure of the cortex (Economo, Betz, Vogt, Bailey, and others). Their maps of cortical fields differ in the number of fields, the absence of clear boundary lines, and great individual variability. The most recognized are the maps of K. Brodman, who identified 52 fields on the surface of the hemispheric cortex ( , ).
I.P. Pavlov believed that the cerebral cortex can be represented as a collection of centers of various analyzers. It is believed that the center consists of a nucleus, which has a certain localization in the cortex, between which there are scattered elements belonging to different analyzers. This allows us to speak about the dynamic localization of functions in the cortex of the cerebral hemispheres. At the same time, the functions of the cortical fields are associated with the opposite half of the human body, because. all the paths connecting them necessarily cross. IP Pavlov divided all analyzer centers into two signal systems.
TO THE FIRST SIGNAL SYSTEM (SI) he attributed those centers that perceive signals from the external or internal environment in the form of sensations, impressions, ideas ( except for speech and words). These centers are present in both animals and humans. They are located in both hemispheres, given from birth and are not restored when destroyed. These include (Fig. 26, 27):
1, 2, 3
- cores of general sensitivity (temperature, pain, tactile and proprioceptive).
4, 6
- the core of the motor analyzer. It has developed cells 5
layer of the cortex that innervates the muscles of the opposite half of the body. The muscles of the body are projected onto the anterior central gyrus (motor field) and the near-central lobule, as it were, upside down (motor homunculus).
8
- premotor field.
46
- Combined head and eye rotation. This nucleus receives impulses from the receptors of the muscles of the eyeball and from representation in the cortex of the retina (from field 17).
5, 7
- stereognosy. The receptors of the upper limb are projected into this center to recognize objects by touch.
40
- praxia. The implementation of all complex combined movements acquired as a result of practical activities, mainly professional.
41, 42, 52
- the core of the auditory analyzer (on the convolutions of Heschl), fibers from the left and right ear approach its cells, therefore, a unilateral lesion of the core does not lead to complete hearing loss:
41
- primary field, it perceives impulses,
42
- psychological field, auditory memory,
52
- evaluation field, with its help we orient ourselves in space.
17, 18, 19
- the core of the visual analyzer, fibers from the lateral side of the retina of the eye of its half of the body, as well as from the medial retina of the eye of the opposite half of the body, approach its cells. Therefore, complete cortical occurs when the centers of both hemispheres are affected:
17
- primary field,
18
- psychological,
19
- appraisal.
A, E, 11- the core of the olfactory analyzer, located in the most ancient structures of the cerebral cortex (in the hook and hippocampus)
43
- the core of the taste analyzer. As V. M. Bekhterev noted, this analyzer is closely interconnected with the olfactory fields of both hemispheres.
Thus, the "psychological" areas of the cortex (19, 42, 5 and 7) cause the evaluation or association of various information. They surround the supramarginal (marginal) lobule and are closely interconnected with it, therefore, a violation in this lobule affects the generalization of information and its understanding.
Rice. 28. Cytoarchitectonic fields of the cerebral cortex (upper lateral surface) 
Rice. 29. Cytoarchitectonic fields of the cerebral cortex (medial surface)
SECOND SIGNALING SYSTEM (SII) is available only in humans. It is due to the development of speech and, as I. P. Pavlov believed, is "signals of signals." They represent a distraction from reality, allow the generalization of information and form the basis of higher thinking. Speech and mental functions are performed with the participation of the entire cortex. However, certain fields can be distinguished, which have strictly defined speech functions. Speech centers develop after birth, usually in the left hemisphere (there are exceptions for left-handers). If they are lost, a person can again develop speech centers, but in this case other fields will take over their function.
44
- the core of the motor analyzer of written speech, innervates the thin muscles of the hand and fingers. For left-handers, this center is located in the right hemisphere. With the destruction of this center, there is a loss of the ability to write - agrophy.
45
- the core of the motor analyzer of oral speech (Brock). Innervates the muscles of the larynx, tongue, lips, and others involved in articulation. Motor aphasia is the loss of the ability to pronounce words.
47
- speech analyzer of singing, allows you to pronounce words in a singsong voice Used to restore speech in children with
Concepts of the functioning of the cerebral hemispheres:
The theory of localizationism - each field of the cortex and each section of the cerebral hemispheres perform strictly defined functions.
The theory of equipotentialism - there are no areas of the cortex and parts of the cerebral hemispheres that perform specific functions. Functions are evenly distributed over the cerebral cortex.
The theory of dynamic localization of functions (according to I.P. Pavlov) - functions may not have a clear link to structures and may be dynamically performed by various departments of the cerebral hemispheres.
The theory of flexible and rigid links in the organization of cerebral systems for ensuring activity (according to N.P. Bekhtereva).
1861 - the scientist Broca discovered in the lower third of the frontal gyrus of the left hemisphere the motor center of speech, the defeat of which leads to the loss of the ability to speak.
1870 - Fries discovered in the frontal lobe the localization of the motor function of the anterior central lobe, the defeat of which causes paralysis.
1874 - psychiatrist Vershke showed that lesions of the posterior third of the temporal gyrus of the left hemisphere impair understanding of speech, but the ability to speak remains.
Modern representations of the localization of functions in the cortex:
a) primary (projection) zones.
b) secondary zones (signal processing)
c) associative (tertiary) zones (zones of overlap of primary zones).
The primary zone is the zone of projection sensory pathways in the CBP. It goes along 3 neurons (1 - in the spinal ganglion, 2 - brain stem, 3 - thalamus). Here the sensation is formed in accordance with the modality of the stimulus that we perceive. It is formed in the form of an image.
The secondary zones surround the primary zone and here the stimulus is identified based on comparison with traces of past experience (stored in memory).
The tertiary zone is formed by overlap zones of secondary zones belonging to different analyzers or sensor systems. The 2nd and 3rd layers of the CBP have reached the greatest development in these zones. These zones are characterized by the presence of polysensory neurons that respond to various stimuli. These zones establish inter-analyzer connections that allow you to evaluate the entire set of properties of objects. The following properties belong to these zones: tosia - the ability to recognize objects (pathology - agnosia), praxia - an acquired memorized motor skill. The defeat of the associative zones is accompanied by a loss of the ability to perform learned movements - apraxia.
telencephalon functions.
The telencephalon is divided into the frontal, occipital, parietal and temporal lobes. Each share is divided into small sections. The limbic lobe is distinguished: these are areas of the frontal, parietal and temporal lobes surrounding the diencephalon. In the depths of the Sylvian furrow, in the depths of the hemisphere lies an island and it is covered by the edges of the frontal, temporal and parietal lobes. It is associated with innervation of internal organs. The frontal lobe is associated with the performance of voluntary movements, with the coordination of the motor mechanisms of speech, language communication, creative or critical thinking.
The motor functions of the regulation of voluntary movements are laid down in the anterior central gyrus (field 4 according to Broadman). In this gyrus there is a representation of body parts (homunkumos). It is for this gyrus that the development of the 5th layer is characteristic, where large pyramidal cells are located. They give rise to descending pyramidal pathways that lead to motor neurons in the gray matter of the SC. The paths cross, the motor commands of the cortex are transmitted to the anterior horns (motor neurons). Each hemisphere is responsible for the movement of the opposite side of the body. The defeat of the first neuron is accompanied by central paralysis on the opposite side of the body, but muscle tone is preserved. The defeat of the second neuron also leads to paralysis, but muscle atrophy and the absence of spinal reflexes will be observed.
The premotor zone is located in the 4th field. It is connected with the extrapyramidal system. Zone 8 is responsible for oculomotor reactions. The anterior frontal lobe is associated with creative thinking. The defeat of this department is caused by drastic personality changes (there is no initiative, no desire to achieve goals, they are in a state of childish satisfaction, there are no problems, they are only interested in everyday trifles and cannot make plans for the future, they lose critical self-esteem, make stupid jokes, such of people, behavioral processes are disturbed when the frontal lobe is removed).
The speech motor center is located in the frontal lobe of the 44th field. When the zone is irritated, the pronunciation of sounds occurs, but not words.
The parietal lobe is associated with somatic sensitivity, with memory related to speech, learning, and simple orientation. Sensitive functions are presented in the posterior central gyrus (fields 1, 2, 3). Transection of the zhth zone leads to the loss of different types of sensitivity.
Further allocate 5 and 7 fields. They make it possible to evaluate the weight, surface properties, dimensions and shapes of the object. The lower parietal lobe is associated with speech comprehension (Wernicke's centre). The parietal lobe conveys a sense of 3D space and perception of body schema. The defeat is accompanied by agnosia. Patients lose the ability to understand letters and numbers, the perception of the body scheme is disturbed. With a complete violation of the body scheme, patients completely deny that one half of the body belongs to the other.
The temporal lobe is associated with the perception of auditory sensations and is involved in the sound control of speech. She has a role in the evaluation of space and she participates in memory. The primary zone is the 41st field, the 42nd field is the secondary zone, where the perceived sounds are evaluated, and the 22nd field is involved in the function of understanding words and, if it is damaged, there is a loss of the ability to understand words. The temporal lobe determines vestibular sensitivity, irritation of the posterior temporal lobe causes dizziness. With irritation of other parts of the temporal lobe, patients hear voices that were in the past, acoustic and visual hallucinations occur. When the temporal lobe is damaged, a misinterpretation of the world occurs. The temporal lobe is responsible for dreams.
The occipital lobe is associated with visual function. Along the spur groove is the primary visual zone (field 17). The identification of the object is carried out by the 18th field surrounding the 17th field. The 19th field, bordering the parietal lobe, takes part in assessing the meaning of what is seen. The visual cortex, organized in a columnar fashion, consists of vertical columns. They contain simple cells that respond to point light stimuli, and complex cells that perceive vertical, horizontal and triangular images. The inner granular layer contains simple cells and the complex cells in the outer granular layer. Complex cells are concentrated in 18-19 fields.
The limbic lobe includes the subcallosal region, cingulate gyrus, isthmus, parahippocampal gyrus, hippocampal sliver, and amygdala. It receives information from the sense of smell (the analyzer in the 34th field), the taste analyzer in the 43rd field. In general, this share is responsible for the behavioral reactions of the body in response to irritation of the external environment, but in accordance with the state of the internal environment. These reactions are aimed at preserving the individual. The amygdala is responsible for the preservation of the individual, the septum and the hippocampus are responsible for the preservation of the species. Irritation of the tonsils causes chewing, swallowing, etc. Damage to the tonsils - the animal becomes obedient ... Irritation of the septum causes sexual (parental) behavior. Transection of the hippocampus is accompanied by fits of rage.
Criteria for classifying different cortical fields:
Cytoarchitectonic
Myeloarchitectonic
Angioarchitectonic
Chemoarchitectonic
Functional
The severity of the layers in different departments of the CBP is different. Based on this, Brodman identified 11 zones and 52 fields.
The 1st zone - motor - is represented by the central gyrus and the frontal zone in front of it - 4, 6, 8, 9 Brodmann's fields. When it is irritated - various motor reactions; when it is destroyed - violations of motor functions
2nd zone - sensitive - areas of the cerebral cortex behind the central sulcus (1, 2, 3, 4, 5, 7 Brodmann fields). When this zone is irritated, sensations arise, when it is destroyed, loss of skin, proprio-, interosensitivity occurs. The 1st and 2nd zones are closely related to each other functionally. In the motor zone, there are many afferent neurons that receive impulses from receptors - these are motosensory zones. In the sensitive area, there are many motor elements - these are sensorimotor zones - are responsible for the occurrence of pain.
3rd zone - visual zone - occipital region of the cerebral cortex (17, 18, 19 Brodmann fields). With the destruction of the 17th field - loss of visual sensations (cortical blindness). when the 17th field is destroyed, the vision of the environment falls out, which is projected onto the corresponding parts of the retina. With the defeat of the 18th field of Brodmann, the functions associated with the recognition of a visual image suffer and the perception of writing is disturbed. With the defeat of the 19th field of Brodmann, various visual hallucinations occur, visual memory and other visual functions suffer.
4th - auditory zone - temporal region of the cerebral cortex (22, 41, 42 Brodmann fields). If 42 fields are damaged, the function of sound recognition is impaired. When the 22nd field is destroyed, auditory hallucinations, impaired auditory orienting reactions, and musical deafness occur. With the destruction of 41 fields - cortical deafness.
The 5th zone - olfactory - is located in the piriform gyrus (11 Brodmann's field).
6th zone - taste - 43 Brodman's field.
The 7th zone - the motor speech zone - in most people (right-handed) is located in the left hemisphere.
This zone consists of 3 departments.
Broca's motor speech center - located in the lower part of the frontal gyri - is the motor center of the muscles of the tongue.
The sensory center of Wernicke - located in the temporal zone - is associated with the perception of oral speech. .
The center of perception of written speech is located in the visual zone of the cerebral cortex.
CHAPTER 7. BRAIN CORK AND HIGHER MENTAL FUNCTIONS. SYNDROMES OF DEFEATCHAPTER 7. BRAIN CORK AND HIGHER MENTAL FUNCTIONS. SYNDROMES OF DEFEAT
In neuropsychology under higher mental functions refers to complex forms of conscious mental activity carried out on the basis of appropriate motives, regulated by appropriate goals and programs, and subject to all laws of mental activity.
The higher mental functions (HMF) include gnosis (cognition, knowledge), praxis, speech, memory, thinking, emotions, consciousness, etc. HMF are based on the integration of all parts of the brain, and not just the cortex. In particular, an important role in the formation of the emotional-volitional sphere is played by the "center of addictions" - the amygdala, the cerebellum and the reticular formation of the brainstem.
Structural organization of the cerebral cortex. The cerebral cortex is a multi-layered neural tissue with a total area of approximately 2200 cm 2 . Based on the shape and arrangement of cells along the thickness of the cortex, in a typical case, 6 layers are distinguished (from the surface to the depths): molecular, outer granular, outer pyramidal, inner granular, inner pyramidal, layer of spindle-shaped cells; some of them can be divided into two or more secondary layers.
In the cerebral cortex, a similar six-layer structure is characteristic of neocortex (isocortex). An older type of bark allocortex- mostly three-layer. It is located deep in the temporal lobes and is not visible from the surface of the brain. The allocortex contains the old cortex archicortex(dentate fascia, ammon horn and hippocampus base), ancient bark - paleocortex(olfactory tubercle, diagonal area, transparent septum, periamygdala area and peripyriform area) and derivatives of the cortex - fence, tonsils and nucleus accumbens.
Functional organization of the cerebral cortex. Modern ideas about the localization of higher mental functions in the cerebral cortex are reduced to the theory of systemic dynamic localization. This means that the mental function is correlated by the brain as a certain multi-component and multi-link system, the various links of which are associated with the work of various brain structures. The founder of this idea is the largest
neurologist A.R. Luria wrote that “higher mental functions as complex functional systems cannot be localized in narrow areas of the cerebral cortex or in isolated cell groups, but must cover complex systems of jointly working zones, each of which contributes to the implementation of complex mental processes and which can be located in completely different, sometimes far apart areas of the brain.
The position on the “functional ambiguity” of brain structures was also supported by I.P. Pavlov, who singled out “nuclear zones of analyzers”, “scattered periphery” in the cerebral cortex and assigned the role of a structure with a plastic function to the latter.
The two hemispheres of a person are not the same in function. The hemisphere where the speech centers are located is called the dominant, for right-handed people it is the left hemisphere. The other hemisphere is called subdominant (in right-handers - right). This division is called lateralization of functions and is determined genetically. Therefore, a retrained left-hander writes with his right hand, but until the end of his life he remains a left-handed type of thinking.
The cortical section of the analyzer consists of three sections.
Primary fields- specific nuclear zones of the analyzer (for example, field 17 according to Brodmann - when it is damaged, homonymous hemianopsia occurs).
Secondary fields- peripheral associative fields (for example, 18-19 fields - if they are damaged, there may be visual hallucinations, visual agnosia, metamorphopsia, occipital seizures).
Tertiary fields- complex associative fields, areas of overlap of several analyzers (for example, 39-40 fields - when they are damaged, apraxia, acalculia occur, when 37 fields are damaged - astereognosis).
In 1903, the German anatomist, physiologist, psychologist and psychiatrist K. Brodmann (Korbinian Brodmann, 1868-1918) published a description of 52 cytoarchitectonic fields of the cortex. In parallel and in agreement with the studies of K. Brodmann in the same 1903, the German psychoneurologists, the spouses O. Vogt and S. Vogt (Oskar Vogt, 1870-1959; Cecile Vogt, 1875-1962), based on anatomical and physiological studies, gave a description of 150 myeloarchitectonic fields cerebral cortex. Later, based on structural studies
Rice. 7.1.Map of cytoarchitectonic fields of the human cerebral cortex (Brain Institute):
a- outside surface; b- internal; in- front; G- back surface. The fields are marked with numbers.
of the brain, which were based on the evolutionary principle, employees of the Institute of the Brain of the USSR (founded in the 1920s in Moscow by O. Vogt, invited for this purpose) created detailed maps of the cytomyeloarchitectonic fields of the human brain (Fig. 7.1).
7.1. Zones and fields of the cerebral cortex
In the cerebral cortex, functional zones are distinguished, each of which includes several Brodmann fields(total 53 fields).
1st zone - motor - represented by the central gyrus and the frontal zone in front of it (4, 6, 8, 9 Brodmann fields). When it is irritated, various motor reactions occur; when it is destroyed - violations of motor functions: adynamia, paresis, paralysis (respectively, weakening, a sharp decrease, disappearance
movements). In the motor zone, the areas responsible for the innervation of various muscle groups are presented differently. The zone involved in the innervation of the muscles of the lower limb is represented in the upper section of the 1st zone; muscles of the upper limb and head - in the lower part of the 1st zone. The largest area is occupied by the projection of mimic muscles, muscles of the tongue and small muscles of the hand.
2nd zone - sensitive - sections of the cerebral cortex posterior to the central sulcus (1, 2, 3, 5, 7 Brodmann fields). When this zone is irritated, paresthesias occur, and when it is destroyed, loss of superficial and part of deep sensitivity occurs. In the upper sections of the postcentral gyrus, there are cortical centers of sensitivity for the lower limb of the opposite side, in the middle sections - for the upper, and in the lower - for the face and head.
The 1st and 2nd zones are closely related to each other functionally. In the motor zone, there are many afferent neurons that receive impulses from proprioreceptors - these are motosensory zones. There are many motor elements in the sensitive zone - these are sensorimotor zones that are responsible for the occurrence of pain.
3rd zone - visual - occipital region of the cerebral cortex (17, 18, 19 Brodmann fields). With the destruction of the 17th field, loss of visual sensations occurs (cortical blindness). Different parts of the retina are differently projected into the 17th Brodmann field and have a different location. With point destruction of the 17th field, the completeness of the visual perception of the environment is disturbed, since a portion of the field of vision falls out. With the defeat of the 18th field of Brodmann, the functions associated with the recognition of a visual image suffer, the perception of writing is disturbed. With the defeat of the 19th field of Brodmann, various visual hallucinations occur, visual memory and other visual functions suffer.
4th zone - auditory - temporal region of the cerebral cortex (22, 41, 42 Brodmann fields). If 42 fields are damaged, the function of sound recognition is impaired. With the destruction of the 22nd field, auditory hallucinations, impaired auditory orienting reactions, and musical deafness occur. With the destruction of 41 fields - cortical deafness.
5th zone - olfactory - located in the piriform gyrus (11 Brodmann field).
6th zone - taste - 43 Brodman field.
7th zone - motor speech (according to Jackson - the center of speech) in right-handers is located in the left hemisphere. This area is divided into 3 sections:
1) Broca's speech motor center (the center of speech praxis) is located in the posterior lower part of the frontal gyri. He is responsible for the praxis of speech, i.e. ability to speak. It is important to understand the difference between Broca's center and the motor center of the speech-motor muscles (tongue, pharynx, face), which is located in the anterior central gyrus posterior to Broca's area. If the motor center of these muscles is affected, their central paresis or paralysis develops. At the same time, a person is able to speak, the semantic side of speech does not suffer, but his speech is fuzzy, his voice is slightly modulated, i.e. sound quality is impaired. With the defeat of Broca's area, the muscles of the speech-motor apparatus are intact, but the person is not able to speak like a child in the first months of life. This state is called motor aphasia;
2) Wernicke sensory center located in the high zone. It is related to the perception of oral speech. When it is damaged, sensory aphasia occurs - a person does not understand oral speech (both someone else's and his own). Due to a lack of understanding of one's own speech production, the patient's speech acquires the character of a "verbal salad", i.e. collection of unrelated words and sounds.
With a joint lesion of Broca's and Wernicke's centers (for example, with a stroke, since both of them are located in the same vascular pool), total (sensory and motor) aphasia develops;
3) center of perception of written speech located in the visual zone of the cerebral cortex - 18 Brodmann's field. With his defeat, agraphia develops - the inability to write.
Similar but undifferentiated zones exist in the subdominant right hemisphere, while the degree of their development is different for each individual. If the right hemisphere is damaged in a left-handed person, the speech function suffers to a lesser extent.
The cerebral cortex at the macroscopic level can be divided into sensory, motor and associative areas. Sensory (projection) zones, which include the primary somatosensory cortex, the primary zones of various analyzers (auditory, visual, gustatory, vestibular), have a connection with certain areas,
organs and systems of the human body, peripheral parts of analyzers. The same somatotopic organization has motor cortex. Projections of body parts and organs are presented in these zones according to the principle of functional significance.
association cortex, which includes the parietal-temporal-occipital, prefrontal and limbic associative zones, is important for the implementation of the following integrative processes: higher sensory functions and speech, motor praxis, memory and emotional (affective) behavior. The associative sections of the cerebral cortex in humans are not only larger in area than the projection ones (sensory and motor), but are also characterized by a finer architectonic and neural structure.
7.2. The main types of higher mental functions and their disorders
7.2.1. Gnosis, types of agnosia
Gnosis (from the Greek gnosis - cognition, knowledge) is the ability to cognize or recognize the world around, in particular various objects of the world around, using information coming from various cortical analyzers. At every moment of our life, analyzer systems supply the brain with information about the state of the external environment, about objects, sounds, smells that surround us, about the position of our body in space, which gives us the opportunity to adequately perceive ourselves in relation to the world around us and respond correctly to all changes that occur. around us.
Agnosia - these are disorders of recognition and cognition, reflecting violations of various types of perception (the shape of an object, symbols, spatial relationships, speech sounds, etc.) that occur when the cerebral cortex is damaged.
Depending on the affected analyzer, visual, auditory and sensory agnosias are distinguished, each of which includes a large number of disorders.
visual agnosia called such disorders of visual gnosis that occur when the cortical structures (and the nearest subcortical formations) are damaged in the posterior parts of the cerebral hemispheres (parietal and occipital regions) and proceed with the relative preservation of elementary visual functions (visual acuity, color perception, visual fields) [fields 18, 19 according to Brodman].
object agnosia characterized by impaired visual recognition of objects. The patient can describe various features of the object (shape, size, etc.), but cannot recognize it. Using information coming from other analyzers (tactile, auditory), the patient can partially compensate for his defect, so such people often behave almost like blind people - although they do not stumble upon objects, they constantly feel, sniff, listen. In milder cases, it is difficult for patients to recognize inverted, crossed out, superimposed images one on top of the other.
Opto-spatial agnosia occurs when the upper part of the parieto-occipital region is affected. The patient's orientation in space is disturbed. Right-left orientation is especially affected. Such patients do not understand the geographical map, do not orientate themselves on the ground, do not know how to draw.
Letter agnosia - impaired recognition of letters, resulting in alexia.
Facial agnosia (prosopagnosia) - impaired recognition of faces that occurs when the posterior sections of the subdominant hemisphere are affected.
Apperceptive agnosia characterized by the inability to recognize integral objects or their images while maintaining the perception of individual features.
Associative agnosia - visual agnosia, characterized by a violation of the ability to recognize and name integral objects and their images while maintaining their distinct perception.
Simultaneous agnosia - the inability to synthetically interpret groups of images that form a whole. Occurs with bilateral or right-sided lesions of the occipito-parietal regions of the brain. The patient cannot simultaneously perceive several visual objects or the situation as a whole. Only one object is perceived, more precisely, only one operational unit of visual information is processed, which is currently the object of the patient's attention.
Auditory agnosia are divided into violations of speech phonemic hearing, intonational side of speech and non-speech auditory gnosis.
Auditory agnosia associated with phonemic hearing, occur mainly with damage to the temporal lobe of the dominant hemisphere. Due to a violation of phonemic hearing, the ability to distinguish speech sounds is lost.
Auditory non-speech (simple) agnosia occurs when the cortical level of the auditory system of the right hemisphere (nuclear zone) is damaged; the patient is not able to determine the meaning of various household (subject) sounds, noises. Such sounds as the creaking of a door, the sound of water, the clinking of dishes cease to be carriers of a certain meaning for these patients, although hearing as such remains intact, and they can distinguish sounds by pitch, intensity, and timbre. When the temporal region is affected, a symptom such as arrhythmia. Patients cannot correctly evaluate various rhythmic structures (a series of claps, taps) by ear and cannot reproduce them.
Amusia- auditory agnosia with a violation of the musical abilities that the patient had in the past. Motor amusia is manifested by the inability to reproduce familiar melodies; sensory- impaired recognition of familiar melodies.
Violation of the intonation side of speech occurs when the temporal region of the subdominant hemisphere is damaged, while the perception of the emotional characteristics of the voice is lost, the distinction between male and female voices, one's own speech loses expressiveness. Such patients cannot sing.
Sensitive agnosias are expressed in the unrecognition of objects when they act on the receptors of superficial and deep sensitivity.
Tactile agnosia, or astereognosis occurs when the post-central areas of the cortex of the lower parietal region are affected, bordering on the zones of representation of the hand and face in the 3rd field, and is manifested by the inability to perceive objects by touch. Tactile perception is preserved, so the patient, feeling the object with closed eyes, describes all its properties (“soft”, “warm”, “prickly”), but cannot identify this object. Sometimes there are difficulties in identifying the material from which the object is made. This type of violation is called tactile agnosia texture object.
Finger agnosia, or Tershtman's syndrome observed with damage to the lower parietal cortex, when the ability to call with closed eyes the fingers on the hand contralateral to the lesion is lost.
Violations of the "body schema", or autopagnosia occurs when the upper parietal region of the cerebral cortex is damaged, which is adjacent to the front
primary sensory cortex of the skin-kinesthetic analyzer. Most often, the patient has impaired perception of the left half of the body due to damage to the right parietal region of the brain. The patient ignores the left limbs, the perception of his own defect is often disturbed - anosognosia (Anton-Babinsky syndrome), those. the patient does not notice paralysis, sensory disturbances in the left limbs. In this case, false somatic images may arise in the form of a sensation of a “foreign hand”, doubling of the limbs - pseudopolymelia, enlargement, reduction of body parts, pseudoamelia -"absence" of a limb.
7.2.2. Praxis, types of apraxia
Praxis (from the Greek. praxis - action) - the ability of a person to perform appropriate sequential sets of movements and perform purposeful actions according to a developed plan.
Apraxia - praxis disorders, which are characterized by the loss of skills developed in the process of individual experience, complex purposeful actions (domestic, industrial, symbolic gestures) without pronounced signs of central paresis or impaired coordination of movements.
According to the classification proposed by A.R. Luria, there are 4 forms of apraxia.
kinesthetic apraxia occurs when the lower sections of the postcentral gyrus of the cortex of the cerebral hemispheres are damaged (fields 1, 2, partially 40, mainly in the left hemisphere). In these cases, there are no clear motor disorders, muscle paresis, but movement control is impaired. Patients can hardly write, the accuracy of reproduction of the postures of the hand (apraxia of the posture) is impaired, they cannot depict this or that action without an object (smoking a cigarette, combing their hair). Partial compensation of this violation is possible with increased visual control over the performance of movements.
With spatial apraxia the correlation of one's own movements with space is violated, spatial representations of "up-down", "right-left" are violated. The patient cannot give a straightened hand a horizontal, frontal, sagittal position, draw an image oriented in space, while writing errors occur in the form of "mirror writing". Such a violation occurs when the parieto-occipital cortex is damaged at the border of the 19th and 39th fields, the bilateral or isolated left hemisphere. It
often combined with visual optic-spatial agnosia; in this case, a complex picture of apractoagnosia arises. This type of disorder also includes constructive apraxia - the difficulty of constructing a whole from individual objects (Kohs cubes, etc.).
Kinetic apraxia associated with damage to the lower parts of the premotor cortex (fields 6 and 8). In this state, there is a violation of the temporal organization of movements (automation of movements). This form of apraxia is characterized by motor perseveration, which manifests itself in the uncontrolled continuation of a movement once begun. It is difficult for the patient to switch from one elementary movement to another, he seems to get stuck on each of them. This is especially evident when writing, drawing, performing graphic tests. Often, apraxia of the hands is combined with speech disorders (motor efferent aphasia), and the commonality of the mechanisms underlying the pathogenesis of these conditions has been established.
Regulatory(or prefrontal) form of apraxia occurs when the convexital prefrontal cortex is damaged in front of the premotor parts of the frontal lobes and is manifested by a violation of the programming of movements. Disabled conscious control over their implementation, the necessary movements are replaced by patterns and stereotypes. Perseverations are characteristic, but already systemic, i.e. not the elements of the motor program, but the entire program as a whole. If such patients are asked to write something under dictation, and after executing this command they are asked to draw a triangle, then they will trace the outline of the triangle with movements characteristic of writing. With a gross breakdown of voluntary regulation of movements, patients experience symptoms of echopraxia in the form of imitative repetitions of the doctor's movements. This type of disorders is closely related to the violation of speech regulation of motor acts.
7.2.3. Speech. Types of aphasia
Speech is a specific human mental function that can be defined as the process of communication through language. Allocate impressive speech(perception of oral, written speech, its decoding, understanding of meaning and correlation with previous experience) and expressive speech(begins with the idea of the utterance, then goes through the stage of internal speech and ends with a detailed external speech utterance).
Aphasia - a complete or partial violation of speech that occurs after a period of its normal formation, due to local
ny damage to the cortex (and adjacent subcortical formations) of the dominant hemisphere of the brain. Aphasia manifests itself in the form of violations of the phonemic, morphological and syntactic structure of one's own speech and understanding of reversed speech with the preservation of the movements of the speech apparatus, providing articulate pronunciation, and elementary forms of hearing.
Sensory aphasia (acoustic-gnostic aphasia) occurs when the posterior third of the temporal gyrus is damaged (field 22); was first described by K. Wernicke in 1864. It is characterized by the impossibility of normal perception of both someone else's and one's own oral speech. It is based on a violation of phonemic hearing, i.e. loss of the ability to distinguish the sound composition of words (distinguishing phonemes). In Russian, phonemes are all vowels and their stress, as well as consonants and their sonority-deafness, hardness-softness. In the case of incomplete destruction of the zone, it is difficult to perceive fast or "noisy" speech (for example, when two or more interlocutors speak). In addition, patients practically cannot distinguish between words that are similar in sound, but different in meaning: “spike-voice-single” or “fence-cathedral”.
In more severe cases, a person completely loses the ability to perceive the phonemes of his native language. Patients do not understand the speech addressed to them, perceiving it as noise, a conversation in an unknown language. There is a secondary decay and active spontaneous oral speech, since there is no auditory control, i.e. understanding and evaluating the correctness of spoken words. Speech statements are replaced by the so-called "word salad", when patients pronounce words and expressions that are incomprehensible in their sound composition. Sometimes the ability to pronounce habitual words remains, however, in them, patients often replace one sound with another; this violation is called literal paraphasias. When replacing whole words, one speaks of verbal paraphasias. In such patients, writing under dictation is disturbed, the repetition of words heard, reading aloud is sharply difficult. However, ear for music with a given localization of the pathological focus is usually not disturbed and articulation is completely preserved.
At motor aphasia (speech apraxia) there are violations of the pronunciation of words with the relative safety of speech perception.
Afferent motor aphasia occurs when the lower parts of the post-central parts of the parietal region of the brain are damaged. Such patients often cannot voluntarily make various sounds,
they can puff out one cheek, stick out their tongue, lick their lips. Sometimes the control of only complex articulatory movements suffers (difficulties in pronouncing words like “propeller”, “space”, “sidewalk”), however, patients feel errors in pronunciation, but are not able to correct them, since “their mouth does not obey ". Violation of articulation also affects written speech in the form of replacing letters with similar ones in pronunciation.
Efferent motor aphasia (classical Broca's aphasia, fields 44, 45) occurs when the lower parts of the premotor cortex (the posterior third of the inferior frontal gyrus) of the dominant hemisphere are destroyed. The leading defect in this violation is the partial or complete loss of the possibility of smooth switching of motor impulses in time. Violations of arbitrary simple movements of the lips, tongue in this pathology are not observed. Such patients can pronounce individual sounds or syllables, but cannot combine them into words, phrases. In this case, a pathological inertia of articulatory actions occurs, manifested in the form speech perseverations(constant repetition of the same syllable, word or expression). Often such a verbal stereotype (“embolus”) becomes a substitute for all other words. In erased cases, difficulties arise when pronouncing words or expressions that are “difficult” in the motor sense. Due to the defeat of connections with various "speech zones", there may also be violations of writing, reading and even speech understanding.
Dynamic motor aphasia occurs when the prefrontal sections are damaged (fields 9, 10, 46). At the same time, the consistent organization of speech utterance is violated, active productive speech is disrupted, and reproductive (repeated, automated) is preserved. The patient can repeat the phrase, but he cannot form an utterance on his own. Passive speech is possible - monosyllabic answers to questions, often echolalia (repetition of the interlocutor's word).
With the defeat of the lower and posterior parts of the parietal and temporal regions, the development of amnestic aphasia (on the border of 37 and 22 fields). The basis of this violation is the weakness of visual representations, visual images of words. This type of violation is also called nominative amnestic aphasia, or optomnestic aphasia. Patients repeat words well and speak fluently, but cannot name objects. The patient easily remembers the purpose of objects (the pen - “what they write with”), but they cannot remember their names. The doctor's prompt often facilitates the task,
because speech comprehension remains intact. Patients are able to write from dictation and read, while spontaneous writing is impaired.
Acoustic-mnestic aphasia occurs when the middle parts of the temporal region of the dominant hemisphere, located outside the zone of the sound analyzer, are affected. The patient correctly understands the sounds of the native language, inverted speech, but is not able to remember even a relatively small text due to a gross impairment of auditory memory. The speech of these patients is characterized by scarcity, frequent omission of words (often nouns). Tips when trying to reproduce words do not help such patients, since speech traces are not retained in memory.
Semantic aphasia occurs when the cortical fields 39 and 40 of the parietal lobe of the left hemisphere are damaged. The patient does not understand speech formulations that reflect spatial relationships. So, the patient cannot cope with tasks, for example, draw a circle under a square, a triangle over a line, not understanding how the figures should be positioned relative to each other; the patient does not understand, cannot understand the comparative constructions: “Sonya is lighter than Manya, and Manya is lighter than Olya; which one is the lightest, the darkest? The patient does not catch the change in the meaning of the phrase when the word is rearranged, for example: “Students stood at the window with books”, “Students with books stood at the window”. It is not possible to understand the attributive constructions: is the father of the brother and the brother of the father - is this the same person? The patient does not understand proverbs and metaphors.
Aphasia should be distinguished from other speech disorders that occur with brain lesions or functional disorders, such as dysarthria, dyslalia.
dysarthria - a complex concept that combines such speech disorders in which not only pronunciation suffers, but also tempo, expressiveness, fluency, modulation, voice and breathing. This violation may be due to central or peripheral paralysis of the muscles of the speech-motor apparatus, damage to the cerebellum, striopallidar system. Violations of perception of speech by hearing, reading and writing in this case most often do not occur. There are cerebellar, pallidar, striatal and bulbar dysarthria.
A speech disorder associated with impaired sound pronunciation is called dyslalia. It occurs, as a rule, in childhood (children “do not pronounce” certain sounds) and lends themselves to logopedic correction.
Alexia (from Greek. a- deny. particle and lexis- word) - a violation of the process of reading or mastering it in case of damage to various parts of the cortex of the dominant hemisphere (fields 39-40 according to Brodman). There are several forms of alexia. When the cortex of the occipital lobes is damaged due to a violation of the processes of visual perception in the brain, optical alexia, in which either letters (literal optical alexia) or whole words (verbal optical alexia) are not defined. With unilateral optical alexia, damage to the occipito-parietal parts of the right hemisphere, half of the text (usually the left one) is ignored, while the patient does not notice his defect. Due to a violation of phonemic hearing and sound-letter analysis of words, auditory (temporal) alexia as one of the manifestations of sensory aphasia. The defeat of the lower parts of the premotor cortex leads to a violation of the kinetic organization of the speech act and the appearance kinetic (efferent) motor alexia, included in the structure of the syndrome of efferent motor aphasia. When the cortex of the frontal lobes of the brain is damaged, regulatory mechanisms are violated and a special form of alexia occurs in the form of a violation of the purposeful nature of reading, turning off attention, and its pathological inertia.
Agraphia (from Greek. a- deny. particle and grapho- I write) - a violation characterized by a loss of the ability to write with sufficient preservation of the intellect and formed writing skills (field 9 according to Brodman). It can be manifested by a complete loss of the ability to write, a gross distortion of the spelling of words, omissions, an inability to connect letters and syllables. Aphatic agraphia occurs with aphasia and is caused by defects in phonemic hearing and auditory-speech memory. Apractical agraphia occurs with ideational aphasia, constructive- with constructive aphasia. Also stands out clean graphics, not associated with other syndromes and due to damage to the posterior sections of the second frontal gyrus of the dominant hemisphere.
Acalculia (from Greek. a- deny. particle and lat. calculation- counting, calculation) is described by S.E. Henschen in 1919. It is characterized by a violation of counting operations (fields 39-40 according to Brodmann). Primary acalculia as a symptom that does not depend on other disorders of higher mental functions, it is observed with damage to the parietal-occipital-temporal cortex of the dominant hemisphere and is a violation of the understanding of spatial relationships, difficulty in performing digital operations with the transition through
a dozen associated with the bit structure of numbers, the inability to distinguish between arithmetic signs. secondary acalculia can occur when the temporal regions are affected due to a violation of the oral count, the occipital regions due to the indistinguishability of numbers similar in writing, the prefrontal regions due to a violation of purposeful activity, planning and control of counting operations.
7.3. Features of the development of speech function in children in normal and pathological conditions
Normally, children acquire the ability to speak and understand speech addressed to them during the first 3 years of life. In the 1st year of life, speech develops from the so-called cooing to pronouncing syllables or simple words. In the 2nd year of life, a gradual accumulation of vocabulary occurs, and at about 18 months, children for the first time begin to pronounce combinations of two words related in meaning. This stage is a harbinger of children learning complex grammar rules, which, according to some linguists, are a basic characteristic of human languages. In the 3rd year, the child's vocabulary increases from ten to hundreds of words, the structure of sentences becomes more complicated - from phrases consisting of two words to complex sentences. By the age of 4, children have practically mastered all the basic rules of the language. The development of expressive speech lags behind impressive speech a little. The pronunciation of intelligible words requires accurate discrimination of speech sounds and perfect operation of motor systems under the control of hearing. The pure pronunciation of all the phonemes of a language improves over the years and not all children master it by the onset of school age. Individual inaccuracies in the pronunciation of some consonants, which generally do not reduce speech intelligibility, are considered more a sign of brain immaturity than speech disorders.
If a child with normal intelligence and hearing has damage to the speech areas of the cerebral hemispheres as a result of injuries or brain diseases in the first 3 years of life, then alalia - Absence or underdevelopment of speech. Alalia, like aphasia, can be divided into motor and sensory.
Alalia may be a clinical manifestation of a complex disorder of speech function, which is called general underdevelopment of speech(a form of speech pathology in children with normal hearing and primary intact intelligence, when the formation of all components of the speech system is disturbed).
7.4. Memory
In the most general sense, memory is the storage of information about a stimulus after its action has already ceased. There are four phases of memory processes: fixation, storage, reading and reproduction of the trace.
According to the duration, memory processes are divided into three categories:
1. instant memory- short-term imprinting of traces, lasting a few seconds.
2. short term memory- imprinting processes that last several minutes.
3. long term memory- long (perhaps throughout life) preservation of traces of memory (dates, events, names, etc.).
In addition, memory processes can be characterized in terms of their modality, i.e. types of analyzer systems. Accordingly, visual, auditory, tactile, motor, olfactory memory are distinguished. There is also affective or emotional memory, or memory for emotionally charged events. Various areas of the brain responsible for one or another type of memory have been identified (hippocampus, cingulate gyrus, anterior nuclei of the thalamus, mamillary bodies, septa, fornix, amygdala complex, hypothalamus), but, by and large, memory, like any complex mental process, is associated with the work of the whole brain, therefore, it is possible to speak of memory centers only conditionally.
There are various types of memory disorders, and the literature describes cases of not only weakening (hypomnesia) or complete loss of memory (amnesia), but also its pathological enhancement (hypermnesia).
Hypomnesia, or memory loss may have different origins. It can be associated with age-related changes, brain diseases, or be congenital. Such patients, as a rule, are characterized by the weakening of all types of memory. Memory impairment with the loss of the ability to retain and reproduce acquired knowledge is called amnesia.
With a lesion at the level of the limbic system, a so-called Korsakov's syndrome. Patients with Korsakov's syndrome have practically no memory for current events, for example, they greet the doctor several times, cannot remember what they did a few minutes ago, at the same time, these
patients relatively well preserved traces of long-term memory, they are able to remember the events of the distant past.
Similar conditions can occur with transient hypoxia of the brain, some intoxications (for example, with carbon monoxide poisoning). This memory loss is also called fixation amnesia. With a pronounced violation of the memorization of new facts and circumstances, amnestic disorientation develops in time, space of one's own personality. Another example of a peculiar temporal disturbance of all types of memory is global transient amnesia with transient ischemia in the vertebrobasilar basin.
A special group of memory disorders are the so-called pseudoamnesia(false memories) characteristic of patients with massive damage to the frontal lobes of the brain. The problems of memorizing the material in this case are connected not so much with the violation of the memory itself, but with the violation of purposeful memorization, since in these patients the process of forming intentions, plans, programs of behavior, i.e. the structure of any conscious mental activity suffers.
7.5. Syndromes of lesions of the cerebral cortex
Syndromes of damage to the cortex of the cerebral hemispheres include symptoms of loss of functions or irritation of the cortical centers of various analyzers (Table 13).
Table 13Syndromes of lesions of the cerebral cortex Frontal Lobe Syndromes
7.6. Violation of the HMF with damage to the cerebellum
Violation of the HMF in case of damage to the cerebellum is explained by the loss of its coordinating role in relation to various parts of the cerebrum. Cognitive disorders develop in the form of impaired working memory, attention, planning and control of actions, i.e. sequencing disorders. There are also visual-spatial disturbances, acoustic-mnestic aphasia, difficulties in counting, reading and writing, and even facial agnosia.
corpus callosum syndrome accompanied by mental disorders in the form of confusion, progressive dementia. Amnesia and confabulations (false memories), a feeling of "already seen", workload, apraxia, akinesia are noted. Disturbed orientation in space.
frontal callous syndrome characterized by akinesia, amimia, astasia-abasia, aspontaneity, reflexes of oral automatism, memory impairment, reduced criticism of one's state, grasping reflexes, apraxia, Korsakoff's syndrome, dementia.
Brodmann fields
- Fields 3, 1 and 2 - somatosensory area, primary zone. They are located in the postcentral gyrus. In connection with the generality of functions, the term " fields 3, 1 and 2» (front to back)
- Field 4 - motor area. Located within the precentral gyrus
- Field 5 - secondary somatosensory zone. Located within the superior parietal lobule
- Field 6 - premotor cortex and additional motor cortex (secondary motor zone). It is located in the anterior sections of the precentral and posterior sections of the superior and middle frontal gyri.
- Field 7 - tertiary zone. Located in the upper parts of the parietal lobe between the postcentral gyrus and the occipital lobe
- Field 8 - located in the posterior sections of the upper and middle frontal gyri. Includes the center of voluntary movements eyes
- Field 9 - dorsolateral prefrontal cortex
- Field 10 - anterior prefrontal cortex
- Field 11 - olfactory area
- Field 12 -
- Field 13 -
- Field 14 -
- Field 15 -
- Field 16 -
- Field 17 - nuclear zone of the visual analyzer - visual area, primary zone
- Field 18 - the nuclear zone of the visual analyzer - the center of perception of written speech, the secondary zone
- Field 19 - nuclear zone of the visual analyzer, secondary zone (assessment of the value of what was seen)
- Field 20 - inferior temporal gyrus (center of the vestibular analyzer, complex pattern recognition)
- Field 21 - middle temporal gyrus (center of the vestibular analyzer)
- Field 22 - sound analyzer nuclear zone
- Field 23 -
- Field 24 - error detector
- Field 25 -
- Field 26 -
- Field 27 -
- Field 28 - projection fields and associative zone of the olfactory system
- Field 29 -
- Field 30 -
- Field 31 -
- Field 32 - dorsal zone of the anterior cingulate cortex. Receptor area of emotional experiences.
- Field 33 -
- Field 34 -
- Field 35 -
- Field 36 -
- Field 37 - Acoustic-gnostic sensory center of speech. This field controls the labor processes of speech, is responsible for the understanding of speech. Face Recognition Center.
- Field 38 -
- Field 39 - angular gyrus, part of Wernicke's area (center of the visual analyzer of written speech)
- Field 40 - marginal gyrus, part of Wernicke's zone (motor analyzer of complex professional, labor and everyday skills)
- Field 41 - sound analyzer nuclear zone, primary zone
- Field 42 - sound analyzer core zone, secondary zone
- Field 43 - taste area
- Field 44 - Center Brock
- Field 45 - triangular part of the Brodmann field (musical motor center)
- Field 46 - motor analyzer of the combined turn of the head and eyes in different directions
- Field 47 - the nuclear zone of singing, its speech motor component
- Field 48 -
- Field 49 -
- Field 50 -
- Field 51 -
- Field 52 - the nuclear zone of the auditory analyzer, which is responsible for the spatial perception of sounds and speech
