The subcortical center of the auditory analyzer is located at. A- subcortical hearing centers

Subcortical centers are located above the diencephalon. Of these, the most important are the striated bodies, which consist of two nuclei: the caudate and the lenticular. The caudate nucleus is adjacent to the optic hillocks. It is separated from the lenticular nucleus by a bundle of white nerve fibers - an internal capsule. The lenticular core is divided into the outer part - the shell and the inner part - the pale ball.

The pallidus is the main motor center of the diencephalon. Its excitement causes strong contractions of the muscles of the neck, arms, trunk and legs, mainly on the opposite side. Overexcitation of the globus pallidus causes obsessive movements of the hands, mainly fingers, - athetosis, and the whole body - chorea. Chorea, or involuntary dance, occurs in children from 6 to 15 years old. The globus pallidus inhibits the red nucleus along centrifugal fibers, suppressing contractile tone. Therefore, turning off the pallidum leads to general stiffness, a sharp increase in muscle tone, a mask-like face, and a quiet monotonous speech. The pallidum clarifies the coordination of movements by participating in the performance of additional movements that contribute to the implementation of the main ones, for example, in fixing the joints, swinging the arms while walking, etc., and coordinates motor reflexes with autonomic functions.

The caudate nucleus and the shell of the lenticular nucleus along the centrifugal fibers inhibit the pallidum and stop the overproduction of movements (hyperkinesis) caused by its excitation. Therefore, their defeat causes hyperkinesis, athetosis and chorea. Centripetal fibers from the optic hillocks and cerebellum enter the caudate nucleus and the shell of the lenticular nucleus, which ensures their participation in the functions of these parts of the nervous system.

The motor nuclei of the striatum, visual hillocks, diencephalon and hypothalamic region and the red nucleus are part of the extra-pyramidal system, which, with the leading role of the pyramidal system, participates in the implementation of the most complex congenital motor acts associated with the activity of internal organs (food, sexual reflexes and others) and in changes in the position and movement of the body (labor and sports movements, walking, running, etc.). In each hemisphere, the limbic, or marginal, lobe of the cerebral hemispheres is closely connected with the listed formations of the brain stem, which, like the cingulate gyrus, encircles the corpus callosum in front and bends around the back, passing into the gyrus of the sea horse (hippocampus). Together with the fornix and amygdala, the limbic lobe constitutes the limbic system.

The limbic system is associated with the reticular formation of the brain stem and causes changes in body functions characteristic of emotions, the leading role in the implementation of which belongs to the frontal lobes.

Sensory system - a set of peripheral and central structures of the nervous system responsible for the perception of signals of various modalities from the surrounding or internal environment. The sensory system consists of receptors, neural pathways, and parts of the brain responsible for processing received signals. The most famous sensory systems are sight, hearing, touch, taste and smell. Through the sensory system, physical properties such as temperature, taste, sound or pressure can be sensed.

Analyzers are also called sensor systems. The notion "analyzer" was introduced by the Russian physiologist I. P. Pavlov. Analyzers (sensory systems) are a set of formations that perceive, transmit and analyze information from the surrounding and internal environment of the body.

An optobiological binocular (stereoscopic) system that evolved in animals and is capable of perceiving electromagnetic radiation of the visible spectrum (light), creating an image in the form of a sensation (sensory sense) of the position of objects in space. The visual system provides vision function.

The visual system (visual analyzer) in mammals includes the following anatomical structures:

· Peripheral paired organ of vision - the eye (with its light-perceiving photoreceptors - rods and cones of the retina);

Nerve structures and formations of the central nervous system: optic nerves, chiasm, optic tract, visual pathways - II pair of cranial nerves, oculomotor nerve - III pair, trochlear nerve - IV pair and abducens nerve - VI pair ;

· The lateral geniculate body of the diencephalon (with subcortical visual centers), anterior hillocks of the midbrain quadruple (primary visual centers);

· Subcortical (and brainstem) and cortical visual centers: the lateral geniculate body and cushions of the optic tubercle, the upper mounds of the roof of the midbrain (quadruple) and the visual cortex.

Human vision

The process of psychophysiological processing of the image of objects of the surrounding world, carried out by the visual system, and allows you to get an idea of \u200b\u200bthe size, shape (perspective) and color of objects, their relative position and distance between them. Due to the large number of stages in the process of visual perception, its individual characteristics are considered from the point of view of different sciences - optics (including biophysics), psychology, physiology, chemistry (biochemistry). At each stage of perception, distortions, errors, failures occur, but the human brain processes the information received and makes the necessary adjustments. These processes are unconscious and are implemented in a multi-level autonomous correction of distortions. In this way, spherical and chromatic aberrations, blind spot effects are eliminated, color correction is carried out, a stereoscopic image is formed, etc. In those cases when subconscious information processing is insufficient or excessive, optical illusions arise.

Auditory system

A sensory system that provides coding for acoustic stimuli and determines the ability of animals to navigate in the environment by assessing acoustic stimuli. The peripheral parts of the auditory system are represented by hearing organs and phonoreceptors lying in the inner ear. Based on the formation of sensory systems (auditory and visual), the nominative (nominative) function of speech is formed - the child associates objects and their names.

The human ear has three parts:

· The outer ear is the lateral part of the peripheral part of the auditory system of mammals, birds, some reptiles and individual species of amphibians [* 1]. In terrestrial mammals, it includes the auricle and the external auditory canal; it is separated from the middle ear by the eardrum. Sometimes the latter is considered as one of the structures of the outer ear.

The middle ear is a part of the auditory system of mammals (including humans) that has developed from the bones of the lower jaw and provides the transformation of air vibrations into vibrations of the fluid that fills the inner ear. The main part of the middle ear is the tympanic cavity - a small space with a volume of about 1 cm³ located in the temporal bone. There are three auditory ossicles: the malleus, incus and stapes - they transmit sound vibrations from the outer ear to the inner ear, while amplifying them.

· The inner ear is one of the three divisions of the organ of hearing and balance. It is the most complex section of the hearing organs, because of its intricate shape it is called a labyrinth.

Midbrain (mesencephalon)(Fig. 4.4.1, 4.1.24) develops in the process of phylogenesis under the predominant influence of the visual receptor. For this reason, its formations are related to the innervation of the eye. Here, centers of hearing were formed, which, together with the centers of vision, subsequently grew in the form of four mounds of the roof of the midbrain. With the appearance of the cortical end of the auditory and visual analyzers in higher animals and humans, the auditory and visual centers of the midbrain fell into a subordinate position. Moreover, they became intermediate, subcortical.

With the development of the forebrain in higher mammals and humans through the midbrain, the pathways connecting the cerebral cortex with the spinal cord began to pass

through the legs of the brain. As a result, the human midbrain contains:

1. Subcortical centers of vision and nerve nuclei
Islands, innervating the muscles of the eye.

2. Subcortical auditory centers.

3. All upstream and downstream navigating
pathways connecting the cerebral cortex
with the spinal cord.

4. Beams of white matter binding
midbrain with other parts of the central
nervous system.

Accordingly, the midbrain has two main parts: the roof of the midbrain (tectum mesencephalicum),where are the subcortical centers of hearing and vision, and the legs of the brain (cms cerebri),where the conducting paths mainly pass.

1. The roof of the midbrain (Fig. 4.1.24) is hidden under the posterior end of the corpus callosum and is subdivided by two criss-crossing grooves - longitudinal and transverse - into four mounds, located in pairs.

Top two mounds (colliculi superiores)are the subcortical centers of vision, both lower (colliculi inferiores)- subcortical

Figure: 4.1.24. Stem part of the brain, including the midbrain (mesencephalon),hindbrain

(metencephalon)and medulla oblongata (myelencephalon):

a- front view (/ - motor root of the trigeminal nerve; 2 - sensitive root of the trigeminal nerve; 3 - Basal groove of the bridge; 4 - vestibular cochlear nerve; 5 - facial nerve; 6 - ventrolateral groove of the medulla oblongata; 7 - olive; 8 - circummolivary bundle; 9 - pyramid of the medulla oblongata; 10 - anterior median fissure; // - cross of pyramidal fibers); b - rear view (/ - pineal gland; 2 - the upper tubercles of the quadruple; 3 - the lower tubercles of the quadruple; 4 - diamond-shaped fossa; 5 - the knee of the facial nerve; 6 - the median fissure of the rhomboid fossa; 7 - the upper leg of the cerebellum; 8 - the middle leg of the cerebellum; 9 - the lower leg of the cerebellum; 10 - the vestibular region; // - triangle of the hypoglossal nerve; 12 - triangle of the vagus nerve; 13 - tubercle of the wedge-shaped bundle; 14 - tubercle of the tender nucleus; / 5 - median groove)

cotton wool

centers of hearing. The pineal gland lies in the flat groove between the upper tubercles. Each mound turns into the so-called knoll handle (brachium colliculum),heading laterally, anteriorly and upward to the diencephalon. Upper mound handle (brachium colliculum superiores)goes under the cushion of the optic hillock to the lateral geniculate body (corpus geniculatum laterale).Lower knob (brachium colliculum inferiores),passing along the top edge trigo-pete lemniscibefore sulcus lateralis mesencephali,disappears under the medial geniculate body (corpus geniculatum mediale).The named geniculate bodies already belong to the diencephalon.

2. Legs of the brain (pedunculi cerebri)contain
all pathways to the forebrain.
The legs of the brain look like two thick semicircles
lindrical white strands that diverge
from the edge of the bridge at an angle and plunge into
the thickness of the cerebral hemispheres.

3. The cavity of the midbrain, which is the wasp
the primary cavity of the midbrain
bubble, looks like a narrow channel and is called
plumbing brain (aqueductus cerebri).is he
presents a narrow, lined with ependyma ka
cash 1.5-2.0 cmlength connecting III and IV
ventricles. Restrict the water supply dorsally
the roof of the midbrain, and ventrally -
the lining of the legs of the brain.

On a cross-section of the midbrain, three main parts are distinguished:

1. Roof plate (lamina tecti).

2. Tire (tegmentum),representing
upper part of the legs of the brain.

3. Ventral part of the legs of the brain, or wasps
new brain stem (basis pedunculi cerebri).
According to the development of the midbrain under
the influence of the visual receptor in it
different kernels related to
nerves of the eye (Fig. 4.1.25).

The aqueduct of the brain is surrounded by a central gray matter, which in its function is related to the autonomic system. In it, under the ventral wall of the aqueduct, in the lid of the brain stem, the nuclei of two motor cranial nerves are laid - n. oculomotorius(III pair) at the level of the upper colliculus and n. trochlearis(IV pair) at the level of the lower colliculus. The nucleus of the oculomotor nerve consists of several sections, respectively, of the innervation of several muscles of the eyeball. A small, also paired, vegetative accessory nucleus is placed medially and posterior to it (nucleus accessorius)and unpaired median nucleus.

Accessory nucleus and unpaired median nucleus innervate the involuntary muscles of the eye (i.e. ciliaris, etc. sphincter pupillae).Above (rostral) the nucleus of the oculomotor nerve in the operculum of the brain stem is the nucleus of the medial longitudinal bundle.

Figure: 4.1.25. The nuclei and connections of the midbrain and its trunk (by Leigh, Zee, 1991):

1 - lower tubercles; 2 - the intermediate core of Kahal; 3 - medial longitudinal bundle; 4 - reticular formation of the medulla oblongata; 5 - the core of Darkshevich; 6 - n. perihypoglos-sal; 7- rostral intermediate medial longitudinal fasciculus; 8 -upper tubercles; 9 -paramedian reticular formation of the bridge; III, IV, VI - cranial nerves

Lateral to the aqueduct of the brain is the nucleus of the midcerebral tract of the trigeminal nerve (nucleus mesencephalicus n. trigemini).

Between the base of the brain stem (basis pedunculi cerebralis)and tire (tegmentum)black matter is located (substantia nigra).In the cytoplasm of the neurons of this substance, a pigment is found - melanin.

From the lining of the midbrain (tegmentum mesencephali)the central tire path departs (tractus tegmentalis centralis).It is a projection descending pathway that contains fibers coming from the optic tubercle, pallidus, red nucleus, as well as the reticular formation of the midbrain in the direction of the reticular formation and the olive of the medulla oblongata. These fibers and nuclear formations belong to the extrapyramidal system. Functionally, the substantia nigra also belongs to the extrapyramidal system.

The base of the cerebral peduncle located ventrally from the substantia nigra contains longitudinal nerve fibers that descend from the cerebral cortex to all the underlying parts of the central nervous system (tractus corticopontinus, corticonuclearis, cortico-spinalisand etc.). The tire located dorsally from the black matter contains predominantly

Brain anatomy

Kernel VI - ^

VI nerve

ascending fibers, including the medial and lateral loops. As part of these loops, all sensory pathways, with the exception of the visual and olfactory pathways, ascend to the large brain.

Among the gray matter nuclei, the most significant nucleus is the red nucleus (nucleus ruber).This elongated formation extends in the tectum of the peduncle from the hypothalamus of the diencephalon to the lower colliculus, where an important descending path begins from it. (tractus rubrospinalis),connecting the red nucleus with the anterior horns of the spinal cord. The bundle of nerve fibers, after leaving the red nucleus, intersects with a similar bundle of fibers of the opposite side in the ventral part of the median suture - the ventral intersection of the tire. The red nucleus is a very important focal point of the extrapyramidal system. Fibers from the cerebellum pass to it, after they cross under the roof of the midbrain. Thanks to these connections, the cerebellum and the extrapyramidal system, through the red nucleus and the red-nuclear-spinal tract extending from it, affect the entire striated muscles.

The reticular formation also continues into the lining of the midbrain. (formatio reticularis)and a longitudinal medial bundle. The structure of the reticular formation is described somewhat below. It is worth dwelling in more detail on the medial longitudinal bundle, which is of great importance in the functioning of the visual system.

Medial longitudinal fasciculus(fasciculus longitudinalis medialis).The medial longitudinal bundle consists of fibers coming from the nuclei of the brain at various levels. It extends from the rostral part of the midbrain to the spinal cord. At all levels, the bundle is located near the midline and several ventral Sylvian aqueduct, the fourth ventricle. Below the level of the nucleus of the abducent nerve, most of the fibers are descending, and above this level, ascending fibers predominate.

The medial longitudinal bundle connects the nuclei of the oculomotor, block and abducens nerves (Fig. 4.1.26).

The medial longitudinal bundle coordinates the activity of the motor and four vestibular nuclei. It also provides intersegmental integration of movements associated with vision and hearing.

Through the vestibular nuclei, the medial bundle has extensive connections with the clumpy-nodular lobe of the cerebellum (lobus flocculonodu-laris),in which the coordination of the complex functions of eight cranial and spinal nerves (visual, oculomotor, block, trigeminal, abducens,

Figure: 4.1.26. The connection between the nuclei of the oculomotor, block and abducens nerves using the medial longitudinal bundle

facial, vestibular cochlear nerves).

Descending fibers form mainly in the medial vestibular nucleus (nucleus vestibularis medialis),the reticular formation, the upper mounds of the quadruple and the intermediate nucleus of Kahal.

Descending fibers from the medial vestibular nucleus (crossed and non-crossed) provide monosynaptic inhibition of the upper cervical neurons in the labyrinthine regulation of the position of the head relative to the body.

Ascending fibers emanate from the vestibular nuclei. They are projected onto the nuclei of the oculomotor nerves. The projection from the superior vestibular nucleus passes in the medial longitudinal fascicle to the block and dorsal oculomotor nucleus from the same side (neurons of the motor of the inferior rectus muscle of the eye).

Ventral parts of the lateral vestibular nucleus (nucleus vestibularis lateralis)are projected onto the opposite nuclei of the abducens and trochlear nerves, as well as part of the nuclei of the oculomotor complex.

The interconnections of the medial longitudinal bundle are the axons of intercalary neurons in the nuclei of the oculomotor and abducens nerves. The intersection of the fibers occurs at the level of the abducens nerve nucleus. There is also a bilateral projection of the oculomotor nucleus onto the nucleus of the abducens nerve.

The intercalary neurons of the oculomotor nerves and the neurons of the superior hillocks of the quadruple are projected onto the reticular formation. The latter, in turn, are projected onto the cerebellar worm. In the reticular

Chapter 4. BRAIN AND EYE

The formation is switching fibers going from the supranuclear structures to the cerebral cortex.

Abducens internuclear neurons are projected mainly on the contralateral oculomotor neurons of the inner and lower rectus muscles.

Upper hillocks (mounds) of the quadruple(collicilus superior)(Fig. 4.1.24-4.1.27).

The upper mounds of the quadruple are two rounded elevations located on the dorsal surface of the midbrain. They are separated from each other by a vertical groove containing the pineal gland. A transverse groove separates the upper mounds from the lower mounds. Above the upper hillocks is the visual hillock. Above the midline lies a large vein in the brain.

The upper mounds of the quadruple have a multi-layered cellular structure (see "The visual pathway"). Numerous nerve tracts approach and exit from them.

Each mound receives an accurate topographic projection of the retina (Fig. 4.1.27). The dorsal part of the quadruple is more sensory. It is projected onto the lateral geniculate body and the pillow.

Hillock pillow

Pretext area

Figure: 4.1.27. Schematic representation of the main connections of the upper tubercles of the quadruple

The ventral part is motor and is projected onto the motor subthalamic regions and the brain stem.

The superficial layers of the quadruple carry out the processing of visual information and, together with the deep layers, provide the orientation of the head and eyes in the process of determining new visual stimuli.

Stimulation of the upper mounds in a monkey induces saccadic movements, the amplitude and direction of which depend on the location of the stimulus. Vertical saccades occur with bilateral stimulation.

Surface cells respond to stationary and moving visual stimuli. Deep cells are usually excited before the saccade.

A third type of cell combines information about the position of the eye with information from the retina. Thanks to this, the required position of the eye relative to the head is monitored and specified. This signal is used to

playing a saccade, the direction of which is directed towards the visual goal. Surface and deep layers can function independently.

The lower mounds are part of the auditory pathway.

The lining of the midbrain is located anterior or ventral of the mounds. In the longitudinal direction, between the roof and the lining of the midbrain, the Sylvian aqueduct runs. The lining of the midbrain contains numerous descending and ascending fibers related to the somatosensory and motor systems. In addition, the cover contains several nuclear groups, among which the nuclei IIIand IV pairs of cranial nerves, red nucleus, as well as an accumulation of neurons related to the reticular formation. The lining of the midbrain is considered as the central accumulation of motor and reticular fibers that run from the diencephalon to the medulla oblongata.

Ventral or anterior to the lining of the midbrain is a large paired bundle of fibers - the brain stem, which contains mainly thick descending motor fibers originating in the cerebral cortex. They transmit motor efferent impulses from the cortex to the nuclei of the cranial nerves and the nuclei of the pons. (tractus corticobulbaris sen corticinuclearis),as well as to the motor nuclei of the spinal cord (tractus corticispinalis).Between these important bundles of fibers on the anterior surface of the midbrain and its tectum is a large nucleus of pigmented nerve cells containing melanin.

The pretectal region receives the adductor fibers from the optic tract (see Fig. 4.1.27). It also receives the occipital and frontal corticotectal fibers to aid vertical gaze, vergent eye movement and accommodation. The neurons in this area selectively respond to visual information, taking into account the change in the localization of the object image on both retinas.

The pretectal region also contains synapses of the pupillary reflex. Some of the efferent fibers intersect in the gray matter area around the sylvian aqueduct. The fibers are directed to the small cell nuclei of the oculomotor nerve, which controls the pupillomotor fibers.

It is also necessary to point out the presence of three tectal pathways of great functional importance. This is the lateral spinnothalamic pathway. (tractus spinothalamicus late-ralis),medial lemniscal path (medial lemniscus; lemniscus medialis)and medial

Brain anatomy

Ny longitudinal bundle. The lateral spinal thalamic pathway carries afferent pain fibers and is located in the tectum of the midbrain outside. The medial lemniscus provides sensory and tactile information as well as body position information. It is located medially in the pons but displaced laterally in the midbrain. It is a continuation of the medial loops. Lemniscus connects the thin and wedge-shaped nuclei with the nuclei of the optic hillock.

The second neuron begins from the auditory nuclei in the medulla oblongata. Some of the nerve fibers from the nuclei go along the side of the same name, and most of them go to the opposite side. Further, the fibers reach the olive of the medulla oblongata, from where the third neuron begins. The fibers of the third neuron end in the subcortical auditory centers - the posterior colliculus and the internal geniculate body. From here begins the last, fourth, neuron of the auditory pathway, ending at the cortical end of the auditory analyzer - the temporal lobe of the brain.

1.4. Central, or cortical, section of the auditory analyzer

The central end of the auditory analyzer is located in the cortex of the upper temporal lobe of each of the cerebral hemispheres (in the auditory cortex). Of particular importance in the perception of sound stimuli are, apparently, the transverse temporal convolutions, or the so-called Heschl convolutions. As already mentioned, in the medulla oblongata, there is a partial crossing of nerve fibers connecting the peripheral section of the auditory analyzer with its central section. Thus, the cortical center of hearing of one hemisphere is connected to the peripheral receptors (organs of Corti) on both sides. Conversely, each organ of Corti is associated with both cortical hearing centers (bilateral representation in the cerebral cortex).

The doctrine of the cytoarchitectonics of the cerebral cortex corresponds to the doctrine of I.P. Pavlova about the cortex as a system of cortical ends of analyzers. The analyzer, according to Pavlov, "is a complex nervous mechanism that begins with the external perceiving apparatus and ends in the brain." The analyzer consists of three parts - the external perceiving apparatus (sensory organ), the conductive part (pathways of the brain and spinal cord) and the final cortical end (center ) in the cerebral cortex of the telencephalon. According to Pavlov, the cortical end of the analyzer consists of a "core" and "scattered elements."

Analyzer core according to structural and functional features, they are divided into the central field of the nuclear zone and the peripheral. In the first, finely differentiated sensations are formed, and in the second, more complex forms of reflection of the external world.

Trace elementsare those neurons that are outside the nucleus and perform simpler functions.

On the basis of morphological and experimental-physiological data in the cerebral cortex, the most important cortical ends of the analyzers (centers), which through interaction provide the functions of the brain, were identified.

The localization of the cores of the main analyzers is as follows:

Cortical end of the motor analyzer (precentral gyrus, precentral lobule, posterior part of the middle and inferior frontal gyrus). The precentral gyrus and the anterior part of the pericentral lobule are part of the precentral region - the motor or motor zone of the cortex (cytoarchitectonic fields 4, 6). In the upper part of the precentral gyrus and the precentral lobule are the motor nuclei of the lower half of the body, and in the lower part - the upper one. The largest area of \u200b\u200bthe entire zone is occupied by the centers of innervation of the hand, face, lips, tongue, and a smaller area, the centers of innervation of the muscles of the trunk and lower extremities. Previously, this area was considered only motor, but now it is considered the area in which the insertion and motor neurons are located. Interneurons perceive stimulation from proprioceptors in bones, joints, muscles, and tendons. The centers of the motor zone provide innervation to the opposite part of the body. Dysfunction of the precentral gyrus leads to paralysis on the opposite side of the body.

The core of the motor analyzer of the combined rotation of the head and eyes in the opposite direction, as well as Motor nuclei of written speech - graphs related to arbitrary movements associated with writing letters, numbers and other signs are localized in the posterior part of the middle frontal gyrus (field 8) and at the border of the parietal and occipital lobes (field 19) ... The center of the graphy is closely connected with field 40, located in the supra-marginal gyrus. If this area is damaged, the patient cannot make the movements that are necessary to draw letters.

Premotor zone located anterior to the motor areas of the cortex (fields 6 and 8). The processes of the cells of this zone are associated both with the nuclei of the anterior horns of the spinal cord, and with the subcortical nuclei, the red nucleus, the substantia nigra, etc.

The core of the motor analyzer of speech articulation (speech-motor analyzer) are located in the posterior part of the inferior frontal gyrus (field 44, 45, 45a). In field 44 - Broca's zone, in right-handers - in the left hemisphere, the analysis of stimuli from the motor apparatus is carried out, through which syllables, words, phrases are formed. This center was formed next to the projection area of \u200b\u200bthe motor analyzer for the muscles of the lips, tongue, larynx. When he is defeated, a person is able to pronounce separate speech sounds, but he loses the ability to form words from these sounds (motor or motor aphasia). In the case of damage to field 45, it is observed: agrammatism - the patient loses the ability to make sentences out of words, to coordinate words into sentences.

Cortical end of the motor analyzer of complex coordinated movements in right-handers, it is located in the inferior parietal lobe (field 40) in the region of the supra-marginal gyrus. When field 40 is affected, the patient, despite the absence of paralysis, loses the ability to use household items, loses production skills, which is called apraxia.

Cortical end of general sensitivity skin analyzer - temperature, pain, tactile, musculo-articular - located in the postcentral gyrus (fields 1, 2, 3, 5). Violation of this analyzer results in loss of sensitivity. The sequence of the centers' location and their territory corresponds to the motor cortex zone.

Cortical end of the auditory analyzer (field 41) is placed in the middle of the superior temporal gyrus.

Auditory Speech Analyzer (control of one's speech and perception of someone else's) is located in the posterior part of the superior temporal gyrus (field 42) (Wernicke's zone_ when it is violated, a person hears speech, but does not understand it (sensory aphasia)

Cortical end of the visual analyzer (fields 17, 18, 19) occupies the edges of the spur sulcus (field 17), complete blindness occurs with bilateral damage to the nuclei of the visual analyzer. In cases of damage to fields 17 and 18, loss of visual memory is observed. When the field is damaged, 19 people lose the ability to orient themselves in a new environment.

Visual analyzer of written signs located in the angular gyrus of the inferior parietal lobe (field 39s). When this field is damaged, the patient loses the ability to analyze the written letters, that is, loses the ability to read (alexia)

Cortical ends of the olfactory analyzer are located in the hook of the parahippocampal gyrus on the lower surface of the temporal lobe and hippocampus.

Cortical ends of the taste analyzer - in the lower part of the postcentral gyrus.

Cortical end of the stereognostic sense analyzer - the center of a particularly complex type of recognition of objects by touch is in the upper parietal lobe (field 7). When the parietal lobe is damaged, the patient cannot recognize the object by feeling it with the hand opposite to the lesion focus - stereognosy. Distinguish auditory gnosia - recognition of objects by sound (bird - by voice, car - by engine noise), visual gnosia - recognition of objects by type, etc. Praxia and gnosia are functions of a higher order, the implementation of which is associated with both the first and the second signaling system, which is a specific function of a person.

Any function is localized not in one specific field, but only predominantly associated with it and spreads over a large extent.

Speech- is one of the phylogenetically new and most complexly localized functions of the cortex, associated with the second signaling system, according to I.P. Pavlov. Speech appeared in the course of human social development, as a result of labor activity. "... First, labor, and then with it articulate speech were the two most important stimuli, under the influence of which the monkey's brain gradually turned into a human brain, which, with all its resemblance to monkeys, far surpasses it in size and perfection" ( K. Marx, F. Engels)

The function of speech is extremely complex. It cannot be localized in any part of the cortex; the entire cortex is involved in its implementation, namely, neurons with short processes located in its surface layers. With the development of new experience, speech functions can move to other areas of the cortex, like gesticulation of the deaf and dumb, reading of the blind, writing with a foot in the armless. It is known that in most people - right-handers - speech functions, functions of recognition (gnosia), purposeful action (praxia) are associated with certain cytoarchitectonic fields of the left hemisphere, in left-handers - the opposite.

Associative zones of the cortex occupy the rest of the significant part of the cortex, they are devoid of explicit specialization, are responsible for the integration and processing of information and programmed action. The associative cortex is the basis of higher processes like memory, learning, thinking, speech.

There are no thought-generating zones. To make the smallest decision, the entire brain is involved, various processes take place in different zones of the cortex and in the lower nerve centers.

The cerebral cortex receives information, processes it and stores it in memory. In the process of adaptation (adaptation) of the organism to the external environment, complex systems of self-regulation, stabilization were formed in the cortex, providing a certain level of function, self-learning systems with a memory code, control systems operating on the basis of the genetic code, taking into account age and providing an optimal level of control and functions in the body , comparison systems that ensure the transition from one form of management to another.

Connections between the cortical ends of one or another analyzer with peripheral regions (receptors) are carried out by the system of the pathways of the brain and spinal cord and peripheral nerves extending from them (cranial and spinal nerves).

Subcortical nuclei.The bases of the telencephalon are located in the white matter and form three paired clusters of gray matter: striatum, amygdala and hedge, which make up approximately 3% of the volume of the hemispheres.

Striped bodieso consists of two nuclei: caudate and lenticular.

Caudate nucleus is located in the frontal lobe and is a formation in the form of an arc lying on top of the optic tubercle and lenticular nucleus. It consists of head, body and tail, which take part in the formation of the lateral part of the wall of the anterior horn of the lateral ventricle of the brain.

Lenticular kernel a large pyramidal accumulation of gray matter, located outwards from the caudate nucleus. The lenticular core is divided into three parts: the outer, dark-colored - shell and two light medial stripes - external and internal segments pallidum.

From each other caudate and lenticular nuclei separated by a layer of white matter - part inner capsule... Another part of the inner capsule separates the lenticular nucleus from the underlying thalamus.

The striated body forms striopallidal system, in which the phylogenetically more ancient structure is the globus pallidus - pallidum... It is isolated as an independent morpho-functional unit that performs a motor function. Thanks to connections with the red nucleus and the black matter of the midbrain, the pallidum realizes the movements of the trunk and arms when walking - cross-coordination, a number of auxiliary movements when changing body positions, facial movements. The destruction of the globus pallidus causes muscle rigidity.

Caudate nucleus and shell younger structures of the striatum - striatum, which does not directly have a motor function, but performs a controlling function in relation to the pallidum, somewhat inhibiting its influence.

With the defeat of the caudate nucleus in humans, rhythmic involuntary movements of the limbs (Huntington's chorea) are observed, with degeneration of the shell - trembling of the limbs (Parkinson's disease).

Fence- a relatively thin strip of gray matter located between the crust of the islet, separated from it by white matter - outer capsule and the shell from which it separates outer capsule... The fence is a complex formation, the connections of which have so far been little studied, and the functional significance is not clear.

Amygdala - a large nucleus, located under the shell in the depths of the anterior temporal lobe, has a complex structure and consists of several nuclei, differing in cellular composition. The amygdala is the subcortical olfactory center and is part of the limbic system.

The subcortical nuclei of the telencephalon function in close relationship with the cerebral cortex, diencephalon and other parts of the brain, and take part in the formation of both conditioned and unconditioned reflexes.

Together with the red nucleus, the black matter of the midbrain, the thalamus of the diencephalon, the subcortical nuclei form extrapyramidal system, carrying out complex unconditioned reflex motor acts.

Olfactory brain human is the most ancient part of the telencephalon, which arose in connection with the olfactory receptors. It is divided into two sections: peripheral and central.

To the peripheral department include: the olfactory bulb, the olfactory tract, the olfactory triangle, and the anterior perforation.

Part central departmentbut includes: vaulted gyrus, consisting of cingulate gyrus, isthmus and parahippocampal gyrus, and hippocampus - a peculiarly shaped formation located in the cavity of the lower horn of the lateral ventricle and dentate gyruslying inside the hippocampus.

Limbic system (border, edge) is so named because the cortical structures included in it are located at the edge of the neocortex and, as it were, border the brain stem. The limbic system includes both certain zones of the cortex (archipaleocortical and interstitial areas) and subcortical formations.

Of the cortical structures, these are: hippocampus with dentate gyrus(old bark), cingulate gyrus (the limbic cortex, which is intermediate), olfactory cortex, septum (ancient crust).

From subcortical structures: mammillary body of the hypothalamus, anterior nucleus of the thalamus, amygdala complex, and vault.

In addition to the numerous two-way connections between the structures of the limbic system, there are long paths in the form of closed circles through which the circulation of excitement occurs. The large limbic circle - peypets circle includes: hippocampus, vault, mammillary body, mastoid-thalamic bundle (bunch of Vic d "Azira), anterior nucleus of the thalamus, cingulate cortex, hippocampus... Of the overlying structures, the limbic system has the closest connections with the frontal cortex. The limbic system directs its descending paths to the reticular formation of the brain stem and to the hypothalamus.

Through the hypothalamic-pituitary system, it exercises control over the humoral system. The limbic system is characterized by a special sensitivity and a special role in the functioning of hormones synthesized in the hypothalamus oxytocin and vasopresin, secreted by the pituitary gland.

The main integral function of the limbic system is not only the olfactory function, but also the reactions, the so-called innate behavior (food, sexual, search and defensive). It carries out the synthesis of afferent stimuli, is important in the processes of emotional-motivational behavior, organizes and ensures the flow of vegetative, somatic and mental processes during emotional-motivational activity, carries out the perception and storage of emotionally significant information, the choice and implementation of adaptive forms of emotional behavior.

So, the functions of the hippocampus are associated with memory, learning, the formation of new behavioral programs when conditions change, in the formation of emotional states. The hippocampus has extensive connections with the cerebral cortex and the hypothalamus of the diencephalon. In the mentally ill, all layers of the hippocampus are affected.

At the same time, each structure that is part of the limbic system contributes to a single mechanism, having its own functional characteristics.

Anterior limbic cortexprovides emotional expressiveness of speech.

Cingulate gyrustakes part in the reactions of alertness, awakening, emotional activity. It is connected by fibers to the reticular formation and the autonomic nervous system.

Almond complex is responsible for eating and defensive behavior, stimulation of the amygdala causes aggressive behavior.

Partitiontakes part in retraining, reduces aggressiveness and fear.

Mamillary bodies play a large role in the development of spatial skills.

Anterior to the vault the centers of pleasure and pain are located in its various departments.

Lateral ventricles are the cavities of the cerebral hemispheres. Each ventricle has a central part adjacent to the upper surface of the optic tubercle in the parietal lobe and three horns extending from it.

Front horn recedes into the frontal lobe, rear horn - into the occipital lobe, the lower horn - into the depth of the temporal lobe. In the lower horn there is an elevation of the inner and partly the lower wall - the hippocampus. The medial wall of each anterior horn is a thin transparent plate. The right and left plates form a common transparent septum between the anterior horns.

The lateral ventricles, like all the ventricles of the brain, are filled with cerebral fluid. Through the interventricular openings, which are in front of the optic hillocks, the lateral ventricles communicate with the third ventricle of the diencephalon. Most of the walls of the lateral ventricles are formed by the white matter of the cerebral hemispheres.

White matter of the telencephalon.Formed by fibers of the pathways, which are grouped into three systems: associative or combination, commissural or adhesive and projection.

Associative fibers the telencephalon connect different parts of the cortex within the same hemisphere. They are divided into short fibers lying superficially and arcuate, connecting the cortex of two adjacent gyri and long fibers lying deeper and connecting parts of the cortex distant from each other. These include:

1) Belt, which can be traced from the anterior perforated substance to the gyrus of the hippocampus and connects the cortex of the gyrus of the medial part of the hemisphere surface - refers to the olfactory brain.

2) Lower longitudinal bundle connects the occipital lobe with the temporal lobe, runs along the outer wall of the posterior and lower horns of the lateral ventricle.

3) Upper longitudinal bundle connects the frontal, parietal and temporal lobes.

4) Hooked bunch connects the rectus and orbital gyrus of the frontal lobe with the temporal.

Commissural nerve pathways connect the areas of the cortex of both hemispheres. They form the following commissures or adhesions:

1) Corpus callosum the largest commissure, which connects different parts of the neocortex of both hemispheres. In humans, it is much higher than in animals. In the corpus callosum, the front end curved downward (beak) is distinguished - the knee of the corpus callosum, the middle part - the trunk of the corpus callosum and the thickened posterior end - the corpus callosum ridge. The entire surface of the corpus callosum is covered with a thin layer of gray matter - a gray vestment.

In women, more fibers pass in a certain area of \u200b\u200bthe corpus callosum than in men. Thus, interhemispheric connections in women are more numerous, in this regard, they have a better integration of information available in both hemispheres, and this explains gender differences in behavior.

2) Anterior corpus callosumlocated behind the beak of the corpus callosum and consists of two bundles; one connects the anterior perforated substance, and the other connects the gyrus of the temporal lobe, mainly the hippocampal gyrus.

3) Spike arch connects the central parts of two arcuate bundles of nerve fibers, which form a vault located under the corpus callosum. In the vault, a central part is distinguished - the columns of the vault and the legs of the vault. The pillars of the vault connect a triangular plate - the vault adhesion, the posterior part of which is spliced \u200b\u200bwith the lower surface of the corpus callosum. The pillars of the fornix, bending backward, enter the hypothalamus and end in the nipple-shaped bodies.

Projection pathways connect the cortex of the cerebral hemispheres with the nuclei of the brain stem and spinal cord. Distinguish: efferent - descending motor pathways that conduct nerve impulses from the cells of the motor areas of the cortex to the subcortical nuclei, motor nuclei of the brain stem and spinal cord. Thanks to these pathways, the motor centers of the cerebral cortex are projected onto the periphery. Afferent - the ascending sensory pathways are the processes of the cells of the spinal ganglia and the ganglion of the cranial nerves - these are the first neurons of the sensory pathways that terminate in the switching nuclei of the spinal cord or medulla oblongata, where the second neurons of the sensory pathways are located, going as part of the medial loop to the ventral nuclei of the thalamus. These nuclei contain the third neurons of the sensory pathways, the processes of which go to the corresponding nuclear centers of the cortex.

Both sensory and motor pathways form a system of radially diverging beams in the material of the cerebral hemispheres - a radiant crown, gathering in a compact and powerful beam - an internal capsule that is located between the caudate and lenticular nuclei, on the one hand, and the thalamus, on the other hand. It distinguishes between the front leg, the knee and the back leg.

The pathways of the brain and these are the spinal pathways.

The meninges of the brain.The brain, as well as the spinal cord, is covered with three membranes - hard, arachnoid and vascular.

Hard shelland the brain differs from that of the spinal cord in that it is spliced \u200b\u200bwith the inner surface of the skull bones, there is no epidural space. The dura mater forms channels for the outflow of venous blood from the brain - the sinuses of the dura mater and gives out processes that ensure the fixation of the brain - this is the crescent of the cerebrum (between the right and left hemispheres of the brain), the outline of the cerebellum (between the occipital lobes and the cerebellum) and the saddle diaphragm (above Turkish saddle, in which the pituitary gland is located). In the places of origin of the processes, the dura mater exfoliates, forming sinuses, where the venous blood of the brain, dura mater, and skull bones flows into the system of external veins through the graduates.

Arachnoidof the brain is located under the solid and covers the brain, without going into its furrows, spreading over them in the form of bridges. On its surface there are outgrowths - pachyon granulations, which have complex functions. Between the arachnoid and the choroid, a subarachnoid space is formed, well expressed in the cisterns, which are formed between the cerebellum and the medulla oblongata, between the cerebral peduncles, in the region of the lateral groove. The subarachnoid space of the brain communicates with those of the spinal cord and the fourth ventricle and is filled with circulating cerebral fluid.

Choroid the brain consists of 2 plates, between which are located arteries and veins. It is closely intertwined with the substance of the brain and enters all the cracks and grooves and participates in the formation of vascular plexuses, rich in blood vessels. Penetrating into the ventricles of the brain, the choroid produce cerebral fluid, thanks to its vascular plexus.

Lymphatic vessels in the membranes of the brain are not found.

The innervation of the membranes of the brain is carried out by V, X, XII pairs of cranial nerves and the sympathetic nerve plexus of the internal carotid and vertebral arteries.