Terminal brain. Furrows and convolutions of the brain superolateral surface Furrows and convolutions are present in the midbrain

Furrows and gyrus of the brain superolateral surface

1 . Lateral furrow, sulcus lateralis (Sylvian furrow).
2 . Tire part, pars opercularis,
frontal tire, operculum frontale.
3 . Triangular part, pars triangularis.

4 . Orbital part, pars orbitalis.
5 . Inferior frontal gyrus, gyrus frontalis inferior.
6 . Inferior frontal sulcus, suicus frontalis inferior.
7 . Superior frontal sulcus, suicus frontalis superior.

8 . Middle frontal gyrus, gyrus frontalis medius.
9 . Superior frontal gyrus, gyrus frontalis superior.
10 . Lower precentral sulcus, sulcus precentralis inferior.
11 . Precentral gyrus, gyrus precentralis (anterior).
12 . Superior precentral sulcus, sulcus precentralis superior.
13 . Central sulcus, sulcus centralis (Roland's sulcus).
14 . Postcentral gyrus, gyrus postcentralis (gyrus centralis posterior).
15 . Intraparietal sulcus, sulcus intraparietalis.
16 . Upper parietal lobule, lobulus parietalis superior.
17 . Lower parietal lobule, lobulus parietalis inferior.
18 . Supramarginal gyrus, gyrus supramarginalis.
19 . Angular gyrus, gyrus angularis.
20 . Occipital pole, polus occipitalis.
21 . Inferior temporal sulcus, suicus temporalis inferior.
22 . Superior temporal gyrus, gyrus temporalis superior.
23 . Middle temporal gyrus, gyrus temporalis medius.
24 . Inferior temporal gyrus, gyrus temporalis inferior.
25 . Superior temporal sulcus, suicus temporalis superior.

Furrows and convolutions of the medial and lower surface of the right hemisphere of the brain.

2 - beak of the corpus callosum,

3 - knee of the corpus callosum,

4 - trunk of the corpus callosum,

5 - groove of the corpus callosum,

6 - cingulate gyrus,

7 - superior frontal gyrus,

8 - waist furrow,

9 - paracentral lobule,

10 - waist furrow,

11 - prewedge,

12 - parieto-occipital sulcus,

14 - spur furrow,

15 - lingual gyrus,

16 - medial occipitotemporal gyrus,

17 - occipital-temporal sulcus,

18 - lateral occipitotemporal gyrus,

19 - furrow of the hippocampus,

20 - parahippocampal gyrus.

Brain stem (sagittal section)

1 - medulla oblongata; 2 - bridge; 3 - legs of the brain; 4 - thalamus; 5 - pituitary gland; 6 - projection of the nuclei of the hypothalamic region; 7 - corpus callosum; 8 - pineal body; 9 - tubercles of the quadrigemina; 10 - cerebellum.

Brain stem (back view).

1. thalamus
2. anterior tubercle
3. pillow
4. medial geniculate body
5. lateral geniculate body
6. end strip
7. caudate nuclei of the hemispheres
8. brain strip
9. pineal gland
10. leash triangle
11. leash
12. III ventricle
13. soldering leashes
14. tubercles of the quadrigemina

Brain stem (back view)

A. medulla oblongata:
1. posterior median sulcus
2. thin beam
3. thin tubercle
4. wedge-shaped bundle
5. sphenoid tubercle
6. intermediate furrow
7. gate valve
8. inferior cerebellar peduncles
9. rhomboid fossa
10. posterolateral groove
11. choroid plexus

B. BRIDGE:
12. middle cerebellar peduncles
13. superior cerebellar peduncles
14. upper brain sail
15. bridle
16. auditory loop triangle

C. MIDBRAIN:
17. optic tubercles
18. auditory tubercles
19. legs of the brain

Brain stem (lateral side)

15. quadrigemina

16. leg of the brain
17. pillow of the thalamus
18. epiphysis
19. medial geniculate bodies (auditory)
20. medial roots
21. lateral geniculate bodies (visual)
22. lateral roots (handles)
23. optic tract

Brain stem (sagittal section)

7. anterior commissure
8. mastoid bodies
9. funnel
10. neurohypophysis
11. adenohypophysis
12. optic chiasm
13. prescient field
14. pineal gland

Sagittal section of the brain.

1.trunk of the corpus callosum
2. roller
3. knee
4. beak
5. terminal plate
6. anterior commissure of the brain
7. vault
8. vault pillars
9. nipple bodies
10. transparent baffle
11. thalamus
12. interthalamic adhesion
13. hypothalamic groove
14. gray bump
15. funnel
16. pituitary gland
17. optic nerve
18. Monroe hole
19. epiphysis
20. epiphyseal adhesion
21. posterior commissure of the brain
22. quadrigemina
23. sylvian aqueduct
23. sylvian aqueduct
24. leg of the brain
25. bridge
26. medulla oblongata
27. cerebellum
28. fourth ventricle
29. upper sail
29. upper sail
30. plexus
31. lower sail

Brain (cross section):

1 - islet;
2 - shell;
3 - fence;
4 - outer capsule;
5 - pale ball;
6 - III ventricle;
7 - red core;
8 - tire;
9 - aqueduct of the midbrain;
10 - roof of the midbrain;
11 - hippocampus;
12 - cerebellum

1 - internal capsule;
2 - islet;
3 - fence;
4 - outer capsule;
5 - visual tract;
6 - red core;
7 - black substance;
8 - hippocampus;
9 - leg of the brain;
10 - bridge;
11 - middle cerebellar peduncle;
12 - pyramidal tract;
13 - olive core;
14 - cerebellum.

The structure of the medulla oblongata

1 - olive cerebellar tract;

2 - olive core;

3 - the gate of the core of the olive;

4 - olive;

5 - pyramidal tract;

6 - hypoglossal nerve;

7 - pyramid;

8 - anterior lateral furrow;

9 - accessory nerve

Medulla oblongata (horizontal section)

11. seam
12. medial loop
13. lower olive
14. medial olive
15. dorsal olive
16. reticular formation
17. medial longitudinal bundle
18. dorsal longitudinal bundle

The structure of the cerebellum:

a - bottom view,

b - horizontal section:

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Lobes of the cerebellum

Worm segments

Lobes of the hemispheres

Front

11. uvula of the cerebellum

12. ligamentous gyrus

13. central

14. wings of the central lobule

15. top of the hill

16. anterior quadrangular

rear

18. back quadrangular

19. leaf

20. superior lunate

21. tubercle

22. inferior lunate

23. pyramid

24. thin, digastric (D)

26. tonsil

Klochkovo-nodular

25. sleeve

28. shred, leg, okolochok

27. knot

Cerebellar nuclei (on the frontal section).

A. Diencephalon
B. Midbrain
C. Cerebellum

12. worm
13. hemisphere
14. furrows
15. bark
16. white matter
17. upper legs
18. core tent
19. spherical nuclei
20. cork kernels
21. jagged nuclei

Thalamus and other parts of the brain on the median longitudinal section of the brain:

1- Hypothalamus; 2- Cavity of the III ventricle; 3- anterior (white soldering);

4- The fornix of the brain; 5- corpus callosum; 6- Interthalamic fusion;

7-Thalamus; 8- Epithalamus; 9- Midbrain; 10- Bridge; 11- Cerebellum;

12- Medulla oblongata.

The fourth ventricle (venticulus quartis) and the vascular base of the fourth ventricle (tela chorioidea ventriculi quarti).

View from above:

1-lingu of the cerebellum;

2-high cerebral sail;

3-fourth ventricle;

4-middle cerebellar peduncle;

5-vascular plexus of the fourth ventricle;

6-tubercle of the sphenoid nucleus;

7-tubercular nucleus;

8-posterior intermediate furrow;

9-wedge-shaped bundle;

10-lateral (lateral) cord;

11-thin beam;

12-posterior median sulcus;

13-posterior lateral groove;

14-median opening (aperture) of the fourth ventricle;

15-co-vascular basis of the fourth ventricle;

16-upper (anterior) cerebellar peduncle;

17-block nerve;

18-lower colliculus (roofs of the midbrain);

19-bridle of the upper medullary sail;

20-upper mound (roofs of the midbrain).

IV ventricle:

1 - roof of the midbrain;
2 - median furrow;
3 - medial elevation;
4 - superior cerebellar peduncle;
5 - middle cerebellar peduncle;
6 - facial tubercle;
7 - lower leg of the cerebellum;
8 - wedge-shaped tubercle of the medulla oblongata;
9 - thin tubercle of the medulla oblongata;
10 - wedge-shaped bundle of the medulla oblongata;
11 - thin bundle of the medulla oblongata

Superior surface of the cerebral hemispheres

(red - frontal lobe; green - parietal lobe; blue - occipital lobe):

1 - precentral gyrus; 2 - superior frontal gyrus; 3 - middle frontal gyrus; 4 - postcentral gyrus; 5 - upper parietal lobule; 6 - lower parietal lobule; 7 - occipital gyrus; 8 - intraparietal groove; 9 - postcentral furrow; 10 - central furrow; 11 - precentral furrow; 12 - lower frontal groove; 13 - upper frontal sulcus.

Inferior surface of the cerebral hemispheres

(red - frontal lobe; blue - occipital lobe; yellow - temporal lobe; lilac - olfactory brain):

1 - olfactory bulb and olfactory tract; 2 - orbital convolutions; 3 - lower temporal gyrus; 4 - lateral occipitotemporal gyrus; 5 - parahippocampal gyrus; 6 - occipital gyrus; 7 - olfactory groove; 8 - orbital furrows; 9 - lower temporal sulcus.

Lateral surface of the right cerebral hemisphere

Red - frontal lobe; green - parietal lobe; blue - occipital lobe; yellow - temporal lobe:

1 - precentral gyrus; 2 - superior frontal gyrus; 3 - middle frontal gyrus; 4 - postcentral gyrus; 5 - superior temporal gyrus; 6 - middle temporal gyrus; 7 - lower temporal gyrus; 8 - tire; 9 - upper parietal lobule; 10 - lower parietal lobule; 11 - occipital gyrus; 12 - cerebellum; 13 - central furrow; 14 - precentral furrow; 15 - upper frontal groove; 16 - lower frontal groove; 17 - lateral furrow; 18 - superior temporal sulcus; 19 - lower temporal sulcus.

Medial surface of the right cerebral hemisphere

(red - frontal lobe; green - parietal lobe; blue - occipital lobe; yellow - temporal lobe; lilac - olfactory brain):

1 - cingulate gyrus; 2 - parahippocampal gyrus; 3 - medial frontal gyrus; 4 - paracentral lobule; 5 - wedge; 6 - lingual gyrus; 7 - medial occipitotemporal gyrus; 8 - lateral occipitotemporal gyrus; 9 - corpus callosum; 10 - superior frontal gyrus; 11 - occipital-temporal groove; 12 - furrow of the corpus callosum; 13 - waist furrow; 14 - parieto-occipital sulcus; 15 - spur furrow.

Frontal section of the diencephalon

15. III-ventricle
16. interthalamic commissure
17. plates of white matter
18. front horns
19. median nuclei
20. ventrolateral nuclei
21. subthalamic nuclei

insular lobe

11. circular furrow
12. central sulcus
13. long gyrus
14. short convolutions
15. threshold

BRIDGE (cross section)

A. basilar part
B. axle tire
C. trapezoid body
IV v - fourth ventricle
20. medial longitudinal bundle
21. superior cerebellar peduncles
22. seam
23. transverse fibers
24. bridge core
25. longitudinal fibers
26. reticular formation
27. medial loop
28. lateral loop
29. rubrospinal put
30. tectospinal path

Cross section of the midbrain

K. roof
P. tire
N. brain stem
13. sylvian aqueduct
14. sylvian aqueduct

III. nucleus of the oculomotor n.
IV. trochlear nucleus
15. posterior longitudinal bundle
16. medial longitudinal p.
17. medial loop
18. lateral loop
19. red cores
20. black substance
21. tectospinal tract
22. rubrospinal tract
23. reticular formation
24. frontal bridge path
25. corticonuclear pathway
26. corticospinal tract
27. occipital-parietal-temporal-pontine
28. gray and white matter
29. pretectal nuclei
30. dorsal-thalamic tr.
31. oculomotor nerve

Topography of the bottom of the rhomboid fossa

1. top sail
2. lower sail
3. choroid plexus
4. superior cerebellar peduncles
5. middle cerebellar peduncles
6. inferior cerebellar peduncles
7. median sulcus
8. medial eminence
9. border furrow
10. cranial fossa
11. caudal fossa
12. bluish spot
13. vestibular field
14. brain strips
15. facial tubercle
16. triangle of the hyoid n.
17. triangle of wandering n.
18. independent cord
19. rearmost field

1 - superior cerebellar peduncle;
2 - pyramidal tract;
3 - leg of the telencephalon;
4 - middle cerebellar peduncle;
5 - bridge;
6 - lower leg of the cerebellum;
7 - olive;
8 - pyramid;
9 - anterior median fissure

General overview of the structure of the cerebral hemispheres

The cerebral hemispheres are the most massive part of the brain. They cover the cerebellum and brainstem. The cerebral hemispheres make up approximately 78% of the total mass of the brain. In the process of ontogenetic development of the organism, the cerebral hemispheres develop from the terminal cerebral bladder of the neural tube, therefore this part of the brain is also called the telencephalon.

The cerebral hemispheres are divided along the midline by a deep vertical fissure into the right and left hemispheres.

In the depth of the middle part, both hemispheres are interconnected by a large adhesion - the corpus callosum. In each hemisphere, lobes are distinguished; frontal, parietal, temporal, occipital and insula.

The lobes of the cerebral hemispheres are separated from one another by deep furrows. The most important are three deep furrows: the central (Roland) separating the frontal lobe from the parietal, the lateral (Sylvian) separating the temporal lobe from the parietal, the parietal-occipital separating the parietal lobe from the occipital on the inner surface of the hemisphere.

Each hemisphere has an upper-lateral (convex), lower and inner surface.

Each lobe of the hemisphere has cerebral convolutions, separated from each other by furrows. From above, the hemisphere is covered with a bark - a thin layer of gray matter, which consists of nerve cells.

The cerebral cortex is the youngest evolutionary formation of the central nervous system. In humans, it reaches its highest development. The cerebral cortex is of great importance in the regulation of the vital activity of the organism, in the implementation of complex forms of behavior and the formation of neuropsychic functions.

Under the cortex is the white matter of the hemispheres, it consists of processes of nerve cells - conductors. Due to the formation of cerebral convolutions, the total surface of the cerebral cortex increases significantly. The total area of ​​the hemispheric cortex is 1200 cm 2, with 2/3 of its surface located in the depths of the furrows, and 1/3 on the visible surface of the hemispheres. Each lobe of the brain has a different functional meaning.

The frontal lobe occupies the anterior sections of the hemispheres. It is separated from the parietal lobe by the central sulcus, and from the temporal lobe by the lateral sulcus. There are four gyri in the frontal lobe: one vertical - precentral and three horizontal - superior, middle and inferior frontal gyrus. The convolutions are separated from each other by furrows.

On the lower surface of the frontal lobes, the direct and orbital gyrus are distinguished. The direct gyrus lies between the inner edge of the hemisphere, the olfactory groove and the outer edge of the hemisphere.

In the depths of the olfactory furrow lie the olfactory bulb and the olfactory tract.

The human frontal lobe makes up 25-28% of the cortex; the average mass of the frontal lobe is 450 g.

The function of the frontal lobes is associated with the organization of voluntary movements, the motor mechanisms of speech, the regulation of complex forms of behavior, and thought processes. Several functionally important centers are concentrated in the convolutions of the frontal lobe. The anterior central gyrus is a "representation" of the primary motor zone with a strictly defined projection of body parts. The face is “located” in the lower third of the gyrus, the hand is in the middle third, the leg is in the upper third. The trunk is represented in the posterior sections of the superior frontal gyrus. Thus, a person is projected in the anterior central gyrus upside down and head down.

The anterior central gyrus, together with the adjacent posterior and frontal gyri, performs a very functionally important role. It is the center of voluntary movements. In the depths of the cortex of the central gyrus, from the so-called pyramidal cells - the central motor neuron - the main motor path begins - the pyramidal, corticospinal path. The peripheral processes of motor neurons emerge from the cortex, gather into a single powerful bundle, pass through the central white matter of the hemispheres and enter the brain stem through the internal capsule; at the end of the brainstem they partially cross (passing from one side to the other) and then descend into the spinal cord. These processes terminate in the gray matter of the spinal cord. There they come into contact with the peripheral motor neuron and transmit impulses to it from the central motor neuron. Impulses of voluntary movement are transmitted along the pyramidal path.

In the posterior sections of the superior frontal gyrus, there is also an extrapyramidal center of the cortex, which is closely connected anatomically and functionally with the formations of the so-called extrapyramidal system. The extrapyramidal system is a motor system that helps to carry out voluntary movement. This is a system of "providing" arbitrary movements. Being phylogenetically older, the human extrapyramidal system provides automatic regulation of “learned” motor acts, maintenance of general muscle tone, readiness of the peripheral motor apparatus to perform movements, and redistribution of muscle tone during movements. In addition, it is involved in maintaining a normal posture.

The motor cortex is located mainly in the precentral gyrus and paracentral lobule on the medial surface of the hemisphere. Separate primary and secondary regions. These fields are motor, but according to their characteristics, according to the research of the Brain Institute, they are different. The primary motor cortex contains neurons that innervate the motor neurons of the muscles of the face, trunk, and limbs.

It has a clear topographic projection of the muscles of the body. The main pattern of topographic representation is that the regulation of the activity of muscles that provide the most accurate and diverse movements (speech, writing, facial expressions) requires the participation of large areas of the motor cortex. Field 4 is completely occupied by the centers of isolated movements, field 6 is only partially occupied.

The preservation of field 4 turns out to be necessary for obtaining movements during stimulation of both field 4 and field 6. In a newborn, field 4 is practically mature. Irritation of the primary motor cortex causes contraction of the muscles of the opposite side of the body (for the muscles of the head, the contraction can be bilateral). With the defeat of this cortical zone, the ability to fine coordinated movements of the limbs and especially the fingers is lost.

The secondary motor cortex has a dominant functional significance in relation to the primary motor cortex, carrying out higher motor functions associated with planning and coordinating voluntary movements. Here, to the greatest extent, a slowly increasing negative potential of readiness is recorded, which occurs approximately 1 s before the start of movement. The cortex of field 6 receives the bulk of the impulses from the basal ganglia and the cerebellum, and is involved in recoding information about complex movements.

Irritation of the cortex of field 6 causes complex coordinated movements, such as turning the head, eyes and torso in the opposite direction, friendly contractions of the flexors or extensors on the opposite side. In the premotor cortex there are motor centers associated with human social functions: the center of written speech in the posterior part of the middle frontal gyrus, the center of motor speech of Brock in the posterior part of the inferior frontal gyrus, providing speech, as well as the musical motor center, providing the tonality of speech, the ability to sing. The lower part of field b (subfield boron), located in the region of the tire, reacts to the electric current with rhythmic chewing movements. Motor cortex neurons receive afferent inputs through the thalamus from muscle, joint, and skin receptors, from the basal ganglia, and the cerebellum. The main efferent output of the motor cortex to the stem and spinal motor centers are the pyramidal cells of layer V.

In the posterior part of the middle frontal gyrus is the frontal oculomotor center, which controls the friendly, simultaneous rotation of the head and eyes (the center of rotation of the head and eyes in the opposite direction). Irritation of this center causes the head and eyes to turn in the opposite direction. The function of this center is of great importance in the implementation of the so-called orienting reflexes (or "what is it?" reflexes), which are very important for the preservation of animal life.

The frontal part of the cerebral cortex also takes an active part in the formation of thinking, the organization of purposeful activity, and long-term planning.

The parietal lobe occupies the upper lateral surfaces of the hemisphere. From the frontal parietal lobe, front and side, it is limited by the central sulcus, from the temporal from below - by the lateral sulcus, from the occipital - by an imaginary line passing from the upper edge of the parietal-occipital sulcus to the lower edge of the hemisphere.

On the upper lateral surface of the parietal lobe there are three convolutions: one vertical - posterior central and two horizontal - superior parietal and inferior parietal. The part of the inferior parietal gyrus, which envelops the posterior part of the lateral sulcus, is called the supramarginal (supramarginal), the part surrounding the superior temporal gyrus is called the nodal (angular) area.

The parietal lobe, like the frontal lobe, makes up a significant part of the cerebral hemispheres. In phylogenetic terms, an old section is distinguished in it - the posterior central gyrus, a new one - the upper parietal gyrus and a newer one - the lower parietal gyrus.

The function of the parietal lobe is associated with the perception and analysis of sensitive stimuli, spatial orientation. Several functional centers are concentrated in the convolutions of the parietal lobe.

In the posterior central gyrus, centers of sensitivity are projected with a body projection similar to that in the anterior central gyrus. In the lower third of the gyrus, the face is projected, in the middle third - the arm, torso, in the upper third - the leg. In the superior parietal gyrus there are centers that are in charge of complex types of deep sensitivity: muscular-articular, two-dimensional-spatial feeling, a sense of weight and volume of movement, a sense of recognizing objects by touch.

Behind the upper sections of the posterior central gyrus, a center is localized, which provides the ability to recognize one's own body, its parts, their proportions and mutual position.

Fields 1, 2, 3 of the postcentral area constitute the main cortical nucleus of the skin analyzer. Together with field 1, field 3 is the primary, and field 2 is the secondary projection area of ​​the skin analyzer. The postcentral region is connected by efferent fibers with subcortical and stem formations, with the precentral and other areas of the cerebral cortex. Thus, the cortical section of the sensitive analyzer is localized in the parietal lobe.

Primary sensory zones are areas of the sensory cortex, irritation or destruction of which causes clear and permanent changes in the sensitivity of the body (the core of the analyzers, according to I.P. Pavlov). They consist mainly of monomodal neurons and form sensations of the same quality. Primary sensory areas usually have a clear spatial (topographic) representation of body parts, their receptor fields.

Around the primary sensory areas are less localized secondary sensory areas, the neurons of which respond to the action of several stimuli, i.e. they are polymodal.

The most important sensory area is the parietal cortex of the postcentral gyrus and the corresponding part of the paracentral lobule on the medial surface of the hemispheres, which is designated as somatosensory area I. There is a projection of skin sensitivity on the opposite side of the body from tactile, pain, temperature receptors, interoceptive sensitivity and sensitivity of the musculoskeletal system - from muscle, joint, tendon receptors.

In addition to the somatosensory region I, a smaller somatosensory region II is isolated, located at the border of the intersection of the central sulcus with the upper edge of the temporal lobe, in the depth of the lateral sulcus. The degree of localization of body parts is less pronounced here.

The praxis centers are located in the lower parietal lobe. Praxis is understood as purposeful movements that have become automated in the process of repetitions and exercises, which are developed in the process of learning and constant practice during an individual life. Walking, eating, dressing, the mechanical element of writing, various types of labor activity (for example, the movement of a driver to drive a car, mowing, etc.) are praxis. Praxis is the highest manifestation of the human motor function. It is carried out as a result of the combined activity of various areas of the cerebral cortex.

In the lower sections of the anterior and posterior central gyri, there is a center for the analyzer of interoceptive impulses of internal organs and blood vessels. The center has close ties with subcortical vegetative formations.

The temporal lobe occupies the inferolateral surface of the hemispheres. From the frontal and parietal lobes, the temporal lobe is limited by the lateral groove. On the upper lateral surface of the temporal lobe there are three convolutions: superior, middle and inferior.

The superior temporal gyrus lies between the sylvian and superior temporal sulci, the middle gyrus lies between the superior and inferior temporal sulci, and the inferior gyrus lies between the inferior temporal sulcus and the transverse cerebral fissure. On the lower surface of the temporal lobe, the inferior temporal gyrus, the lateral occipitotemporal gyrus, and the gyrus of the hippocampus (sea horse legs) are distinguished.

The function of the temporal lobe is associated with the perception of auditory, gustatory, olfactory sensations, the analysis and synthesis of speech sounds, and memory mechanisms. The main functional center of the superior lateral surface of the temporal lobe is located in the superior temporal gyrus. Here is the auditory, or gnostic, center of speech (Wernicke's center).

A well-studied primary projection area is the auditory cortex, which is located deep in the lateral sulcus (the cortex of the transverse temporal gyri of Heschl). The projection cortex of the temporal lobe also includes the center of the vestibular analyzer in the superior and middle temporal gyri.

The olfactory projection area is located in the hippocampal gyrus, especially in its anterior section (the so-called hook). Next to the olfactory projection zones are the gustatory ones.

The temporal lobes play an important role in the organization of complex mental processes, in particular memory.

The occipital lobe occupies the posterior sections of the hemispheres. On the convex surface of the hemisphere, the occipital lobe does not have sharp boundaries separating it from the parietal and temporal lobes, with the exception of the upper part of the parietal-occipital sulcus, which, located on the inner surface of the hemisphere, separates the parietal lobe from the occipital lobe. Furrows and convolutions of the upper lateral surface of the occipital lobe are unstable and have a variable structure. On the inner surface of the occipital lobe there is a spur groove that separates the wedge (a triangular norm of the lobule of the occipital lobe) from the lingual gyrus and the occipitotemporal gyrus.

The function of the occipital lobe is associated with the perception and processing of visual information, the organization of complex processes of visual perception - while the upper half of the retina is projected in the area of ​​the wedge, which perceives light from the lower fields of vision; in the region of the lingular gyrus is the lower half of the retina, which perceives light from the upper visual fields.

The primary visual area is located in the occipital cortex (the cortex of the sphenoid gyrus and the lingual lobule). There is a topical representation of retinal receptors here. Each point of the retina corresponds to its own area of ​​the visual cortex, while the zone of the macula has a relatively large zone of representation. In connection with the incomplete intersection of the visual pathways, the same halves of the retina are projected into the visual region of each hemisphere. The presence in each hemisphere of the projection of the retina of both eyes is the basis of binocular vision. Near field 17 is the cortex of the secondary visual area. The neurons of these zones are polymodal and respond not only to light, but also to tactile and auditory stimuli. In this visual area, various types of sensitivity are synthesized, more complex visual images arise and their recognition is carried out.

The islet, or the so-called closed lobule, is located deep in the lateral groove. The islet is separated from adjacent adjacent sections by a circular groove. The surface of the islet is divided by its longitudinal central groove into anterior and posterior parts. A taste analyzer is projected in the islet.

limbic cortex. On the inner surface of the hemispheres above the corpus callosum is the cingulate gyrus. This gyrus, with an isthmus behind the corpus callosum, passes into the gyrus near the seahorse - the parahippocampal gyrus. The cingulate gyrus together with the parahippocampal gyrus make up the vaulted gyrus.

The limbic cortex is combined into a single functional system - the limbic-reticular complex. The main function of these parts of the brain is not so much to provide communication with the outside world, but to regulate the tone of the cortex, drives and affective life. They regulate complex, multifaceted functions of internal organs and behavioral responses. The limbic-reticular complex is the most important integrative system of the body. The limbic system is also important in the formation of motivations. Motivation (or internal motivation) includes the most complex instinctive and emotional reactions (food, defensive, sexual). The limbic system is also involved in the regulation of sleep and wakefulness.

The limbic cortex also performs an important function of smell. Smell is the perception of chemicals in the air. The human olfactory brain provides the sense of smell, as well as the organization of complex forms of emotional and behavioral reactions. The olfactory brain is part of the limbic system.

The corpus callosum is an arcuate thin plate, phylogenetically young, connecting the median surfaces of both hemispheres. The elongated middle part of the corpus callosum passes into a thickening behind, and in front it curves and curves down in an arcuate manner. The corpus callosum connects the phylogenetically youngest parts of the hemispheres and plays an important role in the exchange of information between them.

14.1. GENERAL PROVISIONS

End brain (telencephalon), or big brain (cerebrum), located in the supratentorial space of the cranial cavity consists of two large

hemispheres (gemispherium cerebralis),separated by a deep longitudinal slit (fissura longitudinalis cerebri), in which the crescent of the brain is immersed (falx cerebri) representing a duplication of the dura mater. The large hemispheres of the brain make up 78% of its mass. Each of the cerebral hemispheres has lobes: frontal, parietal, temporal, occipital and limbic. They cover the structures of the diencephalon and the brain stem and cerebellum located below the cerebellar mantle (subtentorially).

Each of the cerebral hemispheres has three surfaces: upper lateral, or convexital (Fig. 14.1a), - convex, facing the bones of the cranial vault; internal (Fig. 14.1b), adjacent to the large falciform process, and lower, or basal (Fig. 14.1c), repeating the relief of the base of the skull (anterior and middle of its fossae) and the tenon of the cerebellum. In each hemisphere, three edges are distinguished: upper, lower inner and lower outer, and three poles: anterior (frontal), posterior (occipital) and lateral (temporal).

The cavity of each cerebral hemisphere is lateral ventricle of the brain while the left lateral ventricle is recognized as the first, the right - the second. The lateral ventricle has a central part located deep in the parietal lobe (lobus parietalis) and three horns extending from it: the anterior horn penetrates the frontal lobe (lobus frontalis), lower - to the temporal (lobus temporalis), posterior - in the occipital (lobus occipitalis). Each of the lateral ventricles communicates with the third ventricle of the brain through the interventricular hole Monroe.

The central sections of the medial surface of both hemispheres are interconnected by cerebral commissures, the most massive of which is the corpus callosum, and structures of the diencephalon.

The telencephalon, like other parts of the brain, consists of gray and white matter. Gray matter is located in the depths of each hemisphere, forming subcortical nodes there, and along the periphery of the free surfaces of the hemisphere, where it makes up the cerebral cortex.

The main issues related to the structure, functions of the basal ganglia and variants of the clinical picture when they are affected are discussed in chapters 5, 6. The cerebral cortex is approximately

Rice. 14.1.Hemispheres of the brain.

a - upper lateral surface of the left hemisphere: 1 - central sulcus; 2 - orbital part of the lower frontal gyrus; I - frontal lobe; 3 - precentral gyrus; 4 - precentral furrow; 5 - superior frontal gyrus; 6 - middle frontal gyrus; 7 - tegmental part of the inferior frontal gyrus; 8 - lower frontal gyrus; 9 - lateral furrow; II - parietal lobe: 10 - postcentral gyrus; 11 - postcentral furrow; 12 - intraparietal groove; 13 - supramarginal gyrus; 14 - angular gyrus; III - temporal lobe: 15 - superior temporal gyrus; 16 - upper temporal sulcus; 17 - middle temporal gyrus; 18 - middle temporal sulcus; 19 - lower temporal gyrus; IV - occipital lobe: b - medial surface of the right hemisphere: 1 - paracentral lobule, 2 - precuneus; 3 - parieto-occipital sulcus; 4 - wedge, 5 - lingual gyrus; 6 - lateral occipitotemporal gyrus; 7 - parahippocampal gyrus; 8 - hook; 9 - vault; 10 - corpus callosum; 11 - superior frontal gyrus; 12 - cingulate gyrus; c - lower surface of the cerebral hemispheres: 1 - longitudinal interhemispheric fissure; 2 - orbital furrows; 3 - olfactory nerve; 4 - optic chiasm; 5 - middle temporal sulcus; 6 - hook; 7 - lower temporal gyrus; 8 - mastoid body; 9 - base of the brain stem; 10 - lateral occipitotemporal gyrus; 11 - parahippocampal gyrus; 12 - collateral groove; 13 - cingulate gyrus; 14 - lingual gyrus; 15 - olfactory groove; 16 - direct gyrus.

3 times the surface of the hemispheres visible during external examination. This is due to the fact that the surface of the cerebral hemispheres is folded, has numerous depressions - furrows (sulci cerebri) and located between them convolutions (gyri cerebri). The cerebral cortex covers the entire surface of the convolutions and furrows (hence its other name is pallium - a cloak), while sometimes penetrating to a great depth into the substance of the brain.

The severity and location of the furrows and convolutions of the cerebral hemispheres are variable to a certain extent, but the main ones are formed in the process of ontogenesis and are constant, characteristic of each normally developed brain.

14.2. MAJOR GROOCHES AND GRIPS OF THE HEMISPHERES OF THE BRAIN

Upper lateral (convexital) surface of the hemispheres (Fig. 14.1a). The largest and deepest lateral furrow (sulcus lateralis),or sylvian furrow, - separates the frontal and anterior parts of the parietal lobe from the temporal lobe located below. The frontal and parietal lobes are separated central, or Roland, furrow(sulcus centralis), which cuts through the upper edge of the hemisphere and goes down and forward along its convexital surface, slightly short of the lateral groove. The parietal lobe is separated from the occipital lobe located behind it by the parietal-occipital and transverse occipital grooves passing along the medial surface of the hemisphere.

In the frontal lobe in front of the central gyrus and parallel to it is the precentral (gyrus precentralis), or anterior central, gyrus, which is bounded anteriorly by the precentral sulcus (sulcus precentralis). The superior and inferior frontal grooves depart anteriorly from the precentral sulcus, dividing the convexital surface of the anterior sections of the frontal lobe into three frontal gyrus - superior, middle and inferior (gyri frontales superior, media et inferior).

The anterior section of the convexital surface of the parietal lobe is located behind the central sulcus postcentral (gyrus postcentralis), or posterior central, gyrus. Behind it is bordered by the postcentral sulcus, from which the intraparietal sulcus stretches back. (sulcus intraparietalis), separating the superior and inferior parietal lobules (lobuli parietales superior et inferior). In the lower parietal lobule, in turn, the supramarginal gyrus is distinguished (gyrus supramarginalis), surrounding the posterior part of the lateral (Sylvian) groove, and the angular gyrus (girus angularis), bordering the back of the superior temporal gyrus.

On the convexital surface of the occipital lobe of the brain, the furrows are shallow and can vary significantly, as a result of which the nature of the convolutions located between them is also variable.

The convexital surface of the temporal lobe is divided by the superior and inferior temporal sulci, which are almost parallel to the lateral (Sylvian) sulcus, dividing the convexital surface of the temporal lobe into the superior, middle, and inferior temporal gyri (gyri temporales superior, media et inferior). The superior temporal gyrus forms the inferior lip of the lateral (Sylvian) sulcus. On its surface facing

side of the lateral furrow, there are several transverse small furrows, highlighting small transverse gyrus on it (gyrus of Geschl), which can be seen only by spreading the edges of the lateral furrow.

The anterior part of the lateral (Sylvian) groove is a depression with a wide bottom, forming the so-called island (insula) or insular lobe (lubus insularis). The upper edge of the lateral furrow covering this island is called tire (operculum).

Inner (medial) surface of the hemisphere (Fig. 14.1b). The central part of the inner surface of the hemisphere is closely connected with the structures of the diencephalon, from which it is delimited by those related to the large brain vault (fornix) and corpus callosum (corpus callosum). The latter is bordered on the outside by a furrow of the corpus callosum (sulcus corporis callosi), starting at the front of it - the beak (rostrum) and ending at its thickened rear end (splenium). Here, the sulcus of the corpus callosum passes into the deep hippocampal sulcus (sulcus hippocampi), which penetrates deep into the substance of the hemisphere, pressing it into the cavity of the lower horn of the lateral ventricle, as a result of which the so-called ammonium horn is formed.

Somewhat departing from the sulcus of the corpus callosum and the hippocampal sulcus, the corpus callosum, subparietal and nasal sulci are located, which are a continuation of each other. These grooves delimit from the outside the arcuate part of the medial surface of the cerebral hemisphere, known as limbic lobe(lobus limbicus). There are two convolutions in the limbic lobe. The upper part of the limbic lobe is the superior limbic (superior marginal), or girdle, gyrus (girus cinguli), the lower part is formed by the inferior limbic gyrus, or seahorse gyrus (girus hippocampi), or parahippocampal gyrus (girus parahypocampalis), in front of which there is a hook (uncus).

Around the limbic lobe of the brain are the formations of the inner surface of the frontal, parietal, occipital and temporal lobes. Most of the inner surface of the frontal lobe is occupied by the medial side of the superior frontal gyrus. On the border between the frontal and parietal lobes of the cerebral hemisphere is located paracentral lobule (lobulis paracentralis), which is, as it were, a continuation of the anterior and posterior central gyri on the medial surface of the hemisphere. On the border between the parietal and occipital lobes, the parietal-occipital sulcus is clearly visible. (sulcus parietooccipitalis). From the bottom of it departs back spur furrow (sulcus calcarinus). Between these deep furrows is a triangular gyrus, known as a wedge. (cuneus). In front of the wedge is a quadrangular gyrus, related to the parietal lobe of the brain, the precuneus.

Inferior surface of the hemisphere (Fig. 14.1c). The lower surface of the cerebral hemisphere consists of formations of the frontal, temporal and occipital lobes. The part of the frontal lobe adjacent to the midline is the direct gyrus (girus rectus). Outside, it is delimited by the olfactory groove (sulcus olfactorius), to which the formations of the olfactory analyzer are adjacent from below: the olfactory bulb and the olfactory tract. Lateral to it, up to the lateral (Sylvian) groove, which extends to the lower surface of the frontal lobe, there are small orbital gyri (gyri orbitalis). The lateral sections of the lower surface of the hemisphere behind the lateral sulcus are occupied by the inferior temporal gyrus. Medial to it is the lateral temporo-occipital gyrus. (gyrus occipitotemporalis lateralis), or fusiform groove. Before-

its inner parts border on the gyrus of the hippocampus, and the posterior ones - on the lingual (gyrus lingualis) or medial temporoccipital gyrus (gyrus occipitotemporalis medialis). The latter, with its posterior end, is adjacent to the spur groove. The anterior sections of the fusiform and lingual gyri belong to the temporal lobe, and the posterior sections to the occipital lobe of the brain.

14.3. WHITE MATTER OF THE GREAT HEMISPHERES

The white matter of the cerebral hemispheres consists of nerve fibers, mainly myelin, that make up the pathways that provide connections between the neurons of the cortex and clusters of neurons that form the thalamus, subcortical nodes, and nuclei. The main part of the white matter of the cerebral hemispheres is located in its depth semi-oval center, or radiant crown (corona radiata), consisting mainly of afferent and efferent projection pathways connecting the cerebral cortex with subcortical nodes, nuclei and reticular substance of the diencephalon and brain stem, with segments of the spinal cord. They are especially compactly located between the thalamus and subcortical nodes, where they form the internal capsule described in Chapter 3.

Nerve fibers that connect parts of the cortex of one hemisphere are called associative. The shorter these fibers and the connections they form, the more superficial they are; longer associative connections, located deeper, connect relatively distant parts of the cerebral cortex (Fig. 14.2 and 14.3).

The fibers that connect the cerebral hemispheres and therefore have a common transverse orientation are called commissural, or sleeping. Commissural fibers connect identical parts of the cerebral hemispheres, creating the possibility of combining their functions. They form three spikes large brain: the most massive of them - corpus callosum (corpus callosum), in addition, commissural fibers make up anterior commissure, located under the beak of the corpus callosum (rostrum corporis collosum) and connecting both olfactory regions, as well as commissure of the vault (commissura fornicis), or a hippocampal commissure formed by fibers connecting the structures of the ammon horns of both hemispheres.

In the anterior part of the corpus callosum, there are fibers connecting the frontal lobes, then there are fibers connecting the parietal and temporal lobes, the posterior part of the corpus callosum connects the occipital lobes of the brain. The anterior commissure and commissure of the fornix mainly unite sections of the ancient and old cortex of both hemispheres; the anterior commissure, in addition, provides a connection between their middle and lower temporal gyri.

14.4. Olfactory system

In the process of phylogenesis, the development of the large brain is associated with the formation of the olfactory system, the functions of which contribute to the preservation of the viability of animals and are of no small importance for human life.

Rice. 14.2.Associative cortical-cortical connections in the cerebral hemispheres [according to V.P. Vorobyov].

1 - frontal lobe; 2 - knee of the corpus callosum; 3 - corpus callosum; 4 - arcuate fibers; 5 - upper longitudinal beam; 6 - cingulate gyrus; 7 - parietal lobe, 8 - occipital lobe; 9 - vertical bundles of Wernicke; 10 - roller of the corpus callosum;

11 - lower longitudinal beam; 12 - subcausal bundle (frontal-occipital lower bundle); 13 - vault; 14 - temporal lobe; 15 - hook of the gyrus of the hippocampus; 16 - hook bundles (fasciculus uncinatus).

Rice. 14.3.Myeloarchitectonics of the cerebral hemispheres.

1 - projection fibers; 2 - commissural fibers; 3 - associative fibers.

14.4.1. The structure of the olfactory system

The bodies of the first neurons of the olfactory system are located in the mucous membrane nose, mainly upper part of the nasal septum and upper nasal passage. Olfactory cells are bipolar. Their dendrites come to the surface of the mucous membrane and end here with specific receptors, and axons are grouped in the so-called olfactory filaments (filiolfactorii), the number of which on each side is about twenty. Such a bundle of olfactory filaments and makes up the I cranial, or olfactory, nerve(Fig. 14.4). These threads pass into the anterior (olfactory, olfactory) cranial fossa through the ethmoid bone and end at cells located here olfactory bulbs. The olfactory bulbs and the proximal olfactory tracts are, in fact, a consequence of the protrusions of the cerebral substance formed in the process of ontogenesis and represent structures related to it.

The olfactory bulbs contain cells that are the bodies of the second neurons. olfactory pathway, whose axons form olfactory tracts (tracti olfactorii), located under the olfactory grooves, lateral to the direct convolutions located on the basal surface of the frontal lobes. Olfactory tracts are directed backward to the subcortical olfactory centers. Approaching the anterior perforated plate, the fibers of the olfactory tract are divided into medial and lateral bundles, forming an olfactory triangle on each side. Later, these fibers are suitable to the bodies of the third neurons of the olfactory analyzer, located

Rice. 14.4.Olfactory analyzer.

1 - olfactory cells; 2 - olfactory threads (in total they make up the olfactory nerves); 3 - olfactory bulbs; 4 - olfactory tracts; 5 - olfactory triangles; 6 - parahippocampal gyrus; 7 - projection zone of the olfactory analyzer (simplified diagram).

in the perialmond-shaped and subcallosal areas, in the nuclei of the transparent septum, located anterior to the anterior commissure. The anterior commissure connects both olfactory regions and also provides their connection to the limbic system of the brain. Part of the axons of the third neurons of the olfactory analyzer, passing through the anterior commissure of the brain, crosses.

Axons of third neurons olfactory analyzer, located in the subcortical olfactory centers, heading towards phylogenetically old crust mediobasal surface of the temporal lobe (to the piriform and parahippocampal gyrus and to the hook), where the projection olfactory zone is located, or the cortical end of the olfactory analyzer (field 28, according to Brodman).

The olfactory system is thus the only sensory system in which specific impulses bypass the thalamus on their way from the receptors to the cortex. However, The olfactory system has particularly pronounced connections with the limbic structures of the brain, and the information received through it has a significant impact on the state of the emotional sphere and the functions of the autonomic nervous system. Smells can be pleasant and unpleasant, they affect appetite, mood, can cause a variety of vegetative reactions, in particular nausea, vomiting.

14.4.2. Investigation of the sense of smell and the significance of its disorders for topical diagnostics

When examining the state of smell, it is necessary to find out whether the patient smells, whether these sensations are the same on both sides, whether the patient differentiates the nature of the smells felt, whether he has olfactory hallucinations - paroxysmal sensations of smell that are absent in the environment.

To study the sense of smell, odorous substances are used, the smell of which is not sharp (pungent odors can cause irritation of the trigeminal nerve receptors located in the nasal mucosa) and is known to the patient (otherwise it is difficult to recognize the perversion of smell). The sense of smell is checked on each side separately, while the other nostril must be closed. You can use specially prepared sets of weak solutions of odorous substances (mint, tar, camphor, etc.), in practical work, improvised means (rye bread, soap, banana, etc.) can also be used.

Decreased sense of smell - hyposmia, lack of smell - anosmia, heightened sense of smell - hyperosmia, perversion of odors dysosmia, sensation of smell in the absence of a stimulus - parosmia, subjective sensation of an unpleasant odor that actually exists and is caused by organic pathology in the nasopharynx - kakosmiya, odors that do not really exist, which the patient feels paroxysmal - olfactory hallucinations - are more often the olfactory aura of temporal lobe epilepsy, which can be due to various reasons, in particular, a tumor of the temporal lobe.

Hyposmia or anosmia on both sides is usually the result of damage to the nasal mucosa due to acute catarrh, influenza, allergic rhinitis, atrophy of the mucous membrane

nose due to chronic rhinitis and prolonged use of vasoconstrictor nasal drops. Chronic rhinitis with atrophy of the nasal mucosa (atrophic rhinitis), Sjögren's disease dooms a person to persistent anosmia. Bilateral hyposmia can be caused by hypothyroidism, diabetes mellitus, hypogonadism, renal failure, prolonged contact with heavy metals, formaldehyde, etc.

However, unilateral hyposmia or anosmia is often the result of an intracranial tumor, more often meningioma of the anterior cranial (olfactory) fossa, which accounts for up to 10% of intracranial meningiomas, as well as some glial tumors of the frontal lobe. Olfactory disorders occur as a result of compression of the olfactory tract on the side of the pathological focus and may be the only focal symptom of the disease for a certain time. Tumors can be visualized by CT or MRI scanning. As the meningioma of the olfactory fossa increases, as a rule, mental disorders characteristic of the frontal syndrome develop (see Chapter 15).

Unilateral damage to the parts of the olfactory analyzer located above its subcortical centers, due to incomplete decussation of the pathways at the level of the anterior cerebral commissure, usually does not lead to a significant decrease in the sense of smell. Irritation by the pathological process of the cortex of the mediobasal parts of the temporal lobe, primarily the parahippocampal gyrus and its hook, can cause a paroxysmal occurrence olfactory hallucinations. The patient suddenly begins to smell for no reason, often of an unpleasant nature (the smell of burnt, rotten, rotten, burnt, etc.). Olfactory hallucinations in the presence of an epileptogenic focus in the mediobasal regions of the temporal lobe of the brain may be a manifestation of the aura of an epileptic seizure. The defeat of the proximal part, in particular the cortical end of the olfactory analyzer, can cause moderate bilateral (more on the opposite side) hyposmia and impaired ability to identify and differentiate odors (olfactory agnosia). The last form of olfactory disorder, which manifests itself in old age, is most likely associated with a violation of the function of the cortex due to atrophic processes in its projection olfactory zone.

14.5. LIMBIC-RETICULAR COMPLEX

In 1878 P. Broca(Broca P., 1824-1880) under the name "large marginal, or limbic, lobe" (from lat. limbus - edge) united the hippocampus and the cingulate gyrus, interconnected by means of the isthmus of the cingulate gyrus, located above the ridge of the corpus callosum.

In 1937 D. Papets(Papez J.), on the basis of experimental data, put forward a reasoned objection to the previously existing concept of the involvement of the mediobasal structures of the cerebral hemispheres mainly in the provision of smell. He suggested that the main part of the mediobasal parts of the cerebral hemisphere, then called the olfactory brain (rhinencephalon), to which the limbic lobe belongs, is the morphological basis of the nervous mechanism of affective behavior, and united them under the name"emotional circle" which included the hypothalamus,

anterior nuclei of the thalamus, cingulate gyrus, hippocampus and their connections. Since then, these structures have also been referred to by physiologists as around Papetz.

concept "visceral brain" suggested P.D. McLean (1949), thus denoting a complex anatomical and physiological association, which since 1952 has been called "limbic system". Later it turned out that the limbic system is involved in the performance of diverse functions, and now most of it, including the cingulate and hippocampal (parahippocampal) gyrus, is usually combined into the limbic region, which has numerous connections with the structures of the reticular formation, making up with it limbic-reticular complex, providing a wide range of physiological and psychological processes.

Currently to limbic lobe it is customary to attribute elements of the old cortex (archiocortex), covering the dentate gyrus and the hippocampal gyrus; ancient cortex (paleocortex) of the anterior hippocampus; as well as the middle, or intermediate, cortex (mesocortex) of the cingulate gyrus. Term "limbic system" includes components of the limbic lobe and related structures - entorhinal (occupying most of the parahippocampal gyrus) and septal regions, as well as the amygdala complex and mastoid body (Duus P., 1995).

Mastoid body connects the structures of this system with the midbrain and with the reticular formation. Impulses originating in the limbic system can be transmitted through the anterior nucleus of the thalamus to the cingulate gyrus and to the neocortex along pathways formed by associative fibers. Impulses originating in the hypothalamus can reach the orbitofrontal cortex and the medial dorsal nucleus of the thalamus.

Numerous direct and feedback connections ensure the interconnection and interdependence of limbic structures and many formations of the diencephalon and oral parts of the brainstem (nonspecific nuclei of the thalamus, hypothalamus, putamen, frenulum, reticular formation of the brain stem), as well as with subcortical nuclei (pallidus, putamen, caudate nucleus ) and with the neocortex of the cerebral hemispheres, primarily with the cortex of the temporal and frontal lobes.

Despite phylogenetic, morphological, and cytoarchitectonic differences, many of the mentioned structures (limbic region, central and medial structures of the thalamus, hypothalamus, brainstem reticular formation) are usually included in the so-called limbic-reticular complex, which acts as a zone of integration of many functions, providing the organization of polymodal, holistic reactions of the body to various influences, which is especially pronounced in stressful situations.

The structures of the limbic-reticular complex have a large number of inputs and outputs, through which vicious circles of numerous afferent and efferent connections pass, ensuring the combined functioning of the formations included in this complex and their interaction with all parts of the brain, including the cerebral cortex.

In the structures of the limbic-reticular complex, there is a convergence of sensitive impulses that occur in intero- and exteroreceptors, including the receptor fields of the sense organs. On this basis, in the limbic-reticular complex, primary synthesis of information about the state of the internal environment of the body, as well as about the factors of the external environment affecting the body, and elementary needs, biological motivations and accompanying emotions are formed.

The limbic-reticular complex determines the state of the emotional sphere, participates in the regulation of vegetative-visceral relationships aimed at maintaining the relative constancy of the internal environment (homeostasis), as well as energy supply and correlation of motor acts. The level of consciousness, the possibility of automated movements, the activity of motor and mental functions, speech, attention, the ability to orientate, memory, the change of wakefulness and sleep depend on its state.

Damage to the structures of the limbic-reticular complex can be accompanied by a variety of clinical symptoms: pronounced changes in the emotional sphere of a permanent and paroxysmal nature, anorexia or bulimia, sexual disorders, memory impairment, in particular signs of Korsakoff's syndrome, in which the patient loses the ability to remember current events (retains current events in memory for no more than 2 minutes), autonomic-endocrine disorders, sleep disorders, psychosensory disorders in the form of illusions and hallucinations, changes in consciousness, clinical manifestations of akinetic mutism, epileptic seizures.

To date, a large number of studies have been conducted on the study of morphology, anatomical relationships, the function of the limbic region and other structures included in the limbic-reticular complex, however, the physiology and features of the clinical picture of its lesion today still largely need to be clarified. Most of the information about its function, especially the functions of the parahippocampal region, obtained in animal experiments methods of irritation, extirpation or stereotaxis. Obtained in this way results require caution when extrapolating to humans. Of particular importance are clinical observations of patients with lesions of the mediobasal parts of the cerebral hemisphere.

In the 50-60s of the XX century. in the period of development of psychosurgery, there were reports of the treatment of patients with incurable mental disorders and chronic pain syndrome by bilateral cingulotomy (dissection of the cingulate gyrus), while regression of anxiety, obsessional states, psychomotor agitation, pain syndromes was usually noted, which was recognized as evidence of the participation of the cingulate gyrus in the formation emotions and pain. At the same time, bicingulotomy led to profound personality disorders, to disorientation, a decrease in the criticality of one's condition, and euphoria.

An analysis of 80 verified clinical cases of hippocampal lesions on the basis of the Neurosurgical Institute of the Russian Academy of Medical Sciences is given in the monograph by N.N. Bragina (1974). The author comes to the conclusion that temporal mediobasal syndrome includes viscerovegetative, motor and mental disorders, usually manifested in a complex. All the variety of clinical manifestations of N.N. Bragin reduces to two main multifactorial variants of pathology with a predominance of "irritative" and "inhibitory" phenomena.

The first of these includes emotional disorders accompanied by motor anxiety (increased excitability, verbosity, fussiness, a feeling of internal anxiety), paroxysms of fear, vital anguish, various viscerovegetative disorders (changes in pulse, respiration, gastrointestinal disorders, fever, increased sweating and etc.). In these patients, against the background of constant motor restlessness, attacks of motor excitation often occurred.

niya. The EEG of this group of patients was characterized by mild cerebral changes towards integration (accelerated and pointed alpha rhythm, diffuse beta oscillations). Repeated afferent stimuli elicited clear EEG responses, which, unlike normal ones, did not fade as stimuli were repeatedly presented.

The second (“inhibitory”) variant of the mediobasal syndrome is characterized by emotional disturbances in the form of depression with motor retardation (depressed mood background, impoverishment and slowing of the pace of mental processes, changes in motor skills, resembling akinetic-rigid syndrome in type. Viscerovegetative paroxysms noted in the first group are less characteristic. The EEG of patients in this group was characterized by cerebral changes, manifested in the predominance of slow forms of activity (irregular, delayed alpha rhythm, groups of theta oscillations, diffuse delta waves).A sharp decrease in EEG reactivity attracted attention.

Between these two extreme variants there were also intermediate ones with transitional and mixed combinations of individual symptoms. So, some of them are characterized by relatively weak signs of agitated depression with increased motor activity and fatigue, with a predominance of senestopathic sensations, suspicion, which in some patients reaches paranoid states, and hypochondriacal delirium. The other intermediate group was distinguished by the extreme intensity of depressive symptoms against the background of the patient's stiffness.

These data allow us to speak about the dual (activating and inhibitory) influence of the hippocampus and other structures of the limbic region on behavioral reactions, emotions, mental status, and bioelectrical activity of the cortex. Currently, complex clinical syndromes of this type should not be regarded as primary focal. Rather, they should be considered in the light of ideas about a multilevel system of organization of brain activity.

S.B. Buklina (1997) cited data from a survey of 41 patients with arteriovenous malformations in the area of ​​the cingulate gyrus. Before surgery, 38 patients had memory disorders in the forefront, and five of them had signs of Korsakoff's syndrome, in three patients Korsakoff's syndrome arose after surgery, while the severity of the increase in memory defects correlated with the degree of destruction of the cingulate gyrus itself, as well as with involvement in pathological process of the adjacent structures of the corpus callosum, while the amnesic syndrome did not depend on the side of the malformation location and its localization along the length of the cingulate gyrus.

The main characteristics of the identified amnestic syndromes were disorders in the reproduction of auditory-speech stimuli, violations of the selectivity of traces in the form of inclusions and contaminations, and inability to retain meaning in the transmission of a story. In most patients, the criticality of assessing their condition was reduced. The author noted the similarity of these disorders with amnestic defects in patients with frontal lesions, which can be explained by the presence of connections between the cingulate gyrus and the frontal lobe.

More widespread pathological processes in the limbic region cause pronounced disorders of the vegetative-visceral functions.

corpus callosum(corpus callosum)- the largest commissure between the cerebral hemispheres. Its anterior sections, in particular the knee of the corpus callosum

body (genu corporis callosi), connect the frontal lobes, the middle sections - the trunk of the corpus callosum (truncus corporis callosi)- provide communication between the temporal and parietal sections of the hemispheres, the posterior sections, in particular the corpus callosum ridge (splenium corporis callosi), connect the occipital lobes.

Lesions of the corpus callosum are usually accompanied by disorders of the mental state of the patient. The destruction of its anterior section leads to the development of the “frontal psyche” (aspontaneity, violations of the action plan, behavior, criticism, characteristic of frontal callous syndrome - akinesia, amimia, aspontaneity, astasia-abasia, apraxia, grasping reflexes, dementia). Disconnection of connections between the parietal lobes leads to perversion understanding "body plans" and appearance of apraxia mostly in the left hand. Dissociation of the temporal lobes may manifest violation of the perception of the external environment, the loss of the correct orientation in it (amnestic disorders, confabulations, the syndrome of what has already been seen etc.). Pathological foci in the posterior parts of the corpus callosum are often characterized by signs of visual agnosia.

14.6. ARCHITECTONICS OF THE BRAIN CORTEX

The structure of the cerebral cortex is heterogeneous. Less complex in structure, early emerging in the process of phylogenesis ancient bark (archiocortex) and old bark (paleocortex), related mostly to limbic lobe brain. The greater part of the cerebral cortex (95.6%), due to its later phylogenetic formation, is called new bark (neocortex) and has a much more complex multilayer structure, but also heterogeneous in its various zones.

Due to the fact that the architectonics of the cortex is in a certain connection with its function, much attention has been devoted to its study. One of the founders of the doctrine of the cytoarchitectonics of the cortex was V.A. Betz (1834-1894), who for the first time in 1874 described the large pyramidal cells of the motor cortex (Betz cells) and determined the principles for dividing the cerebral cortex into main areas. In the future, a great contribution to the development of the theory of the structure of the cortex was made by many researchers - A. Campbell (A. Cambell), E. Smith (E. Smith), K. Brodmann (K. Brodmann), Oscar Vogt and Cecilia Vogt (O. Vogt , S. Vogt). Great merit in the study of the architectonics of the cortex belongs to the staff of the Institute of the Brain of the Academy of Medical Sciences (S.A. Sarkisov, N.I. Filimonov, E.P. Kononova, etc.).

The main type of structure of the new crust (Fig. 14.5), with which all its sections are compared - a cortex consisting of 6 layers (homotypic cortex, according to Brodman).

Layer I - molecular, or zonal, the most superficial, poor in cells, its fibers have a direction, mainly parallel to the surface of the cortex.

II layer - outer granular. Consists of a large number of densely arranged small granular nerve cells.

III layer - small and medium pyramids, the widest. It consists of pyramidal cells, the sizes of which are not the same, which allows dividing this layer into sublayers in most cortical fields.

IV layer - internal granular. It consists of densely arranged small cells-grains of a round and angular shape. This layer is the most variable

Rice. 14.5.Cytoarchitectonics and myeloarchitectonics of the motor zone of the cerebral cortex.

Left: I - molecular layer; II - outer granular layer; III - layer of small and medium pyramids; IV - inner granular layer; V - layer of large pyramids; VI - layer of polymorphic cells; on the right - elements of myeloarchitectonics.

in some fields (for example, field 17), it is divided into sublayers, in some places it sharply becomes thinner and even completely disappears.

V layer - large pyramids, or ganglionic. Contains large pyramidal cells. In some areas of the brain, the layer is divided into sublayers, in the motor zone it consists of three sublayers, the middle of which contains Betz's giant pyramidal cells, reaching 120 microns in diameter.

VI layer - polymorphic cells, or multiform. Consists mainly of triangular spindle-shaped cells.

The structure of the cerebral cortex has a large number of variations due to changes in the thickness of individual layers, thinning or disappearance or,

on the contrary, thickening and division into sublayers of some of them (heterotypic zones, according to Brodman).

The cortex of each cerebral hemisphere is divided into several regions: occipital, superior and inferior parietal, postcentral, central gyri, precentral, frontal, temporal, limbic, insular. Each of them in accordance with the characteristics subdivided into a number of fields, moreover, each field has its own conventional ordinal designation (Fig. 14.6).

The study of the architectonics of the cerebral cortex, along with physiological, including electrophysiological, studies and clinical observations, contributed in many respects to the solution of the problem of the distribution of functions in the cortex.

14.7. PROJECTION AND ASSOCIATION FIELDS OF THE CORTUS

In the process of developing the doctrine of the role of the cerebral cortex and its individual sections in the performance of certain functions, there were different, sometimes opposite, points of view. Thus, there was an opinion about a strictly local representation in the cerebral cortex of all human abilities and functions, up to the most complex, mental (localizationism, psychomorphologism). He was opposed by another opinion about the absolute functional equivalence of all parts of the cerebral cortex (equipotentialism).

An important contribution to the theory of localization of functions in the cerebral cortex was made by I.P. Pavlov (1848-1936). He singled out the projection zones of the cortex (the cortical ends of the analyzers of certain types of sensitivity) and the associative zones located between them, studied the processes of inhibition and excitation in the brain, and their influence on the functional state of the cerebral cortex. The division of the cortex into projection and associative zones contributes to understanding the organization of the work of the cerebral cortex and justifies itself in solving practical problems, in particular, in topical diagnostics.

projection zones provide mainly simple specific physiological acts, primarily the perception of sensations of a certain modality. The projection pathways approaching them connect these zones with the receptor territories on the periphery that are in functional correspondence with them. Examples of projection cortical zones are the region of the posterior central gyrus already described in previous chapters (zone of general types of sensitivity) or the region of the spur groove located on the medial side of the occipital lobe (projection visual zone).

Association zones the cortex does not have direct connections with the periphery. They are located between the projection zones and have numerous associative links with these projection zones and with other associative zones. The function of the associative zones is to carry out a higher analysis and synthesis of many elementary and more complex components. Here, in essence, there is an understanding of the information entering the brain, the formation of ideas and concepts.

G.I. Polyakov in 1969, based on a comparison of the architectonics of the human cerebral cortex and some animals, found that associative

Rice. 14.6.Architectonic fields of the cerebral cortex [according to Brodman]. a - outer surface; b - medial surface.

zones in the human cerebral cortex are 50%, in the cortex of higher (humanoid) monkeys - 20%, in lower monkeys this figure is 10% (Fig. 14.7). Among the association areas of the cortex of the human brain, the same author suggested isolating secondary and tertiary fields. Secondary associative fields are adjacent to the projection ones. They carry out the analysis and synthesis of elementary sensations that still retains a specific orientation.

Tertiary associative fields are located mainly between the secondary ones and are overlapping zones of neighboring territories. They are related primarily to the analytical activity of the cortex, providing the highest mental functions inherent in man in their most complex intellectual and speech manifestations. Functional maturity of tertiary as-

Rice. 14.7. Differentiation of projection and associative areas of the cerebral cortex during the evolution of primates [according to G.I. Polyakov]. a - the brain of the lower monkey; b - the brain of a higher ape; c - the human brain. Large dots indicate projection zones, small dots - associative ones. In lower monkeys, associative zones occupy 10% of the area of ​​the cortex, in higher ones - 20%, in humans - 50%.

social fields of the cerebral cortex occurs most late and only in a favorable social environment. Unlike other cortical fields, the tertiary fields of the right and left hemispheres are characterized by a pronounced functional asymmetry.

14.8. TOPICAL DIAGNOSIS OF LESIONS OF THE BRAIN CORTEX

14.8.1. Manifestations of damage to the projection zones of the cerebral cortex

In the cortex of each cerebral hemisphere, behind the central gyrus, there are 6 projection zones.

1. In the anterior part of the parietal lobe, in the region of the posterior central gyrus (cytoarchitectonic fields 1, 2, 3) located projection zone of general types of sensitivity(Fig. 14.4). The areas of the cortex located here receive sensitive impulses coming along the projection pathways of general types of sensitivity from the receptor apparatus of the opposite half of the body. The higher the area of ​​this projection zone of the cortex is, the lower the located parts of the opposite half of the body it has projection connections. Parts of the body with extensive reception (tongue, palmar surface of the hand) correspond to inadequately large parts of the area of ​​projection zones, while other parts of the body (proximal limbs, torso) have a small area of ​​cortical representation.

Irritation by the pathological process of the cortical zone of general types of sensitivity leads to an attack of paresthesia in parts of the body corresponding to the irritated areas of the cerebral cortex (sensitive Jacksonian seizure), which can turn into a secondary generalized paroxysm. The defeat of the cortical end of the analyzer of general types of sensitivity can cause the development of hypalgesia or anesthesia in the corresponding zone of the opposite half of the body, while the site of hypesthesia or anesthesia can be of a vertical circulatory or radicular-segmental type. In the first case, the sensitivity disorder manifests itself on the side opposite to the pathological focus in the region of the lips, thumb, or in the distal part of the limb with a circular border, sometimes like a sock or glove. In the second case, the zone of sensitivity impairment has the form of a strip and is located along the inner or outer edge of the arm or leg; this is explained by the fact that the inner side of the limbs is presented in the anterior, and the outer side - in the posterior sections of the projection zone of the analyzer of general types of sensitivity.

2. Visual projection zone located in the cortex of the medial surface of the occipital lobe in the region of the spur groove (field 17). In this field, there is a stratification of the IV (internal granular) layer of the cortex with a bundle of myelin fibers into two sublayers. Separate sections of field 17 receive impulses from certain sections of the homonymous halves of the retinas of both eyes; while the impulses coming from the lower parts of the homonymous halves of the retinas reach

the cortex of the lower lip of the spur groove, and the impulses coming from the upper parts of the retinas are directed to the cortex of its upper lip.

The defeat of the pathological process of the visual projection zone leads to the appearance on the opposite side of the quadrant or complete homonymous hemianopia on the side opposite to the pathological focus. Bilateral damage to the cortical fields 17 or the projection visual pathways leading to them can lead to complete blindness. Irritation of the cortex of the visual projection zone can cause the appearance of visual hallucinations in the form of photopsies in the corresponding parts of the opposite halves of the visual fields.

3. Hearing projection area located in the cortex of the convolutions of Heschl on the lower lip of the lateral (Sylvian) furrow (fields 41 and 42), which are, in fact, part of the superior temporal gyrus. Irritation of this zone of the cortex can cause the occurrence of auditory hallucinations (attacks of feeling noise, ringing, whistling, buzzing, etc.). The destruction of the auditory projection zone on the one hand can cause some hearing loss in both ears, to a greater extent in the opposite with respect to the pathological focus.

4 and 5. Olfactory and gustatory projection zones are on the medial surface of the vaulted gyrus (limbic region) of the brain. The first of them is located in the parahippocampal gyrus (field 28). The projection zone of taste is usually localized in the cortex of the opercular area (field 43). Irritation of the projection zones of smell and taste can cause their perversion or lead to the development of the corresponding olfactory and gustatory hallucinations. Unilateral loss of the function of the projection zones of smell and taste can cause a slight decrease in smell and taste, respectively, on both sides. Bilateral destruction of the cortical ends of the same analyzers is manifested by the absence of smell and taste on both sides, respectively.

6. Vestibular projection zone. Its localization is not specified. At the same time, it is known that the vestibular apparatus has numerous anatomical and functional connections. It is possible that the localization of the representation of the vestibular system in the cortex has not yet been clarified because it is polyfocal. N.S. Blagoveshchenskaya (1981) believes that in the cerebral cortex the vestibular projection zones are represented by several anatomical and functional interacting complexes, which are located in field 8, at the junction of the frontal, temporal and parietal lobes and in the zone of the central gyri, while it is assumed that each of these areas of the cortex performs its own functions. Field 8 is an arbitrary center of the gaze, its irritation causes the gaze to turn in the direction opposite to the pathological focus, changes in the rhythm and nature of the experimental nystagmus, especially soon after an epileptic seizure. In the cortex of the temporal lobe there are structures, the irritation of which causes dizziness, which manifests itself, in particular, in temporal lobe epilepsy; the defeat of the areas of representation of the vestibular structures in the cortex of the central gyri affects the state of the tone of the striated muscles. Clinical observations suggest that the nuclear-cortical vestibular pathways make a partial decussation.

It should be emphasized that signs of irritation of the listed projection zones can be a manifestation of the aura of an epileptic seizure corresponding in nature.

I.P. Pavlov considered it possible to consider the cortex of the precentral gyrus, which affects the motor functions and muscle tone of the predominantly opposite half of the body, with which it is connected primarily by the cortical-nuclear and cortical-spinal (pyramidal) pathways, as the projection zone of the so-called motor analyzer. This zone occupies first of all, field 4, on which the opposite half of the body is projected in an inverted form. This field contains the bulk of giant pyramidal cells (Betz cells), the axons of which make up 2-2.5% of all fibers of the pyramidal pathway, as well as medium and small pyramidal cells, which, together with the axons of the same cells located in the adjacent to the field 4 more extensive field 6, are involved in the implementation of monosynaptic and polysynaptic cortical-muscular connections. Monosynaptic connections provide mainly fast and precise targeted actions, depending on the contractions of individual striated muscles.

Damage to the lower parts of the motor zone usually leads to development on the opposite side brachiofacial (shoulder facial) syndrome or linguofaciobrachial syndrome, which are often observed in patients with impaired cerebral circulation in the basin of the middle cerebral artery, with combined paresis of the muscles of the face, tongue and arm, primarily the shoulder in the central type.

Irritation of the cortex of the motor zone (fields 4 and 6) leads to the appearance of convulsions in the muscles or muscle groups projected onto this zone. More often, these are local convulsions of the type of Jacksonian epilepsy, which can transform into a secondary generalized epileptic seizure.

14.8.2. Manifestations of damage to the associative fields of the cerebral cortex

Between the projection zones of the cortex are association fields. They receive impulses mainly from the cells of the projection zones of the cortex. In the associative fields, the analysis and synthesis of information that has undergone primary processing in the projection fields takes place. Associative zones of the cortex of the superior parietal lobule provide a synthesis of elementary sensations, in connection with this, such complex types of sensitivity as a sense of localization, a sense of weight, a two-dimensional-spatial sense, as well as complex kinesthetic sensations are formed here.

In the region of the interparietal sulcus, there is an associative zone that provides a synthesis of sensations emanating from parts of one's own body. Damage to this region of the cortex leads to autopagnosia, those. to not recognizing or ignoring parts of one's own body, or to pseudomelia the feeling of having an extra arm or leg, and anosognosia - lack of awareness of a physical defect that has arisen in connection with the disease (for example, paralysis or paresis of a limb). Usually, all types of autopagnosia and anosognosia occur when the pathological process is located on the right.

The defeat of the lower parietal lobule can be manifested by a disorder in the synthesis of elementary sensations or the inability to compare the synthesized complex sensations with "there was once in the perception of similar

in the same way, on the basis of the results of which recognition occurs ”(V.M. Bekhterev). This is manifested by a violation of the two-dimensional spatial sense (grafoesthesia) and three-dimensional spatial sense (stereognosis) - astereognosis.

In the case of damage to the premotor zones of the frontal lobe (fields 6, 8, 44), frontal ataxia usually occurs, in which the synthesis of afferent impulses (kinesthetic afferentation) is disturbed, signaling the position of body parts in space that changes during the movements made.

In violation of the function of the cortex of the anterior parts of the frontal lobe, which has connections with the opposite hemisphere of the cerebellum (fronto-bridge-cerebellar connections), statokinetic disturbances occur on the opposite side of the pathological focus (frontal ataxia). Particularly distinct are violations of late developing forms of statokinetics - upright standing and upright walking. As a result, the patient has uncertainty, unsteadiness of gait. While walking, his body leans back. (Henner sign) he puts his feet in a straight line (fox gait) sometimes when walking there is a "braiding" of the legs. In some patients with damage to the anterior frontal lobes, a peculiar phenomenon develops: in the absence of paralysis and paresis and the ability to make full movements of the legs, patients cannot stand (astasia) and walk (abasia).

The defeat of the associative zones of the cortex is often characterized by the development of clinical manifestations of a violation of higher mental functions (see Chapter 15).

The brain is the most perfect, and therefore one of the most difficult parts of the human body to study. And its most highly organized component is the cerebral cortex. More about the anatomy of this formation, the structure of the furrows and convolutions of the brain later in the article.

parts of the brain

In the process of intrauterine development, a complex brain was formed from an ordinary neural tube. This was due to the protrusion of five brain bubbles, which gave rise to the corresponding parts of the brain:

• telencephalon, or forebrain, from which the cerebral cortex, basal nuclei, anterior part of the hypothalamus were formed;
• the diencephalon, or diencephalon, which gave rise to the thalamus, epithalamus, the back of the hypothalamus;
• mesencephalon, or midbrain, from which the quadrigemina and brain stems subsequently formed;
• the metencephalon, or hindbrain, which gave rise to the cerebellum and pons;
• myelencephalon, or medulla oblongata.

bark structure

Due to the presence of the cortex, a person is able to experience emotions, navigate in himself, in the surrounding space. Remarkably, the structure of the bark is unique. The furrows and convolutions of the cerebral cortex of one person have a shape and size different from those of another. But the general plan of the building is the same.

What is the difference between the sulci and convolutions of the brain? Furrows are depressions in the cerebral cortex that look like gaps. It is they who divide the bark into shares. There are four lobes of the cerebral hemispheres:

• frontal;
• parietal;
• temporal;
• occipital.

Convolutions are convex areas of the cortex that are located between the furrows.

Formation of the cortex in embryogenesis

Embryogenesis is the intrauterine development of the fetus from conception to birth. First, uneven depressions form on the cerebral cortex, which give rise to furrows. First of all, primary furrows are formed. This happens around the 10th week of fetal development. After that, secondary and tertiary recesses are formed.

The deepest furrow is lateral, it is one of the first to form. It is followed in depth by the central one, which separates the motor (motor) and sensory (sensitive) zones of the cerebral cortex.

Most of the cortical relief develops from 24 to 38 weeks of gestation, and some of it continues to develop after the birth of the baby.

Varieties of furrows

Furrows are classified according to the function they perform. There are such types of them:

• primary formed - the deepest in the brain, they divide the cortex into separate lobes;
• secondary - more superficial, they perform the function of forming the convolutions of the cerebral cortex;
• additional, or tertiary - the most superficial of all types, their function is to provide an individual relief of the bark, to increase its surface.

Main furrows

Although the shape and size of some furrows and convolutions of the cerebral hemispheres differ from individual to individual, their number is normally unchanged. Every person, regardless of age and gender, has the following furrows:

• sylvian furrow - separates the frontal lobe from the temporal lobe;
• lateral groove - separates the temporal, parietal and frontal lobes, and is also one of the deepest in the brain;
• Roland's groove - separates the frontal lobe of the brain from the parietal;
• parieto-occipital sulcus - separates the occipital region from the parietal region;
• cingulate groove - located on the medial surface of the brain;
• circular - is the boundary for the insular part on the basal surface of the cerebral hemispheres;
• the hippocampal sulcus is a continuation of the cingulate sulcus.

Main convolutions

The relief of the cerebral cortex is very complex. It consists of numerous convolutions of different shapes and sizes. But you can select the most important of them, performing the most important functions. The main convolutions of the brain are presented below:

• angular gyrus - located in the parietal lobe, is involved in the recognition of objects through vision and hearing;
• Broca's center - the back of the lower frontal gyrus on the left (in right-handers) or on the right (in left-handers), which is necessary for the correct reproduction of speech;
• Wernicke's center - located in the back of the superior temporal gyrus on the left or right (by analogy with Broca's area), is involved in the understanding of oral and written speech;
• cingulate gyrus - located on the medial part of the brain, takes part in the formation of emotions;
• hippocampal gyrus - located in the temporal region of the brain, on its inner surface, necessary for normal memorization;
• fusiform gyrus - located in the temporal and occipital regions of the cerebral cortex, is involved in face recognition;
• lingual gyrus - located in the occipital lobe, plays an important role in processing information from the retina;
• precentral gyrus - located in the frontal lobe in front of the central sulcus, necessary for processing sensitive information entering the brain;
• postcentral gyrus - located in the parietal lobe behind the central sulcus, necessary for the implementation of voluntary movements.

Outside surface

The anatomy of the cerebral convolutions and sulci is best studied in parts. Let's start with the outer surface. It is on the outer surface of the brain that the deepest groove is located - the lateral one. It begins in the basal (lower) part of the cerebral hemispheres and passes to the outer surface. Here it branches into three more depressions: the ascending and anterior horizontal, which are shorter, and the posterior horizontal, which is much longer. The last branch has an upward direction. It is further divided into two parts: descending and ascending.

The bottom of the lateral furrow is called the islet. Further, it continues as a transverse gyrus. The islet is divided into anterior and posterior lobes. These two formations are separated from each other by a central sulcus.

parietal lobe

The boundaries of this part of the brain are outlined by the following furrows:

• central;
• parieto-occipital;
• transverse occipital;
• central.

Behind the central sulcus is the postcentral gyrus of the brain. Behind, it is limited by a furrow with the corresponding name - postcentral. In some lettered editions, the latter is divided into two more parts: upper and lower.

The parietal lobe is divided into two regions, or lobules, by means of the interparietal sulcus: superior and inferior. In the latter, supramarginal and angular gyrus of the cerebral hemispheres pass.

In the post-central, or posterior central, gyrus, there are centers that receive sensory (sensitive) information. It should be noted that the projection of different parts of the body in the posterior central gyrus is located unevenly. So, most of this formation is occupied by the face and hand - the lower and middle third, respectively. The last third is occupied by projections of the torso and legs.

In the lower part of the parietal lobe are the centers of praxis. It implies the development of automatic movements during the life. It includes, for example, walking, writing, tying shoelaces, and so on.

frontal lobe

The frontal part of the cerebral hemispheres is in front of all other formations of the brain. Behind, this area is limited from the parietal lobe by the central sulcus, from the side by the lateral sulcus - from the temporal region.

In front of the central sulcus is the precentral gyrus of the brain. The latter, in turn, is limited from the rest of the formations of the cortex of the frontal lobe with the help of a precentral depression.

The precentral gyrus, together with the posterior parts of the frontal lobe adjacent to it, plays an important role. These structures are necessary for the implementation of voluntary movements, that is, those that are under the control of consciousness. In the fifth layer of the cortex of the precentral gyrus are giant motor neurons, which are called pyramidal cells, or Betz cells. These neurons have a very long process (axon), the ends of which reach the corresponding segment of the spinal cord. This pathway is called the cortico-spinal pathway.

The relief of the frontal region of the brain is formed by three large convolutions:

• upper frontal;
• middle;
• bottom.

These formations are delimited from one another by means of the upper and lower frontal furrows.

In the back of the superior frontal gyrus, there is an extrapyramidal center, which is also involved in the implementation of movements. This system is historically older than the pyramid. It is necessary for the accuracy and smoothness of movements, for the automatic correction of motor acts that are already normal for a person.

In the back of the inferior frontal gyrus is Broca's motor center, which was already mentioned earlier in the article.

Occipital lobe

The boundaries of the occipital region of the brain are outlined by such formations: it is separated from the parietal lobe by the parietal-occipital depression, from below the occipital part smoothly flows into the basal surface of the brain.

It is in this part of the brain that the most unstable structures are located. But the posterior occipital gyrus of the brain is present in almost all individuals. Moving closer to the parietal region, transitional gyrus is formed from it.

On the inner surface of this area is a spur groove. It separates three convolutions from each other:

• wedge;
• lingual gyrus;
• occipitotemporal gyrus.

There are also polar furrows that have a vertical direction.

The function of the posterior lobe of the brain is the perception and processing of visual information. It is noteworthy that the projection of the upper half of the retina of the eyeball is in the wedge, but it perceives the lower part of the visual field. And the lower half of the retina, which receives light from the upper field of view, is projected into the region of the lingual gyrus.

temporal lobe

This structure of the brain is limited by such grooves: lateral from above, a conditional line between the lateral and posterior occipital grooves from behind.

The temporal lobe, by analogy with the frontal lobe, consists of three large convolutions:

• upper temporal;
• average;
• lower.

The name of the recesses corresponds to the convolutions.

On the lower surface of the temporal region of the brain, the hippocampal gyrus and the lateral occipitotemporal gyrus are also isolated.

In the temporal lobe is the speech center of Wernicke, which was already mentioned earlier in the article. In addition, this area of ​​the brain performs the functions of perception of taste, olfactory sensations. It provides hearing, memory, synthesis of sounds. Specifically, the superior temporal gyrus, as well as the inner surface of the temporal region, is responsible for hearing.

Thus, the lobes and convolutions of the brain are a complex and multifaceted topic to understand. In addition to the parts discussed in the article, there is also a limbic cortex with its own relief, a structure called an island. There is a cerebellum, which also has a cortex with its own characteristics. But to study the anatomy of the brain should be gradual, so this article provides only basic information.

The cortex of the hemispheres is covered with furrows and gyrus. Among them, the most deeply lying primary formed furrows are distinguished, dividing the hemispheres of the brain into lobes. The Sylvian sulcus separates the lobe of the frontal region from the temporal region, Roland's is the border between the frontal and parietal lobes.

The furrow of the parietal-occipital region is located on the medial plane of the cerebral hemisphere and divides the occipital region with the parietal region. The superolateral plane has no such border and is not divided into lobes.

The medial plane has a cingulate sulcus on itself, which passes into the sulcus of the hippocampus, thereby delimiting the brain, designed to perform the function of smell, from other lobes.

Secondary furrows in their structure, in comparison with primary ones, are intended for dividing the lobes into parts - gyrus, which are located on the outside of this type of gyrus.

I distinguish the third type of furrows - tertiary or, as they are also called, nameless. They are designed to give concrete shape to the convolutions, while also increasing the surface area of ​​the cortex.

At a depth, in the lower part of the lateral recess, there is a share of the island. It is surrounded on all sides by a circular furrow, and its area is completely riddled with folds and depressions. In its functions, the insula is connected with the brain of smell.

Speaking about the convolutions of the brain, I want to understand a little about the structure of the brain and consider its anatomical structure in more detail.

So, each hemisphere has three types of surface: medial, lower, upper-pateral.

The largest depression on the surface of this type is the lateral furrow. An adult has a very deep and wide depression in the lobes of the cerebral hemispheres, the so-called insula. This furrow begins at the base of the brain, as soon as it reaches the upper-pateral surface, it begins to divide into a deep, short one, which goes up, and a long one, going backwards, which is divided at the end into branches of a descending and ascending direction. This branching complex separates the temporal lobe anteriorly from the frontal and posteriorly from the parietal region.

The island that forms the bottom of this recess has a protrusion that points downwards. This feature of the structure is called the pole. From the front, top, back, the island is separated by a deep annular groove from the frontal, parietal, and temporal regions bordering it. They, in turn, form a tire, which is divided into fronto-parietal, temporal and suprafrontal.

The covering of the insula is divided by the main recess, which runs obliquely in the center, into the anterior and posterior lobes. The anterior lobe of the insula in front of the main sulcus is crossed by the precentral sulcus. These grooves and gyrus are called the anterior central gyrus of the insula.

From the anterior part of the location of the anterior central gyrus of the brain, two or three short gyruses diverge, which are separated from each other by small grooves of the insula. Its posterior lobe is slightly smaller than the anterior one, it is divided by a furrow into several long folds, which are located behind the central depression. The lower section of the island creates the pole of the island, or the polar furrow. To the base of the brain, the polar gyrus descends to the threshold of the insula, after which it goes further to the frontal part, becoming narrower than the lower frontal sulcus.

There is another furrow located in the upper-pateral part of the hemisphere - this is the central (main) gyrus. It crosses the upper part of the hemisphere behind, slightly affecting the medial area. Further, it stretches to the bottom and slightly forward, without touching the bottom of the lateral gyrus, thereby separating the frontal area from the parietal lobe. In the back of the head, the parietal region is in contact with the occipital region.

The distinction between them is the formed two convolutions and the furrows of the brain - from above - the furrow of the parieto-occipital region, which does not completely touch its upper-lateral surface. In general, it is located on its medial section, below - the occipital gyrus, which runs vertically, connects to the interparietal gyrus adjacent to it at an angle of ninety degrees.

The frontal area is represented by the central gyrus at the back and the lateral one from below. The anterior portion forms the pole of the frontal lobe. From the anterior part of the main gyrus, a pair of precentral sulci runs parallel to it: from above - the upper, from below - the lower. They are at a fairly large distance from each other, but in some places they intersect. That gyrus, which is located between the main and precentral sulci, is called the "precentral gyrus".

At the base, it turns into a tire, after which it connects to the transcentral furrow. This happens due to the fact that the central gyrus does not touch the bottom of the lateral sulcus. There is also a connection with the transcentral gyrus in the upper part, but only in the medial area, on the paracentral lobule.

From the two precentral convolutions, the furrows of the frontal lobe, which have an arcuate shape, diverge almost at an angle of 90 degrees.

From the top - the upper frontal, from the bottom - the lower frontal. These sulci and convolutions of the brain separate the three convolutions of the frontal lobe. The upper one is located above in relation to the frontal sulcus and touches the medial part of the hemisphere. The middle sulcus in the anterior part merges with the fronto-marginal sulcus.

Slightly above this gyrus, the anterior part of the hemisphere is cut through by orbital sulci, which flow into the medial surface of the hemisphere into a sulcus called the cingulate. The frontal inferior gyrus, which is located under the frontal inferior sulcus, is divided into three:

• opercular (located between the lower edge of the inferior sulcus of the brain and the branch of the ascending lateral gyrus);
• triangular (located between the ascending and extreme branches of the lateral gyrus);
• orbital (located to the front of the brain);

The superior frontal sulcus, located in the superior frontal gyrus, consists of three parts:

• cover part. This indicates the location between the ascending branch in the anterior part of the lateral recess and the lower surface of the groove of the precentral destination;
• triangular part. It is located between the ascending and horizontally lying branches of the furrow of the lateral destination;
• ophthalmic part. It is located slightly lower than the horizontal branch of the lateral furrow;

The lower plane of the frontal surface in its structure contains several convolutions of a small size. Along the edges of the medial lumen are straight convolutions. Further, they are joined by furrows intended for smell, small furrows of the orbital part, gyrus.

The lobe of the parietal part has a central sulcus in the anterior part, a lateral sulcus in the lower part, and a parieto-occipital and transverse occipital sulcus in the back.

Next to the central sulcus, near its posterior part, there is a postcentral sulcus, usually divided into an inferior and an superior gyrus. In the lower part, it, like the precentral gyrus, turns into a tire, and in the upper part - into the paracentral lobe.

The transcentral and main sulci and convolutions of the parietal region often merge into the interparietal sulcus. It is arcuate, goes back, parallel to the upper part of the hemisphere. The interparietal sulcus ends at the delimitation of the occipital lobe, while flowing in a large area into the transverse sulcus of the occipital part. The interparietal gyrus divides the parietal region into superior and inferior lobules.

The temporal region in the upper region is separated by a lateral formation, and the posterior region is delimited by a line that connects the posterior marginal surface of this brain of the sulcus with the underlying edge of the transverse sulcus of the occipital region. The border of the temporal region is separated by a line that connects two regions: the occipital-parietal and pre-occipital notches. The outer surface of the temporal region has temporal longitudinally lying folded formations, which are located parallel to the lateral one.

The temporal superior gyrus in the posterior part, however, like the lateral one, ends in a divergence into several branches, releasing two main ones - rising up and falling down. The branch, which is called ascending, flows into the lower part of the parietal lobule and is ringed by a gyrus, which is located at an angle. The middle fold of the temporal lobe consists of several, successive segments.

The inferior gyrus of the temporal region, in turn, is located on the lower lying part of the hemisphere. The temporal sulci of the brain distinguish three temporal folds located longitudinally. The temporal folded formation, located at the top, is located between the temporal region and the lateral region of the furrows. The middle one is located between the middle and upper recesses.

The lower one is laid between the lower groove and the middle one, a small part of it is located on the outer surface of the temporal region, the rest goes into the base. The lower wall of the lateral recess is formed by the upper part of the temporal gyrus, which, in turn, is divided into: the opercular, which is covered by the operculum of the fronto-parietal part, and the smaller one, the anterior section, covering the insula.

The opercular part is presented in the form of a triangle, in its area the transverse folds of the temporal lobe diverge like a fan, which are separated by transverse recesses. One of the transverse convolutions is not interrupted, while the rest are formed in the form of transitional convolutions and lead to the upper and lower planes of the temporal part.

The occipital region ends with a pole, from the front it is delimited by the parietal lobe with the parietal and occipital transverse furrows. It does not have a clear border with the temporal region and the border between them is conditional. It passes approximately in descending order to the lower part of the transverse groove of the occiput, heading to the notch of the preoccipital region, which is presented as a depression at the site of the transformation of the upper-lateral plane into its lower plane. The channels of the occipital region on the upper-lateral plane of the cerebral hemisphere are very unstable, both in number and in terms of direction.

Most of it is still represented by a number of lateral convolutions of the occiput, among which the largest, unchanged and constant is considered to be the gyrus that runs along the upper part of the occipital region, passing over the interocciput groove. This gyrus is a continuation of the interparietal deepening. The bridge, which is listed as the transition of the parietal region to the occipital region, has several convolutions of the transition connecting both regions.

Medial

The main on the medial plane are two furrows, concentrated around the corpus callosum. One of these furrows, which is most closely adjacent to the corpus callosum, is called the "sulcus of the corpus callosum".

From the back, it smoothly passes into a furrow with the name "hippocampus". This groove deeply lowers the wall of the brain, protruding it into the space of the horn of the ventricle in the form of a horn. Hence the name hippocampus. Another groove extends over the deepening of the corpus callosum of the brain, which has an arched shape and is called the cingulate. The next, going to the back, is the furrow of the subtopic part.

In the inner space of the temporal cavity, the rhinal sulcus extends parallel to the hippocampal sulcus. All three furrows are in their own way a border with an arcuate region that stands out against the whole background due to the general functions of the marginal lobe.

Its upper section, which is located between the deepening of the corpus callosum, the furrows, is called the cingulate gyrus, or the superior limbic gyrus. The lower part (limbic, parahippocampal gyrus) is located between the hippocampal and rhinal sulci.

These two convolutions are connected in the back of the corpus callosum to each other by means of the isthmus of the gyrus called the cingulate. The limbic gyrus in its anterior plane forms a bend that extends to the back, having the appearance of a hook. Its small end forms the intralimbic gyrus.

The posterior part of the medial plane has two very deep-lying grooves: one of them is parietal-occipital, the second is spur. The first penetrates into the upper part of the cerebral hemisphere in the place where the border of the occipital region with the parietal passes. Its exit ends on the upper-lateral plane.

In its advantage, it is located on the outer plane of the medial region of the cerebral hemisphere, after which it descends, while the spur groove rises towards it. Between the furrows of the parietal-occipital and marginal parts of the cingulate recess there is a gyrus, which has the shape of a quadrangle. It belongs to the parietal region and is called the precuneus.

The longitudinal direction is inherent in the spur groove, which moves forward, moving away from the occipital pole. The spur groove often diverges into two branches - upper and lower, and then merges with the groove of the parieto-occipital region at a certain angle. In place, the horn of the lateral cerebral ventricle, there is a bird's spur, which explains the elevation of the spur groove. Its continuation forward from the place where it connects with the furrow of the parieto-occipital region is called the trunk.

The end of the trunk is located on the back of the corpus callosum, and at the end from the bottom and from the top it has a roller - the isthmus. It belongs to the cingulate gyrus. Between the spur and parietal-occipital recess there is a folded formation, which is presented in the form of a triangle and called the "wedge".

The limbic, as it is also called, the cingulate fold, completely wraps around the corpus callosum, or, to be more precise, the commissure, which serves as a connection for both hemispheres. Toward the end, this gyrus ends with a roller. Passing under the corpus callosum, it is adjacent to its back and has the shape of an arc arch. Its lower part is presented in the form of a choroid plate.

This plate is a derivatory part of the telencephalon wall, but in this place it is maximally reduced. The area that it covers is called the choroid plexus, which protrudes into the space of the lateral cerebral ventricles, as a result of which a very early, according to ontogenetic indicators, furrow is formed. The triangle, which is formed between the column of the arch and the corpus callosum, is turned to the bottom, has a transparent bridge in its structure.

From the place where the rostral plate touches the column of the fornix, an end plate extends downward, which reaches down to the decussation. In its structure, it has an anterior wall of the cerebral bladder, which is located in front, between two protruding bladders of the telencephalon and is the border with the cavity of the third ventricle.

From the end plate, a near-terminal (subcallosal) gyrus extends forward, located parallel to the plate.

The lower part of the cerebral hemisphere

The lower part is represented mainly by the lower parts of the temporal, frontal and occipital regions. Between them there is a border, which is formed by a recess emanating from the base, a lateral type. On the plane of the frontal area there is a furrow of smell, which has in its structure the bulb of smell and the tract of olfactory functions.

It extends deeply, through the anterior part it goes beyond the boundaries of the olfactory bulb, and in the posterior part it diverges in half - into the medial and lateral processes. A straight fold extends between the deepening of the sense of smell and the marginal part of the medial plane of the hemisphere. Toward the outer part, proceeding from the furrow of smell, the lower part of the frontal area is covered with recessed channels that are very variable in shape and appearance, which constantly fold into an “H” - a shaped letter and are called orbital recesses. The groove, which transversely crosses the plane and forms a jumper "H", is commonly called the transverse orbital.

The grooves of the longitudinal type that depart from it are called the medial and lateral orbital grooves. They are located between the recesses of the orbital fold and are called orbital sulci.

The lower surface of the temporal region in its structure allows you to see the temporal inferior sulcus, which in some places comes into the outer plane of the hemisphere. Closer to the deep lying part and approximately parallel to it, the collateral groove extends. In a place around the horn of the cerebral ventricle, it corresponds to an elevation called collateral. The fold that penetrates inward, from the location of the collateral, lying between this formation and the spur groove, is called reed.

Each of the convolutions is designed to perform certain functions. Any factor that precedes the disruption of the performance of functions defined for the gyrus must be immediately identified and eliminated, otherwise it promises disruption of the body as a whole.

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