The telencephalon (large brain) is a derivative of the anterior cerebral bladder and is represented by two cerebral hemispheres. In each hemisphere, the cloak, olfactory brain and basal nuclei are distinguished. Inside each hemisphere there is a cavity - the lateral ventricle, which communicates with the third ventricle.

The outer layer of the cloak is the cortex, under which is located the white matter, which makes up the largest part of the hemisphere.

cerebral cortex

The cerebral cortex is a layer of gray matter, the thickness of which varies in different parts and averages 2–3 mm. The surface of the cortex has a complex relief, characterized by numerous furrows of the cerebrum and elevations located between them - the convolutions of the cerebrum. The convolutions differ among themselves in shape and size, however, the convolutions of the same name on the cortex of the hemispheres in different people are fundamentally similar and are localized in certain places.

In each hemisphere of the large brain, the upper-lateral, medial and lower surfaces are distinguished. The upper lateral surface of the cerebral hemisphere, the most extensive, has a convex shape, facing upwards and laterally. The flat medial surface faces the longitudinal fissure of the large brain, in the middle part it is connected by the corpus callosum with the same surface of the other hemisphere. The lower surface is flattened in the anterior and concave in the posterior. The transverse fissure of the cerebrum separates the cerebrum from the posterior cerebellum. Three main sulci divide each hemisphere into four lobes of the cerebrum.

• 1. The lateral groove begins on the lower surface of the hemisphere in the form of a lateral (Sylvian) fossa of the brain, goes up and back along the lateral side. It separates the frontal and temporal lobes.
• 2. The central sulcus runs frontally along the upper lateral surface of the hemisphere, starting from its upper edge. Usually it passes to its medial side and bottom slightly does not reach the Sylvian furrow. She shares upper part hemisphere into the anterior (smaller) section (frontal lobe) and posterior (larger), including the parietal and occipital lobes.
• 3. The parietal-occipital sulcus is located in the posterior part of the medial surface of the hemisphere, continuing slightly to the upper lateral surface. This groove is the boundary between the parietal and occipital lobes. On the medial surface, there is no real border between the frontal and parietal lobes; here they are separated by an imaginary continuation of the central sulcus.

Thus, the frontal lobe occupies the upper lateral surface of the hemisphere anterior to the central sulcus; the lower surface is anterior to the lateral groove. The temporal lobe occupies the upper lateral surface downward from the lateral sulcus and the lower surface of the hemisphere posterior to the lateral fossa (Sylvian fossa) of the brain. On the medial surface, it is located below the brain stem.

The parietal lobe lies in the center of the brain. On the upper lateral surface, it belongs to the area of ​​the hemisphere between the central sulcus in front, the lateral sulcus from below, and the imaginary continuation of the parietooccipital sulcus. On the medial surface of the hemisphere, the parietal lobe occupies the area between the parietal-occipital sulcus, an imaginary continuation of the central sulcus in front and the corpus callosum from below.

The occipital lobe is distinctly delimited from the parietal lobe only on the medial surface by the parietal-occipital sulcus. On the upper-lateral and lower surfaces of the hemisphere, its border is drawn by imaginary lines, which are continuations of the indicated furrow.

In addition to the four lobes described, there is also an islet. It lies in the depths of the lateral furrow and is visible only when the convolutions that limit this furrow are pulled apart.

The anterior end of the cerebral hemisphere is called the frontal pole, and its posterior end is the occipital pole.

Relief of the frontal lobe. On the upper lateral surface, the precentral sulcus passes in front of the central sulcus. Sometimes it is divided into two - the upper and lower precentral furrows. From this furrow originate, heading forward, two frontal furrows - upper and lower (Fig. 3.18).

These furrows describe the surface of the frontal lobe is divided into the following convolutions. Anterior to the central sulcus is the precentral gyrus. Three frontal gyrus are distinguished in the rest of the area: the superior frontal gyrus is located above the superior frontal sulcus along the upper edge of the hemisphere; the middle frontal gyrus lies between the superior and inferior frontal sulci; the inferior frontal gyrus is located under the inferior frontal sulcus (Fig. 3.19).

The relief of the parietal lobe. On the upper lateral surface, the postcentral sulcus runs parallel to the central sulcus. From it begins in the sagittal direction a long intraparietal groove. These two furrows divide the surface of the parietal lobe into three sections. Between the central and postcentral sulci is the postcentral gyrus. Above, it continues to the medial surface of the hemisphere. The area of ​​the cortex located above the interparietal sulcus is called the superior parietal lobule, the underlying area is called the inferior parietal lobule. It contains two very important convolutions - supramarginal, closing the end of the lateral sulcus, and angular, which surrounds the posterior end of the superior temporal sulcus.

The relief of the occipital lobe. On its upper lateral surface, the furrows vary greatly. Here, the superior occipital and lateral occipital sulci are distinguished. In accordance with this, superior and lateral occipital gyrus are distinguished.

The relief of the temporal lobe. On the upper lateral surface in the anteroposterior direction, the superior temporal sulcus passes, which, with its posterior end, extends into the region of the parietal lobe. The inferior temporal sulcus is located closer to the lower edge of the temporal lobe. These furrows separate the three temporal gyrus from each other. The superior temporal gyrus is located between the lateral and superior temporal sulci. Below the latter is the middle temporal gyrus. Along the lower edge of the hemisphere is the inferior temporal gyrus, located below the sulcus of the same name.

Rice. 3.18.

1 - central furrow; 2 - postcentral furrow; 3 - interparietal furrow; 4 - upper occipital furrows; 5 - lateral occipital furrows; 6 - transverse fissure of the brain; 7 - horizontal sulcus of the cerebellum; 8 - medulla oblongata; 9 - lower temporal sulcus; 10 - superior temporal sulcus; 11 - lateral furrow; 12 - lower frontal furrow; 13 - upper frontal furrow; 14 - precentral furrow

The island (islet lobe) is clearly visible only when the edges of the lateral sulcus are pushed apart or after the removal of the parts of the frontal, parietal and temporal lobes hanging over them (Fig. 3.20). The islet bears some resemblance to a cone, the base of which is surrounded by a deep circular furrow of the islet. Its surface is divided by means of the central sulcus of the insula into anterior and posterior lobes. The posterior lobe usually consists of only one long insular gyrus, while the anterior lobe contains several short insular gyrus.

Rice. 3.19.

1 - precentral furrow; 2 - central furrow; 3 - postcentral furrow; 4 - interparietal furrow; 5 - upper occipital furrows; 6 - superior occipital gyrus; 7 - lateral occipital sulcus; 8 - lateral occipital gyrus; 9 - lower temporal sulcus; 10 - superior temporal sulcus; 11 - lateral furrow; 12 - lower frontal furrow; 13 - upper frontal groove

Rice. 3.20.

1 - olive; 2 - pyramid; 3 - bridge; 4 - short gyrus of the island; 5 - circular furrow of the island; 6 - long gyrus of the island; 7 - central furrow of the island; 8 - cerebellum; 9 - medulla oblongata

The relief of the medial surface of the hemispheres. All its lobes extend to the medial surface of the cerebral hemisphere. The main sulcus is the sulcus of the corpus callosum, which surrounds the corpus callosum on its convex side, continuing into the hippocampal sulcus (Fig. 3.21). Approximately in the middle between the sulcus of the corpus callosum and the upper edge of the hemisphere is the cingulate sulcus. It turns to the upper edge of the hemisphere with its posterior end - the marginal branch - and slightly enters the upper lateral surface, posterior to the central sulcus. In front of the marginal branch, approximately above the middle of the corpus callosum, the cingulate gyrus gives up the paracentral sulcus. The immediate continuation of the cingulate sulcus is the subtopic sulcus. Below the posterior end of the corpus callosum, two grooves begin as a common trunk, diverging to the edge of the hemisphere - the already described parietal-occipital and spur grooves.

Rice. 3.21.

1 - paracentral furrow; 2 - marginal branch of the cingulate furrow; 3 - parieto-occipital sulcus; 4 - subtopic furrow; 5 - lingual gyrus; 6 - spur furrow; 7 - hippocampal sulcus; 8 - collateral furrow; 9 - nasal furrow; 10 - furrow of the corpus callosum; 11 - waist furrow

Near the occipital pole, on the lower surface of the hemisphere, a collateral groove begins, heading anteriorly. Its continuation in the anterior part of the temporal lobe is the nasal sulcus.

The part of the medial surface lying above the cingulate gyrus belongs to the frontal lobe. This is the superior frontal gyrus extending here. Behind, it reaches the level of the projection of the upper end of the central sulcus. Within the parietal lobe, there is a near-central lobule, which is adjacent to the marginal branch of the cingulate sulcus from behind. The pericentral lobule connects the parietal lobe with the frontal lobe on the medial surface (more precisely, the precentral and postcentral gyrus). The precuneus is located anterior to the marginal branch of the cingulate sulcus, posterior to the parietooccipital sulcus, and inferior to the subparietal sulcus (lies between them). Between the parieto-occipital sulcus and the spur sulcus (already in the occipital lobe) there is a wedge. On the medial surface of the same lobe is the lingual gyrus, the upper edge of which is adjacent to the spur groove. Below the collateral sulcus is the medial occipitotemporal gyrus.

Within the temporal lobe, on the medial surface of the hemispheres, directly under the legs of the brain, there is a parahippocampal gyrus, which ends in front with a hook. From the legs of the brain, the parahippocampal gyrus and the hook are separated by the hippocampal groove. Below the parahippocampal gyrus lies the lateral occipitotemporal gyrus. The named convolutions are separated behind by a collateral groove, in front - by a nasal groove.

The inferior temporal gyrus runs along the lowest edge of the medial surface of the temporal lobe, above which the lateral occipitotemporal gyrus is located.

The convolutions, annularly bordering the corpus callosum and the legs of the brain and extending from the frontal lobe to the temporal, as a whole constitute the vaulted gyrus, which is isolated as the limbic lobe. It consists of two parts - the cingulate and parahippocampal gyrus, connected to each other by an isthmus behind the ridge of the corpus callosum.

The cingulate gyrus lies between the sulcus of the corpus callosum on one side, the cingulate sulcus and the subparietal sulcus on the other. The parahippocampal gyrus, as already noted, is limited from above by the hippocampal sulcus, from below by the anterior end of the collateral and nasal sulci.

The relief of the lower surface of the hemispheres. On the lower (basal) surface of the frontal lobe is the olfactory groove, which runs parallel to the longitudinal fissure of the brain, and more laterally, the orbital grooves. Between these grooves there are convolutions of variable shape: a direct gyrus, which is limited by the longitudinal slit of the brain and the olfactory groove, as well as the orbital gyrus, which lies laterally from the olfactory groove (Fig. 3.22).

Rice. 3.22.

1 - orbital furrows; 2 - olfactory groove

Within the temporal and occipital lobes, there is no clear boundary between the medial and inferior surfaces. They gradually pass into each other. In this regard, the furrows and convolutions located on the medial surface of the hemispheres in the lower parts of the occipital and temporal lobes are also visible on the lower surface of the hemispheres. In particular, within the occipital lobe is the medial occipitotemporal gyrus. Within the temporal lobe lie the parahippocampal, lateral occipitotemporal, and inferior temporal gyrus. The sequence of location of these convolutions is considered in the lateral direction. The furrows separating these convolutions were named earlier.

The above description of the sulci and convolutions of the cerebral cortex can be considered schematic, since individual variants of their architectonics are often found.

Topic 14. Telencephalon.

telencephalon (telencephalon) represented by two hemispheres (hemispheri cerebri). Each hemisphere contains raincoat, or mantle (pallium), olfactory brain (rhinencephalon) and base nodes(basal ganglia). The remains of the original cavities of both vesicles of the telencephalon are lateral ventricles. The forebrain, from which the end brain is secreted, first arises in connection with the olfactory receptor (olfactory brain), and then becomes the organ for controlling the behavior of the animal, and centers of instinctive behavior based on species reactions (unconditioned reflexes) arise in it - subcortical nodes, and centers individual behavior, based on individual experience (conditioned reflexes), - the cerebral cortex. Accordingly, in the terminal brain, the following groups of centers are distinguished in the order of historical development:

Olfactory brain- the oldest and at the same time the smallest part, located ventrally.

Basal, or central, nuclei of the hemispheres, "subcortex", the old part of the telencephalon (paleencephalon), hidden in the depths.

New bark (cortex)- the youngest part (neoencephalon) and at the same time the largest part, covering the rest like a cloak, hence its name - a cloak, or mantle.

Since in the process of evolution of all parts of the central nervous system the telencephalon grows fastest and most of all, in humans it becomes the largest part of the brain and takes the form of two volumetric hemispheres - the right and left .

In the depths of the longitudinal fissure of the brain, both hemispheres are connected by a thick horizontal plate - corpus callosum (corpus collosum), which consists of nerve fibers running transversely from one hemisphere to the other. In the corpus callosum, a downward-curving end, or knee, is distinguished ), middle part , and the rear end, thickened in the form of a roller . All these parts are clearly visible on the longitudinal section of the brain between the hemispheres. The knee of the corpus callosum, bending down, sharpens and forms a beak , which passes into a thin plate, which in turn continues into the final plate.

Rice. 1. Sagittal section of the brain:

1 - frontal lobe; 2 - cingulate gyrus; 3 - corpus callosum; 4 - transparent partition; 5 - vault; 6 - anterior commissure; 7 - optic chiasm; 8 - hypothalamus; 9 - pituitary gland; 10 - temporal lobe; 11 - bridge; 12 - cerebellum; 13 - fourth ventricle; 14 - medulla oblongata; 15 - aqueduct of the brain; 16 - occipital lobe; 17 - the roof of the brain; 18 - epiphysis; 19 - parietal lobe; 20 - thalamus.

Under the corpus callosum is the so-called vault (fornix), representing two arched white strands, which are interconnected in their middle part, and diverge in front and behind, forming arch columns in front , behind the same - the legs of the vault. The legs of the arch, heading backwards, descend into the lower horns of the lateral ventricles and pass into the fimbria of the hippocampus. . Between the legs of the arch under the posterior end of the knee of the corpus callosum, transverse bundles of nerve fibers are stretched, forming the commissure of the arch. The anterior ends of the fornix continue in them to the base of the brain, where they end in the papillary bodies, passing through the gray matter of the hypothalamus. The columns of the arch limit the interventricular openings lying behind them, connecting the third ventricle with the lateral ventricles. Ahead of the columns of the vault is anterior spike, having the appearance of a white transverse crossbar, consisting of nerve fibers. A thin vertical plate of brain tissue is stretched between the anterior part of the arch and the knee - a transparent septum.

The cerebral cortex. The cerebral cortex is a layer of gray matter, the thickness of which varies in different parts and averages 2-3 mm. The surface of the crust has a complex relief, characterized by numerous furrows, and elevations located between them - convolutions. The convolutions differ among themselves in shape and size, however, the convolutions of the same name on the cortex of the hemispheres in different people are fundamentally similar and are localized in certain places. The area of ​​the cortex of an adult is about 220,000 mm 2, and 2/3 lies in the depth between the convolutions and only 1/3 lies on the surface.

In each hemisphere of the large brain, there are:

medial,

Dorso-lateral,

bottom surface.

Dorso-lateral surface hemisphere is convex, the most extensive, facing upwards and laterally, borders on the medial surface with a clearly defined edge.

flat medial surface facing the midline, in the middle part connected by the corpus callosum with the same surface of the other hemisphere.

bottom surface in the anterior section it is flattened, and in the posterior section it is concave.

Three major sulci divide each hemisphere into four lobes: frontal, parietal, temporal, occipital, and insula.

Consider the relief of the cerebral cortex.

Rice. 2. Upper lateral surface of the hemisphere: 1 - lateral furrow; 2 - middle frontal gyrus; 3 - superior frontal gyrus; 4 - precentral gyrus; 5 - upper and lower precentral furrows; 6 - central furrow; 7 - postcentral gyrus; 8 - postcentral furrow; 9 - intraparietal furrow; 10 - upper parietal lobule; 11 - lower parietal lobule; 12 - supramarginal gyrus; 13 - angular gyrus; 14 - occipital pole; 15 - lower temporal sulcus; 16 - inferior temporal gyrus; 17 - middle temporal gyrus; 18 - superior temporal gyrus; 19 - superior temporal sulcus; 20 lower frontal sulcus; 21 lower frontal gyrus; 22 - upper frontal furrow; 23 - cerebellum; 24 - medulla oblongata.

In the anterior part of each hemisphere of the brain is frontal lobe.

It ends in front with the frontal pole and is bounded below. lateral furrow(Sylvian furrow), and behind - deep central sulcus. Lateral furrow, starting on the lower surface of the hemisphere, goes up and then back along the lateral side, separating the frontal and temporal lobes. central sulcus located in the frontal plane. It begins in the upper part of the medial surface of the cerebral hemisphere, cuts its upper edge, descends without interruption along the upper lateral surface of the hemisphere down and ends, slightly short of the lateral groove. It separates the frontal lobe from the parietal and temporal. In front of the central sulcus, almost parallel to it, is located precentral sulcus. The latter ends at the bottom, not reaching the lateral furrow. The precentral sulcus is often interrupted in the middle part and consists of two independent sulci. From the precentral sulcus forward superior and inferior frontal sulci. They are located almost parallel to each other and divide the upper lateral surface of the frontal lobe into convolutions. Between the central sulcus posteriorly and the precentral sulcus anteriorly is precentral gyrus. Above the superofrontal sulcus lies superior frontal gyrus. Between the upper and lower frontal furrows stretches middle frontal gyrus. Down from the inferior frontal sulcus is located inferior frontal gyrus. The branches of the lateral sulcus protrude into this gyrus from below: ascending branch and anterior branch, which divide the lower part of the frontal lobe into three parts: tire part(frontal tire), covering the insular lobe (islet) lying in the depths of the furrow; triangular part and orbital part.

Behind the central sulcus is parietal lobe. The trailing edge of this fraction is parieto-occipital sulcus. This groove is located on the medial surface of the hemisphere, deeply cuts the upper edge of the cerebral hemisphere and passes to its upper lateral surface. The border between the parietal and occipital lobes on the dorsolateral surface of the cerebral hemisphere is a conditional line - the continuation of the parietal-occipital sulcus downwards. The lower border of the parietal lobe is the lateral groove that separates this lobe from the temporal lobe.

Within parietal lobe allocate noctcentral sulcus. It starts from the lateral groove at the bottom and ends at the top, not reaching the upper edge of the hemisphere. The postcentral sulcus lies behind the central sulcus and is almost parallel to it. Between the central and postcentral furrows is located postcentral gyrus. At the top, it passes to the medial surface of the cerebral hemisphere, where it connects with the precentral gyrus of the frontal lobe, forming with it paracentral lobule. Departs posteriorly from the postcentral sulcus intraparietal sulcus. It is parallel to the upper edge of the hemisphere. Above the intraparietal sulcus is a group of small convolutions, called superior parietal lobule. Below this furrow lies inferior parietal lobule, within which two convolutions are distinguished: supramarginal, and corner. The supramarginal gyrus covers the end of the lateral sulcus, and the angular gyrus covers the end of the superior temporal sulcus. The lower part of the inferior parietal lobule and the lower sections of the postcentral gyrus adjacent to it, together with the lower part of the precentral gyrus, hanging over the insular lobe, form fronto-parietal tegmentum of the insula.

Occipital lobe, is located behind the parietal-occipital sulcus and its conditional continuation on the upper lateral surface of the hemisphere. Compared to other shares, it is small in size. The occipital lobe ends at the occipital pole. The sulci and gyri on the superolateral surface of the occipital lobe are very variable. Most often and best expressed transverse occipital sulcus, which is, as it were, a continuation of the posterior intraparietal sulcus of the parietal lobe.

temporal lobe, occupies the lower lateral parts of the hemisphere and is separated from the frontal and parietal lobes by the lateral groove. The edge of the temporal lobe covering the insular lobe is called temporal operculum. The anterior part of the temporal lobe forms the temporal pole. Two furrows are visible on the lateral surface of the temporal lobe - superior and inferior temporal almost parallel to the lateral sulcus. The convolutions of the temporal lobe are oriented along the furrows. Superior temporal gyrus, located between the lateral groove at the top and the upper temporal at the bottom. Between the superior and inferior temporal sulci is middle temporal gyrus. The inferolateral edge of the temporal lobe occupies inferior temporal gyrus, bounded from above by the furrow of the same name. The posterior end of this gyrus continues into the occipital lobe.

insular lobe(islet), located in the depth of the lateral groove. This lobe can be seen if the frontal, parietal, and temporal lobes covering the insula are expanded or removed. deep circular furrow of the islet separates the islet from the surrounding parts of the brain.

On the medial surface above the corpus callosum, separating it from the rest of the hemisphere, is sulcus of the corpus callosum. Bending around the back of the corpus callosum, this furrow is directed downward and forward and continues into the hippocampal groove. Above the sulcus of the corpus callosum is girdle furrow. This sulcus begins anterior and inferior to the beak of the corpus callosum, rises up, then turns back and follows parallel to the sulcus of the corpus callosum, ends above and posterior to the ridge of the corpus callosum as subtopic sulcus. Between the sulcus of the corpus callosum and the cingulate sulcus is cingulate gyrus, covering the corpus callosum in front, above and behind. Behind and downward from the ridge of the corpus callosum, the cingulate gyrus narrows, forming isthmus of the cingulate gyrus. Further down and anteriorly, the isthmus passes into a wider parahippocampal gyrus bounded above by the groove of the hippocampus. The cingulate gyrus, isthmus, and parahippocampal gyrus are known as vaulted gyrus. The dentate gyrus is located deep in the hippocampal sulcus.

On the medial surface of the occipital lobe, there are two deep grooves merging with each other at an acute angle, open backwards: parieto-occipital sulcus that separates the parietal lobe from the occipital lobe, and spur furrow. The latter begins on the medial surface of the occipital pole and goes forward to the isthmus of the cingulate gyrus. The area of ​​the occipital lobe lying between the parietal-occipital and spur sulci and having the shape of a triangle with its apex facing the confluence of these sulci is called wedge. The spur groove, clearly visible on the medial surface of the hemisphere, limits lingual gyrus, extending from the occipital pole behind to the lower part of the isthmus of the cingulate gyrus. Below the lingual gyrus is located collateral groove, which already belongs to the lower surface of the hemisphere.

Rice. 3. Medial surface of the hemisphere: 1 - vault; 2 - beak of the corpus callosum; 3 - knee of the corpus callosum; 4 - trunk of the corpus callosum; 5 - furrow of the corpus callosum; 6 - cingulate gyrus; 7 - superior frontal gyrus; 8 -, 10 - belt furrow; 9 - paracentral lobule; 11 - prewedge; 12 - parieto-occipital sulcus; 13 - wedge; 14 - spur furrow; 15 - medial occipitotemporal gyrus; 16 - middle occipitotemporal gyrus; 17 - occipital-temporal groove; 18 - lateral occipitotemporal gyrus; 19 - hippocampal groove; 20 - parahippocampal gyrus

The relief of the lower surface of the hemisphere is very complex. The anterior sections of this surface are formed by the frontal lobe of the hemisphere, behind which the temporal pole protrudes, and there are also the lower surfaces of the temporal and occipital lobes, passing one into the other without noticeable boundaries. On the lower surface of the frontal lobe, somewhat lateral and parallel to the longitudinal fissure of the large brain, is olfactory groove. Below it are adjacent olfactory bulb and olfactory tract, passing from behind to olfactory triangle. The area of ​​the frontal lobe between the longitudinal fissure of the cerebrum and the olfactory sulcus is called direct gyrus. The surface of the frontal lobe, lying lateral to the olfactory sulcus, is divided by shallow orbital furrows, into several variable in shape, location and size orbital gyri.

Rice. 4. The lower surface of the hemisphere: 1- direct gyrus; 2 - olfactory groove; 3 - orbital furrows; 4 - orbital convolutions; 5 - anterior perforated substance; 6 - temporo-occipital furrow; 7 lateral temporo-occipital gyrus; 8 - medial temporo-occipital gyrus; 9 - collateral furrow; 10 - hippocampal groove; 11 - medial occipitotemporal gyrus; 12 - spur furrow; 13 - parahippocampal gyrus; 14 - hook; 15 - mastoid bodies; 16 - midbrain; 17 - olfactory bulb; 18 - olfactory tract; 19 - optic chiasm

In the posterior part of the lower surface of the hemisphere, it is clearly visible collateral groove, lying downward and laterally from the lingual gyrus on the lower surface of the occipital and temporal lobes, laterally from the parahippocampal gyrus, Somewhat anterior to the anterior end of the collateral sulcus is located nasal furrow sulcus rhindlis. It limits on the lateral side the curved end of the parahippocampal gyrus - hook. Lateral to the collateral groove lies medial occipitotemporal gyrus. Between this gyrus and located outward from it lateral occipitotemporal gyrus, located occipitotemporal groove.

Olfactory brain. Olfactory brain (rhinencephalon) - phylogenetically the most ancient part the forebrain, which arose in connection with the olfactory receptor, when the forebrain had not yet become an organ of animal behavior. Therefore, all its components are various parts olfactory analyzer. The olfactory brain is located on the lower and medial surfaces of the cerebral hemispheres and is conditionally divided into peripheral and central sections.

To peripheral department olfactory brain include olfactory bulb and olfactory tract, located on the lower surface of the frontal lobe in the olfactory groove. Olfactory tract ends olfactory triangle, which diverges in front of the anterior perforated substance in two olfactory stripes. Lateral strip ends in the cortex of the hook of the temporal lobe. medial strip goes to the subcallosal gyrus and the olfactory field, which are located under the beak of the corpus callosum.

To central department olfactory brain include: vaulted gyrus, hippocampus, dentate gyrus and hook.

hippocampus- a paired formation, represents an invagination of gray matter from the side of the medial wall of the lower horn of the lateral ventricle. The hippocampus is clearly visible in the cavity of the lower horn in the form of a club-shaped body. Many afferent systems are diffusely projected into the hippocampus, while efferent influences are directed mainly to the hypothalamus. The hippocampus is thought to play essential role in maintaining permanence internal environment organism, participates in the higher coordination of the functions of reproduction and emotional behavior, as well as in the processes of learning and memory preservation. The hippocampus is also the center of smell.

Basal ganglia located deep in the white matter of the hemispheres. They include striatum, consisting caudate and lenticular nuclei, almond nucleus and fence. These nuclei are separated from each other by layers of white matter, forming the inner, outer and outer capsules.

Rice. 5. Basal (subcortical) nuclei on the frontal section of the brain: 1-vascular plexus of the lateral ventricle (central part); 2-thalamus; 3-inner capsule; 4-islet bark; 5-fence; 6-almond-shaped body; 7-optic tract; 8-mastoid body; 9-pale ball; 10-shell; 11-fornix of the brain; 12-tailed nucleus; 13-callosal body.

striatum is divided by a bundle of nerve fibers coming from the cortex and called the internal capsule, into two parts, the caudate nucleus and the shell. Caudate nucleus club-shaped and curved backwards. Its anterior part is expanded, called the head, and is located above the lentiform nucleus, and its posterior part, the tail, runs above and lateral to the thalamus, separated from it by brain stripes. The head of the caudate nucleus is involved in the formation of the lateral wall of the anterior horn of the lateral ventricle. The caudate nucleus consists of small and large pyramidal cells.

Lenticular nucleus located lateral and anterior to the thalamus and caudate nucleus. On the frontal section it has the shape of a triangle. Two parallel vertical layers of white matter divide the lenticular nucleus into 3 parts: shell(the most lateral part) and the medial and lateral plates pale ball. The caudate nucleus and putamen are phylogenetically new formations, they are united under the common name neostriatum. Pale ball - a more ancient formation, is called paleostriatum or pallidum. Together they form the so-called striopallidary system.

The striatum receives afferent impulses mainly from the thalamus, partly from the cortex; sends efferent impulses to the pale ball. The striatum is considered as an effector nucleus that does not have independent motor functions, but controls the functions of a phylogenetically older motor center - the pale ball. The striatum regulates and partially inhibits the unconditioned reflex activity of the pale ball, that is, it acts on it in the same way as the pale ball acts on the red nucleus. The striatum is considered the highest subcortical regulatory and coordination center of the motor apparatus. In the striatum, according to experimental data, there are also higher vegetative coordination centers that regulate metabolism, heat generation and heat removal, as well as vascular reactions. Apparently, in the striatum there are centers that integrate, combine unconditioned reflex motor and vegetative reactions into a single holistic act of behavior.

With lesions of the striatum, a person has athetosis - stereotypical movements of the limbs, as well as chorea - strong irregular movements that occur without any order and sequence and capture almost all the muscles ("St. Witt's dance"). Both athetosis and chorea are considered as the result of the loss of the inhibitory effect that the striatum exerts on the pale nucleus.

pale ball- a paired formation, which is part of the lenticular nucleus, and which is the motor nucleus. With its irritation, you can get a contraction of the cervical muscles, limbs and the entire body, mainly on the opposite side. The pale nucleus receives impulses along afferent fibers coming from the thalamus and closing the thalamopallidar reflex arc. The pale nucleus, being effectorally connected with the centers of the middle and hindbrain, regulates and coordinates their work. One of the functions of the pale nucleus is the inhibition of the underlying nuclei, mainly the red nucleus of the midbrain, and therefore, if the pale ball is damaged, there is a strong increase in the tone of the skeletal muscles - hypertonicity, since the red nucleus is freed from the inhibitory influence of the pale ball. The thalamo-hypothalamo-pallidar system takes part in higher animals and humans in the implementation of complex unconditioned reflexes- defensive, indicative, food, sexual.

Almond nucleus represents a group of nuclei and is localized inside the anterior pole of the temporal lobe, lateral to the septum of the perforated substance. In functional terms, it is part of the limbic system, is involved in the regulation of autonomic and neuroendocrine reactions. The amygdala is characterized by a very low threshold of excitation, which may contribute to the development of epileptiform activity. When the amygdala is stimulated, convulsions, emotionally colored reactions, fear, aggression, etc. occur.

fence - a thin layer of gray matter, separated by an outer capsule of white matter from the lenticular nucleus. The fence below is in contact with the nuclei of the anterior perforated substance. Assume participation in the implementation of oculomotor reactions of tracking the object.

Between the caudate nucleus and the thalamus on one side and the lenticular nucleus on the other, there is a layer of white matter called internal capsule. All projection fibers pass through it to the cerebral cortex and from the cortex to the underlying parts of the central nervous system. It is divided into 3 sections: anterior leg, knee and posterior leg.

AT anterior leg of the internal capsule fibers formed by neurons of the frontal areas of the cortex pass: frontal-thalamic (tr. frontothalamicus), frontal-red nuclear (tr. frontorubralis) and frontal-pontine (tr. frontopontinus) paths.

AT knee of the internal capsule the cortical-nuclear pathway (tr. corticonuclearis) is located.

back leg in the anteroposterior direction they form: cortical-spinal (tr. corticospinalis), thalamo-cortical (tr. thalamocorticalis), occipital-temporal-bridge (tr. occipitotemporopontinus), auditory radiance (radiatio acustica), visual radiance (radiatio optica). Down the fibers are sent to the legs of the midbrain. Above the inner capsule, the fibers form radiant crown.

The internal structure of the new cortex. The human cortex is divided into six layers:

1 - molecular plate,

2 - outer granular plate,

3 - outer pyramidal plate,

4 - inner granular plate.

5 - inner pyramidal plate,

6 - multiform plate.

Rice. 6. The structure of the new cortex. I - molecular lamina, II - external granular lamina, III - external pyramidal lamina, IV - internal granular lamina, V - internal pyramidal lamina, VI - multiform lamina.

molecular plate, is the outermost layer of the cortex, poor in cellular elements. Here is a dense network formed by the dendrites of pyramidal neurons and axons of cells of other layers. The main purpose of this layer is to provide interneuronal connections between cells of different layers.

Outer granular plate consists of stellate neurons and small pyramids. In this layer, dichotomous branching of the dendrites of pyramidal neurons occurs, and many horizontal fibers pass through. The main function is the formation of vertical links.

Outer pyramidal layer contains pyramidal cells of various sizes. Their axons do not form long pathways. Associative afferents end on the neurons of this layer.

Inner granular lamina composed of densely packed stellate neurons. This is where the thalamocortical fibers end.

Internal pyramidal plate contains large and giant pyramids. Their apical dendrites rise into the first layer. From this layer, the cortico-nuclear and cortical-spinal pathways begin.

Multiform plate contains neurons of transitional forms of different sizes and continues into the white matter without a sharp border. Provides upward and horizontal links.

The functional unit of the cortex is a vertical column consisting of 3-7 cells, they together respond to the same stimulus.

Localization of functions in the neocortex. The type, mutual arrangement of neurons are not the same in different areas of the cortex. Cytoarchitectonic studies (studies of the location of neurons) made it possible to map the cortex. The classification of the fields by K. Brodman (1909) is generally accepted, which provides for the division of the cortex into 52 fields and the digital designation of the latter. This numbering formed the basis of the cytoarchitectonic map compiled by the Institute of the Brain of the Russian Academy of Sciences. In it, the row of fields is divided into zones, denoted by Latin letters.

Rice. 7. Cytoarchitectonic map of the cerebral cortex.

At present, the functional significance of various areas of the cortex has been established. Areas of the cortex with certain cytoarchitectonics and characteristic nerve connections involved in the performance of certain functions are called nerve centers. Traditionally, the centers of the neocortex are usually divided into projection(primary and secondary) and associative. projection centers- areas of the cortex, which are the cortical part of a particular analyzer. The criterion for assigning centers to primary- the existence of a direct input from the projection nuclei of the thalamus. They are characterized by a strict topological organization of inputs and a proportional dependence of the area of ​​representation on the density of innervation of the corresponding section of the prescription surface. The consequence of damage to the primary projection zone is the loss of perception of stimuli coming to the corresponding section of the receptor surface.

Secondary zones are located near the primary projection centers and are their peripheral parts. They are characterized, in addition to direct inputs from the projection thalamic nuclei, inputs from the primary projection centers, as well as the predominant representation of the most intensively innervated, and therefore the most functionally important departments. The role of secondary fields in the processes of perception and organization of movements turns out to be more complex than the primary ones. Damage leads to disruption complex shapes perception, recognition and evaluation of stimuli.

Association centers in the human brain, they occupy more than half of the entire surface of the hemispheres of the large chalk and are the youngest formations. The associative centers are associated with the associative nuclei of the thalamus and with the projection centers of the cortex. Associative centers take part in the organization of complex forms of behavior, in the implementation of higher nervous activity. Anatomically and functionally, associative centers are often asymmetric.

Main projection centers are:

1. Center of general sensitivity(tactile, temperature, pain, conscious proproceptive). It is localized in the postcentral gyrus (fields 3 - primary zone; 1.2 - secondary zone). The fields are somatotopically organized. In the upper section of the postcentral gyrus, the torso and lower limb are projected, in the middle - the upper limb, in the lower - the head. The defeat of the center is accompanied by a loss of tactile, temperature, pain sensitivity and muscle-articular feeling on the opposite half of the body.

2. Center for motor functions occupies field 4 of the precentral gyrus (primary zone) and field 6 of the paracentral lobule (secondary zone). Here the analysis of proprioceptive stimuli is carried out. The pyramidal tracts originate from the neurons of the inner pyramidal layer. In field 4 there is a clear somatotopic organization - "Penfield's motor homunculus". The body is projected "upside down" onto the cortex of the opposite hemisphere. The defeat of the zone leads to a violation of the perception of proprioceptive stimuli, central paralysis may occur. The center of motor functions is necessary to perform integrative functions when performing voluntary movements.

3. Body Map Center located in the parietal lobe (field 40). It presents somatotopic projections of all parts of the body. This is where conscious proprioceptive sensitivity comes in. The purpose of the center is to determine the position of the body and its parts in space and assess muscle tone. Violation of the center leads to the impossibility of recognizing parts of one's own body, the sensation of extra limbs, and the violation of determining the position of the body and its parts in space.

4. Center of vision located in the occipital lobe (field 17 - primary zone, fields 18, 19 - secondary). The retina is projected on field 17 neurons. Neurons 18 of the field provide visual memory, and 19 - orientation in an unusual environment. Unilateral damage to field 17 is accompanied by partial blindness in both eyes, but in different parts of the retina. The defeat of 18 and 19 fields leads to distorted visual perception.

5. hearing center located in the superior temporal gyrus, on the surface facing the insula (field 41). This is the primary auditory center, a unilateral lesion of which leads to hearing loss in both ears, on the opposite side - to a greater extent. Bilateral damage leads to complete deafness.

6. Center of taste located on the medial surface of the temporal lobe (fields 11, A, E). Here the fibers of the taste pathway of their own and opposite sides end. These areas belong to the limbic lobe of the brain, the defeat of which causes a disorder of taste, smell, and the appearance of hallucinations.

7. smell center located in the same place as the projection center of taste. Here the fibers of the olfactory pathway of their own and opposite sides end. Unilateral damage leads to a decrease in the sense of smell and olfactory hallucinations.

8. Center for vestibular functions located on the dorsal surface of the temporal lobe (fields 20,21,22). The defeat of these departments leads to spontaneous dizziness, a feeling of instability, a feeling of failure, a feeling of deformation of surrounding objects and their movement.

9. The center of visceroreception occupies the field 43 of the lower third of the postcentral and precentral gyri. This is where information comes from the interoreceptors of the internal organs. In the center, mainly pain sensations are analyzed.

Main association centers are:

1. Center for Stereognosy(recognition of objects by touch). It is located in the upper parietal lobule (field 7). The function of the center is the recognition of previously encountered objects. The center is constantly evolving. With the defeat of the center, the ability to create a general holistic view about the subject, while individual properties (shape, texture, mass, temperature, etc.) are determined correctly.

2. Praxia Center(purposeful habitual movements). It is located in the lower parietal lobule (field 40) in right-handers - in the left hemisphere, in left-handers - in the right. Ambidexes (equally wielding both hands) have a center in both hemispheres. The center develops as a result of repeated repetition of complex purposeful movements. The defeat leads to the loss of voluntary movements acquired by practice.

3. visual memory center. It is located on the dorsal surface of the occipital lobe (fields 18-19) for right-handers - on the left, for left-handers - on the right. Provides memorization of objects by their shape, appearance, color. The defeat of the center leads to visual agnosia. Partial agnosia may be observed (does not recognize acquaintances, his home, himself in the photo).

Centers associated with speech function.

4. Acoustic Speech Center(Wernicke Center). Located in the region of the superior temporal gyrus (field 42). The defeat of the center leads to sensory aphasia (verbal deafness). Although the patient hears, he does not understand speech. The auditory control of one's own speech is disturbed, which leads to the impossibility of constructing coherent sentences. The speech of such patients is a set of meaningless words and sounds.

5. Motor Speech Center(Brock's center). It is located in the region of the inferior frontal gyrus (field 44) ​​for right-handers - on the left, for left-handers - on the right. With a lesion, motor aphasia develops - the inability to speak with full preservation of understanding and inner speech.

6. Singing Speech Analyzer Center. Located next to the previous one (central sections of the inferior frontal gyrus) (field 45). The defeat of the center is accompanied by vocal amusia - the inability to perceive and compose musical phrases, and agrammatism - the inability to compose meaningful sentences from individual words. The speech of patients is an unrelated set of words.

7. Visual analyzer of written speech. Located in the angular gyrus of the inferior parietal lobule (field 39). The center analyzes visual information about letters, numbers, composition of words and understands their meaning. Defeat leads to the inability to read - alexia. The patient sees the letters, but does not understand the meaning.

8. Motor analyzer of written speech. It occupies the posterior sections of the midfrontal gyrus (field 8). When the center is affected, agraphia occurs (the inability to make precise and subtle movements with the hand necessary for writing).

These centers develop only in man and improve throughout life.

Auditory and motor centers of speech are laid at 3-4 months of life. The visual center of speech is in the fourth year of life. The motor center of writing begins to form at the age of 5-6 years.

The cerebral cortex, subcortical structures, and peripheral components of the body are connected by neuron fibers that form several types of pathways. association fibers- pass inside only one hemisphere and connect neighboring convolutions in the form short arcuate bundles, or the bark of various lobes, which requires more long fibers. The purpose of associative links is to ensure the holistic work of one hemisphere as an analyzer and synthesizer of multimodal excitations. Projection fibers- connect peripheral structures with the cerebral cortex. Ascending pathways. - transmit information to the corresponding cortical representations of one or another analyzer. Downward fibers- start from the motor areas of the brain. The task of these fibers is the organization of motor activity. Commissural fibers- provide a holistic joint work of the two hemispheres. They are presented alone

Lecture 8

The telencephalon, or large brain, in the process of evolution arose later than other parts of the brain. In its mass and size, it significantly exceeds all other parts of the brain and is directly related to the most complex manifestations of human mental and intellectual activity.

The telencephalon consists of two cerebral hemispheres, interconnected by the corpus callosum, the anterior and posterior commissures, and the fornix commissure. The cavities of the telencephalon form the right and left lateral ventricles of the brain, each of which is located in the corresponding hemisphere. The medial wall of each lateral ventricle in the rostral region is formed by a transparent septum.

The cerebral hemispheres are covered on top by the cerebral cortex - a layer of gray matter formed by more than fifty types of neurons. Under the cerebral cortex in the cerebral hemispheres is white matter, consisting of myelinated fibers, most of which connect the cortex with other parts and centers of the brain. In the thickness of the white matter of the hemispheres are accumulations of gray matter - the basal ganglia.

The thalamus and cerebral peduncles are fused with the cerebral hemispheres. The layer of white matter that limits the hemispheres from the thalamus of the diencephalon is called the internal capsule.

The right and left hemispheres of the brain are separated from each other by a longitudinal fissure. In each hemisphere, three surfaces are distinguished - lateral, medial and lower, as well as three edges - upper, medial and lower, and three poles - frontal, occipital and temporal.

The surface of the mantle part of each hemisphere is divided with the help of cracks and furrows into lobes, lobules and gyrus. The fissures and primary furrows are deep and belong to the permanent formations of the brain. They appear on the 5th month of intrauterine development and divide the hemispheres into lobes. The largest fissures are the longitudinal fissure of the brain, which separates the hemispheres from each other, and the transverse fissure, which separates the cerebellum from the occipital lobes. Secondary and especially tertiary furrows determine the individual relief of the surface of the hemispheres. Their formation occurs from birth to 7-8 years.

In most people, the main relief - the location of deep permanent furrows and large convolutions, is of a similar nature. Large furrows and fissures divide each hemisphere into 6 lobes: frontal, parietal, occipital, temporal, insular and limbic.

On the lateral surface of the hemisphere, a central (Roland) sulcus is distinguished, which separates the frontal lobe from the parietal, and a lateral (Sylvian) sulcus, which separates the temporal lobe from the frontal and parietal. The parietal lobe is limited from the occipital parietal-occipital sulcus. The anteroinferior border of the occipital lobe is a conditional line drawn from the upper end of the parietal-occipital sulcus down to the lower edge of the hemisphere. Deep in the lateral sulcus is the insular lobe (or islet). This lobe is covered by parts of the frontal, parietal and temporal lobes. On the medial surface of the hemisphere, next to the corpus callosum, is its limbic lobe, separated from the other lobes by the cingulate groove.

The frontal lobe contains the following sulci and gyri:

1 precentral sulcus; between the precentral and central sulcus is the precentral gyrus;

2. The upper and lower frontal grooves, between which the upper,

middle and inferior frontal gyri. The inferior frontal gyrus is divided into three parts: opercular (cover), triangular (triangular) and orbital (orbital).

3. Anterior horizontal sulcus and its ascending branch;

4. Medial frontal gyrus, separated from the limbic lobe by a cingulate groove;

5. Part of the cingulate gyrus;

6. Olfactory and orbital grooves located on the lower surface of the frontal lobe. The olfactory bulb, olfactory tract and olfactory triangle lie in the olfactory groove.

7. Direct gyrus, located between the olfactory groove and the medial

edge of the hemisphere.

The frontal lobe corresponds to the anterior horn of the lateral ventricle.

Functional characteristics of the cortical zones of the frontal lobe. 1. In the region of the precentral gyrus of the frontal lobe, there is the cortical nucleus of the motor analyzer - the kinesthetic center. This area is also called the sensorimotor cortex. Here comes part of the afferent fibers from the thalamus, carrying proprioceptive information from the muscles and joints of the body. Descending pathways to the brainstem and spinal cord also begin here, providing the possibility of conscious regulation of movements (pyramidal pathways). The defeat of this area of ​​the cortex leads to paralysis of the opposite half of the body.

2. In the posterior third of the middle frontal gyrus lies the center of writing - the center of graphics, or the associative center of written characters. This zone of the cortex gives projections to the nuclei of the oculomotor cranial nerves, and also communicates with the center of vision in the occipital lobe and the control center of the muscles of the arms and neck in the precentral gyrus with the help of cortical-cortical connections. The defeat of this center leads to impaired writing skills under visual control (agraphia).

3. In the posterior third of the inferior frontal gyrus, there is a motor speech center (Broca's center) - the center of speech articulation. It has a pronounced functional asymmetry. When it is destroyed in the right hemisphere, the ability to regulate timbre and intonation is lost, speech becomes monotonous. With the destruction of the speech-motor center on the left, speech articulation is irreversibly disturbed, up to the loss of the ability to articulate speech (aphasia) and singing (amusia). With partial violations, agrammatism can be observed - the inability to correctly build phrases.

4. In the area of ​​​​the anterior and middle thirds of the upper, middle and partially lower frontal gyri, there is an extensive anterior associative cortical zone that programs complex forms of behavior (planning different forms activities, decision-making, analysis of the results obtained, volitional reinforcement of activities, correction of the motivational hierarchy). The region of the frontal pole and the medial frontal gyrus is associated with the regulation of the activity of the emotional areas of the brain that are part of the limbic system, and is related to the control of psycho-emotional states. Disturbances in this area of ​​the brain can lead to a change in what is commonly called "personality structure" and will affect the character of a person, his value orientations, intellectual activity.

The orbital region contains the centers of the olfactory analyzer and is closely connected in anatomical and functional terms with the limbic system of the brain.

5. In the anterior section of the middle frontal gyrus, the center of the combined rotation of the head and eyes is located.

PARETIAL LOBE. The structure of the parietal lobe includes the postcentral gyrus, the postcentral sulcus, the interparietal sulcus, the superior and inferior parietal lobules; in the lower parietal lobule - the supramarginal and angular gyrus, the posterior part of the paracentral lobule; behind it lies the pre-wedge; parieto-occipital and sub-parietal sulci. The parietal lobe corresponds to the central part of the lateral ventricle.

Functional characteristics of the cortical zones of the parietal lobe. The cortical zones of the parietal lobe contain the following centers:

1. Projection center of general sensitivity - skin analyzer of general

sensitivity (tactile, pain, temperature and conscious proprioceptive) - the cortex of the postcentral gyrus.

2. The projection center of the body scheme is the edge of the intraparietal sulcus.

3. The associative center of "stereognosia" - the core of the skin recognition analyzer

objects to the touch - the cortex of the upper parietal lobule.

4. The associative center of "praxia" is an analyzer of purposeful habitual

movements (playing the piano, working on a typewriter) - supramarginal bark

convolutions.

5. Associative optical center of speech - a visual analyzer of written

speech - the center of the lexia (Dejerine) - the cortex of the angular gyrus.

temporal lobe. In the region of the temporal lobe on its lateral surface, the superior and inferior temporal sulci are distinguished. These grooves and the lateral groove are limited to the upper, middle, lower temporal gyrus.

On the lower surface, the temporal lobe does not have clear boundaries with the occipital lobe. Next to the lingual gyrus is the lateral occipital-temporal gyrus of the temporal lobe, which is limited from above by the collateral groove from the limbic lobe, and laterally by the occipital temporal groove. The temporal lobe corresponds to the inferior horn of the lateral ventricle.

Functional characteristics of the cortical zones of the temporal lobe.

1. In the region of the middle part of the superior temporal gyrus, on its upper surface, there is a cortical center of the auditory analyzer. Its damage leads to deafness. In the posterior third of the superior temporal gyrus lies the auditory speech center (Wernicke's center). Injuries to this area lead to an inability to understand spoken language: it is perceived as noise.

2. In the region of the middle and inferior temporal gyri, there is a cortical representation of the vestibular analyzer. Damage to this area leads to imbalance when standing and a decrease in the sensitivity of the vestibular apparatus.

ISLAND SHARE (ISLE). The insular lobe is located deep in the lateral sulcus. The islet is bounded by a circular furrow.

Functional characteristics of the cortical zones of the islet. It is assumed that the insula is related to the analysis of olfactory and taste sensations, as well as to the processing of somatosensory information and auditory perception of speech.

LIMBIC LOBE. This lobe is located on the medial surface of the hemisphere. It includes the cingulate gyrus, isthmus, dentate gyrus, and parahippocampal gyrus. One of the boundaries of this lobe is the groove of the corpus callosum. This groove, descending, continues into the groove of the hippocampus. Under the groove of the hippocampus in the cavity of the lower horn of the lateral ventricle is the gyrus of the hippocampus, or hippocampus.

Above the sulcus of the corpus callosum passes another border of the limbic lobe - the cingulate sulcus, which separates the cingulate gyrus. The cingulate groove separates the limbic lobe from the frontal and parietal lobes. The cingulate gyrus, through the isthmus, passes into the parahippocampal gyrus, which ends with a hook.

Functional characteristics of the cortical zones of the limbic lobe. The cingulate and parahippocampal gyrus are directly related to the limbic system of the brain. This system controls a complex of vegetative and behavioral psycho-emotional reactions to external environmental influences. In the hook and parahippocampal gyrus, there is a cortical representation of the gustatory and olfactory analyzer. At the same time, the hippocampus plays an important role in learning: the mechanisms of short-term and long-term memory are associated with it.

occipital lobe. On the lateral surface in the occipital lobe is a transverse occipital sulcus. On the medial surface are located: a wedge, bounded in front by the parietal-occipital groove, and behind by the spur groove; lingual gyrus, bounded above by the spur groove, and below by the collateral groove. The occipital lobe corresponds to the posterior horn of the lateral ventricle.

Functional characteristics of the cortical zones of the occipital lobe. The occipital lobe has the following centers:

The projection center of vision (the core of the visual analyzer) is located in the cortex, which limits the spur groove.

The associative center of vision (visual memory analyzer) is located in the cortex of the dorsal surface of the occipital lobe.

WHITE MATTER OF THE BRAIN HEMISPHERES. The white matter of the cerebral hemispheres is represented by numerous fibers, which are divided into three groups:

1. Projection fibers - bundles of afferent and efferent fibers that connect the projection centers of the cerebral cortex with the basal nuclei, the nuclei of the trunk and spinal cord. The projection fibers form the inner capsule and fornix of the brain.

2. Associative fibers connect areas of the cortex within the same hemisphere. They are divided into short and long.

3. Commissural fibers connect parts of the cortex of opposite hemispheres of the brain. The commissural formations include the corpus callosum, the anterior commissure of the brain, the commissure of the fornix, and the posterior commissure of the brain.

STRUCTURE OF THE BRAIN CORTEX. The cerebral cortex is

a huge accumulation of neurons and glial cells. The thickness of the cortex is from 1.2 to 4.5 mm, and the surface area in an adult is from 1700 to 2200 sq. cm. in the bark

The large brain is located according to various sources from 10 to 14 billion neurons.

The main part of the cerebral cortex (95.9% of the entire surface of the hemispheres) is a neocortex - a new cortex. Phylogenetically this is the most later education brain. The remaining 4.1% of the area covers

1. old bark - archiocortex, located in the temporal lobe, is called the hippocampus, or Amon's horn;

2. ancient cortex - paleocortex, which occupies a section of the cortex of the frontal lobe near the olfactory bulbs;

3. Small areas adjacent to the paleocortex are called the mesocortex - the interstitial cortex.

The ancient and old bark in the phylogeny of vertebrates appear earlier and bear the features of a relatively primitive internal structure. Main Feature

of these cortical areas is their weak stratification (division into layers). For example, the hippocampal cortex has five cortical layers, while the dentate gyrus cortex has only three layers. The neurons that form these layers are also more primitive than those of the neocortex.

The layered arrangement of neurons in the cortex is called cytoarchitectonics. In the neocortex of the cerebral hemispheres, neurons are grouped into six to seven cortical layers:

I - outer molecular, or pleximorphic;

II - external granular, or external granular;

III- external pyramidal, or ganglionic;

IV - internal granular, or internal granular;

V- internal pyramidal, or internal ganglionic;

VI and VII - layers of polymorphic neurons.

In each of the layers of the cortex, neurons of a certain size and shape predominate.

The first layer is poor in cells and contains mainly ramifications of the apical dendrites of pyramidal neurons of the underlying layers, as well as ramifications of axons of neurons. Thanks to the molecular layer, intra- and interhemispheric connections are carried out between different areas of the cortex.

The second layer includes small pyramidal and stellate (granular) neurons that provide partial processing of information and its transfer from the structures of the molecular layer to the underlying cortical layers. These neurons are also called interneurons or interneurons.

Granular neurons are also located in layer IV, where they process and transmit information from the endings of afferent fibers that enter the cortex and branch within layer IV to pyramidal neurons in layers III and V.

Layers III and V contain a large number of large pyramidal neurons, the axons of which provide different types of intracortical, intercortical, and cortical-subcortical connections. In the fifth layer, in the region of the precetral gyrus, there are the largest pyramidal neurons, which are called Betz's pyramidal cells. In layers III and V, interneurons of various sizes and shapes are also found in large numbers (bifascicular cells, long-axon and short-axon basket neurons, candelabra cells). Interneurons provide selective intracortical interactions between neurons of different types. This is required for:

Transfer of information between afferent fibers entering the cortex and

pyramidal neurons;

Exchange of information between neurons lying in different cortical layers;

Exchange of information between centers located in different convolutions, lobes and hemispheres;

Storage and reproduction of information.

Long-term circulation of excitation in the cortex and in the related parts and centers of the brain with the participation of interneurons accompanies cognitive operations and other higher forms mental activity. Ultimately, all information processes occurring in the structures of the brain are of an integrative, systemic nature and are mediated by a multitude of interneurons.

The lowest cortical layers VI and VII differ mainly in the density of cells on the section: layer VI is denser and contains larger neurons than layer VII. The lower layers are older than the rest, therefore they contain polymorphic cells that differ in shape from the pyramidal neurons and interneurons of the overlying layers. Layers VI and VII neurons provide U-shaped connections between the cortex in adjacent gyri and projection cortical-thalamic connections.

In addition to cellular elements (neurons and glia), branching fibers of various origins are located in the gray matter of the cortex. Among them, there are associative, commissural and projection fibers. The layered arrangement of fibers in the cortex is called myeloarchitectonics.

MODULAR ORGANIZATION OF THE GREAT HEMISPHERE CORTEX. The cortical module (neural ensemble) is a group of neurons, as well as glial cells and blood vessels, located in a special way in space and functionally interconnected. Such a module provides processing and storage of incoming information in the cerebral cortex. It has the appearance of a discrete columnar block of cells with a diameter of 300-600 microns, covering all the cortical layers in the vertical direction. A certain set of afferent fibers is associated with the module, bringing information that it undergoes standard discrete processing, as well as a set of efferent fibers that deliver it to certain areas of the brain. The various modules of the cortex are closely interconnected with the help of interneurons and intracortical fibers. The principle of modular structural and functional organization is valid for all departments of the central nervous system.

telencephalon anatomy

General morphology of the cerebral hemispheres, their lobes, main sulci and gyri, phylogeny of the cerebral hemispheres. Superolateral, medial and inferior surfaces of the cerebral hemispheres, their structures

The telencephalon (telencephalon) consists of two cerebral hemispheres, separated from each other by a longitudinal fissure. In the depths of the gap is the corpus callosum connecting them. In addition to the corpus callosum, the hemispheres are also connected by the anterior, posterior commissures and the commissure of the fornix. Three poles stand out in each hemisphere: frontal, occipital and temporal. Three edges (superior, inferior, and medial) divide the hemisphere into three surfaces: superior lateral, medial, and inferior. Each hemisphere is divided into lobes. The central sulcus (Roland) separates the frontal lobe from the parietal, the lateral sulcus (Sylvian) separates the temporal from the frontal and parietal, the parietal-occipital sulcus separates the parietal and occipital lobes. In the depth of the lateral groove is the insular lobe. Smaller furrows divide the lobes into convolutions.

Superolateral surface of the cerebral hemisphere. The frontal lobe, located in the anterior part of each cerebral hemisphere, is bounded from below by the lateral (Sylvian) groove, and behind by the deep central groove (Roland), located in the frontal plane. In front of the central sulcus, almost parallel to it, is the precentral sulcus. From the precentral sulcus forward, almost parallel to each other, the superior and inferior frontal sulci are directed, which divide the upper lateral surface of the frontal lobe into convolutions. Between the central sulcus behind and the precentral anterior is the precentral gyrus. Above the superior frontal sulcus lies the superior frontal gyrus, which occupies the upper part of the frontal lobe.

The middle frontal gyrus runs between the superior and inferior frontal sulci. Down from the inferior frontal sulcus is the inferior frontal gyrus, into which the ascending and anterior branches of the lateral sulcus protrude from below, dividing the lower part of the frontal lobe into small gyrus. The tegmental part (frontal tegmentum), located between the ascending branch and the lower part of the lateral sulcus, covers the insular lobe, which lies deep in the sulcus. The orbital part lies downward from the anterior branch, continuing to the lower surface of the frontal lobe. In this place, the lateral sulcus widens, passing into the lateral fossa of the brain.

The parietal lobe, located posterior to the central sulcus, is separated from the occipital parietal-occipital sulcus, which is located on the medial surface of the hemisphere, deeply protruding into its upper edge. The parietal-occipital sulcus passes into the upper-lateral surface, where the border between the parietal and occipital lobes is a conditional line - the continuation of this sulcus downwards. The lower border of the parietal lobe is the posterior branch of the lateral sulcus, which separates it from the temporal lobe. The postcentral sulcus runs behind the central sulcus, almost parallel to it.

Between the central and postcentral sulci, there is a postcentral gyrus, which at the top passes to the medial surface of the cerebral hemisphere, where it connects with the precentral gyrus of the frontal lobe, forming together with it the precentral lobule. On the upper lateral surface of the hemisphere below, the postcentral gyrus also passes the precentral gyrus, covering the central sulcus from below. An intraparietal sulcus extends posteriorly from the postcentral sulcus, parallel to the upper edge of the hemisphere. Above the intraparietal sulcus is a group of small convolutions, called the superior parietal lobule; below is the lower parietal lobule.

The smallest occipital lobe is located behind the parietal-occipital sulcus and its conditional continuation on the upper lateral surface of the hemisphere. The occipital lobe is divided into several gyri by sulci, of which the transoccipital sulcus is the most constant.

The temporal lobe, which occupies the lower lateral parts of the hemisphere, is separated from the frontal and parietal lobes by the lateral groove. The insular lobe is covered by the edge of the temporal lobe. On the lateral surface of the temporal lobe, almost parallel to the lateral sulcus, are the superior and inferior temporal gyri. On the upper surface of the superior temporal gyrus, several weakly expressed convolutions (Geschl's gyrus) are visible. The middle temporal gyrus is located between the superior and inferior temporal sulci. Below the inferior temporal sulcus is the inferior temporal gyrus.

The insular lobe (islet) is located in the depth of the lateral groove, covered by a tire formed by sections of the frontal, parietal and temporal lobes. The deep circular groove of the insula separates the islet from the surrounding brain regions. The lower anterior part of the islet is devoid of furrows and has a slight thickening - the threshold of the islet. On the surface of the island, a long and a short gyrus are distinguished.

Medial surface of the cerebral hemisphere. All of its lobes, except for the insula, take part in the formation of the medial surface of the cerebral hemisphere. The sulcus of the corpus callosum goes around it from above, separating the corpus callosum from the lumbar gyrus, goes down and forward and continues into the sulcus of the hippocampus.

Above the cingulate gyrus is the cingulate groove, which begins anteriorly and downwards from the beak of the corpus callosum. Rising up, the groove turns back and goes parallel to the groove of the corpus callosum. At the level of its ridge, its marginal part departs upward from the cingulate sulcus, and the sulcus itself continues into the subtopic sulcus. The marginal part of the cingulate groove posteriorly limits the near-central lobule, and in front - the precuneus, which belongs to the parietal lobe. From top to bottom and back through the isthmus, the cingulate gyrus passes into the parahippocampal gyrus, which ends in front with a hook and is bounded from above by the groove of the hippocampus. The cingulate gyrus, isthmus, and parahippocampal gyrus are collectively referred to as the vaulted gyrus. The dentate gyrus is located deep in the hippocampal sulcus. At the level of the ridge of the corpus callosum, the marginal part of the cingulate sulcus branches upward from the cingulate sulcus.

The lower surface of the cerebral hemisphere has the most complex relief. In front is the surface of the frontal lobe, behind it is the temporal pole and the lower surface of the temporal and occipital lobes, between which there is no clear boundary. Between the longitudinal fissure of the hemisphere and the olfactory sulcus of the frontal lobe is a straight gyrus. Lateral to the olfactory sulcus lie the orbital gyri. The lingual gyrus of the occipital lobe is bounded on the lateral side by the occipital-temporal (collateral) groove. This groove passes to the lower surface of the temporal lobe, separating the parahippocampal and medial occipitotemporal gyrus. Anterior to the occipital-temporal sulcus is the nasal sulcus, which limits the anterior end of the parahippocampal gyrus - the hook. The occipitotemporal sulcus separates the medial and lateral occipitotemporal gyri.

On the medial and lower surfaces, there are a number of formations related to the limbic system (from lat. Limbus-border). These are the olfactory bulb, olfactory tract, olfactory triangle, anterior perforated substance, mastoid bodies located on the lower surface of the frontal lobe ( peripheral department olfactory brain), as well as the cingulate, parahippocampal (together with the hook) and dentate gyrus. The subcortical structures of the limbic system are the amygdala, septal nuclei, and anterior thalamic nucleus.

The limbic system is connected with other areas of the brain: with the hypothalamus, and through it with the midbrain, with the cortex of the temporal and frontal lobes. The latter, apparently, regulates the functions of the limbic system. The limbic system is a morphological substrate that controls the emotional behavior of a person, controls his general adaptation to conditions. external environment. All signals coming from the analyzers pass through one or more structures of the limbic system on their way to the corresponding centers of the cerebral cortex. Downward signals from the cerebral cortex also pass through the limbic structures.

The structure of the cerebral cortex. The cerebral cortex is formed by gray matter, which lies along the periphery (on the surface) of the cerebral hemispheres. The neocortex predominates in the cerebral cortex (about 90%) - a new cortex that arose for the first time in mammals. Phylogenetically older areas of the cortex include the old cortex - the archecortex (the dentate gyrus and the base of the hippocampus) as well as the ancient cortex - the paleocortex (preperiform, preamygdala and entorial regions). The thickness of the cortex in different parts of the hemispheres ranges from 1.3 to 5 mm. The thickest cortex is located in the upper parts of the precentral and postcentral gyri and near the paracentral lobule. The bark of the convex surface of the gyri is thicker than on the lateral and bottom furrows. The surface area of ​​the cortex of the cerebral hemispheres of an adult reaches 450,000 cm2, one third of which covers the convex parts of the convolutions and two thirds - the lateral and lower walls of the furrows. The cortex contains 10-14 billion neurons, each of which forms synapses with about 8-10 thousand others.

For the first time, the domestic scientist V.A. Betz showed that the structure and interaction of neurons is not the same in different parts of the cortex, which determines its neurocytoarcheny. Cells of more or less the same structure are arranged in separate layers (plates). In the new cerebral cortex, the bodies of neurons form six layers. In different departments, the thickness of the layers, the nature of their boundaries, the size of the cells, their number, etc. vary. Pyramid-shaped cells of various sizes (from 10 to 140 microns) predominate in the cerebral cortex. Small pyramidal cells located in all layers of the cortex are associative or commissural intercalary neurons. Larger ones generate impulses of voluntary movements directed to the skeletal muscles through the corresponding motor nuclei of the brain and spinal cord.

Outside is a molecular layer. It contains small multipolar association neurons and many fibers - processes of neurons of the underlying layers, passing as part of the tangential layer parallel to the surface of the cortex. The second layer - the outer granular one - is formed by many small multipolar neurons, the diameter of which does not exceed 10-12 microns. Their dendrites are directed to the molecular layer, where they pass as part of the tangential layer. The third layer of the cortex is the widest. This is the pyramidal layer, which contains pyramid-shaped neurons whose bodies increase from top to bottom from 10 to 40 microns. This layer is best developed in the precentral gyrus. The axons of large cells of this layer, covered with a myelin sheath, are sent to the white matter, forming associative or commissural fibers. Axons of small neurons do not leave the cortex. Large dendrites extending from the top of the pyramidal neurons are sent to the molecular layer, the remaining small dendrites form synapses within the same layer.

The fourth layer - internal granular - is formed by small stellate neurons. This layer is unevenly developed in different parts of the cortex. In the fifth layer, the inner pyramidal layer, which is most well developed in the precentral gyrus, there are pyramidal cells discovered by V.A. Betz in 1874. These are very large nerve cells (up to 80-125 microns), rich in chromatophilic substance. The axons of these cells leave the cortex and form descending corticospinal and corticonuclear (pyramidal) pathways. Collaterals depart from the axons, heading to the cortex, to the basal nodes (ganglia), the red nucleus, the reticular formation, the nuclei of the bridge and olives. In the sixth layer - polymorphic cells - there are neurons of various shapes and sizes. The axons of these cells are sent to the white matter, and the dendrites - to the molecular layer. However, not all cortex is built this way. On the medial and lower surfaces of the cerebral hemispheres, sections of the old (archecortex) and ancient (paleocortex) cortex, which have a two- and three-layer structure, have been preserved.

In each cell layer, in addition to nerve cells, there are nerve fibers. The structure and density of their occurrence are also not the same in different parts of the crust. Features of the distribution of fibers in the cerebral cortex are defined by the term "myeloarchitectonics". K. Brodman in 1903-1909 identified 52 cytoarchitectonic fields in the cerebral cortex.

O. Vogt and C. Vogt (1919-1920), taking into account the fiber structure, described 150 myeloarchitectonic areas in the cerebral cortex. At the Academy's Brain Institute medical sciences created detailed maps cytoarchitectonic fields of the human cerebral cortex (I.N. Filimonov, S.A. Sarkisov). The fibers of the cortex of the cerebral hemispheres are divided into commissural, which connect the sections of the cortex of both hemispheres, associative, connecting various functional areas cortex of the same hemisphere, and projection, which connect the cerebral cortex with the underlying parts of the brain. They form radially oriented layers that end on the cells of the pyramidal layer. In the molecular, inner granular and pyramidal layers, there are tangential plates of myelin fibers that form synapses with cortical neurons.

J. Szentagothai (1957) developed the concept of a modular structure of the cerebral cortex. The module is a vertical cylindrical column of the cortex with a diameter of about 300 μm, the center of which is the cortico-cortical associative or commissural fiber, extending from the pyramidal cell. They terminate in all layers of the cortex, and branch into horizontal branches in the first layer. About 3 million modules have been identified in the human cerebral cortex.

Thus, the telencephalon consists of two hemispheres: left and right, connected by spikes ( corpus callosum, commissure fornix, anterior commissure).

Three surfaces are distinguished in each hemisphere: upper lateral, medial, lower.

In each hemisphere, 3 edges are distinguished: top, bottom, middle.

Each hemisphere has: frontal pole, occipital pole, temporal pole.

The surface of the hemispheres is divided by furrows into convolutions. There are gyri of different order: primary gyrus, secondary gyrus, tertiary gyrus.

Each hemisphere of the telencephalon consists of five shares: frontal, parietal, occipital, temporal, insular.

The frontal lobe is bounded below by the Sylvian sulcus, and posteriorly by the Roland sulcus. In front of the central sulcus, almost parallel to it, is the precentral sulcus. From the precentral sulcus, the superior and inferior frontal sulci run forward, dividing the superolateral surface of the frontal lobe into convolutions.

The parietal lobe is separated from the frontal lobe by the central (Roland) sulcus, and from the occipital lobe by the parietal-occipital sulcus. The postcentral sulcus runs behind the central sulcus, almost parallel to it. Between the central and postcentral sulci is the postcentral gyrus. The intraparietal sulcus departs posteriorly from the postcentral sulcus.

The occipital lobe is divided into several convolutions by sulci, of which the transverse occipital sulcus is the most constant.

The temporal lobe is separated from the frontal and parietal lobes by the lateral (Sylvian) groove. On the lateral surface are the superior and inferior temporal gyri. On the upper surface of the superior temporal gyrus, several weakly expressed transverse gyrus of Heschl are visible. Between the upper and lower is the middle temporal gyrus.

The insular lobe is located deep in the lateral sulcus. The deep circular groove of the insula separates the islet from the surrounding brain regions. On the surface, long and short gyrus of the island are distinguished.

On the medial surface of the cerebral hemispheres stand out:

sulcus of the corpus callosum,

lumbar gyrus,

furrow of the hippocampus,

Vaulted gyrus (cingulate sulcus, parahippocampal gyrus, isthmus)

Dentate gyrus.

The entire surface of the hemispheres is covered with a cloak of gray matter - the bark. The cerebral cortex consists of six layers:

1. Molecular;

2. Outer granular;

3. Layer of pyramidal cells;

4. Inner grainy;

5. Ganglionic;

6. Layer of polymorphic cells.

The bark is topographically heterogeneous, therefore, it is distinguished cytoarchitectonic areas:

1. Frontal,

2. Occipital,

3. Upper parietal,

4. Lower parietal,

5. Precentral,

6. Postcentral,

7. Temporal,

8. Islet,

9. Limbic.

All these areas are divided into cytoarchitectological fields, there are more than 50 of them.

The anterior part of the telencephalon is called olfactory brain. They belong to the olfactory brain.

telencephalon, telencephalon,- the most massive of the affairs of the human brain. It occupies most of the cranial cavity. The telencephalon consists of paired cerebral hemispheres, hemispheria cerebri, separated by a longitudinal fissure and covering from above most of the brain stem and cerebellum. The convex upper surface of the cerebral hemispheres has three poles: frontal, temporal and occipital. The lower surface of the cerebral hemispheres is flattened. The length of the hemisphere is approximately 17.5 cm, the width is 6.5 cm. Outside, the hemispheres are covered with gray matter - the bark of the cerebral hemispheres, it is also called a cloak or mantle. Under the cortex is a white matter, in the depths of which lie the basal nuclei (kernels of the telencephalon, basal ganglia). The cavities of the hemispheres are the lateral ventricles.

White matter of the hemispheres consists of three fiber systems:

1. Projection fibers are ascending and descending pathways connecting the hemispheres with the rest of the CNS. An example of descending fibers is the fibers of the corticospinal (pyramidal), corticorubral and corticospinal tracts, and ascending fibers are fibers that go from the thalamus to the cortex.

2. Associative fibers connect different areas of the cortex of one hemisphere.

3. Commissural fibers connect the symmetrical parts of the right and left hemispheres. The largest commissure of the brain is corpus callosum, corpus callosum, is a thick horizontal plate located deep in the longitudinal fissure separating the hemispheres. From this plate in the thickness of the hemispheres fibers diverge, forming the radiance of the corpus callosum. In the corpus callosum, an anterior part is distinguished (see Fig. 41), the anterior part is the knee, the middle part is the body and the posterior part is the roller. The knee bends down and passes into the beak of the corpus callosum. In addition to the corpus callosum, the telencephalon includes the anterior commissure, which connects some of the olfactory structures and areas of the temporal lobes where callosal fibers (fibers of the corpus callosum) do not extend. Basal nuclei include the caudate nucleus, pale ball, shell, fence and amygdala (Fig. 37, 38).

Rice. 37. Basal nuclei:

1-3 - caudate nucleus: 1- head, 2- body, 3- tail;

4 - shell and pale ball; 5- almond-shaped nucleus;

6 - lateral ventricle

The largest of these nuclei is caudate nucleus. It is elongated in the rostro-caudal direction (from front to back) and has a C-shape. The thickened anterior part forms the head of the caudate nucleus, it passes into the body and ends with a tail. On the frontal section (Fig. 38), only the head of this nucleus is visible.

Rice. 38. Frontal section through the cerebral hemispheres

at the level of the gray hillock: 1- corpus callosum; 2- transparent partition;

3 - the central part of the lateral ventricle; 4- vault; 5 - III ventricle;

6 - caudate nucleus; 7- thalamus; eight- fence; nine- shell;

10 - pale ball; eleven- amygdala; 12- gray bump;

13 - funnel; fourteen- visual tract; fifteen- visual chiasma;

16 - optic nerve; 17- bark of the insular lobe;

18 - lateral furrow

The pale ball, shell and fence are located lateral and lower from the caudate nucleus. They are separated from it by a layer of white matter (fibers of the cortical tracts). The most medial position is pale ball, lateral to it lies a cup-shaped shell, separated from the pale ball by a strip of white matter. Between the shell and the insular cortex (see below) lies a strip of gray matter - fence.

The caudate nucleus, the globus pallidus, and the shell appear as alternating bands of gray and white matter on section. Because of this, they were united under the general name of the striatum, corpus striatum. Later, when studying the cellular composition and nature of the connections of the basal ganglia, it turned out that the globus pallidus is a phylogenetically older formation and differs significantly from the caudate nucleus and putamen. In this regard, the pale ball, globus pallidus, isolated from the striatum as a separate unit - the pallidum. Phylogenetically younger caudate nucleus and putamen are called striatum. Together they form the striapallidar system, which has very extensive connections, primarily with the thalamus, as well as with the cerebral cortex, cerebellum, substantia nigra, and the red nucleus. Very significant connections are open within the system itself - between its individual cores.

The main functions of the striapallidar system are related to the control of movements. Along with the cerebellum, it is the largest subcortical motor center. Moreover, if the cerebellum is associated with the regulation of specific parameters of performed movements (the amplitude of muscle contractions, their consistency during simultaneous implementation, etc.), then the striapallidar system is considered as an area that controls the start of movements and contains information about motor programs - sequential complexes of movements. Indeed, when movements are initiated, activation of nerve cells is observed first in the associative frontal cortex, then in the striatum and globus pallidus, and only then in the motor cortex of the cerebral hemispheres and the cerebellum. Like the cerebellum, the structures of the striapallidar system are involved in motor learning and the transformation of initially voluntary (i.e., performed under the control of consciousness) movements into automated ones. If, for example, the striatum is damaged, pathological movements are triggered - high-amplitude twitching of the hands (chorea), twisting of the torso (athetosis). Manifestations of parkinsonism (tremor, etc.) are also mainly associated with a violation of the influence of the substantia nigra on the caudate nucleus.

amygdaloid body, corpus amygdaloideum,- a spherical formation located under the shell near the inside of the anterior temporal cortex. The amygdala (tonsil) is in contact with the tail of the caudate nucleus, which, twisting, enters the temporal lobes. It has numerous connections with the cerebral cortex, hypothalamus, and olfactory brain structures. The amygdala is part of the limbic system of the brain and plays a large role in the organization of emotions. Damage to the amygdala often leads to profound changes in the psyche, depressive and manic states.

The cerebral cortex- the highest department of the central nervous system, it is responsible for the perception of all information entering the brain, for managing complex movements, mental and speech activity. Phylogenetically this is the young education nervous system. For the first time in evolution, it appears in reptiles, but it develops in full only in mammals.

The cerebral cortex of humans and a number of other mammals has a folded appearance. Numerous convolutions separated by furrows are distinguished on its surface, which greatly increases its area. The surface of the cortex of both hemispheres of an adult varies from 1470 to 1670 cm 2. Large furrows divide each hemisphere into five lobes - frontal, parietal, occipital, temporal and insula. Island, insula,- lobe that does not come to the surface of the hemisphere; the insular cortex is located deep in the lateral sulcus, is an extension of its bottom and is covered by the temporal lobe (see Fig. 38). In addition, the limbic lobe can be distinguished in the cortex, located on the medial (middle) surface and representing a group of convolutions surrounding the brain stem and corpus callosum (see Fig. 41). A person is characterized by the predominance of the frontal and temporal lobes, the surface of which in total is 47% of the entire surface of the hemispheres.

The main furrows and convolutions of the cerebral cortex are shown in Figures 39, 40, 41.

Location of furrows and convolutions on the lateral (lateral) surface(Fig. 39) is not difficult to study. We only note that here are the two deepest furrows - the central (Roland's), separating the frontal lobe from the parietal, and the lateral (lateral or Sylvian), separating the temporal lobe from the frontal and parietal. Anterior central (precentral) gyrus lies in front of the central sulcus, and behind it lies the posterior central (postcentral) gyrus. The parietal lobe is separated from the occipital parietal-occipital groove, clearly visible only on the medial surface of the brain (see Fig. 41)

Rice. 39. Lateral surface of the hemispheres:

1 - lateral (Sylvian) furrow; 2- central (roland)

furrow; 3- 14 - frontal lobe: 3- precentral sulcus,

4 - precentral gyrus, 5- superior frontal sulcus,

6 - inferior frontal sulcus, 7 - superior frontal gyrus,

8 - middle frontal gyrus, 9- inferior frontal gyrus,

10 - anterior branch, 11- ascending branch, 12- tire

part 13- triangular part, 14- orbital (orbital)

part; 15-21- parietal lobe: 15- postcentral sulcus,

16 - postcentral gyrus, 17- intraparietal groove,

18 - superior parietal lobule, 19- lower parietal lobe,

20 - supramarginal gyrus, 21- angular gyrus; 22-26- temporal

share: 22- superior temporal sulcus, 23- inferior temporal groove,

24 - superior temporal gyrus, 25- middle temporal gyrus,

26 - inferior temporal gyrus; 27- occipital pole

Considering basal (lower) surface hemispheres (Fig. 40), it must be borne in mind that the brain stem in this figure has been removed (compare with Fig. 21 - the lower surface of the brain). The lower surface of the frontal lobe is called the "orbital cortex".

Rice. 40. Lower surface of the hemispheres:

1 – 10 - frontal lobe: 1- olfactory furrow, 2- straight curve,

3 - orbital furrows, 4- orbital gyri, 5- olfactory

bulb, 6- olfactory tract, 7-lateral olfactory

stripe, 8- medial olfactory strip, 9- anterior

perforated substance, 10- olfactory triangle;

11 – 19 - temporal and occipital lobes: 11- occipitotemporal

furrow, 12- circumferential furrow, 13- hippocampal sulcus,

14 - spur furrow, 15-

gyrus, 16- medial occipitotemporal gyrus,

17 - parahippocampal gyrus, 18- hook,

19 - lingual gyrus

On the right, the olfactory bulb and part of the olfactory tract have been removed.

In the medial part of the frontal lobe, there is an olfactory groove, in which the olfactory bulb and the olfactory tract extending from it lie (they are removed in the figure in the left hemisphere). The fibers of the olfactory nerve approach the inferior surface of the olfactory bulb. The olfactory tract at its base branches into lateral, middle and medial olfactory strips. The olfactory triangle lies between the lateral and medial stripes. In its depth is the anterior olfactory nucleus, and at its base is the anterior perforated substance. Through it, as well as through the posterior perforated substance (see 7.2.5), many vessels enter the brain.

Most of the furrows and convolutions of the occipital and temporal lobes are visible both on the lower and on the medial surface of the hemispheres (see Fig. 40, 41). These are the occipital-parietal, roundabout, hippocampal and spur sulci; the medial and lateral occipital-parietal gyrus, the lingual and parahippocampal gyrus, and the gyrus called the hook.

The greatest number of formations of the forebrain is seen in medial (middle) surface(Fig. 41). In order to better imagine the mutual spatial arrangement of structures, it is useful to compare this figure with Fig. 38 (horizontal section through the basal ganglia) and fig. 20 (medial section through the brain).

In the center of the medial surface is the corpus callosum. An anterior commissure is visible at the base of its beak. Under the corpus callosum, fibers of the fornix pass from the hippocampus to the mamillary bodies. Between the arch and the knee of the corpus callosum stretched a thin plate of glial cells - a transparent septum. Between the septa of the right and left hemispheres there is a small cavity, which is sometimes considered as the 5th cerebral ventricle. Next to the septum (under its lower part) are clusters of neurons - the nuclei of the transparent septum, which are part of the limbic system.

Rice. 41. Medial surface of the hemispheres:

1-4 - corpus callosum: 1- beak, 2- knee, 3- body, 4- roller",

5- vault; 6- transparent partition; 7- anterior commissure;

8 - sulcus of the corpus callosum; nine- girdle furrow; ten- hippocampal groove; eleven- cingulate gyrus; 12- isthmus;

13 - parahippocampal gyrus; fourteen- hook; fifteen- roundabout

furrow; sixteen- occipital-temporal furrow; 17- medial

occipitotemporal gyrus; eighteen- lateral occipitotemporal

gyrus; nineteen- parieto-occipital sulcus; 20- spur furrow;

21 - wedge; 22- lingual gyrus; 23- subcallosal gyrus

Between the corpus callosum and the cortex is the groove of the corpus callosum. Above it is the girdle groove. It begins under the beak of the corpus callosum, and its posterior end curves upward. Between these grooves lies the cingulate gyrus. Behind, it continues into the isthmus, which from below passes into the parahippocampal gyrus, ending with a hook. The parahippocampal gyrus is bounded by the hippocampal and oblique furrows. Together, the cingulate gyrus, isthmus, parahippocampal gyrus, and uncus are referred to as the vaulted gyrus. It describes an almost full circle and is considered as the limbic lobe of the hemisphere. In the depths of the hippocampal sulcus, almost invisible on the surface of the brain, lies the dentate gyrus.

In the frontal lobe, we note the subcallosal gyrus, located in front of the beak of the corpus callosum.

In the back of the hemisphere passes the parieto-occipital sulcus, which separates the parietal lobe from the occipital lobe. The area between it and the spur furrow is called a wedge.

According to its phylogeny, the cerebral cortex is divided into ancient, paleocortex, old archicortex, and new neocortex. Most of the cortex (96% in humans) is occupied by the new cortex. The ancient and old cortex (paleocortex and archicortex) occupies only small areas on the basal and medial surfaces of the frontal and temporal lobes of the hemispheres. These sites are more primitive in their structure. The new cortex (neocortex) has a six-layer structure, which is not characteristic of the ancient and old cortex. Most of the structures of the paleo- and archicortex are part of the limbic system of the brain.

The paleocortex includes structures mainly associated with the analysis of olfactory stimuli: olfactory bulbs, olfactory tract, olfactory triangles, anterior olfactory nuclei, subcallosal gyrus, septal region (subcallosal gyrus and septal nuclei - accumulations of gray matter under the beak of the corpus callosum), anterior sections of the medial surface temporal lobes, etc.

Olfactory nerve fibers originate from receptors located in the wall of the nasal cavity. They end in the olfactory bulb, located on the lower surface of the frontal lobe of the cerebral hemispheres. The axons of the neurons of the olfactory bulb form the olfactory tract, the fibers of which go to the structures listed above, as well as to a number of other formations, for example, to the hypothalamus.

Most of the structures of the paleocortex are included in the limbic system, in connection with which we can talk about its participation in the organization of emotional behavior.

Archicortex. This is sea ​​Horse, or hippocampus, hippocampus, located on the inner surface of the temporal lobe, and the dentate gyrus. The hippocampus runs along the entire medial wall of the inferior horn of the lateral ventricle. It is formed as a result of the fact that in the process of ontogenesis the hippocampal groove invaginates into the wall of the lower horn, pressing the medulla there. Thus, the hippocampus is located at the bottom of the hippocampal sulcus behind the parahippocampal gyrus. The dentate gyrus, which was already mentioned in the description of the medial surface of the hemispheres, is somewhat medial to the hippocampus. Through the dentate gyrus, information is carried from various cortical zones to the hippocampus.

Translated from Latin, hippocampus- sea Horse. It is so named for the characteristic shape of its cross section.

As already mentioned, from the hippocampus to the mamillary bodies of the hypothalamus there is a thick bundle of fibers - the fornix. The arch includes axons coming from each of the hippocampus - the legs of the arch (a commissure passes between them). Further, bending around the thalamus, the legs are combined into the body of the arch. When approaching the mamillary bodies, they diverge again, forming the pillars of the vault (Fig. 42). A small part of the fornix fibers goes to other formations (thalamus, amygdala, paleocortex structures).

The hippocampus is closely associated with learning and memory. With various injuries of the hippocampus, memorization processes are disrupted.

Rice. 42. Hippocampus and fornix:

1 - hippocampus; 2- arch legs; 3- vault body;

4 - vault pillars; 5- mamillary bodies; 6- anterior commissure

Neocortex. The new cortex has six layers (Fig. 43), its thickness in humans is approximately 3 mm.

In each cortical layer, neurons of a certain structure predominate. The functions of these neurons also differ. The axons of the nerve cells of the cortex and the fibers from other structures approaching them form the white matter of the hemispheres.

The system of descending projection fibers is mainly connected with the 5th layer (if you count from the surface) - the inner pyramidal layer. It contains large cells, the bodies of which are in the form of pyramids (see Fig. 9, D). The axons of these cells form the main efferent pathway of the cerebral cortex - corticospinal (pyramidal). It is in pyramidal neurons that pulses are generated that ultimately control the work of muscles during voluntary movements. The main afferent fibers entering the cortex from the thalamus terminate on the neurons of the 4th (inner granular) layer, which includes small granular and stellate neurons.

Callosal and associative fibers mainly come from the neurons of the 3rd layer (outer pyramidal), and come to the 2nd layer (outer granular).

Rice. 43. Layers of the neocortex:

A B C- image of the bark with various types of coloring (A- only processes of neurons are stained, B- only the bodies of neurons are stained, B- neurons are colored whole).

1 - molecular layer; 2- outer granular layer; 3- outer pyramidal layer; 4- inner granular layer; 5- inner pyramidal layer; 6- polymorphic layer

The cerebral cortex is further subdivided into 52 fields, differing in their cellular structure and functions (Fig. 44).

Rice. 44. Fields of the cerebral cortex of the human brain: A- lateral surface, B- medial surface

Currently, the cerebral cortex is usually divided into sensory (primary projection), motor and associative zones (Fig. 45).

To sensory areas of the cortex refer to the fields into which fibers come from the projection nuclei of the thalamus. These are zones of cortical representation of sensory systems. This is where the shortest paths from the receptors end. These zones are characterized by a very strong development of the 4th layer of the cortex and, at the same time, a poorly expressed 5th layer.

Each sensory system has its own projection zones. visual area is located in the occipital lobe of the cerebral cortex. It is located on the area called "wedge" on the medial surface. Hearing area located in the superior temporal gyrus. Taste zones found in the lower part of the postcentral gyrus and in the insular (insular) cortex. Cortical olfactory zones have already been described (cf. paleocortex).

Rice. 45. The main zones of the cerebral cortex

Up- lateral surface of the left hemisphere.

Down below- median surface of the right hemisphere.

I - frontal pole, II - temporal pole, III - occipital pole,

1- central furrow; 2 - lateral furrow; 3 - skin zone

sensitivity; 4 - motor zone; 5 - Broca's center; 6 - zone

auditory sensitivity; 7 - Wernicke's center; 8 - visual zone

sensitivity; 9- zone of olfactory sensitivity;

10 - olfactory bulb; 11 - corpus callosum;

12 limbic lobe

Large area occupies zone of musculoskeletal sensitivity. It is located behind the central sulcus, in the postcentral gyrus of the parietal lobe of the cerebral cortex. As already noted (see 6.4), musculocutaneous projections are organized according to the somatotopic principle. But the "body map" in the cortex has somewhat shifted proportions. The fact is that the number of neurons receiving information from a certain area of ​​the body is directly proportional to the density of receptors in this area. The density of receptors depends on the significance of the information received from a particular area of ​​the skin surface. Therefore, on the “body map” in the cortex, disproportionately large zones of the hands and lips are noted, but very small zones of the back, abdomen, etc. (Fig. 46).

Motor (motor) zone located in the precentral gyrus of the frontal lobe of the cerebral cortex in front of the central sulcus. It is from here that most of the fibers of the corticospinal tract depart. As already mentioned, this path begins in the 5th layer of the cortex, which is much more pronounced here than in other zones. At the same time, the 4th layer in the motor cortex is practically absent, for which the cortex in this area was called "agranular" (granular - granular). Just as in the zone of skin-muscle sensitivity, in the precentral gyrus, you can draw a "body map", and it will also have certain distortions in the proportions of the human body (Fig. 46). This is due to the fact that some muscles (fingers, mimic) must perform much more subtle movements, therefore, to control them, it is necessary large quantity neurons.

The nonspecific or association cortex refers to areas that cannot be attributed to any predominantly sensory or motor functions. In humans, associative zones occupy more than half of the entire cortex. These zones connect (associate) sensory and motor zones with each other and at the same time serve as substrates for higher mental functions.

Rice. 46. ​​Representation of zones of skin sensitivity

and motor areas in the cerebral cortex. projection zone

skin sensitivity (A). Motor zones (B).

The disproportion of proportions is illustrated in the form of a sensory (A1) and motor (B1) homunculus (little man)

The main non-specific areas of the cerebral cortex are the parietal-temporal-occipital (located on the border of these lobes), prefrontal (frontal lobe of the cortex with the exception of the precentral gyrus) and limbic (vaulted gyrus) associative zones. If we simply imagine their functions, each of these areas is especially important for the following integrative processes, respectively: higher sensory functions and speech; higher motor functions and the launch of behavioral acts; memory and emotional behavior.

Although the human right and left hemispheres practically do not differ in their structure, they are characterized by functional asymmetry, i.e. they perform different functions. First of all, this refers to the associative zones of the cortex. In everyday life, these differences are not noticeable, since information easily passes from hemisphere to hemisphere through the commissures of the brain (primarily through the corpus callosum). Ideas about the differences in the functions of the hemispheres were formed during observations of patients with unilateral brain lesions and in special experiments, where information was received only in one of the hemispheres.

It turned out that left hemisphere(at least for right-handers) is more associated with speech, abstract-conceptual thinking, mathematical abilities. The right hemisphere predominantly controls imaginative thinking and largely determines such properties as musicality, recognition of complex visual images, expression and perception of emotions.

The speech centers are located in the frontal and temporal regions of the left hemisphere (see Fig. 45). With the defeat of the speech center in the temporal cortex (Wörnicke's center), located on the border with the auditory cortex, the understanding of audible speech is impaired. With the defeat of the center of speech, which lies on the border of the shear area in the frontal cortex (Broc's center), the patient hears and understands speech, but cannot speak himself. With the defeat of some areas of the right hemisphere, profound disorientation in space is noted, for example, patients cannot find their way to the house in which they have lived for many years. Some patients with right hemisphere damage cannot recognize familiar faces, and sometimes cannot recognize people at all.

In conclusion, it must be emphasized that the brain has extremely large compensatory capabilities. Of course, many of its zones (nuclei) have inherently determined functions (this is especially true for primary sensory zones, centers of the medulla oblongata, etc.). However, many areas, primarily cortical formations, acquire specific "duties" as the CNS matures and learns. This property of the brain predetermines the possibility that when different parts of the CNS are affected, the corresponding functions are assumed by other parts of the CNS.

8. Vegetative (autonomous)

nervous system

All functions of the body can be divided into somatic, "animal", and vegetative, "vegetative". Somatic functions are associated with the perception of external stimuli and motor reactions carried out by skeletal muscles. The implementation of metabolism in the body (digestion, blood circulation, respiration, excretion, etc.), as well as growth and reproduction, depend on the vegetative functions.

As is known (see 1.2), in addition to morphological differences between smooth and skeletal muscles, there are also functional differences between them. The skeletal muscle of the tour responds to the impact of the environment with quick, purposeful movements that can be adjusted arbitrarily. Smooth muscles embedded in the internal organs and blood vessels work slowly but rhythmically; its activity is usually not amenable to arbitrary regulation. These functional differences are associated with a difference in innervation: skeletal muscles receive impulses from the somatic part of the NS, and smooth muscles receive impulses from the autonomic part. The autonomic nervous system (ANS) innervates not only smooth muscles, but also other executive organs that are not amenable to arbitrary regulation - the heart muscle and glands.

In general, the ANS performs an adaptive-trophic function, i.e. adapts the level of activity of tissues and organs to the tasks they perform at the current time. These tasks, in turn, are usually associated with one or another activity of the organism in changing environmental conditions.

The arcs of vegetative reflexes and their differences from the arcs of somatic reflexes were discussed earlier (see 6.2, Fig. 19, B).

Recall that in autonomous nervous system the efferent part of the arc consists of two neurons: preganglionic (the last or only central neuron) and ganglionic (located in the autonomic ganglion). From this arrangement of neurons, the main sign of ANS follows - two-neuronality of the efferent pathway.

The axons of the central neurons of the ANS, which end on the cells of the autonomic ganglia, are called preganglionic fibers, and the axons of the executive neurons (which are located in the ganglia) are called postganglionic. Preganglionic fibers are covered with a myelin sheath, postganglionic fibers are distinguished by its absence (the so-called gray fibers).

There are some exceptions to the two-neuronity effector pathway rule:

1. Postganglionic sympathetic fibers that go to the smooth muscles of the gastrointestinal tract mainly terminate not on muscle fibers, but on parasympathetic ganglion cells located in the walls of the stomach and intestines. Apparently, they reduce the activity of these cells and thus have an inhibitory effect on smooth muscle (3-neuronal structure of the efferent pathway).

2. Chromaffin cells of the adrenal medulla are innervated not by post-, but by preganglionic sympathetic fibers. Chromaffin cells form, under the influence of impulses coming to them through sympathetic fibers, adrenaline. These cells essentially correspond to postganglionic neurons, with which they have a common origin from the ganglionic plate (1-neuronal structure of the efferent pathway).

The ANS is divided into two sections - sympathetic and parasympathetic, which are commonly called systems. Most organs are innervated by both sympathetic and parasympathetic fibers. However, in some cases, the predominant importance of any department is observed. The lacrimal glands and glands of the nasopharynx are innervated only by the parasympathetic nervous system. Basically, the bladder has parasympathetic innervation. On the other hand, only sympathetic fibers approach the smooth muscles of blood vessels (with the exception of cerebral vessels and genital arteries), sweat glands, spleen, and secretory cells of the adrenal glands.

The sympathetic and parasympathetic systems differ from each other functionally (according to the activity performed), morphologically (in structure), as well as mediators used in the transmission of a nerve impulse.

Functional differences due to the fact that the sympathetic and parasympathetic systems, as a rule, affect various organs and tissues in the opposite way. If the sympathetic department excites any part of the body, then the parasympathetic inhibits it and vice versa. So, irritation of the sympathetic nerve that innervates the heart enhances its work, and irritation of the parasympathetic vagus nerve inhibits heart contractions. However, one should not think that there is a rigid antagonism between the sympathetic and parasympathetic parts of the ANS, and that their functions are completely opposed. These are interacting parts, the ratio between them changes dynamically at different phases of the activity of a particular organ, i.e. they function in harmony. For example, both sympathetic and parasympathetic stimulation cause salivation. But in the first case, saliva will be thick, saturated with organic substances, and in the second - liquid, watery.

The activity of the entire ANS is regulated by the hypothalamus (higher autonomic center), the reticular formation, and a number of other autonomic centers.

Sympathetic nervous system prepares the body for action. It increases metabolism, enhances breathing and heart function, increases oxygen supply to the muscles, dilates the pupil, and slows down work. digestive system, reduces the sphincters (circular obturator muscles) of some hollow organs (bladder, gastrointestinal tract), expands the bronchi. The work of the sympathetic nervous system is enhanced by stressful stimuli.

parasympathetic nervous system performs a protective function, it helps to relax the body and restore its energy reserves. Irritation of parasympathetic fibers leads to a weakening of the heart, contraction of the pupil, increased motor and secretory activity of the gastrointestinal tract, emptying of hollow organs, narrowing of the bronchi.

Thus, the sympathetic department of the nervous system adapts the body to intense activity. The parasympathetic division of the nervous system helps to restore the spent resources of the body. Each of them has a central and peripheral parts.

Morphological differences between the sympathetic and parasympathetic systems are associated with the location of the last two neurons (central and peripheral) of the autonomic reflex arc (Fig. 47). Such neurons are grouped into autonomic nuclei within the CNS and into autonomic ganglia in the peripheral NS. Sympathetic nuclei are located in the thoracic and upper lumbar sections of the spinal cord (in its lateral horns), and parasympathetic nuclei- in the brain stem and sacral spinal cord (in the intermediate substance). In connection with the position of the central neurons, the sympathetic system is usually called the sternolumbar, or thoraco-lumbar. (thoracale- chest; lumbale- lumbar), and parasympathetic - craniosacral, or cranio-sacral (kranion- scull; sacred- sacral).

Rice.47. Division of the autonomic nervous system into sympathetic (A) and parasympathetic (B) parts: I - VII- CNS structures: I- midbrain II- bridge III- medulla oblongata, IV- cervical, V- chest, VI- lumbar, VII- sacral parts of the spinal cord; 1-8- structures of the peripheral nervous system: 1- superior cervical ganglion, 2- stellate ganglion, 3- solar plexus, 4 - superior mesenteric ganglion, 5- inferior mesenteric ganglion, 6- oculomotor nerve fibers, 7- fibers of the facial and glossopharyngeal nerve, 8- vagus nerve fibers; 9 - 20- internal organs: 9- eye, 10- lacrimal and salivary glands, 11 - lungs,

12 - heart, 13- liver, 14- stomach, 15- pancreas

iron, 16- adrenals, 17- intestines, 18- rectum,

19 - bladder, 20- sexual organs

Sympathetic ganglia go along the spine, forming two (right and left) sympathetic chains. In the chains, the cervical, thoracic, lumbar and sacral regions are distinguished, each of which has several pairs of ganglia. It should be noted that in the reflex arc of the sympathetic NS, the last neuron can be located not only in the nodes of the sympathetic trunk, but also in the nerve plexuses (ganglia celiaca - celiac node, g.mesenterica - mesenteric node, etc.). parasympathetic ganglia are located either near the innervated organ (extramural ganglia), or in its walls (intramural ganglia). Thus, it turns out that the preganglionic fibers of the sympathetic nervous system are short, and the postganglionic fibers are long. The reverse pattern is typical for the parasympathetic system.

It should be noted that the number of nerve cells in the ganglia is several times greater than the number of preganglionic fibers (32 times in the cervical sympathetic ganglion, 2 times in the ciliary ganglion). Accordingly, each of the preganglionic fibers branches and forms synapses on several ganglion cells. Thus, the expansion of the zone of influence of preganglionic fibers is achieved.

From the foregoing it is clear that there are no sympathetic centers in the brain. However, the smooth muscles and glands of the head have sympathetic innervation. These organs are approached by fibers coming from the superior cervical ganglia. They penetrate the cranial cavity, forming plexuses around the internal carotid and vertebral arteries. In addition to the head, the cervical ganglia, together with the pectoral ganglia, innervate the organs of the neck and chest cavity. The lumbar ganglia send fibers to the abdominal organs, and the sacral ganglia send fibers to the rectum and genitals.

The parasympathetic fibers of the cranial region run in the oculomotor, facial, glossopharyngeal, and vagus nerves (see 7.2.1). Recall that the parasympathetic fibers of the vagus nerve, leaving the cranial cavity, form synapses on the parasympathetic ganglia that innervate most of the internal organs of the body. Fibers extending from the sacral region are associated with parasympathetic influences on the rectum, bladder, and genital organs.

Another difference between the sympathetic and parasympathetic systems can be called neurochemical, in connection with different mediators involved in the transmission of a nerve impulse in the ANS. All neurons of the autonomic nuclei (i.e. central neurons) are acetylcholinergic. Thus, the mediator that transmits the nerve impulse in the autonomic ganglia (both sympathetic and parasympathetic) is acetylcholine. At the same time, the neurons of the autonomic ganglia differ in the mediator they produce. In the sympathetic nervous system, this is usually norepinephrine, and in the parasympathetic nervous system, acetylcholine. Thus, in the sympathetic nervous system, the signal is transmitted to the executive organ using norepinephrine, and in the parasympathetic nervous system - acetylcholine.

Recently, another department has been distinguished in the autonomic nervous system - metasympathetic (enteric) nervous system. Its distinctive feature is the reflex arcs that do not pass through the central nervous system. That is, both sensitive, and intercalary, and executive neurons are located outside the central nervous system, directly in the walls of the innervated organ. Due to this, many internal organs, after cutting the sympathetic and parasympathetic pathways, or even after being removed from the body (under the creation of appropriate conditions), continue to perform their inherent functions without any visible changes. For example, the peristaltic function of the intestine is preserved, the heart washed with saline is reduced, the lymphatic vessels are compressed and unclenched, etc.

At the same time, having a sufficiently large independence, the metasympathetic nervous system retains its connection with the rest of the nervous system, since both sympathetic and parasympathetic neurons form synapses on its nerve cells.
9. Limbic system

The limbic system (LS) is a complex of anatomically and functionally interconnected structures involved in the regulation of behavioral reactions, primarily emotions, and also plays a significant role in the regulation of autonomic reactions.

The basis of the LS is the so-called Peipets circle, described back in 1937. It includes the hippocampus, the arch coming from it, then the mamillary bodies of the hypothalamus, the limbic (anterior) nuclei of the thalamus and the cingulate gyrus (limbic cortex). All structures of the Peipez circle are closed in a ring system (Fig. 48). In the future, this circle was supplemented by a number of other structures. Currently, the LS includes the entire limbic lobe of the cerebral cortex, the archicortex, a number of structures of the paleocortex, as well as some subcortical formations - the amygdala complex, septal nuclei (kernels of the septum pellucidum), epithalamus, and some formations of the midbrain (reticular formation). Parts of the LAN are united by numerous two-way links. The connections of the LS with other brain formations (with the basal ganglia, neocortex, etc.) have also been revealed.

A necessary condition for the inclusion of any structure in the LS is participation in the organization of motivational-emotional behavior. When different parts of the LS are damaged or stimulated, a variety of behaviors are observed, including emotional reactions. Thus, the centers of positive and negative reinforcement already mentioned (see 7.4.1) are found not only in the hypothalamus, but also in other structures of the LS (cingulate gyrus, septal region, amygdala).

Rice. 48. Basic structures

limbic system and connections between them

(bold arrows indicate the Peipez circle)

In addition, all limbic formations are directly or indirectly associated with the hypothalamus, the highest autonomic center (see 7.4.1). In connection with the latter fact, they talk about the participation of drugs in the regulation of autonomic functions.

The drug is involved in the occurrence of some diseases. This, for example, is clearly manifested in epilepsy. Thus, the localization of the epileptic focus near the amygdala is characterized by the presence of emotional and motivational disorders, among which the most frequent are outbreaks of unmotivated aggression, as well as emotional dysphoria - sudden unreasonable mood swings. Often such emotional disturbances accompanied by auditory, visual and kinesthetic hallucinations, reflecting a complex picture of the late stage of epilepsy, when the epileptogenic process can capture many structures of the LS.

APPENDIX

1. In its structure, a neuron differs from other cells of the body:

a) the presence of processes;

b) the presence of contacts between cells;

c) the presence of polar processes and synapses;

d) the presence of one diploid nucleus.

2. What is the difference between an axon and a dendrite?

a) the presence of a myelin sheath;

b) the direction of the nerve impulse;

c) the axon is always longer than the dendrite;

d) each neuron has one axon, but several dendrites.

3. What specific structures are characteristic of a nerve cell?

a) lysosomes and Golgi apparatus;

b) Nissl substance;

c) mitochondria;

d) fibrillar structures.

4. What are effector neurons?

a) excited neurons;

b) switching neurons;

c) motor neurons;

d) neurons whose axons approach the executive organ.

5. What are nerves?

a) bundles of axons covered with connective tissue sheaths;

b) bundles of dendrites covered with connective tissue membranes;

c) nerve fibers covered with connective tissue sheaths;

d) any white matter

6. White matter is:

a) fibers located in the central nervous system;

b) fibers located in the peripheral nervous system;

c) bundles of nerve fibers;

d) bodies of nerve cells and their short processes.

7. What is in the synaptic vesicles?

a) a hormone

b) acetylcholine;

c) mediator;

8. Which of the following sets of cells are only neuroglial?

a) pyramidal cells, microglia, Schwann cells, neuroectodermal cells;

b) oligodendrocytes, astrocytes, pyramidal cells, basket cells;

c) ependymocytes, astrocytes, oligodendrocytes, microglia;

d) pyramidal cells, microglia, Schwann cells, astrocytes.

9. The ratio of the size of the synapse and the width of the synaptic cleft is approximately:

10. What does the expression "a neuron is dopaminergic" mean?

a) the neuron uses dopamine to synthesize L-DOPA;

b) the neuron changes its work under the influence of dopamine;

c) the neuron inactivates dopamine;

d) the neuron uses dopamine as a mediator.

11. In what part of the body of the embryo does the laying of the nervous system take place?

a) in the dorsal;

b) in the ventral;

c) in the rostral;

d) in the caudal.

12. Which of these parts of the brain is formed from the anterior cerebral bladder?

a) pons varolii;

b) basal nuclei;

c) the roof of the brain;

d) legs of the brain.

13. Determine which of the properties of the 3rd ventricle is indicated incorrectly:

a) located inside the diencephalon;

b) is located between the 2nd and 4th ventricles;

c) has a slit-like shape;

d) enters the funnel of the pituitary gland.

14. What is in the subarachnoid space?

b) liquor;

d) tissue fluid.

15. What combination of the listed cavities applies only to the cavities of the nervous system?

a) ventricles and blood vessels of the brain;

b) spinal canal and blood vessels;

c) ventricles of the brain and spinal canal;

d) Sylvian aqueduct and lymphatic vessels;

16. What cavity is the cavity of the hindbrain?

a) lateral ventricles;

b) the third cerebral ventricle;

c) sylvian aqueduct;

d) the fourth cerebral ventricle;

17. The composition of the peripheral nervous system includes:

a) cranial nerves and ganglia, spinal nerves and ganglia;

b) the brain, cranial nerves and their ganglia;

c) spinal cord, spinal ganglia and spinal nerves;

d) None of the answers are correct.

18. The somatic nervous system is called:

19. Vegetative (autonomous) nervous system is called:

a) the central nervous system;

b) peripheral nervous system;

c) part of the nervous system that innervates the viscera;

d) the part of the nervous system that innervates the voluntary muscles.

20. Hind brain consists of:

a) the hindbrain and cerebellum proper;

b) the hindbrain proper and the medulla oblongata;

c) medulla oblongata and quadrigemina;

d) bridge and medulla oblongata;

21. What is a brain stem?

a) medulla oblongata + pons + cerebellum + midbrain;

b) medulla oblongata + pons + midbrain;

c) hindbrain + midbrain roof + diencephalon;

d) None of the answers are correct.

22. The spinal nerve consists of:

a) only afferent fibers;

b) only efferent fibers;

c) afferent and efferent fibers;

d) motor and autonomic fibers;

e) sensory and motor fibers.

23. The longest of the cranial nerves is

a) olfactory nerve;

b) trigeminal nerve;

c) vagus nerve;

d) accessory nerve.

24. How do sensory nuclei differ from motor nuclei?

a) the shape of their constituent neurons;

b) motor nuclei communicate with effectors, and sensory nuclei receive information from receptors;

c) sensory nuclei are located in the peripheral nervous system, and motor nuclei in the central nervous system;

d) motor nuclei perform a reflex function, but sensory nuclei do not.

25. Choose the correct statement:

a) with cortical organization, neurons are arranged in layers, but with nuclear organization they are not;

b) with nuclear organization, neurons are diffusely scattered among the white matter;

c) the nuclei are located in the surface structures of the central nervous system;

d) nuclei and cortex form the white matter of the nervous system.

26. What is the function of the neurons of the lateral horns of the spinal cord?

a) intercalary neurons of the sympathetic reflex arc;

b) intercalary neurons of the parasympathetic reflex arc;

c) executive autonomic neurons;

d) sensory neurons.

27. What is the main function of the corticospinal tract?

a) providing unconditioned (innate) reflexes;

b) carrying information from tactile receptors;

c) providing automated movements;

d) providing voluntary movements.

28. Which pathway transmits the main part of pain sensitivity to the brain?

a) dorsal-thalamic;

b) tender and wedge-shaped cords;

c) spinal-reticular;

d) dorsal-tectal.

29. In what area are the nuclei of the vestibulo-auditory nerve located?

a) in the tegmentum of the midbrain;

b) under the olives;

c) in the lateral corners of the rhomboid fossa;

d) under the facial tubercle.

30. The structure of the double nucleus includes the nuclei of the following nerves:

31. What parts of the brain form a rhomboid fossa?

a) bridge and medulla oblongata;

b) bridge and midbrain;

c) medulla oblongata and midbrain;

d) midbrain and diencephalon.

32. Choose the correct answer: autonomic fibers are included in the following pairs of cranial nerves:

b) IV, VII, VIII, X;

c) VII, IX, XI;

d) III, VII, IX, X.

33. Efferent fibers from the cerebellar cortex form:

a) basket cells;

b) Purkinje cells;

c) stellate cells;

d) granule cells.

34. Where does information on liana fibers come from?

a) from the cerebral cortex;

b) from the vestibular nuclei;

c) from olive kernels;

d) from the spinal cord.

35. What is the function of the inferior colliculi of the quadrigemina?

a) visual centers;

b) auditory centers;

c) motor centers;

d) vegetative centers.

36. What area of ​​the midbrain is located around the canal of the cerebral aqueduct?

a) tire;

b) central gray matter;

c) black substance;

d) interpeduncular nucleus.

37. What is the function of the subthalamus?

a) holding sensory information;

b) regulation of locomotion;

c) regulation of vegetative reactions;

d) ensuring the cycle "sleep - wakefulness".

38. What nerve is connected with the diencephalon?

a) olfactory;

b) oculomotor;

c) wandering;

d) visual.

39. Where is the nucleus of the thalamus located and what is it called, which is associated with the regulation of movements?

a) ventrolateral nucleus;

b) pillow;

c) lateral geniculate body;

d) medial geniculate body.

40. What is the name of the area connecting the pituitary and hypothalamus?

b) funnel;

c) gray bump;

d) visual chiasm.

a) caudate nucleus;

b) pale ball;

c) a fence;

d) shell.

42. Where does the vault come from and where does it go?

a) from the mammillary bodies to the hippocampus;

b) from the hippocampus to the mamillary bodies;

c) from the mamillary bodies to the limbic nuclei of the thalamus;

d) from the cingulate cortex to the hippocampus.

43. The two deepest furrows of the cerebral cortex are:

a) central and sulcus of the corpus callosum;

b) roundabout and lateral;

c) hippocampal and cingulate;

d) lateral and central.

44. What is the function of the ancient bark?

a) olfactory;

b) visual;

c) motor;

d) associative.

45. Which of these structures belong to the old bark?

a) an island

c) hippocampus;

d) pituitary.

46. ​​Where is the amygdala located?

a) in the diencephalon;

b) in the telencephalon;

c) in the midbrain;

d) on the bridge.

47. Why in sensory areas cortex very well expressed fourth layer?

a) sensory information comes to this layer;

b) sensory information is analyzed in this layer;

c) from this layer, sensory information is transmitted to other areas of the cortex;

d) in this layer there is a synthesis of different types of sensory information.

48. Where is the cortical zone of skin and muscle sensitivity located?

a) in the precentral gyrus;

b) in the postcentral gyrus;

c) in the superior temporal gyrus;

d) in the superior frontal gyrus.

49. If you move in the ventrodorsal direction, in what order will you meet the following structures: vault; epiphysis; transparent partition; wedge; olfactory tract?

a) transparent septum, epiphysis, olfactory tract, fornix, wedge;

b) olfactory tract, transparent septum, fornix, epiphysis, wedge;

c) epiphysis, olfactory tract, wedge, transparent septum, fornix;

d) transparent septum, wedge, fornix, olfactory tract, epiphysis.

50. If you move in the ventrodorsal direction, in what order will you meet the following structures: direct gyrus, olfactory triangle, mamillary bodies, posterior perforated substance, olive nuclei?

a) mamillary bodies, olfactory triangle, direct gyrus, olive nuclei, posterior perforated substance;

b) olfactory triangle, straight gyrus, olive nuclei, mamillary bodies, posterior perforated substance;

c) mamillary bodies, olfactory triangle, straight gyrus, posterior perforated substance, olive nuclei;

d) direct gyrus, olfactory triangle, mamillary bodies, posterior perforated substance, olive nuclei.

			Answers	for tests
	in		BUT		B		a		in
	b		B		AT		G		b
	B		B		AT		b		G
	G		B		B		in		a
	AT		AT		BUT		b		in
	AT		G		BUT		b		b
	AT		BUT		G		b		a
	AT		G		BUT		G		b
	D		AT		AT		a		b
	G		B		G		b		G

Glossary

Anastomosis- connection between tubular organs, for example, vessels.

Afferents- fibers that carry nerve impulses to any structures.

Ventral- abdominal.

Visceroreceptors- receptors of internal organs.

Ganglion- a compact non-layered accumulation of neuron bodies in the peripheral nervous system.

Hemisphere- hemisphere.

homeostasis- maintaining the constancy of the internal environment of biological systems.

Diencephalic- pertaining to the diencephalon.

Dorsal- dorsal.

innervation- supply nerve fibers(both afferent and efferent) of any organ or tissue, which ensures their connection with the central nervous system.

Caudal- tail.

Commissure- fibers that connect symmetrical parts of the brain.

Bark(cortical organization) - layered arrangement of neurons.

Lateral- side.

locomotion- the movement of the body in space.

Medial- middle.

mesencephalic- pertaining to the midbrain.

Metabolism- metabolism.

Ontogenesis- individual development of the organism.

Pathology- deviation from the norm, disease.

Proprioreceptors- musculoskeletal receptors.

Rostral- head.

Sensory- sensitive.

Sphincter- annular muscle that blocks the entrance to or exit from a hollow organ during contraction

Terms- terminal ramifications of the axon.

Trophic- food, nutrition.

Enzymes- specific proteins that play the role of biological catalysts.

Phylogenesis- historical development of organisms.

Function- specific activity of an organism, its organs, tissues or cells.

Evolution- the process of historical change of the living.

Exogenous- external origin, caused by external causes.

Endogenous- internal origin, caused by internal causes.

Effector- executive agency.

Efferents- fibers that carry nerve impulses from any structures.

Core(in the nervous system, as opposed to the cell nucleus) - a compact non-layered accumulation of neuron bodies in the central nervous system.

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VI. In the diary for practical work, draw a graph structure of the brain

A. Individual tasks for students for oral response at the blackboard (25 minutes). 1. General characteristics of the telencephalon