White matter of the cerebellum. Cerebellar peduncles (cerebellar peduncles). What is the cerebellum responsible for in the body? Vestibular functions of the cerebellum

What is the cerebellum responsible for in the body? This small formation, like the large brain, consists of white and gray matter (of cells and conducting fibers). This structure is located behind and below the cerebral hemispheres, between the middle and oblong sections and the bridge. The functions of the cerebellum are the regulation of movements, their coordination, and articulation. The cerebellum (cerebellum) connects the parts of the central nervous system with each other and ensures their integration.

Structure

Where is the cerebellum of the human brain located, look at the photo: it is located in the skull, its posterior fossa next to the midbrain and medulla oblongata. In this structure there is a rhomboid fossa - the bottom of the fourth ventricle, a cavity with fluid. It consists of two hemispheres and a worm between them, its weight is about 120 g, its transverse dimensions are approximately 10 cm.

Each hemisphere consists of three lobes separated by fissures. The surface is not smooth, covered with grooves similar to the convolutions of the cerebral hemispheres. The worm is connected to the lobes of the hemispheres by white fibers, which, diverging, form the “tree of life”. The cerebellum contains accumulations of gray matter: the dentate roof nuclei, the tent nuclei, the corky nucleus and the spherical nucleus.

Core functions:

1. The dentate nuclei are necessary for the initiation of movements, their control, and planning.
2. The tent nuclei are responsible for maintaining balance and saccadic (jumping) movement of the eyeballs. This formation contains GABAergic neurons (inhibitory).

The globular nucleus is located deep, is an ancient formation, belongs to the old cerebellum. The anterior inferior cerebellar artery supplies the cerebellum anteriorly and inferiorly. There is also the posterior inferior cerebellar artery, the superior cerebellar artery.

The cerebellum, whose structure is similar to the cerebral hemispheres, has “legs” - nerve fibers. These are pathways that connect it with neighboring sections: the pons, medulla oblongata, midbrain. Connected to the spinal cord to transmit impulses to its anterior horns, which provide signal transmission to the skeletal muscles. The connection with the reticular formation provides a role in the regulation of autonomic functions.

Important! Structure and functions of the cerebellumconnected: it integrates all departments into the process of coordinating complex motor acts, being a connecting element.

Intensive development of this department occurs in childhood, when the child masters basic movements. The accumulation of experience in motor acts leads to the establishment of communication between different parts of the central nervous system. The cerebellum is a link between the motor centers of the cerebral hemispheres and the motor neurons of the spinal cord located in their anterior horns.

What is it needed for?

What is the cerebellum of the brain responsible for? First of all, it regulates gait and other actions with stereotypical movements, keeps the body in balance and in the desired position. In addition, this department is necessary for regulating the tone of flexors, extensors, and other antagonist muscles.

The functions of the cerebellum of the human brain include the regulation of speech due to the coordinated control of the muscles of the tongue and lips, fine motor skills (handwriting).

In case of injuries, hemorrhagic and inflammatory processes, multiple sclerosis, tumors, the cortex or nerve fibers can be damaged. The pathways are affected, and adequate transmission of nerve impulses to the motor neurons of the spinal cord does not occur.

Symptoms of the lesion

When the structure of the cerebellum is destroyed, a disorder of the sense of balance appears, as evidenced by nystagmus: trembling of the eyeballs when moving them to the side, as well as unsteadiness of gait, dizziness. A coordination disorder of motor acts is called cerebellar.

Speech is disrupted: it becomes incoherent, but rhythmic (chanted), the tongue seems to be slurred. When an organ is damaged, the patient emphasizes words not according to the rules of orthoepy, but in accordance with the rhythm of speech.

Cerebellum regulates the coordinated work of muscles: thanks to it, antagonist muscles work separately, without interfering with each other. However, during pathological processes this function is disrupted and asynergy develops. There is a decrease in muscle tone.

Intentional and postural are another consequence of damage to the cerebellum and trunk. Postural tremors of the body or its limbs occur when the patient tries to maintain the desired position. Intention tremor is an involuntary oscillatory movement made towards a specific object for a specific purpose.

An increase in trembling, an increase in its amplitude, and sweep occurs when approaching the target object. This dyskinesia does not allow a person suffering from cerebellar damage to take the necessary objects in his hands or perform complex acts that require coordination. The neurologist checks for the presence of intention tremor by asking the patient to touch the tip of his nose with his eyes closed.

Adiadochokinesis is the inability of a person to switch between opposite movements, i.e., a person suffering from a cerebellar disorder is unable to perform alternate flexion and extension, adduction, abduction, pronation, supination. Switching between the activity of opposing muscle groups occurs slowly.

The dentate nuclei are connected by conducting fibers to the red nucleus of the midbrain. When this connection is disrupted, extrapyramidal disorders occur in the form of various hyperkinesis: athetosis,.

If the inferior olive of the medulla oblongata (medulla oblongata), its communication with the dentate nucleus, is affected, then myoclonic disorders occur in the form of twitching of the tongue, muscles of the palate, and pharynx. Swallowing problems may occur.

If the worm is affected, disturbances in gait and maintaining posture dominate. Damage to the hemispheres leads to incoordination of movements of the same limbs. Often symptoms of damage include mental disorders.

Conclusion

Cerebellum is an important formation of the central nervous system, responsible for performing motor acts and maintaining balance. Its defeat is a serious problem leading to human disability.

White matter of the cerebellum in cross-section it looks like small plant leaves corresponding to each gyrus, covered on the periphery with the bark of the gray matter. As a result, the overall picture of white and gray matter on a section of the cerebellum resembles tree, arbor vitae cerebelli (tree of life; the name is given based on its appearance, since damage to the cerebellum is not an immediate threat to life). The white matter of the cerebellum is composed of various types of nerve fibers. Some of them connect the gyri and lobules, others go from the cortex to the internal nuclei of the cerebellum, and, finally, others connect the cerebellum with neighboring parts of the brain. These last fibers come as part of three pairs of cerebellar peduncles:

1. Lower legs, pedunculi cerebellares inferiores (to the medulla oblongata). In their composition they go to the cerebellum tractus spinocerebellaris posterior, fibrae arcuatae extenae- from the nuclei of the posterior cords of the medulla oblongata and fibrae olivocerebellares- from olive. The first two tracts end in the cortex of the vermis and hemispheres. In addition, there are fibers from the nuclei of the vestibular nerve, ending in nucleus fastigii. Thanks to all these fibers, the cerebellum receives impulses from the vestibular apparatus and the proprioceptive field, as a result of which it becomes the core of proprioceptive sensitivity, making automatic corrections to the motor activity of the rest of the brain. As part of the lower legs there are also descending pathways in the opposite direction, namely: from nucleus fastigii to the lateral vestibular nucleus (see below), and from it to anterior horns of the spinal cord, tractus vestibulospinalis. Through this pathway, the cerebellum influences the spinal cord.

2. Middle legs, pedunculi cerebellares medii (towards the bridge). They contain nerve fibers from the pontine nuclei to the cerebellar cortex. The pathways that arise in the pons nuclei to the cerebellar cortex, tractus pontocerebellares, are ongoing cortical-pontine tract, fibrae corticopontinae, ending in the cores of the bridge after the cross. These pathways connect the cerebral cortex with the cerebellar cortex, which explains the fact that the more developed the cerebral cortex, the more developed the pons and cerebellar hemispheres are, which is observed in humans.

3. Upper legs, pedunculi cerebellares superiores (to the roof of the midbrain). They consist of nerve fibers going in both directions: 1) to the cerebellum - tractus spinocerebelldris anterior and 2) from nucleus dentatus cerebellum to tegmentum of the midbrain - tractus cerebellotegmentalis, which after decussation ends in the red nucleus and thalamus. Along the first paths, impulses from the spinal cord go to the cerebellum, and along the second, it sends impulses to the extrapyramidal system, through which it itself influences the spinal cord.

This article describes in detail the structure and functions of the cerebellum, one of the most important parts of the brain. Despite its relatively small size, it controls the performance of a large number of tasks, and dysfunction of this organ has a greater impact on a person’s quality of life.

So, the cerebellum is responsible for performing purposeful movements, their speed, coordinating the body in space and maintaining muscle tone. Recent research in the field of neurophysiology indicates that it, along with the cerebral cortex, is involved in memory and thought processes.

The cerebellum of the brain is relatively small in size (about 150 g in an adult), but contains about 50% of the neurons of the entire central nervous system. Inside the cranium, it is geographically located in the posterior fossa, between the temporal lobes. Despite the connection with the cerebral hemispheres, it is controlled at the subconscious level.

The cerebellum has an optimal location in the brain, and at the same time connects with other parts of the central nervous system, which control the functioning of the entire body. For example, the inner layer of the cerebellar cortex is connected with the medulla oblongata through the lower pair of legs, and with the midbrain through the upper ones.

The cerebellum is the functional extension of the telencephalon-spinal cord axis and is located under the posterior part of the cerebral hemispheres, and in front of it is the brain stem and pons. This location of the cerebellum is due to its main purpose: it is responsible for coordinating purposeful movements and controlling the quality of their execution.

The lobes of the cerebellum also affect the functioning of the internal organs of a person - for example, with a defect in the floculonodular zone, there is a violation of the tone of the muscles running along the spine.

Structure and functions of the cerebellum

It is known that at human birth this section noticeably lags behind in development and size compared to the cerebral hemispheres. But already during the first year of life it begins to increase rapidly, reaching a lower weight limit of 120 g by the age of 6. Its development can be tracked by the intensity of the child’s mastery of his body: for example, in the first three months of life, the child cannot coordinate movements, while the body is in constant tone.

In the period from 5 to 11, this organ rapidly enlarges, when learning to sit and walk upright begins, and already at 6 years old the child has relatively good command of fine motor skills of the fingers. The final development of this organ occurs at the age of 16.

The cerebellum is not part of the human brainstem, but is an appendage of it. This part of the central nervous system is involved in almost all physiological tasks of the body. Therefore, the quality of performance of its functions depends on the physical state of the cerebellum.

To understand what role this part plays in the brain, you first need to study its structure in detail. There are currently 2 descriptions of this organ.

The first option reflects the internal structure of the cerebellum. It includes a description of the anatomical features of the constituent structures. According to him, the main function of the cerebellum of the human brain is performed with the help of the cortex of this organ.

Anatomy of the human cerebellum

Structurally, this section resembles: it consists of 2 hemispheres connected by an unpaired part - the vermis. Like the telencephalon, the cerebellum is covered on the outside with cortex or gray matter, which is dotted with grooves similar to the convolutions of the cerebral cortex.

Also, the gray matter in the body of the cerebellum forms nuclei, through which impulses are exchanged with other structures and the cerebral cortex, through pathways that run through the cerebellar peduncles.

The cerebellar cortex has a complex structure and contains 3 layers represented by 5 types of neurons.

1. Outer or molecular layer. Consists of basket and stellate neurons. With their help, the impulses sent by the pyriform Purkinje cells are inhibited.
2. Ganglion layer. Contains piriform neurons or Purkinje cells. Due to their large size, these particles are arranged in one row, and their branched processes penetrate the molecular layer. The axons of these neurons connect the cortex with the cerebellar nuclei.
3. Granular or granular layer. It has a complex structure and consists of granular, large stellate and spindle-shaped horizontal neurons. In this case, granular cells transmit impulses to pyriform cells, stellate cells, with the help of long axons, connect all parts of the cerebellar cortex, and fusiform cells combine the granular layer with the molecular one and go into the white matter.

The structure of the cerebellar cortex is determined by its main function: it processes incoming information and transmits it to the nuclei and other parts of the brain.

The leaves of the cerebellum are located on the entire surface and are outlined by grooves of different depths. The deepest of them divide the cerebellum into 3 main lobes:

1. Cerebrocerebellum;
2. Paleocerebellum;
3. The flocculo-nodular zone or archicerebellum.

With the help of 3 pairs of legs, the cerebellar system communicates with the corresponding part of the brain. Thus, the middle pair of cerebellar peduncles unites it with the pons, the upper ones with the midbrain, and the lower one with the medulla oblongata.

Inside the legs there are pathways that consist of long fibers of neurons. Depending on the direction of the signal, they are of 2 types:

1. Afferent or sensory fibers - receive incoming information;
2. Efferent or motor fibers transmit impulses between the cerebellum and parts of the brain.

Interneuronal connections are also represented by afferent mossy and climbing fibers. They start from the pons, vestibular nuclei and spinal cord, and through the cerebellar cortex are directed to the nuclei. The first (bryophytes) form intracerebellar connections, and the climbing ones connect parts of the brain and cerebellar structures.

Efferent fibers of the cortex are fibrous processes of Purkinje cells, which form the 2nd layer of the cerebellar cortex. With their help, the gray matter contacts the nuclei of the brain through the upper and lower legs. In addition, information is exchanged between cores through them.

The cerebellar nuclei are located in the white matter and consist of gray matter cells. Inside they are located closer to the center and the worm. The human cerebellum includes the following nuclei:

• toothed;
• corky;
• spherical;
• tent core.

The first three are in the lobes, and only the core of the tent is located in the worm.

The body of this section is represented by white matter, consisting of long processes of Purkinje cells and axons of afferent pathways, through which signals are sent through the cortex to other structures of this section.

The cerebellar vermis is formed by white nerve fibers. It connects the 2 hemispheres together and is responsible for maintaining posture in space and muscle tone.

Thus, the main work is performed by the gray matter of the nuclei and the cerebellar cortex, and the remaining components are engaged in the transmission of information generated as a result of the activity of the main parts.

The second method reflects the external neurophysiological structure of the cerebellum.

Thus, visually we can distinguish 3 main lobes, each of which was formed in the process of evolution.

Archicerebellum or vestibulocerebellum. The most ancient structure of the cerebellum. In humans, it is represented by the lower part of the worm containing the nucleus of the tent and the flocculonodular lobe, which consists of a nodule and a shred. It is separated from the rest by a deep prepyramidal groove.

The vestibulocerebellum forms a connection with the reticular formations of the medulla oblongata and the vestibular nuclei, which are located above the bottom of the fourth ventricle. Under its control is the vestibular apparatus, with the help of which it controls the coordination of eye and head movements, and the balance of the body in space. Damage to this lobe leads to problems with the muscles running along the spine, as a result a “drunken gait” develops, and the person loses control over the apples of the eyes.

Paleocerebellum or Spinocerebellum. Consists of the second half of the worm, the periclocular lobule, round and corky nuclei. This part is separated from the remaining lobes by the main groove. The spinocerebellar tract connects the cerebellum with the spinal cord. The paleocerebellum is involved in regulating muscle tone and controls the movement of the limbs with the help of muscles running along the spine. When this lobe is damaged, a person experiences disorientation in space.

Cerebrocerebellum or neocerebellum. This is the youngest and largest part of the cerebellum, consisting of the posterior lobe of the hemispheres and the dentate nucleus. This section is present only in mammals, but is most developed in humans, since with its help the verticalization of the body in space is controlled. The dentate nucleus sends an impulse to the cortex, then the signal is transmitted to the motor section of the cerebral cortex and returns back to the cerebellum. This is how preparation occurs for the purposeful movement of a person’s limbs, with each half controlling the actions on its part.

The main functions of the cerebellum are to coordinate movements, and it also controls their speed and direction, maintains muscle tone and body balance in space, and participates in the regulation of the autonomic system.

Each of the departments is in charge of implementing one of the tasks, but the main activity is carried out using the ganglion layer of the cerebellar cortex or, in other words, Purkinje cells. It is on their fibers that penetrate the cerebellum that the quality and speed of transmitted information depends. An interesting fact is that this organ is capable of learning, since a person, repeating the same movement, subsequently masters it perfectly, performing it “automatically”.

The influence of the cerebellum on the functioning of other body systems

Through the cerebellar pathways, this part of the brain communicates with other parts of the central nervous system. Thus, it exercises control over the coordination of movements and regulates muscle tone, and also reflexively monitors the execution of vital processes: heartbeat, breathing and digestion. That is why this small department received its second name - “small brain”, since a person’s life depends on the quality of performing these tasks. Moreover, the activity of the cerebellum is not regulated by consciousness, but is controlled by the cerebral cortex.

For example, in a stressful situation or during a long run, the heart rate increases and breathing becomes deepest. The occurrence of this behavior of the body is the work of the cerebellum - this is how the flow of blood rich in oxygen and nutrients increases to the muscle tissues, and metabolic processes are also accelerated.

The afferent pathways of the cerebellum transmit information along neuronal fibers from parts of the brain to the nuclei and cells of this organ. These pathways form a dense network, and their proportional ratio with efferent ones is 40:1. Through these connections, data is exchanged between the structures of the central nervous system.

The middle crura transmit afferent information from the cerebral cortex.

The fronto-pontine-cerebellar tract starts from the frontal gyrus of the cerebral cortex, crosses the pons and goes to the opposite peduncle and stops in the Purkinje cells.

The temporopontine-cerebellar pathway begins in the temporal lobes of the brain, then follows the same trajectory as the first type of connection.

The occipital-pontine-cerebellar tract transmits visual data from the occipital cortex of the cerebral hemispheres.
The lower legs serve as a conductor of afferent connections coming from the spinal and diencephalon.

The posterior spinocerebellar tract connects the spinal cord to the cerebellum. Transmits impulses from tendon and joint cells to the cortex of this organ.

The olivocerebellar tract consists of climbing fibers and begins in the inferior olive of the medulla oblongata and ends with Purkinje cells. In this case, the lower nucleus receives data from the cerebral cortex from the remotor areas that plan movement.

The vestibulocerebellar tract originates from the superior vestibular nucleus and transmits information through the legs to the archicerebellum. Then it switches to the processes of Purkinje cells and reaches the nucleus located in the tent.

The reticulocerebellar tract connects the reticular zone of the brain stem and reaches the cortex of the vermis.
The efferent connections of the cerebellum transmit information from the cortex of this organ to the parts of the brain, and they pass only through the upper pair of legs.

The dentate red tract starts from the dentate nucleus and ends at the red nuclei of the midbrain. It is involved in the coordination of movements and provides tone to the back muscles when changing posture. It is the control center for the limbs.

The cerebellothalamic pathway is directed to the vertebral thalamic nuclei. Through them, a connection is formed between the cerebellar cortex and the part of the cerebral cortex responsible for motor movements.

Cerebellar-reticular tract - connects the cerebellum with the reticular nuclei of the brain stem, which control breathing, the cardiovascular system and provide the body's protective reflexes: sneezing, coughing, chewing, swallowing and sucking.

The cerebellovestibular tract consists of long fibers of Purkinje cells and follows from the tent nucleus to the nuclei of the vestibular apparatus. Directly through this pathway, the cerebellum maintains body balance and regulates muscle tone while maintaining posture.

In addition, an afferent connection runs through the upper pair of legs, connecting the spinal processes of neurons through the diencephalon and pons, and then through the cerebellar cortex with the dentate nucleus, which is located in the cerebrocerebellum.

Thus, this department serves as the main clarifying subcortical apparatus of the central nervous system (CNS).

Symptoms of cerebellar damage

Failure in the functioning of this organ can be determined by minor changes in motor activity or the inability to hold a posture in one position. Thus, the patient may not have a reflex to point his leg in the direction of falling, but a small push is enough for him to fall.

In medicine, this phenomenon is called static ataxia, and its cause lies in the damage of the worm. In this state, the patient tries to spread his legs as wide as possible to maintain balance. To test this reflex, the doctor asks the sick person to stand up and bring their legs together, then close their eyes and stretch their arms forward.

If the cerebellar vermis is truly damaged, then the body usually tilts backward; if the hemispheres are damaged, then the sick person leans towards the affected lobe. If the condition is severe, the patient will not be able to stand up, and difficulties will arise in maintaining a sitting posture.

With extensive damage to the hemispheres, the appearance of dynamic or kinetic ataxia is noted. In this case, the patient loses the ability to accurately carry out movements. Diagnosis of such disorders consists of performing certain exercises or tests under the supervision of a doctor.

With eyes closed, the patient is asked to stand up straight, then stretch his arms straight out in front of him and touch the tip of his nose. If one of the lobes is damaged, the index finger deviates towards it.

It is proposed to rotate your hands simultaneously and in one direction with your eyes closed; if one of the hemispheres is disrupted, the hand on its side will lag behind.

In the supine position, you need to lift one of your legs and then lower the heel of that leg onto the knee of the other. If everything went well, the doctor suggests lowering the heel further down the bone. If the leg begins to slip, this indicates the development of pathology.

Another simple way to test the functions of this organ is to be able to hold a full vessel of water without spilling a drop.

The patient has a deterioration in speech: rhythm appears, sentences lose meaning, and words are stressed incorrectly. Tremors in the limbs and changes in handwriting are also observed.

If the disturbances affect the cerebellar nuclei, then the patient experiences convulsive contractions of the muscles of the limbs, inertial trembling in the fingers when completing a movement, the movement of the eyeballs cannot be controlled, rhythmic speech appears and muscle tone decreases.

The cerebellar peduncles transfer received information from parts of the brain to the cortex and nuclei, and back through efferent communication they give a command to perform a specific task, therefore, when this structure is damaged, different symptoms are observed. For example, if the upper pair of crura and the dentate nucleus are damaged, choreic hyperkinesis develops, which is characterized by rapid chaotic movements of the facial muscles, reminiscent of a grimace, the autonomic functions of the cerebellum cease to be performed - breathing becomes erratic, cardiac arrhythmia and surges in blood pressure may be observed.

A number of diseases, both congenital and acquired, are also characterized by atrophy of the structures of this organ. For example, in Marie-Foy-Alajouanine disease, Purkinje neurons, the granular layer of the cerebellar cortex, and part of the vermis are damaged. In this case, the following symptoms are noted: gait disturbance, decreased tone in the lower extremities. There may be little or no hand shaking. Such changes are most often characteristic of middle-aged and elderly people.

With such a congenital disease as Chiari disease, a low location of the cerebellar tonsils is noted. Depending on the type of disease, the manifestation of clinical signs may differ, but most often there is pain in the neck and its muscles, nausea and vomiting occurs, independent of food intake. With different degrees of prolapse, the following symptoms may also appear: speech dysfunction, noise in the head, frequent dizziness, impaired breathing and muscle tone in the limbs, numbness of the arms and legs, changes in blood pressure.

Consequences of defeats

In a healthy person, all movements are clearly coordinated, and the muscles with which they are produced contract and relax in the required sequence and with the appropriate strength. This can be observed when performing unconditioned reflexes such as breathing or swallowing. For example, when swallowing food or water, the muscles contract in a strict sequence, and a malfunction in their work can lead to the reflux of what is swallowed into the respiratory tract.

Damage to the structures causes dysfunction of the cerebellum. The symptoms are expressed in the following signs of the disorder - the patient develops asthenia, ataxia and atony. These disorders arise due to the destruction of the motor centers of movements responsible for performing basic tasks.

Types and symptoms of lesions

Asthenia is expressed in rapid muscle fatigue and a decrease in the strength of their contractions.

Ataxia is manifested by an uncertain, shaky gait, while the patient places his legs wide apart and has his arms in different directions to balance the body position in space. At the same time, the steps become unnatural and jerky; as a result, the sick person cannot rise on his toes or fall only on his heels.

Atony is the lack of normal tone of the muscles of the skeleton and internal organs. It manifests itself, for example, in digestion or blood pressure disorders.

These three symptoms occur first and are the so-called Luciani triad.

Dysarthria . This condition is characterized by a loss of plasticity in the movements produced. Also, when all areas of the cerebellar cortex are damaged, slow, inarticulate monotonous speech is observed.

Dysmetria is characterized by a delay in muscle contractions at the end of a movement and manifests itself in the difficulty of performing precise actions.

Adiadochokinesis. Symptoms of the lesion depend on the location of the damaged area. For example, when the hemispheres are damaged, the speed, amplitude, and strength of movements change, and the motor response to external stimuli is also delayed. When the neocerebellum is damaged, there is a decrease in muscle tone, while movements become jerky, the patient loses the ability to synchronously act with both limbs - one of them will lag behind.

Inertial tremor appears when the cerebellum is unable to process signals received from its own cortex and the cerebral cortex, while trembling of the limbs is noted at the end of the completed action. This behavior is a hallmark of disorders in the structure of this organ.

The neocerebellum is involved in motor learning, planning and control of movements. This feature is explained by changes in the activity of neurons in the nuclei located in its thickness. This activity occurs synchronously with the motor cortex, even before movement begins. The vestibulocerebellum and spinocerebellum are also involved in motor functions through the vestibular and reculatory nuclei located in the brainstem.

The efferent pathways of the cerebellum are located in the superior peduncles, so they do not connect it directly with the spinal cord, and the interaction between these sections is carried out using the motor nuclei of the brain stem. In this way, the cerebellum can control and make changes to the trajectory or force of movement of the limb muscles. Therefore, when the legs are damaged, the connection between the neurons of the nuclei weakens, which leads to a decrease in the sensitivity of the receptors responsible for muscle tone. Thus, there is a violation of plasticity and accuracy of movements.

Dystonia and asthenia. Sometimes, different tone is observed in the motor muscles, while there is a disturbance in the sense of balance in space, the patient is not able to coordinate the movements of the limbs. The process of standing or moving forward expends a large amount of energy, so as a result, asthenia or rapid muscle fatigue and a decrease in the strength of their contraction develop.

Most often, this condition is characterized by a change in gait and body balance, in particular, when the flocculo-nodular zone is damaged, dystonia is noted, the inability to maintain a certain position in space, the apples of the eyes make spontaneous, uncontrolled movements.

Ataxia and dysmetria. When the efferent connection of the upper legs with the motor areas of the cerebral cortex is damaged, ataxia and dysmetria develop. At the same time, a person is not able to complete an action that has been started correctly, since trembling and uncertainty develop at the end. Such a violation can be detected with a finger-nose and knee-heel test - the patient, trying to complete the movement he has started, performs additional actions.

As a result of damage to the structures and connections of the cerebellum, there may be a breakdown of complex movements (asynergia), the inability to synchronize the actions of both hands (dysdiadochokinesia), and also as a result of improper functioning of the muscles responsible for the patient’s speech, the development of speech ataxia or dysarthria is noted.

With all these deviations, the role of the cerebellum in the regulation of motor activity is clearly visible, since when this organ is damaged, there is a violation of any motor activity of the body, be it maintaining a posture or participating in programming a planned action. The dependence of the work of the cerebellum on its physiological state is clearly visible in the diagnosis of certain diseases.

For example, agenesis of the cerebellar vermis leads to impaired motor function; symptoms become noticeable in the first days of a child’s life and manifest themselves in the inability to maintain even breathing, hold the head level and make coordinated muscle movements.

An ascitoma, or tumor, can be located in any part of the brain, but in children it most often forms in the area of ​​the cerebellar vermis. It is a pathology and develops due to improper division of specific ascites cells that protect neurons from negative effects. Depending on the degree of malignancy, it can be piloid, fibrillary, anaplastic, or develop into glioblastoma. The first 2 occur in childhood, and the latter in adulthood and old age. A distinctive feature of this disease in the first stages is a violation of orientation in space and coordination of movements.

Diagnosis of problems

Some congenital pathologies, such as aplasia of the cerebellar vermis, are most often diagnosed during an ultrasound examination of the fetus during pregnancy. Unfortunately, such children are most often born with a large number of neurological abnormalities, the signs and symptoms of which appear in the first months of life, which is why they are in dire need of rehabilitation and treatment. In such a situation, neurologists usually prescribe developmental massage, exercises for the development of the vestibular apparatus, as well as taking neurostimulating drugs.

Diagnosis of disorders of the structures of this organ begins in the neurologist’s office, with the help of tests and special exercises that indicate the development of any pathology. Thus, when one hemisphere of the cerebellum is destroyed, the damaged lobe is identified using the finger-nose test, when the deviation of the finger will indicate the affected area. If the ancient cerebellum or archicerebellum is damaged, then the patient experiences a lack of coordination of eye movements and the balance of the body in space is lost.

Diagnosis of cerebellar ataxia caused by tumors of various natures is carried out in conjunction with other medical specialists, such as a neurologist, endocrinologist, traumatologist and oncologist. Typically, examination of the cerebellum, like other parts of the brain, involves the use of a large amount of equipment and may include:

• spinal puncture and cerebrospinal fluid analysis;
• CT and MRI of the head;
• dopplerography;
• electronystagmography (allows you to evaluate the conduction pathways);
• DNA diagnostics.

Adenomas and cysts are detected using MRI of the brain. This diagnostic method makes it possible to identify cerebellar disease at an early stage of development. Therapy in this case depends on the size and quality of the tumor. Thus, when treating a malignant tumor, radiation therapy or surgical removal of the tumor can be used.

It is important to realize that disturbances in the functioning of the cerebellum and its dysfunction require careful attention, since the connection of this part of the brain with other structures of the human body is obvious. And treatment with folk remedies will only worsen the disease, so at the first signs of damage to this organ you need to consult a specialist.

Video

The brain is protected by a bony sheath of the cerebral part of the skull. The brain has an ovoid shape due to the prominent frontal and occipital poles. The structure of the brain is represented by several sections: the trunk, the medulla oblongata, the cerebellum, the pons, the midbrain and the cerebral cortex. A longitudinal fissure running along the midline of the brain separates its right and left hemispheres - the hemisphere. Under the occipital pole of the cerebrum there is a transverse fissure that separates the cerebellum, the center of coordination of movements.

Structure and functions of the cerebellum

Deep in the cerebellum there are paired nuclei consisting of gray matter. This structure, the core of the tent, belongs to the vestibular apparatus. On the sides of the tent are the spherical and cork-shaped nuclei, which coordinate the work of the muscles of the trunk, as well as the dentate nucleus, which controls the work of the limbs. The cerebellum is connected to the periphery through other parts of the brain by 3 pairs of peduncles. The superior cerebellar peduncles go to the midbrain, the middle peduncles to the pons, and the inferior peduncles to the medulla oblongata.

The functions of the cerebellum in the human body are coordination of movements, participation in the regulation of the work of internal organs and skeletal muscles.

Embryonic development

Symptoms of cerebellar damage

Cerebellar movement disorders have characteristic signs:
loss of smooth movements of arms and legs;
trembling at the end of a purposeful movement - intention tremor;
change in handwriting;
scanned speech, which is distinguished by rhythmic rather than semantic placement of stress in words;
slowing down of voluntary movements and speech.

Cerebellar imbalances are expressed in dizziness and gait disorder - ataxia. Cerebellar ataxia is similar to the gait of a drunk person; the patient staggers towards the lesion. Disorders of the movements of the oculomotor muscles are manifested by nystagmus - rhythmic twitching of the eyeballs when looking away to extreme positions. A mismatch in the work of the muscles of the limbs and torso also manifests itself when the patient tries to rise from a lying position and sit down without using his hands.
Cerebellar ataxia is observed in many diseases and lesions of the human nervous system: tumors of the posterior cranial fossa, inflammation of the brain and its membranes, poisoning, hereditary genetic defects, hemorrhages of various origins.

Congenital diseases

There are several more options for chronic atrophy of the cerebellar system: Friedreich's familial ataxia, torsion dystopia and other diseases. For hereditary forms of cerebellar ataxia, conservative treatment is used, which reduces the severity of symptoms, improves blood supply and nutrition of nerve cells.

Acquired diseases

Traumatic brain injury can lead to damage to the cerebellum, compression of it by hemorrhage - traumatic hematoma. When a diagnosis of hemorrhage is made, a surgical operation is performed - removal of the hematoma.

The cause of hemorrhage can also be a stroke - cerebellar infarction, resulting from atherosclerosis of blood vessels or a hypertensive crisis. As a result of the resorption of small hemorrhages, cysts are formed in the cerebellum - defects in nervous tissue filled with fluid. The functions of dead nerve cells are partially replaced by the remaining neurons.

An accurate diagnosis of focal lesions in any part of the brain is established using magnetic resonance imaging ( MRI). Surgical treatment of cerebellar diseases is carried out for tumors, focal suppurations ( abscesses), hemorrhages, traumatic injuries.

About transplantation

CEREBELLUM, a part of the brain located under the occipital lobes of the cerebral hemispheres. Its purpose is to regulate muscle tone, maintain balance and coordinate movements. Scientific and technical dictionary