Thalamus - visual tubercle

The structure in which the processing and integration of almost all signals going to the cerebral cortex from the spinal cord, midbrain, cerebellum takes place.

In the nuclei of the thalamus, the information coming from the extero-, proprioreceptors and interoceptors is switched and thalamocortical pathways begin. Given that the geniculate bodies of the thalamus are the subcortical centers of vision and hearing, and the frenulum node and the anterior visual nucleus are involved in the analysis of olfactory signals, it can be argued that the thalamic thalamus as a whole is a subcortical "station" for all types of sensitivity. Here irritations of the external and internal environment integrated, after which they enter the cerebral cortex.

The visual hillock, together with the hypothalamus, takes part in the formation and implementation of instincts, drives, emotions. There are about 120 multifunctional nuclei in the thalamus, which form peculiar complexes that can be divided according to the projection into the cortex into 3 groups: the anterior one projects the axons of its neurons into the cingulate gyrus of the cerebral cortex; medial - in the frontal lobe of the cortex; lateral - in the parietal, temporal, occipital lobes of the cortex. The function of the nuclei is also determined from the projections. Such a division is not absolute, since one part of the fibers from the nuclei of the thalamus goes to strictly limited cortical formations, the other to different areas of the cerebral cortex.

The nuclei of the thalamus are functionally divided into specific, nonspecific and associative, according to the nature of the incoming and outgoing pathways.

Specific nuclei include the anterior ventral, medial, ventrolateral, postlateral, postmedial, lateral, and medial geniculate bodies. The latter belong to the subcortical centers of vision and hearing, respectively. The basic functional unit of specific thalamic nuclei are "relay" neurons, which have few dendrites and a long axon; their function is to switch information going to the cerebral cortex from skin, muscle and other receptors. From specific nuclei, impulses arrive in strictly defined areas of the III-IV layers of the cerebral cortex (somatotopic localization). Violation of the function of specific nuclei leads to the loss of specific types of sensitivity, since the nuclei of the thalamus, like the cerebral cortex, have a somatotopic organization. Signals from the receptors of the skin, eyes, ear, muscular system. Signals from the interoreceptors of the projection zones of the vagus and celiac nerves, the hypothalamus also converge here.

The lateral geniculate body has direct efferent connections with the occipital lobe of the cerebral cortex and afferent connections with the retina and anterior colliculi. The neurons of the lateral geniculate bodies react differently to color stimuli, turning on and off the light, i.e. can perform a detective function.

The medial geniculate body (MC) receives afferent impulses from the lateral loop and from the inferior tubercles of the quadrigeminae. The efferent pathways from the medial geniculate bodies go to the temporal zone of the cerebral cortex, reaching there the primary auditory cortex. MKT has a clear tonotopicity, i.e. the ability to respond to a certain frequency of sound vibrations. Consequently, already at the level of the thalamus, the spatial distribution of the sensitivity of all sensory systems organism, including sensory messages from interoreceptors of vessels, organs of the abdominal and thoracic cavities.

The associative nuclei of the thalamus are represented by the anterior mediodorsal, lateral dorsal, and pillow nuclei. The anterior nucleus is associated with the limbic cortex (cingulate gyrus), the mediodorsal - with the frontal lobe of the cortex, the lateral dorsal - with the parietal, the pillow - with associative zones, the parietal and temporal lobes of the cerebral cortex.

Convergence of excitations of different modalities occurs on the polysensory neurons of the thalamus, an integrated signal is formed, which is then transmitted to the associative cortex of the brain. The neurons of the pillow are mainly associated with the associative zones of the parietal and temporal lobe cerebral cortex, neurons of the lateral nucleus - with the parietal, neurons of the medial nucleus - with the frontal lobe of the cerebral cortex.

Nonspecific nuclei of the thalamus are represented by: the median center, paracentral nucleus, central medial and lateral, submedial, ventral anterior, parafascicular complexes, reticular nucleus, periventricular and central gray mass. The neurons of these nuclei form their connections according to the reticular type. Their axons rise to the cerebral cortex and contact with all its layers, forming not local, but diffuse connections. Connections from the RF of the brain stem, hypothalamus, limbic system, basal ganglia, and specific nuclei of the thalamus come to nonspecific nuclei. Excitation of non-specific nuclei causes the generation in the cortex of a specific spindle-shaped electrical activity indicating the development of a sleepy state. Violation of the function of non-specific nuclei makes it difficult for spindle-shaped activity to appear, i.e. sleep development.

Hypothalamus (hypothalamic region) - the presentation of the material will be in the section "Limbic system".

Cerebellum

The cerebellum (cerebellum) is a structure of the brain that is involved in the coordination and regulation of voluntary, involuntary movements, in the regulation of autonomic and behavioral functions. The implementation of these functions is provided by the following morphological features of the cerebellum:

1) the cerebellar cortex is built quite uniformly, has stereotyped connections, which creates conditions for fast information processing;

2) main neural element cortex - Purkinje cell, has a large number of inputs and forms the only axon output from the cerebellum, the collaterals of which end on its nuclear structures;

3) almost all types of sensory stimuli are projected onto Purkinje cells: proprioceptive, skin, visual, auditory, vestibular, etc.;

4) exits from the cerebellum provide its connections with the cerebral cortex, with stem formations and the spinal cord.

The cerebellum is anatomically and functionally divided into old, ancient and new parts.

Information leaves the cerebellum through the upper and lower legs. Through the upper legs, the signals go to the thalamus, the pons, the red nucleus, the nuclei of the brain stem, and the reticular formation of the midbrain. Through the lower legs of the cerebellum, the signals go to the medulla oblongata to its vestibular nuclei, olives, and the reticular formation. The middle cerebellar peduncle connects the new cerebellum with the frontal lobe of the brain.

The impulse activity of neurons is recorded in the layer of Purkinje cells and the granular layer, and the frequency of generation of impulses of these cells ranges from 20 to 200 per second. The cells of the cerebellar nuclei generate impulses much less frequently - 1-3 impulses per second.

Signals from skin receptors, muscles, articular membranes, and periosteum enter the cerebellar cortex through the so-called spinocerebellar tracts: along the posterior (dorsal) and anterior (ventral) tracts. These paths to the cerebellum pass through the inferior olive of the medulla oblongata. From the olive cells come the so-called climbing fibers that branch on the dendrites of the Purkinje cells.

The nuclei of the bridge send afferent pathways to the cerebellum, forming mossy fibers that terminate on the granule cells of layer III of the cerebellar cortex. Between the cerebellum and the blue spot there is an afferent connection with the help of adrenergic fibers. These fibers are capable of diffusely ejecting norepinephrine into the intercellular space of the cerebellar cortex, thereby humorally changing the state of excitability of its cells.

Axons of cells of the third layer of the cerebellar cortex cause inhibition of Purkinje cells and granule cells of their own layer.

Purkinje cells, in turn, inhibit the activity of neurons in the cerebellar nuclei. The nuclei of the cerebellum have a high tonic activity and regulate the tone of a number of motor centers of the intermediate, middle, oblong, spinal cord.

The subcortical system of the cerebellum consists of three functionally different nuclear formations: the tent nucleus, the corky, spherical, and dentate nuclei.

The tent nucleus receives input from the medial cerebellar cortex and is connected to the Deiters nucleus and RF of the medulla and midbrain. From here, the signals travel along the reticulospinal pathway to the motor neurons of the spinal cord.

The intermediate cortex of the cerebellum projects to the cork and globular nuclei. From them, connections go to the midbrain to the red nucleus, then to the spinal cord along the rubrospinal path. The second path from the intermediate nucleus goes to the thalamus and further to the motor cortex.

The dentate nucleus, receiving information from the lateral zone of the cerebellar cortex, is connected with the thalamus, and through it - with the motor zone of the cerebral cortex.

The control of motor activity by the cerebellum is provided by efferent signals to the spinal cord, and regulate the strength of muscle contractions, provide the ability for prolonged tonic muscle contraction, the ability to maintain optimal muscle tone at rest or during movement, to make adequate voluntary movements, to quickly switch from flexion to extension and vice versa.

The cerebellum provides coordinated contractions different muscles with complex movements. For example, when walking, when a person takes a step, then at the same time the center of gravity of the body is transferred forward. In cases where the cerebellum does not perform its regulatory function, a person has disorders motor functions which is expressed by the following symptoms.

1) asthenia (asthenia - weakness) - a decrease in the strength of muscle contraction, rapid muscle fatigue;

2) astasia (astasia, from Greek a - not, stasia - standing) - loss of the ability to prolonged muscle contraction, which makes it difficult to stand, sit, etc .;

3) dystonia (distonia - violation of tone) - an involuntary increase or decrease in muscle tone;

4) tremor (tremor - trembling) - trembling of the fingers, hands, head at rest; this tremor is aggravated by movement;

5) dysmetria (dismetria - violation of the measure) - a disorder of the uniformity of movements, expressed either in excessive or insufficient movement. The patient tries to take an object from the table and brings his hand behind the object (hypermetry) or does not bring it to the object (hypometry);

6) ataxia (ataksia, from Greek a - negation, taksia - order) - impaired coordination of movements. Here, the impossibility of performing movements in right order, in a certain sequence.

Manifestations of ataxia are also asynergy, drunken staggering gait. With adiadochokinesis, a person is not able to quickly rotate his palms up and down. With muscle asynergy, he is unable to sit up from a prone position without the help of hands. The drunken gait is characterized by the fact that a person walks with his legs wide apart, staggering from side to side from the line of walking. Most of the movements a person learns during his life, and they become automatic (walking, writing, etc.). When the function of the cerebellum is disturbed, the movements become inaccurate, scattered, and often do not reach the goal. The data that damage to the cerebellum leads to disorders of acquired movements allow us to conclude that learning itself took place with the participation of cerebellar structures, and, consequently, the cerebellum takes part in the organization of processes of higher nervous activity.

To have an idea of ​​what the thalamus and hypothalamus are, you must first understand what the diencephalon is. This part of the brain is located under the so-called corpus callosum, just above the midbrain.

It includes the metathalamus, hypothalamus, and thalamus. The functions of the diencephalon are very extensive - it integrates motor, sensory and autonomic reactions, which are extremely important for normal human activity. The diencephalon develops from the anterior cerebral bladder, while its walls form the third ventricle of the brain structure.

The thalamus is the substance that makes up the bulk of the diencephalon. Its functions are to receive and transmit to the cerebral cortex and central nervous system almost all impulses, with the exception of olfactory ones.

The thalamus has two symmetrical parts and is part of the limbic system. This structure is located in the forebrain, near the center of the head directions.

The functions of the thalamus are carried out through the nuclei, of which it has 120. These nuclei are actually responsible for receiving and sending signals and impulses.

The neurons that branch off from the thalamus are divided as follows:

1. Specific- transmit information received from the eye, auditory, muscle and other sensitive areas.
2. Non-specific- are mainly responsible for a person’s sleep, therefore, if damage to these neurons occurs, the person will want to sleep all the time.
3. Associative- regulate excitation modality.

Based on the foregoing, we can say that the thalamus regulates various processes occurring in the human body, and is also responsible for receiving signals about the state of the sense of balance.

If we talk about the regulation of sleep, then if the functionality of some thalamic neurons is impaired, a person can develop insomnia so persistent that he can even die from it.

Diseases of the thalamus

With damage to the visual tubercle, a thalamic syndrome develops, the symptoms can be very diverse, since it depends on what function the nuclei that have lost their functionality performed. The cause of the development of the thalamic syndrome is a functional disorder of the vessels of the posterior cerebral artery. In this case, you may observe:

• violation of the sensitivity of the face;
• pain syndrome that covers one half of the body;
• lack of vibration sensitivity;
• paresis;
• in the affected half of the body, muscle atrophy is observed;
• a symptom of the so-called thalamic hand - a certain position of the phalanges of the fingers and the hand itself,
• attention disorder.

Hypothalamus of the brain

The structure of the hypothalamus is very complex, so only its functions will be considered in this article. They consist in the behavioral responses of a person, as well as in the influence on the vegetative system. In addition, the hypothalamus is actively involved in the regeneration of reserves.

The hypothalamus also has many nuclei, which are divided into posterior, middle and anterior. The nuclei of the posterior category regulate the sympathetic reactions of the body - increased pressure, rapid pulse, dilation of the pupil of the eye. The nuclei of the middle category, on the contrary, reduce sympathetic manifestations.

The hypothalamus is responsible for:

• thermoregulation;
• feeling full and hungry;
• fear;
• sex drive and so on.

All these processes occur as a result of activation or inhibition of various nuclei.

For example, if a person’s blood vessels dilate and he becomes cold, then an irritation of the anterior group of nuclei has occurred, and if the nuclei of the posterior order are damaged, this can provoke a lethargic dream.

The hypothalamus is responsible for the regulation of movements, if excitation occurs in this area, a person can make chaotic movements. If violations occur in the so-called gray tubercle, which is also part of the hypothalamus, then the person begins to suffer from metabolic disorders.

Pathologies of the hypothalamus

All ailments of the hypothalamus are associated with a violation of the function of this structure, or rather with the peculiarities of hormonal synthesis. Diseases can occur due to excessive production of hormones, due to reduced secretion of hormones, but also ailments can occur with normal production of hypothalamic hormones. There is a very close connection between the hypothalamus and the pituitary gland - they have a common blood circulation, similar anatomical structure and identical functions. Therefore, diseases are often combined into one group, which is called pathologies of the hypothalamic-pituitary system.

Often the cause of pathological symptoms is the occurrence of an adenoma of the pituitary gland or the hypothalamus itself. In this case, the hypothalamus begins to produce a large amount of hormones, as a result of which the corresponding symptoms appear.

A typical lesion of the hypothalamus is prolactinoma - a tumor that is hormonally active, as it produces prolactin.

Another dangerous disease is the hypothalamic-pituitary syndrome, this disease is associated with a violation of the functionality of both the pituitary gland and the hypothalamus, which leads to the development of a characteristic clinical picture.

Due to the fact that there are many diseases that affect the hypothalamic-pituitary system, below will be given general symptoms, according to which pathologies of this part of the brain can be suspected:

1. Problems with saturation of the body. The situation can develop in two directions - either a person completely loses his appetite, or does not feel full, no matter how much he eats.
2. Problems with thermoregulation. This manifests itself in an increase in temperature, while no inflammatory processes not seen in the body. In addition, an increase in temperature is accompanied by chills, increased sweating, increased thirst, obesity and uncontrolled hunger.
3. Epilepsy on a hypothalamic basis - interruptions in the work of the heart, increased blood pressure, pain in the epigastric region. During an attack, a person loses consciousness.
4. Changes in the work of the vegetovascular system. They manifest themselves in the work of digestion (belching, abdominal pain, stool breakdowns), in the work of the respiratory system (tachypnea, shortness of breath, suffocation) and in the work of the heart and blood vessels (malfunctions in heart rate, high or low blood pressure, retrosternal pain).

Neurologists, endocrinologists and gynecologists are engaged in the treatment of diseases of the hypothalamus.

Conclusion and Conclusions

1. Since the hypothalamus regulates the day and night rhythms of a person, it is important to observe the daily routine.
2. It is necessary to improve blood circulation and oxygenate all parts of the brain. Smoking and consumption of alcoholic beverages is not allowed. Walks are recommended fresh air and sports activities.
3. It is important to normalize the synthesis of hormones.
4. It is recommended to saturate the body with all the necessary vitamins and minerals.

Disruption of the thalamus and hypothalamus leads to various diseases, most of which end sadly, so you need to be very careful about your health and, at the first ailments, contact specialists for advice.

θάλαμος - "hill") - an area of ​​\u200b\u200bthe brainresponsible for the redistribution of information from the senses, with the exception of smell, to the cerebral cortex. This information (impulses) enters the nuclei of the thalamus. The nuclei themselves are composed of gray matter, which is formed by neurons. Each nucleus is a collection of neurons. The nuclei are separated by white matter.

Four main nuclei can be distinguished in the thalamus: a group of neurons redistributing visual information; nucleus redistributing auditory information; a core that redistributes tactile information; and a core that redistributes a sense of equilibrium and balance.

After information about any sensation has entered the nucleus of the thalamus, its primary processing takes place there, that is, the temperature, visual image, etc., are realized for the first time. It is believed that the thalamus plays important role in the implementation of memory processes. Fixation of information is carried out as follows: the first stage of engram formation occurs in the SS. It begins when a stimulus excites peripheral receptors. From them, along the pathways, nerve impulses go to the thalamus, and then to the cortical region. It carries out the highest synthesis of sensation. Damage to the thalamus can lead to anterograde amnesia, as well as tremors—involuntary shaking of the extremities at rest—although these symptoms are absent when the patient is consciously performing the movements.

associated with the thalamus rare disease called fatal familial insomnia.

Links

• Integral medicine of the XXI CENTURY: theory and practice. thalamus
• Human Physiology, ed. V.M. Pokrovsky, G.F. Korotko. thalamus

Wikimedia Foundation. 2010 .

Synonyms:

Like any other brain organ, the thalamus has an extremely important and indispensable function for the body. It is hard to imagine, but this relatively small organ is responsible for all mental functions: perception and understanding, memory and thinking, because thanks to it we see, understand, feel the world and perceive everything that surrounds us. Thanks to its work, we orient ourselves in space and time, feel pain, this “collector of sensitivity” perceives and processes information received from all receptors, except for the sense of smell, and transmits the necessary signal to the desired section of the cerebral cortex. As a result, the body gives the right reaction, shows correct models behavior in response to an appropriate stimulus or signal.

General information

The diencephalon is located under the corpus callosum and consists of: the thalamus (thalamic brain) and the hypothalamus.

The thalamus (aka: visual tubercle, sensitivity collector, body informant) is a section of the diencephalon located in its upper part, above the brain stem. Sensory signals flow here, impulses from the most different parts body and from all receptors (except for the sense of smell). Here they are processed, the body evaluates how important the incoming impulses are for a person and sends the information further to the central nervous system (central nervous system) or to the cerebral cortex. This painstaking and vital process occurs due to the components of the thalamus - 120 multifunctional nuclei that are responsible for receiving signals, impulses and for sending processed information to the appropriate one.

Due to its complex structure, the "visual thalamus" is able not only to receive and process signals, but also to analyze them.

Ready-made information about the state of the body and its problems goes to the cerebral cortex, which, in turn, develops a strategy for solving and eliminating the problem, a strategy for further actions and behavior.

Structure

The thalamus is a paired ovoid formation consisting of nerve cells that unite into nuclei, due to which the perception and processing of signals and impulses coming from different sense organs takes place. The thalamus occupies the main part of the diencephalon (approximately 80%). Consists of 120 multifunctional nuclei of gray matter. It is shaped like a small chicken egg.

Based on the structure and location of individual parts, the thalamic brain can be divided into: metathalamus, epithalamus and subthalamus.

Metathalamus(subcortical auditory and visual center) - consists of medial and lateral geniculate bodies. The auditory loop ends in the nucleus of the medial geniculate body, and the optic tracts end in the lateral one.

The medial geniculate bodies make up the auditory center. In the medial part of the metathalamus, from the subcortical auditory center, cell axons go to the cortical end of the auditory analyzer (superior temporal gyrus). Dysfunction of this part of the metathalamus can lead to hearing loss or deafness.

Lateral geniculate bodies constitute the subcortical visual center. This is where the optic tracts end. Axons of cells form visual radiance, along which visual impulses reach the cortical end visual analyzer (occipital lobe). Dysfunction of this center can lead to vision problems, and severe lesions can lead to blindness.

Epithalamus(suprathalamus) - the upper back part of the thalamus, which rises above it: includes the pineal gland, which is the supracerebral endocrine gland (pineal gland). The epiphysis is in limbo, as it is located on leashes. It is responsible for the production of hormones: during the day it produces the hormone serotonin (the hormone of joy), and at night it produces melatonin (the regulator of the day regimen and the hormone responsible for the color of the skin and eyes). The epithalamus plays a role in the regulation life cycles, regulates the onset of puberty, sleep and wakefulness, slows down the aging process.

Lesions of the epithalamus lead to disruption of life cycles, including insomnia, as well as sexual dysfunction.

Subthalamus(subthalamus) or prethalamus is a medulla of small volume. Consists mainly of the subthalamic nucleus and has connections to the globus pallidus. The subthalamus controls muscle responses and is responsible for action selection. Damage to the subthalamus leads to movement disorders, tremor, paralysis.

In addition to all of the above, the thalamus has connections with the spinal cord, with the hypothalamus, subcortical nuclei and, of course, with the cerebral cortex.

Each department of this unique organ has a specific function and is responsible for vital processes, without which the normal functioning of the body is impossible.

Functions of the thalamus

The “sensitivity collector” receives, filters, processes, integrates and sends information to the brain that comes from all receptors (except for smell). It can be said that in its centers the formation of perception, sensation, understanding takes place, after which the processed information or signal enters the cerebral cortex.

The main functions of the body are:

• processing of information received from all organs (receptors of sight, hearing, taste and touch) senses (except for smell);
• management of emotional reactions;
• regulation of involuntary motor activity and muscle tone;
• maintaining a certain level of activity and excitability of the brain, which is necessary for the perception of information, signals, impulses and irritations coming from outside, from the environment;
• responsible for the intensity and feeling of pain.

As we have already said, each lobe of the thalamus consists of 120 nuclei, which, based on functionality, can be divided into 4 main groups:

• lateral (lateral);
• medial (median);
• associative.

Reticular group of nuclei (responsible for balance) - responsible for ensuring balance when walking and balance in the body.

Lateral group (center of vision) - responsible for visual perception, receives and transmits impulses to the parietal, occipital part of the cerebral cortex - the visual zone.

Medial group (hearing center) - responsible for auditory perception, receives and transmits impulses to the temporal part of the cortex - the auditory zone.

Associative group (tactile sensations) - receives and transmits tactile information to the cerebral cortex, that is, signals emanating from receptors skin and mucous membranes: pain, itching, shock, touch, irritation, etc.

Also, from a functional point of view, the nuclei can be divided into: specific and non-specific.

Specific nuclei receive signals from all receptors (except for smell). They provide an emotional reaction to a person and are responsible for the occurrence of pain.

Specific nuclei, in turn, are:

• external - receive impulses from the corresponding receptors and send information to specific areas of the cortex. Through these impulses feelings and sensations arise;
• internal - do not have direct connections with receptors. They receive information already processed by the relay cores. From them, impulses go to the cerebral cortex in the associative zones. Thanks to these impulses, primitive sensations arise and the relationship between the sensory zones and the cerebral cortex is provided.

Non-specific kernels support general activity cerebral cortex, sending non-specific impulses and stimulating brain activity. Having no direct connection with the cortex, the nonspecific nuclei of the thalamus transmit their signals to the subcortical structures.

Separately about the visual tubercle

Previously, it was believed that the thalamus processes only visual impulses, then the organ was called the visual tubercles. Now this name is considered obsolete, since the organ processes almost the entire range of afferent systems (except for smell).

The system that provides visual perception is one of the most interesting. The main external organ of vision is the eye - a receptor that has a retina and is equipped with special cells (cones, rods) that transform the light beam and electrical signal. The electrical signal, in turn, passing through nerve cells, enters the lateral center of the thalamus, which sends the processed signal to central department cerebral cortex. Here the final analysis of the signal takes place, due to which what is seen, that is, the picture, is formed.

What are dangerous dysfunctions of the thalamus zones

The thalamus has a complex and well-established structure, therefore, if there are malfunctions or problems in the work of even a single zone of an organ, this leads to different consequences, affecting individual functions of the body and even the entire body as a whole.

Before getting to the corresponding center of the cortex, the signals from the receptors enter the thalamus, or rather, in a certain part of it. If certain nuclei of the thalamus are damaged, then the impulse is not processed, does not reach the cortex, or reaches it in an unprocessed form, therefore, the cerebral cortex and the whole organism do not receive the necessary information.

Clinical manifestations of thalamic dysfunctions depend on the specific affected area and can manifest themselves as: problems with memory, attention, understanding, loss of orientation in space and time, disorders of the motor system, problems with vision, hearing, insomnia, mental disorders.

One of the manifestations of organ dysfunctions can be specific amnesia, which leads to partial memory loss. In this case, a person forgets the events that occurred after damage or damage to the corresponding zone of the organ.

Another rare disease that affects the thalamus is fatal insomnia, which can spread to several members of the same family. The disease occurs due to a mutation of the corresponding zone of the thalamus, which is responsible for regulating the processes of sleep and wakefulness. Due to the mutation, a malfunction occurs in the correct operation of the corresponding section, and the person stops sleeping.

The thalamus is also the center of pain sensitivity. With the defeat of the corresponding nuclei of the thalamus, unbearable pain occurs or, conversely, a complete loss of sensitivity.

The thalamus, and the brain as a whole, continue to be not fully understood structures. And further research promises great scientific discoveries and help in understanding this vital and complex organ.

Inside it is the cavity of the third cerebral ventricle. The diencephalon consists of:

1. visual brain

   • thalamus

   • Epithalamus (suprathalamic region - epiphysis, leashes, commissure of leashes, triangles of leashes)

   • Metathalamus (zathalamic region - medial and lateral geniculate bodies)

2. Hypothalamus (subthalamic region)

• Anterior hypothalamic region (visual - optic chiasm, tract)

• Intermediate hypothalamic region (gray tubercle, infundibulum, pituitary gland)

• Posterior hypothalamic region (papillary bodies)

• Proper subthalamic region (Posterior hypothalamic nucleus of Luisi)

thalamus

The visual tubercle consists of gray matter, separated by layers white matter into separate nuclei. The fibers originating from them form a radiant crown that connects the thalamus with other parts of the brain.

The thalamus is the collector of all afferent (sensory) pathways leading to the cerebral cortex. This is the gate on the way to the cortex, through which all information from the receptors passes.

thalamus nuclei:

1. Specific - switching afferent impulses to strictly localized areas of the cortex.

1.1. Relay (switching)

1.1.1.Touch(ventral posterior, ventral intermediate nucleus) switching of afferent impulses to sensory areas of the cortex.

1.1.2.Non-sensory - switching non-sensory information to the cortex.

• limbic nuclei(anterior nuclei) - subcortical center of smell. Anterior nuclei of the thalamus limbic cortex-hippocampus-hypothalamus-mamillary bodies of the hypothalamus - the anterior nuclei of the thalamus (Peypets reverb circle - the formation of emotions).
• Motor cores: (ventral) switch impulses from the basal ganglia, the dentate nucleus of the cerebellum, the red nucleus to motor and premotor area(transmission of complex motor programs formed in the cerebellum and basal ganglia).

1.2. Associative (integrative function, receive information from other nuclei of the thalamus, send impulses to the associative areas of the KGM, there is feedback)

1.2.1. Pillow nuclei - impulses from the geniculate bodies and non-specific nuclei of the thalamus, to the temporal-parietal-occipital zones of the CGM, involved in gnostic, speech and visual reactions (integration of a word with a visual image), perception of the body scheme. Electrical stimulation of the pillow leads to a violation of the naming of objects, the destruction of the pillow - a violation of the body scheme, eliminates severe pain.

1.2.2. Mediodorsal nucleus - from the hypothalamus, amygdala, hippocampus, thalamic nuclei, central gray matter of the trunk, to the associative frontal and limbic cortex. Formation of emotions and behavioral motor activity, participation in memory mechanisms. Destruction - eliminates fear, anxiety, tension, suffering from pain, but decreases initiative, indifference, hypokinesia.

1.2.3. Lateral nuclei - from the geniculate bodies, the ventral nucleus of the thalamus, to the parietal cortex (gnosis, praxis, body scheme.)

1. Nonspecific nuclei - (intralaminar nuclei, reticular nucleus) signaling in all sections of KGM. Many incoming and outgoing fibers, analogue of the RF stem - an integrating role between the brain stem, cerebellum and basal ganglia, neonatal and limbic cortex. Modulating influence, provide fine regulation of behavior, "smooth tuning" of GNI.

Metathalamus The medial geniculate bodies together with the inferior tubercles of the quadrigemina of the midbrain form the subcortical center of hearing. They play the role of switching centers for nerve impulses sent to the cerebral cortex. On the neurons of the nucleus of the medial geniculate body, the fibers of the lateral loop end. The lateral geniculate bodies, together with the superior tubercles of the quadrigemina and the pillow of the thalamus, are the subcortical centers of vision. They are communication centers at which the optic tract ends, and in which the pathways that conduct nerve impulses to visual centers cerebral cortex.

Epithalamus The pineal gland is associated with the parietal organ of some higher fish and reptiles. In cyclostomes, it retained to a certain extent the structure of the eye; in anurans, it is found in a reduced form under the scalp. In mammals and humans, the pineal gland has a glandular structure and is an endocrine gland (hormone - melatonin).

The epiphysis (pineal gland) refers to the glands of internal secretion. It produces serotonin, from which melatonin is then formed. The latter is an antagonist of melanocyte-stimulating hormone of the pituitary gland, as well as sex hormones. The activity of the pineal gland depends on the illumination, i.e. the circadian rhythm is manifested, and this regulates the reproductive function of the body.

Hypothalamus

The hypothalamic region contains forty-two pairs of nuclei, which are divided into four groups: anterior, intermediate, posterior, and dorsolateral.

The hypothalamus is the ventral part of the diencephalon, anatomically consists of the preoptic area, the area of ​​the chiasm optic nerves, gray tubercle and funnel, mastoid bodies. The following groups of nuclei are distinguished:

• Anterior group of nuclei (anterior to the gray nucleus) - preoptic nuclei, suprachiasmatic, supraoptic, paraventricular
• Intermediate (tuberal) group (in the region of the gray tubercle and infundibulum) - dorsomedial, ventromedial, arcuate (infundibular), dorsal hypotuberous, posterior PVN and own nuclei of the tubercle and infundibulum. The first two groups of nuclei are neurosecretory.
• Posterior - the nuclei of the papillary bodies (subcortical center of smell)
• Subthalamic nucleus of Louis (integration function

The hypothalamus has the most powerful network of capillaries in the brain and the highest level of local blood flow (up to 2900 capillaries per mm square). Capillary permeability is high, because The hypothalamus has cells that are selectively sensitive to changes in blood parameters: changes in pH, the content of potassium and sodium ions, oxygen tension, carbon dioxide. The supraoptic nucleus has osmoreceptors, the ventromedial nucleus has chemoreceptors glucose-sensitive in the anterior hypothalamus sex hormone receptors. There is thermoreceptors. The sensitive neurons of the hypothalamus do not adapt, and are excited until one or another constant in the body returns to normal. The hypothalamus exerts efferent influences with the help of sympathetic and parasympathetic nervous systems and endocrine glands. Here are the centers of regulation various kinds exchanges: protein, carbohydrate, fat, mineral, water, as well as centers of hunger, thirst, satiety, pleasure. The hypothalamic region is referred to the higher subcortical centers of autonomic regulation. Together with the pituitary gland, it forms the hypothalamic-pituitary system, through which the nervous and hormonal regulation is interfaced in the body.

In the hypothalamic region, endorphins and enkephalins are synthesized, which are part of the natural pain system and affect the human psyche.

Nerve pathways to the hypothalamus come from the limbic system, CGM, basal ganglia, RF trunk. From the hypothalamus - to the Russian Federation, the motor and autonomic centers of the brainstem are the autonomic centers of the spinal cord, from the mamillary bodies to the anterior nuclei of the thalamus, then to limbic system, from the SOYA and PVN to the neurohypophysis, from the ventromedial and infundibular to the adenohypophysis, there are also connections with the frontal cortex and the striatum.

Hormones SOYA and PVN:

1. ADH (vasopressin)
2. Oxytocin

Hormones of the mediobasal hypothalamus: ventromedial and infundibular nuclei:

1. Liberins (releasing) corticoliberin, thyroliberin, luliberin, folliberin, somatoliberin, prolactoliberin, melanoliberin

2. Statins (inhibins) somatostatin, prolactostatin and melanostatin

Functions:

1. Maintenance of homeostasis
2. Integrative Center for Autonomic Functions
3. High Endocrine Center
4. Regulation of heat balance (front nuclei - the center of heat transfer, rear - the center of heat generation)
5. Regulator of the sleep-wake cycle and other biorhythms
6. Role in eating behavior middle group nuclei: the lateral nucleus is the center of hunger and the ventromedial nucleus is the center of saturation)
7. Role in sexual, aggressive-defensive behavior. Irritation of the anterior nuclei stimulates sexual behavior, irritation of the posterior nuclei inhibits sexual development.
8. Center for the regulation of various types of metabolism: protein, carbohydrate, fat, mineral, water.
9. It is an element of the antinociceptive system (pleasure center)