Details about the cerebral hemispheres of the brain. Forebrain

The functional parts of the brain are the brainstem, the cerebellum and the terminal section, which includes the cerebral hemispheres. The last component is the most voluminous part - it occupies about 80% of the mass of the organ and 2% of the weight of the human body, while up to 25% of the total energy produced in the body is spent on its work.

The hemispheres of the brain differ slightly in size, depth of convolutions and the functions they perform: the left is responsible for logical and analytical thinking, and the right is responsible for motor skills. Moreover, they are interchangeable - if one of them is damaged, the other can partially take over its functions.

While studying the brains of famous people, experts noticed that a person’s abilities depend on which half of the terminal section is more developed. For example, artists and poets most often have a developed right hemisphere, since this part of the brain is responsible for creativity.

Basic aspects of the physiology of the cerebral hemispheres, or hemispheres as they are also called, using the example of brain development in a child from the moment of conception.

The central nervous system begins to develop almost immediately after fertilization of the egg and already at 4 weeks after implantation of the embryo into the uterine mucosa, it consists of 3 brain vesicles connected in series. The first of them is the rudiment of the anterior part of the brain and, therefore, its cerebral hemispheres, the second is the midbrain, and the last, third forms the rhomboid part of the brain.

In parallel with this process, the birth of the cerebral cortex occurs - at first it looks like a small long plate of gray matter, consisting mainly of a cluster of neuron bodies.

Next, the physiological maturation of the main parts of the brain occurs: by the 9th week of pregnancy, the anterior part increases and forms 2 cerebral hemispheres, connected to each other by a special structure - the corpus callosum. Just like the smaller nerve commissures (superior and posterior commissure, fornix of the brain), it consists of a large bundle of nerve cell processes - axons, located mainly in the transverse direction. This structure subsequently allows information to be instantly transferred from one part of the brain to another.

The rudiment of the cortex, covering the white matter of the hemispheres, also undergoes changes at this time: there is a gradual build-up of layers and an increase in the coverage area. In this case, the upper cortical layer increases faster than the lower one, due to which folds and grooves appear.

By the age of 6 months of the embryo, for example, the left hemisphere of the brain has all the main primary gyri: lateral, central, callosal, parieto-occipital and calcarine, while the pattern of their location is mirrored in the right hemisphere. Then the convolutions of the second row are formed, and at the same time the number of layers of the cerebral cortex increases.

By the time of birth, the final section and, accordingly, the large hemispheres of the human brain have a familiar appearance to everyone, and the cortex has all 6 layers. The growth of the number of neurons stops. The subsequent increase in the weight of the medulla is the result of the growth of existing nerve cells and the development of glial tissue.

As the child develops, neurons form an even larger branched network of interneuronal connections. For most people, brain development ends by age 18.

The adult cerebral cortex, covering the entire surface of the cerebral hemispheres, consists of several functional layers:

molecular;
external granular;
pyramidal;
internal granular;
ganglionic;
multimorphic;
white matter.

The neurons of these structures have different structures and functional purposes, but they form the gray matter of the brain, which is an integral part of the cerebral hemispheres. Also, with the help of these functional units, the cerebral cortex carries out all the main manifestations of human higher nervous activity - thinking, remembering, emotional state, speech and attention.

The thickness of the cortex is not uniform throughout; for example, it reaches its greatest value in the upper parts of the precentral and postcentral gyri. At the same time, the pattern of the location of the convolutions is strictly individual - there are no two people on earth with the same brains.

Anatomically, the surface of the cerebral hemispheres is divided into several parts or lobes, limited by the most significant convolutions:

Frontal lobe. At the back it is limited by the central groove, at the bottom - by the lateral groove. In the direction forward from the central sulcus and parallel to it, the superior and inferior precentral sulci lie. Between them and the central sulcus is the anterior central gyrus. From both precentral sulci the superior and inferior frontal sulci extend at right angles, bounding the three frontal gyri - the superior middle and inferior.
Parietal lobe. This lobe is bounded anteriorly by the central sulcus, inferiorly by the lateral sulcus, and posteriorly by the parieto-occipital and transverse occipital sulcus. Parallel to and anterior to the central sulcus is the postcentral sulcus, which divides into the superior and inferior sulci. Between it and the central sulcus is the posterior central gyrus.
Occipital lobe. The grooves and convolutions on the outer surface of the occipital lobe can change their direction. The most constant of them is the superior occipital gyrus. At the border of the parietal lobe and the occipital lobe there are several transitional gyri. The first surrounds the lower end, which extends onto the outer surface of the hemisphere of the parieto-occipital sulcus. In the posterior part of the occipital lobe there are one or two polar grooves, which have a vertical direction and limit the descending occipital gyrus at the occipital pole.
Temporal lobe. This part of the hemisphere is bounded in front by the lateral sulcus, and in the posterior section by a line connecting the posterior end of the lateral sulcus with the lower end of the transverse occipital sulcus. On the outer surface of the temporal lobe there are the superior, middle and inferior temporal sulci. The surface of the superior temporal gyrus forms the lower wall of the lateral sulcus and is divided into two parts: the opercular, covered by the parietal operculum, and the anterior insular.
Island. Located in the depth of the lateral sulcus.

Thus, it turns out that the cerebral cortex, which covers the entire surface of the cerebral hemispheres, is the main element of the central nervous system, which allows you to process and reproduce information received from the environment through the senses: vision, touch, smell, hearing and taste. It also participates in the formation of cortical reflexes, purposeful actions and participates in the formation of human behavioral characteristics.

What are the left and right hemispheres of the brain responsible for?

The entire surface of the forebrain cortex, which includes the terminal section, is covered with grooves and ridges that divide the surface of the cerebral hemispheres into several lobes:

Frontal. Located in the front part of the cerebral hemispheres, it is responsible for performing voluntary movements, speech and mental activity. It also controls thinking and determines human behavior in society.
Parietal. Participates in understanding the spatial orientation of the body, and also analyzes the proportions and size of external objects.
Occipital. With its help, the brain processes and analyzes incoming visual information.
Temporal. Serves as an analyzer of taste and auditory sensations, and is also involved in understanding speech, forming emotions and remembering incoming data.
Island. Serves as a taste analyzer.

In the course of research, experts have found that the cerebral cortex perceives and reproduces information coming from the senses in a mirror way, that is, when a person decides to move his right hand, then at that moment the motor zone of the left hemisphere begins to work and vice versa - if the movement is made with the left hand, then the right hemisphere of the brain works.

The right and left hemispheres of the brain have the same morphological structure, but despite this, they perform different functions in the body.

In short, the work of the left hemisphere is aimed at logical thinking and analytical perception of information, while the right hemisphere is a generator of ideas and spatial thinking.

The areas of specialization of both hemispheres are discussed in more detail in the table:

	Left hemisphere	Right hemisphere
No.	The main area of activity of this part of the final department is logic and analytical thinking:	The work of the right hemisphere is aimed at perceiving nonverbal information, that is, coming from the external environment not in words, but in symbols and images:
1	With its help, a person develops his speech, writes, and remembers dates and events from his life.	It is responsible for the spatial position of the body, namely its location at the moment. This feature allows a person to navigate well in the environment, for example in a forest. Also, people with a developed right hemisphere do not solve puzzles for long and easily cope with mosaics.
2	In this part of the brain, analytical processing of information received from the senses occurs and rational solutions to the current situation are sought.	The right hemisphere determines the creative abilities of the individual, for example, the perception and reproduction of musical compositions and songs, that is, a person who has developed this perception zone hears false notes when singing or playing a musical instrument.
3	Recognizes only the direct meaning of words, for example, people who have damage to this zone cannot understand the meaning of jokes and proverbs, since they require the formation of a mental cause-and-effect relationship. In this case, data received from the environment is processed sequentially.	With the help of the right hemisphere, a person comprehends the meaning of proverbs, sayings and other information presented in the form of a metaphor. For example, the word “burns” in the poem: “A red rowan fire is burning in the garden” should not be taken in the literal sense, since in this case the author compared the rowan fruits with the flame of a fire.
4	This part of the brain is the analytical center of incoming visual information, therefore people who have developed this hemisphere show abilities in the exact sciences: mathematics or, for example, physics, since they require a logical approach when solving assigned problems.	With the help of the right hemisphere, a person can dream and invent the development of events in various situations, that is, when he fantasizes with the words: “imagine if ...”, then at that moment this part of the brain is activated. This feature is also used when writing surreal paintings, which require the artist’s rich imagination.
5	Controls and gives signals for purposeful movement of limbs and organs right side bodies.	The emotional sphere of the psyche, although not a product of the activity of the cerebral cortex, is still more subordinate to the right cerebral hemisphere, since non-verbal perception of information and its spatial processing, which requires good imagination, often play a fundamental role in the formation of feelings.
6	-	The right hemisphere of the brain is also responsible for the sensory perception of a sexual partner, while the process of copulation is controlled by the left part of the terminal section.
7	-	The right hemisphere is responsible for the perception of mystical and religious events, for dreams and the installation of certain values in the life of an individual.
8	-	Controls movements on the left side of the body.
9	-	It is known that the right hemisphere of the brain is capable of simultaneously perceiving and processing a large number of information without analyzing the situation. For example, with its help, a person recognizes familiar faces and determines the emotional state of the interlocutor by facial expression alone.

Also, the cortex of the left and right hemispheres of the brain is involved in the appearance of conditioned reflexes, the characteristic feature of which is that they are formed throughout a person’s life and are not constant, that is, they can disappear and reappear depending on environmental conditions.

In this case, the incoming information is processed by all functional centers of the cerebral hemispheres: auditory, speech, motor, visual, which allows the body to respond without resorting to mental activity, that is, at the subconscious level. For this reason, newborn children do not have conditioned reflexes, since they do not have life experience.

Left hemisphere of the brain and related functions

Externally, the left side of the brain is practically no different from the right - for each person, the location of the zones and the number of convolutions are the same on both sides of the organ. But at the same time it is a mirror image of the right hemisphere.

The left hemisphere of the brain is responsible for the perception of verbal information, that is, data transmitted through speech, writing or text. His motor area is responsible for the correct pronunciation of speech sounds, beautiful handwriting, and a predisposition to writing and reading. At the same time, a developed temporal zone will indicate a person’s ability to remember dates, numbers and other written symbols.

Also, in addition to the main functions, the left hemisphere of the brain performs a number of tasks that determine certain character traits:

The ability to think logically leaves its mark on human behavior, so there is an opinion that people with developed logic are selfish. But this is not because such people see benefit in everything, but because their brain is looking for more rational ways to solve problems, sometimes to the detriment of others.
Lovingness. People with a developed left hemisphere, thanks to their persistence, are able to achieve the object of attraction in various ways, but, unfortunately, after obtaining what they want, they quickly cool down - they simply become not interested, due to this, most people are predictable.
Thanks to their punctuality and logical approach to everything, most “left-hemisphere” people have innate politeness towards others, although for this they often have to be reminded of certain norms of behavior in childhood.
People with a developed left hemisphere almost always reason logically. For this reason, they cannot accurately interpret the behavior of others, especially when the situation is not ordinary.
Since individuals with a developed left hemisphere are consistent in everything, they rarely make syntactic and spelling errors when writing texts. In this regard, their handwriting is distinguished by the correct spelling of letters and numbers.
They learn quickly because they can concentrate all their attention on one thing.
As a rule, people with a developed left hemisphere are reliable, that is, you can rely on them in any matter.

If a person exhibits all of the above qualities, then this suggests that his left hemisphere is more developed than the right part of the brain.

The right hemisphere of the brain and its functions

The specialization of the right hemisphere of the brain is intuition and perception of non-verbal information, that is, data expressed in facial expressions, gestures and intonation of the interlocutor.

It is noteworthy that people with a developed right hemisphere are able to demonstrate their abilities in certain types of art: painting, modeling, music, poetry. This is explained by the fact that they are able to think spatially, without focusing on unimportant events in life. Their imagination is rich, which is manifested when writing paintings and musical works. They also say about such people: “Having their head in the clouds.”

People with a developed right hemisphere also have a number of characteristic features:

They are overly emotional, and their speech is rich in epithets and comparisons. Often such a speaker swallows sounds, trying to bring as much meaning as possible into the spoken words.
People with a developed right hemisphere are holistic, open, trusting and naive in communicating with others, but at the same time they are easily offended or offended. At the same time, they are not shy about their feelings - they can cry or become angry in a matter of minutes.
They act according to their mood.
Right-brain people are able to find non-standard ways to solve problems; this is explained by the fact that they consider the whole situation as a whole, without focusing on one thing.

Which half of the brain is dominant?

Since the left hemisphere of the brain is responsible for logic and a rational approach in everything, it was previously believed that it was leading in the entire central system. However, this is not so: in humans, both hemispheres of the brain participate in life activity almost equally, they are simply responsible for different areas of higher mental activity.

It is noteworthy that in childhood, in most people, the right hemisphere is usually larger than the left. For this reason, the world around them is perceived somewhat differently than in adulthood - children are prone to fantasies and perception of non-verbal information, everything seems interesting and mysterious to them. Also, by fantasizing, they learn to communicate with the environment: they play out different situations from life in their minds and draw their own conclusions, that is, they gain experience, which is so necessary in adulthood. Subsequently, this information is stored mostly in the left hemisphere.

However, over time, when the basic aspects of life are learned, the activity of the right hemisphere fades away and the body gives preference to the left side of the brain as the storehouse of acquired knowledge. Such disunity in the functioning of parts of the brain negatively affects a person’s quality of life: he becomes unresponsive to everything new and remains conservative in his views on the future.

Which part of the brain is working at the moment can be determined by doing a basic test.

Look at the moving image:

If it rotates clockwise, this means that the left hemisphere of the brain, which is responsible for logic and analysis, is currently active. If it moves in the opposite direction, this means that the right hemisphere, which is responsible for emotions and intuitive perception of information, is working.

However, if you make an effort, the picture can be made to rotate in any direction: to do this, you first need to look at it with a defocused gaze. Do you see the changes?

Synchronized work of both hemispheres

Despite the fact that the two hemispheres of the telencephalon perceive the world around them differently, it is extremely important for a person that they work harmoniously with each other.

Anatomically, this interaction of the cerebral hemispheres is carried out through the corpus callosum and other adhesions containing a large number of myelin fibers. They symmetrically connect all zones of one part of the telencephalon to another, and also determine the coordinated work of asymmetrical areas of different hemispheres, for example, the frontal gyrus of the right with the parietal or occipital of the left. At the same time, with the help of special neuron structures - associative fibers, different parts of the same hemisphere are connected.

The human central nervous system has a cross distribution of responsibilities - the right hemisphere controls the left half of the body, and the left hemisphere controls the right, while the cooperation of both halves can be clearly demonstrated by trying to simultaneously raise your arms parallel to the floor at a right angle - if this works, then this indicates the interaction of both hemispheres at the moment.

It is known that with the help of the left hemisphere, the world looks simpler, while the right side perceives it as it is. This approach allows a person to find more and more new solutions to difficult situations without complicating the task for himself.

Since the right hemisphere is responsible for emotional perception, without it people would remain soulless “machines”, capable of adapting the world around them to the needs of their life. This is of course not correct - after all, a person would not be a person if he did not have, for example, a sense of beauty or compassion for others.

In most people, the left hemisphere dominates, and in childhood it develops through the perception of information by the right side of the brain, which allows one to significantly expand the experience gained and shape some of the body’s reactions to the world around us.

Since the brain is able to perceive and remember incoming information almost throughout life, with the exception of cases caused by specific diseases, this allows a person to participate in the development of this organ.

What will the development of each hemisphere give?

First, let's summarize: any human activity begins with a comparison of new data with previous experience, that is, the left hemisphere is involved in this process. At the same time, the right side of the brain influences the final decision - it is physically impossible to come up with something new based only on previous experience.

Such a holistic perception of reality allows one not to get hung up only on generally accepted norms and, accordingly, moves a person’s personal growth forward.

The development of the right hemisphere will help a person to more easily come into contact with others, and the left hemisphere will contribute to the correct expression of thoughts. This approach has a beneficial effect on achieving success not only in professional activities, but also in other activities related to communication within society. Therefore, thanks to the coordinated activity of both hemispheres, a person’s life becomes more harmonious.

To develop these abilities, experts recommend doing simple exercises that activate brain activity several times a day:

If a person is not good with logic, then he is recommended to do as much mental work as possible - solve crosswords or frying pans, and also give preference to solving mathematical problems. If you need to develop creative abilities, then you can try to understand the meaning in fiction or painting.
You can activate the work of one of the hemispheres by increasing the load on the side of the body for which it is responsible: for example, to stimulate the left hemisphere, you need to work with the right side of the body, and vice versa. In this case, the exercises do not have to be too complicated - just hop on one leg or try to rotate an object with your hand.

Examples of simple physical exercises to develop brain activity

"Ear-nose"

With your right hand you need to touch the tip of your nose, and with your left hand you need to touch the opposite right ear. Then we release them at the same time, clap our hands and repeat the action, mirroring the position of our hands: with our left hand we hold the tip of our nose, and with our right hand we hold the left ear.

"Ring"

This exercise is familiar to almost everyone since childhood: you need to quickly alternately connect your thumb with your index, middle, ring and little fingers into a ring. If everything works out without a hitch, then you can try doing the exercise with 2 hands at the same time.

"Mirror drawing"

Sit down, put a large sheet of white paper on the table, and a pencil in each hand. Then you need to try to simultaneously draw any geometric shapes - a circle, square or triangle. Over time, if everything works out, then you can complicate the task - try to draw more complex images.

It is noteworthy that an integrated approach to improving the activity of the cerebral cortex will help not only improve a person’s communication abilities, but will also slow down age-related changes in the psyche - as is known, an active lifestyle and mental work allow a person to remain young at heart and preserve his intellectual abilities.

Video: Dominant Hemisphere Test

Shoshina Vera Nikolaevna

Therapist, education: Northern Medical University. Work experience 10 years.

Articles written

Scientists consider the human brain and its functions to be a mystery of science. We already know a lot about it and its work, so we are able to treat numerous diseases that were considered fatal. Knowledge about the structure and functioning of the cerebral hemispheres plays an important role in understanding the functioning of the brain, and also helps to understand the problems that arise in diseases and.

Conditions and pathologies that lead to severe consequences and even death can be treated surgically and conservatively, returning people to normal life after serious injuries and complex surgical interventions.

The structure of the cerebral hemispheres

The human spinal cord is connected to the brain and looks like a solid element up to the midbrain. It is then divided into two symmetrical but ambiguous halves, which are called the “cerebral hemispheres”.

Both together are called the anterior one. The connecting element between them is the corpus callosum. The part located below is called the “base of the brain”.

Differing in size from the structure of the organ of other mammals, the cerebral hemispheres of Homo sapiens are developed and cover the intermediate and middle hemispheres. In size, only similar formations in dolphins and some species of higher primates can be compared with them.

The structure of tissues includes two types of substance:

Gray, forming the outer layer or cortex of the brain. This substance in the form of subcortical structures is scattered throughout the white mass.
White, representing the internal mass of the brain matter, predominant in volume. It forms pathways.

Organs, their functions and the coordinated work of all systems are controlled by the PD cortex. It is a thin layer of several millimeters of gray matter consisting of neuron bodies. The cortex is the main part of the brain. It covers the surface of the anterior and has a large area due to the fact that the hemispheres have pronounced folding, which is called grooves and convolutions. The approximate surface area is from 2000 to 2500 square centimeters.

The structure and features of the cerebral cortex determine our interactivity, that is, the ability to come into contact with the environment, evaluate it, and obtain the most important data.

It has a rather complex organization and an original structure and structure. It is dotted with deep grooves and folds called convolutions. The deepest of all divide the entire forebrain (each hemisphere) into lobes:

Frontal.
Temporal.
Parietal.
Occipital.
Island.

Beneath the occipital lobes is the cerebellum, or “little brain.” It has three pairs of “legs” through which it receives extremely important information from the cortex, spinal cord, brain stem, ganglia and other sources. This is an extremely important part, although small in size.

It performs the functions of correcting errors that can creep in with incoming and outgoing signals. It contains up to 10% of the neurons in the human central nervous system. The so-called granular layer is especially rich in them.

Functions

The main activities of BP are related to the following most important human functions and qualities:

Thinking.
Memory.
Speech.
Manifestations and characteristics of personality.
Creativity, talents and skills.

The large hemispheres are not the same - they are responsible for different functions. The right is responsible for everything connected with it. The left hemisphere is associated with the abstract and the ability to speak. So, with diseases and injuries to this part of the brain, a person is deprived of coherent speech.

The hemispheres are separated from each other by a longitudinal fissure, in the depth of which there is a corpus callosum that connects them to each other. The transverse lobe separates the occipital lobes from the cerebellum, and it borders the medulla oblongata, which connects to the spinal cord. The weight of the cerebral hemispheres ranges from 78 to 90% of the mass of the organ.

The cerebral cortex has layers that form its architectonics:

Molecular.
External granular.
Layer of pyramidal neurons.
Internal grainy.
Ganglion layer. It is also called internal pyramidal or Betz cells.
Multimorphic cells.

The cortex is a highly organized analyzer that allows you to process information received from the outside through the senses - vision, hearing, touch, smell, taste. It contains more cellular fluid than white matter and is supplied with more blood vessels. The cerebral cortex is involved in the formation of cortical reflexes.

Furrows and convolutions

The surface of the cerebrum is covered with the so-called pallium, or cloak. It is this that forms the folds, which are commonly called convolutions and grooves. The pallium consists of gray and white matter.

The large hemispheres of the brain are covered with recognizable deep folds formed by grooves and convolutions. They give the human brain its characteristic appearance by increasing the area of the cortex. The pattern of convolutions is individual not only for each individual person, but even for the hemispheres of the same brain.

Each of them has a structure consisting of different types of surfaces:

The superior lateral surface has a convex shape and is directly adjacent to the inner part of the cranial vault.
The lower one, located in the anterior and middle sections deep at the base of the skull, and in the posterior section on the upper part of the cerebellum.
The medial surface located towards the fissure separating both hemispheres.

Each part of the brain has its own “pattern” of convolutions and sulci.

Furrows are usually divided into three categories:

The first, or constant, main ones. There are 10 of them, they are less susceptible to change than others, arise in the early stages of brain formation and have common features for all people and animals.
The second category, or non-permanent furrows. They are folds on the surface of the hemispheres, individual for a particular individual. They may have varying amounts or even be completely absent. The irregular furrows are deep, but shallower than the representatives of the first category.
The third, or non-permanent grooves are the grooves. They are usually much smaller and shallower than the previous ones, have various changing outlines, their location is associated with ethnic traits or personal characteristics. Grooves of the third category are not inherited.

The pattern can be compared to fingerprints, since it is individual and is never completely identical even among close relatives.

Consequences of damage to the PD lobes

The cerebral cortex of the human brain does not duplicate the structures of the subcortex, so any damage to it entails various disorders. They differ depending on which area is injured. Interestingly, in the cortex there are no specific control centers for individual muscles, but only a general set of “rules” for their work.

Damage to certain lobes of the cerebral hemispheres leads to the following consequences:

The frontal is the largest part. The two frontal parts make up half of the entire forebrain. The cortex of this lobe is called associative, because all information comes to this area. She is responsible for speech, behavior, feelings, learning. With serious injuries to this part of the brain, the formation of tumors, hemorrhages in a person, the connections between the appearance, taste, smell, shape of an object and its name are disrupted, that is, for example, the patient sees an apple, can smell it, touch it and eat it, but does not understand, what exactly is in his hands. Also in the central anterior is the motor room. Its damage leads to changes in behavior, coordination and movement disorders. It has been established that congenital underdevelopment of the frontal lobe or its damage in early childhood, especially the area responsible for emotions, leads to the emergence of antisocial personalities and serial killers, dangerous maniacs and simply sociopaths, petty domestic tyrants suffering from a lack of empathy. The centers responsible for smell and taste are located on the inner surfaces of the frontal and temporal lobes, so injuries to these areas of the brain often lead to disruption or complete loss of these functions.
The temporal region is responsible for the auditory center. In addition to complete or partial deafness, pathologies in this area can lead to so-called Wernicke's sensory aphasia or word deafness. The patient is able to hear everything perfectly, but he simply does not understand the words, as if they were talking to him in an unfamiliar foreign language. Such aphasia occurs when the analytical center of speech (Wernicke's center) is damaged.
The parietal part, namely its central posterior gyrus, controls skin-muscular sensitivity. Therefore, its damage entails the loss of these sensations or their severe dulling. Damage to the front part of the crown leads to problems with precise movements, the central part is responsible for basic movements, and the back part is responsible for tactile functions. Injuries or diseases in these areas provoke corresponding health problems.
The occipital lobe has a visual center designed to regulate, recognize and process information coming from the visual organs. Any problems in this area affect quality, and severe injuries can cause blindness - temporary or permanent. The upper occipital region is responsible for visual recognition, so a person with problems in this region may not be able to recognize faces or perceive their surroundings.
The insular region is not visible when viewing the surface of the brain. Many scientists do not distinguish it as a separate element of the hemispheres, but consider it part of the other lobes. Therefore, the characteristics of the pathologies are the same as those of the nearest departments - the frontal and temporal.

The structure of the brain gradually reveals all its secrets, allowing scientists to learn the relationships between its individual parts and human behavior, character, health and emotions. There is still a lot that is unknown, but careful study allows us to delve deeper into the sources of many diseases that until recently were considered incurable.

Despite all the similarities of our brain with similar structures of other mammals, the human organ and cerebral hemispheres are, first of all, a unique creation of nature, which makes us intelligent people.

Issues for discussion:

1. Functions of the subcortical nuclei of the forebrain.

2. Structure and functions of the limbic system

2. Structure and functions of the cerebral cortex.

3. Sensory and motor areas of the cerebral cortex.

4. Primary, secondary and tertiary fields of the cerebral cortex.

Tasks:

As you study the material, fill out the table:

Brain area	Brodmann field	Disturbances arising in case of defeat
Primary visual cortex
Secondary visual cortex	…
Primary auditory cortex
Secondary auditory cortex
Primary cutaneous-kinesthetic cortex
Secondary cutaneous-kinesthetic cortex
Primary motor cortex
Secondary motor cortex
SRW zone (Tertiary crust)
Precentral frontal area (tertiary cortex)
Postcentral temporo-occipital regions of the brain (tertiary cortex)

Note! The table must be completed by the end of the course.

Literature:

1. General course of human and animal physiology. In 2 books. Ed. prof. HELL. Nozdracheva. Book 1. Physiology of the nervous, muscular and sensory systems. – M.: “Higher School”, 1991, p.222-235.

2. Physiology of the human body: Compendium. Textbook for higher educational institutions / Ed. Academician of the Russian Academy of Medical Sciences B.I. Tkachenko and prof. V.F. Pyatina, St. Petersburg. – 1996, p. 272 – 277.

3. Smirnov V.M., Yakovlev V.N. Physiology of the central nervous system: Textbook. aid for students higher textbook establishments. – M.: Academy, 2002. – p. 181 – 200.

4. Luria A.R. Fundamentals of neuropsychology. – M., 2003 (see chapter 1).

5. Khomskaya E.D. Neuropsychology. – St. Petersburg: Peter, 2005. – 496 p.

Materials for preparing for the lesson

Anatomy of the telencephalon

The telencephalon develops from the forebrain and consists of highly developed paired parts - the right and left hemispheres and the middle part connecting them.

The hemispheres are separated by a longitudinal fissure, in the depth of which lies a plate of white matter, consisting of fibers connecting the two hemispheres - the corpus callosum. Under the corpus callosum there is a vault, which consists of two curved fibrous cords, which are connected to each other in the middle part, and diverge in front and behind, forming the pillars and legs of the vault. Anterior to the columns of the arch is the anterior commissure. Between the anterior part of the corpus callosum and the fornix is a thin vertical plate of brain tissue - a transparent septum.

The hemisphere is formed by gray and white matter. It contains the largest part, covered with grooves and convolutions - a cloak formed by the gray matter lying on the surface - the cortex of the hemispheres; the olfactory brain and accumulations of gray matter inside the hemispheres - the basal ganglia. The last two sections constitute the oldest part of the hemisphere in evolutionary development. The cavities of the telencephalon are the lateral ventricles.

In each hemisphere, three surfaces are distinguished: the superolateral (superolateral) is convex according to the cranial vault, the middle (medial) is flat, facing the same surface of the other hemisphere, and the bottom is irregular in shape. The surface of the hemisphere has a complex pattern, thanks to grooves running in different directions and ridges between them - convolutions. The size and shape of the grooves and convolutions are subject to significant individual fluctuations. However, there are several permanent grooves that are clearly expressed in everyone and appear earlier than others during the development of the embryo.

They are used to divide the hemispheres into large areas called lobes. Each hemisphere is divided into five lobes: the frontal, parietal, occipital, temporal and hidden lobe, or insula, located deep in the lateral sulcus. The boundary between the frontal and parietal lobes is the central sulcus, and between the parietal and occipital lobes is the parieto-occipital sulcus. The temporal lobe is separated from the rest by the lateral sulcus. On the superolateral surface of the hemisphere in the frontal lobe, there is a precentral sulcus, separating the precentral gyrus, and two frontal sulci: superior and inferior, dividing the rest of the frontal lobe into the superior, middle and inferior frontal gyri.

In the parietal lobe there is a postcentral sulcus, separating the postcentral gyrus, and an intraparietal sulcus, dividing the rest of the parietal lobe into the superior and inferior parietal lobes. In the lower lobule, the supramarginal and angular gyri are distinguished. In the temporal lobe, two parallel grooves - the superior and inferior temporal - divide it into the superior, middle and inferior temporal gyri. In the region of the occipital lobe, transverse occipital sulci and gyri are observed. On the medial surface, the sulcus of the corpus callosum and the cingulate are clearly visible, between which the cingulate gyrus is located.

Above it, surrounding the central sulcus, lies the paracentral lobule. Between the parietal and occipital lobes runs the parieto-occipital sulcus, and behind it is the calcarine sulcus. The area between them is called a wedge, and the one lying in front is called a pre-wedge. At the point of transition to the lower (basal) surface of the hemisphere lies the medial occipitotemporal, or lingual, gyrus. On the lower surface, separating the hemisphere from the brain stem, there is a deep groove of the hippocampus (seahorse groove), lateral to which is the parahippocampal gyrus. Laterally, it is separated by a collateral groove from the lateral occipitotemporal gyrus. The insula, located deep in the lateral (side) sulcus, is also covered with grooves and convolutions. The cerebral cortex is a layer of gray matter up to 4 mm thick. It is formed by layers of nerve cells and fibers arranged in a certain order.

Figure: grooves and convolutions of the left hemisphere of the cerebrum; superolateral surface

The most typically structured areas of the phylogenetically newer cortex consist of six layers of cells; the old and ancient cortex has fewer layers and is simpler in structure. Different areas of the cortex have different cellular and fibrous structures. In this regard, there is a doctrine about the cellular structure of the cortex (cytoarchitectonics) and the fibrous structure (myeloarchitectonics) of the cerebral hemisphere cortex.

The olfactory brain in humans is represented by rudimentary formations, well expressed in animals, and constitutes the oldest parts of the cerebral cortex.

The basal ganglia are clusters of gray matter within the hemispheres. These include the striatum, consisting of the caudate and lenticular nuclei, interconnected. The lenticular nucleus is divided into two parts: the shell, located on the outside, and the globus pallidus, which lies on the inside. They are subcortical motor centers.

Outside the lenticular nucleus there is a thin plate of gray matter - the fence; in the anterior part of the temporal lobe lies the amygdala. Between the basal ganglia and the optic thalamus there are layers of white matter, the inner, outer and outermost capsules. Conducting pathways pass through the internal capsule.

Figure: sulci and convolutions of the right hemisphere of the cerebrum; medial and inferior surfaces.

The lateral ventricles (right and left) are cavities of the telencephalon, lie below the level of the corpus callosum in both hemispheres and communicate through the interventricular foramina with the third ventricle. They have an irregular shape and consist of anterior, posterior and lower horns and a central part connecting them. The anterior horn lies in the frontal lobe; it continues posteriorly into the central part, which corresponds to the parietal lobe. At the back, the central part passes into the posterior and inferior horns, located in the occipital and temporal lobes. In the lower horn there is a cushion - the hippocampus (seahorse). From the medial side, the choroid plexus invaginates into the central part of the lateral ventricles, continuing into the inferior horn. The walls of the lateral ventricles are formed by the white matter of the hemispheres and the caudate nuclei. The thalamus is adjacent to the central part below.

The white matter of the hemispheres occupies the space between the cortex and the basal ganglia. It consists of a large number of nerve fibers running in different directions. There are three systems of fibers of the hemispheres: associative (combinative), connecting parts of the same hemisphere; commissural (commissural) connecting parts of the right and left hemispheres, which in the hemispheres include the corpus callosum, anterior commissure and commissure of the fornix, and projection fibers, or pathways connecting the hemispheres with the underlying parts of the brain and spinal cord.

Section "Anatomy" of the portal http://medicinform.net

Physiology of the telencephalon

The telencephalon, or the cerebral hemispheres, which have reached their highest development in humans, is rightly considered the most complex and most amazing creation of nature.

The functions of this part of the central nervous system are so different from the functions of the brainstem and spinal cord that they are allocated to a special chapter of physiology called higher nervous activity. This term was introduced by I.P. Pavlov. The activity of the nervous system, aimed at uniting and regulating all organs and systems of the body, I.P. Pavlov called lower nervous activity. By higher nervous activity he understood behavior, activity aimed at adapting the body to changing environmental conditions, at balancing with the environment. In the behavior of an animal, in its relationships with the environment, the leading role is played by the telencephalon, the organ of consciousness, memory, and in humans - the organ of mental activity and thinking.

To study the localization (location) of functions in the cerebral cortex, or, in other words, the significance of individual zones of the cortex, various methods are used: partial removal of the cortex, electrical and chemical stimulation, recording of brain biocurrents and the method of conditioned reflexes.

The stimulation method made it possible to establish the following zones in the cortex: motor (motor), sensitive (sensory) and silent, which are now called associative.

Motor (motor) zones of the cortex.

Movements occur when the cortex is stimulated in the area of the precentral gyrus. Electrical stimulation of the upper part of the gyri causes movement of the muscles of the legs and torso, the middle part of the arms, and the lower part of the facial muscles.

The size of the cortical motor area is proportional not to muscle mass, but to the accuracy of movements. The area that controls the movements of the hand, tongue, and facial muscles is especially large. In the V layer of the cortex of the motor zones, giant pyramidal cells (Betz's pyramids) were found, the processes of which descend to the motor neurons of the middle, medulla oblongata and spinal cord, innervating the skeletal muscles.

The path from the cortex to the motor neurons is called the pyramidal tract. This is the path of voluntary movements. After damage to the motor area, voluntary movements cannot be carried out.

Irritation of the motor zone is accompanied by movements on the opposite half of the body, which is explained by the intersection of the pyramidal tracts on their way to the motor neurons innervating the muscles.

Figure: motor homunculus. Projections of parts of the human body onto the area of the cortical end of the motor analyzer are shown.

Sensory areas of the cortex.

Extirpation (eradication) of various parts of the cortex in animals made it possible to establish in general terms the localization of sensory functions. The occipital lobes were associated with vision, the temporal lobes with hearing.

The area of the cortex where this type of sensitivity is projected is called the primary projection zone.

Human skin sensitivity, feelings of touch, pressure, cold and heat are projected into the postcentral gyrus. In its upper part there is a projection of the skin sensitivity of the legs and torso, below - the arms and completely below - the head.

The absolute size of the projection zones of individual areas of the skin is not the same. For example, the projection of the skin of the hands occupies a larger area in the cortex than the projection of the surface of the torso.

The magnitude of the cortical projection is proportional to the significance of a given receptive surface in behavior. Interestingly, the pig has a particularly large projection into the cortex of the snout.

Articular-muscular, proprioceptive sensitivity is projected into the postcentral and precentral gyri.

The visual cortex is located in the occipital lobe. When it is irritated, visual sensations arise - flashes of light; removing it leads to blindness. Removal of the visual zone on one half of the brain causes blindness in one half of each eye, since each optic nerve is divided at the base of the brain into two halves (forming an incomplete decussation), one of them goes to its half of the brain, and the other to the opposite.

If the outer surface of the occipital lobe is damaged, not the projection, but the associative visual zone, vision is preserved, but recognition disorder occurs (visual agnosia). The patient, being literate, cannot read what is written, recognizes a familiar person after he speaks. The ability to see is an innate property, but the ability to recognize objects is developed throughout life. There are cases when a person blind from birth is restored to sight at an older age. For a long time he continues to navigate the world around him by touch. It takes a long time for him to learn to recognize objects using his vision.

Drawing: sensitive homunculus. Projections of parts of the human body onto the area of the cortical end of the analyzer are shown.

The hearing function is provided by the precise lobes of the cerebral hemispheres. Their irritation is caused by simple auditory sensations.

Removal of both auditory zones causes deafness, and unilateral removal reduces hearing acuity. When areas of the auditory cortex are damaged, auditory agnosia can occur: a person hears, but ceases to understand the meaning of words. His native language becomes just as incomprehensible to him as a foreign language unfamiliar to him. The disease is called auditory agnosia.

The olfactory cortex is located at the base of the brain, in the region of the parahippocampal gyrus.

The projection of the taste analyzer appears to be located in the lower part of the postcentral gyrus, where the sensitivity of the oral cavity and tongue is projected.

Limbic system.

In the telencephalon there are formations (cingulate gyrus, hippocampus, amygdala, septal area) that make up the limbic system. They are involved in maintaining the constancy of the body’s internal environment, regulating autonomic functions and forming emotions and motivations. This system is otherwise called the “visceral brain”, since this part of the telencephalon can be considered as a cortical representation of interoreceptors. Information from internal organs comes here. For stomach irritation, Bladder Evoked potentials occur in the limbic cortex.

Electrical stimulation of various areas of the limbic system causes changes in autonomic functions: blood pressure, respiration, movements of the digestive tract, tone of the uterus and bladder.

The destruction of individual parts of the limbic system leads to behavioral disturbances: animals can become calmer or, on the contrary, aggressive, easily reacting with rage, and sexual behavior changes. The limbic system has extensive connections with all areas of the brain, the reticular formation and the hypothalamus. It provides higher cortical control of all autonomic functions (cardiovascular, respiratory, digestive, metabolism and energy.

Figure: brain formations related to the limbic system (circle of Papez).

1 - olfactory bulb; 2 - olfactory pathway; 3 - olfactory triangle; 4 - cingulate gyrus; 5 - gray inclusions; 6 - vault; 7 - isthmus of the cingulate gyrus; 8 - end strip; 9 - hippocampal gyrus; 11 - hippocampus; 12 - mastoid body; 13 - amygdala; 14 - hook.

Association areas of the cortex.

The projection zones of the cortex occupy a small proportion of the total surface of the cortex in the human brain. The rest of the surface is occupied by so-called associative zones. The neurons of these areas are not connected either to the senses or to the muscles; they communicate between different areas of the cortex, integrating and combining all impulses flowing into the cortex into integral acts of learning (reading, speech, writing), logical thinking, memory and providing the possibility of an appropriate reaction behavior.

When associative zones are violated, agnosia appears - the inability to recognize and apraxia - the inability to perform learned movements. For example, stereoagnosia is expressed in the fact that a person cannot find either a key or a box of matches in his pocket by touch, although visually he immediately recognizes them. Above were examples of visual agnosia - the inability to read written words and auditory - a lack of understanding of the meaning of words.

If the associative zones of the cortex are disrupted, aphasia can occur - loss of speech. Aphasia can be motor or sensory. Motor aphasia occurs when the posterior third of the inferior frontal gyrus on the left, the so-called Broca's center, is damaged (this center is located only in the left hemisphere). The patient understands speech, but cannot speak himself. With sensory aphasia, a lesion of Wernicke's center in the posterior part of the superior temporal gyrus, the patient does not understand speech.

With agraphia, a person forgets how to write, and with apraxia, he forgets how to make learned movements: light a match, fasten a button, sing a melody, etc.

Studying the localization of function using the method of conditioned reflexes on a living healthy animal allowed I.P. Pavlov discovered the facts on the basis of which he built a theory of dynamic localization of functions in the cortex, which was then brilliantly confirmed using microelectrode studies of neurons. The dogs developed conditioned reflexes, for example, to visual stimuli - light, various figures - a circle, a triangle, and then the entire occipital, visual, cortex zone was removed. After this, the conditioned reflexes disappeared, but time passed and the impaired function was partially restored. This is the phenomenon of compensation, or restoration, of the IP function. Pavlov explained by suggesting the existence of an analyzer core located in a certain zone of the cortex, and scattered cells scattered throughout the cortex in the zones of other analyzers. Due to these preserved scattered elements, the lost function is restored. A dog can distinguish light from darkness, but subtle analysis, establishing differences between a circle and a triangle, is inaccessible to it; it is characteristic only of the analyzer core.

Microelectrode removal of potentials from individual cortical neurons confirmed the presence of scattered elements. Thus, in the motor zone of the cortex, cells were found that produce a discharge of impulses to visual, auditory, and skin stimuli, and in the visual zone of the cortex, neurons were identified that respond with electrical discharges to tactile, sound, vestibular and olfactory stimuli. In addition, neurons were found that respond not only to “their” stimulus, as they now say, a stimulus of its modality, its own quality, but also to one or two strangers. They were called polysensory neurons.

Dynamic localization, i.e. the ability of some zones to be replaced by others, provides the cortex with high reliability.

General course of human and animal physiology in 2 books. Book 1. Physiology of the nervous, muscular and sensory systems: Textbook. for biol. and medical specialist. universities/ A.D. Nozdrachev, I.A. Barannikova, A.S. Batuev and others; Ed. HELL. Nozdracheva. – M.: Higher. school, 1991. – 512 p.

The forebrain is the most rostral part of the nervous system. It consists of (cortex) and basal ganglia. The latter, located in the cortex, are located between the frontal parts of the brain and the diencephalon. These nuclear structures include the putamen, which together make up the striatum. It got its name due to the alternation of gray matter, consisting of nerve cells, and white matter. These elements of the brain, together with the globus pallidus, which is called the pallidum, form the striopallidal system. This system in mammals, including humans, is the main nuclear apparatus and is involved in the processes of motor behavior and other important functions.

The basal ganglia have a very diverse cellular composition. The globus pallidus contains large and small neurons. The striatum has a similar cellular organization. The neurons of the striopallidal system receive impulses from the cerebral cortex, thalamus, and brainstem nuclei.

What functions do the subcortical nuclei perform?

The nuclei of the striopallidal system are also involved in motor activity. Irritation of the caudate nucleus causes stereotypical head turns and trembling movements of the arms or forelimbs in animals. During the study, it was found that it is important in the processes of memorizing movements. An irritating effect on this structure also disrupts learning. has an inhibitory effect on motor activity and its emotional components, for example on aggressive reactions.

Cerebral cortex

The forebrain includes a structure called the cortex. It is considered the youngest formation of the brain. Morphologically, the cortex consists of gray matter that covers the entire brain and has a large area due to numerous folds and convolutions. Gray matter consists of a huge number of nerve cells. Due to this, the number of synoptic connections is very large, which ensures the processes of storing and processing the received information. Based on the appearance and evolution, ancient, old and new bark are distinguished. During the evolution of mammals, the neocortex developed especially rapidly. The ancient cortex contains olfactory bulbs and tracts, olfactory tubercles. The old one includes the cingulate gyrus, amygdala and hippocampal gyrus. The remaining areas belong to the neocortex.

The nerve cells of the cerebral cortex are arranged in layers and in an orderly manner, forming six layers in their composition:

1st - called molecular, formed by a plexus of nerve fibers and contains a minimal number of nerve cells.

2nd - called external granular. It consists of small neurons of different shapes, similar to grains.

3rd - consists of pyramidal neurons.

4th - internal granular, like the outer layer, consists of small neurons.

5th - contains Betz cells (giant pyramidal cells). The processes of these cells (axons) form a pyramidal tract, which reaches the caudal areas and passes into the anterior roots

6th - multiform, consists of triangular and spindle-shaped neurons.

Although the neural organization of the cortex has much in common, a more detailed study of it showed differences that appear in the course of the fibers, the size and number of cells and the branching of their detritus. By studying, a map of the crust was compiled, which includes 11 regions and 52 fields.

What is the forebrain responsible for??

Very often, ancient and old bark are combined. They form the olfactory brain. The forebrain is also responsible for alertness and attention, and is involved in autonomic reactions. The system takes part in instinctive behavior and the formation of emotions. In animal experiments, when the old cortex is irritated, effects associated with the digestive system appear: chewing, swallowing, peristalsis. Also, an irritating effect on the tonsils causes a change in the function of internal organs (kidneys, uterus, bladder). Some areas of the cortex are involved in memory processes.

Together, the hypothalamus, limbic region and forebrain (ancient and old cortex) form which maintains homeostasis and ensures the preservation of the species.

The forebrain is the most developed structure in the process of evolution.

It predetermines a person’s inclinations, his orientation, behavior, and personality development.

Location: cerebral part of the skull.

The article is intended for a general understanding of the structure and purpose.

General information

Formed from the anterior end of the primary neural tube. In embryogenesis, it is divided into 2 parts, one of which gives rise to the telencephalon, the second - the intermediate brain.

According to Alexander Luria’s model, it consists of 3 blocks:

Block regulating brain activity levels. Ensures the implementation of certain types of activities. Responsible for emotional reinforcement of activity based on predicting its results (success - failure).
Block for receiving, processing and storing incoming information. Participates in the formation of ideas about ways to implement activities.
Block of programming, regulation and control over the organization of mental activity. Compares the resulting result with the original intent.

The forebrain takes part in the work of all blocks. Based on information processing, it controls behavior. Administrator of higher psychological functions: perception, memory, imagination, thinking, speech.

Anatomy

The structure of a living individual is not easy to describe. Especially such a component as the brain. This universe that exists in everyone continues to hide its secrets. But this does not mean that they are not worth understanding.

Development

The forebrain is formed at 3-4 weeks of prenatal development. By the end of the 4th week of embryogenesis, the telencephalon, diencephalon, and the cavity of the third ventricle are formed from the forebrain.

It consists of the thalamic and hypothalamic regions, which are located on the sides of the third ventricle between the hemispheres and the midbrain.

The thalamic region unites:

The thalamus is an ovoid formation located deep under the cerebral cortex. The oldest, largest (3-4 cm) formation of the diencephalon;
The epithalamus is located above the thalamus. It is famous for the fact that it contains the pineal gland. It used to be believed that the soul lived here. Yogis associate the pineal gland with the seventh chakra. By awakening the organ, you can open the “third eye”, becoming clairvoyant. The gland is tiny, only 0.2 g. But the benefits for the body are enormous, although previously it was considered a rudiment;
subthalamus - a formation located below the thalamus;
metathalamus - bodies located in the posterior part of the thalamus (previously considered a separate structure). Together with the midbrain, they determine the work of the visual and auditory analyzers;

The hypothalamic region includes:

hypothalamus. Located under the thalamus. Weighs 3-5 g. Consists of specialized groups of neurons. Connected with all departments. Controls the pituitary gland;
the posterior lobe of the pituitary gland is the central organ of the endocrine system, weighing 0.5 g. Located at the base of the skull. The posterior lobe, together with the hypothalamus, forms the hypothalamic-pituitary complex, which controls the activity of the endocrine glands.

Unites:

cortical hemispheres. The bark appeared late in the development of the animal world. Occupies half the volume of the hemispheres. Its surface can exceed 2000 cm 2;
corpus callosum - a nerve tract connecting the hemispheres;
striped body. Located on the side of the thalamus. On a section it looks like repeating stripes of white and gray matter. Promotes regulation of movements, motivation of behavior;
olfactory brain. Unites structures that differ in purpose and origin. Among them is the central section of the olfactory analyzer;

Anatomical features

Intermediate

The thalamus is egg-shaped and gray-brown in color. Structural unit - nuclei, which are classified according to functional and compositional characteristics.

The epithalamus consists of several units, the most famous of which is the grayish-reddish pineal gland.

The subthalamus is a small region of gray matter nuclei connected to white matter.

The hypothalamus consists of nuclei. There are about 30 of them. Most are paired. Classified by location.

Posterior lobe of the pituitary gland. - a rounded formation, location - the pituitary fossa of the sella turcica.

Finite

Unites the hemispheres, corpus callosum and striatum. The largest department by volume.

The hemispheres are covered with gray matter 1-5 mm thick. The mass of the hemispheres is about 4/5 of the mass of the brain. Convolutions and grooves significantly increase the area of the cortex, containing billions of neurons and nerve fibers arranged in a certain order. Underneath the gray matter lies white matter—the processes of nerve cells. About 90% of the cortex has a typical six-layer structure, where neurons are connected through synapses with each other.

From the point of view of phylogenesis, the cerebral cortex is divided into 4 types: ancient, old, intermediate, new. The main part of the human cortex is the neocortex.

The corpus callosum is shaped like a wide strip. Consists of 200-250 million nerve fibers. The largest structure connecting the hemispheres.

Functions

Mission – organization of mental activity.

Intermediate

Participates in coordinating the work of organs, regulating body movement, maintaining temperature, metabolism, and emotional background.

Thalamus. The main task is to sort information. It works like a relay - it processes and sends data coming from receptors and pathways to the brain. The thalamus affects the level of consciousness, attention, sleep, wakefulness. Supports speech functioning.

Epithalamus. Interaction with other structures occurs through melatonin, a hormone produced by the pineal gland in the dark (therefore, it is not recommended to sleep in the light). A derivative of serotonin - the “happiness hormone”. Melatonin is a participant in the regulation of circadian rhythms, being a natural sleep aid, it affects memory and cognitive processes. It affects the localization of skin pigments (not to be confused with melanin), puberty, and suppresses the growth of a number of cells, including cancer cells. Through connections with the basal ganglia, the epithalamus participates in the optimization of motor activity, and through connections with the limbic system, in the regulation of emotions.

Subthalamus. Controls the body's muscle responses.

Hypothalamus. Forms a functional complex with the pituitary gland and directs its work. The complex controls the endocrine system. The hormones it produces help cope with distress and maintain homeostasis.

Thirst and hunger centers are located in the hypothalamus. The department coordinates emotions, human behavior, sleep, wakefulness, and thermoregulation. Here are found similar in action to opiates, which help to endure pain.

Hemispheres

They act together with subcortical structures and the brain stem. Main destination:

Organization of interaction of an organism with the environment through its behavior.
Consolidation of the body.

Corpus callosum

The corpus callosum received attention after operations to dissect it in the treatment of epilepsy. The operations relieved seizures while changing a person’s personality. It was found that the hemispheres are adapted to work independently. However, to coordinate activities, information exchange between them is necessary. The corpus callosum is the main transmitter of information.

Striatum

Reduces muscle tone.
Contributes to the coordination of internal organ function and behavior.
Participates in the formation of conditioned reflexes.

The olfactory brain contains centers that control the sense of smell.

Cerebral cortex

Head of mental processes. Controls sensory and motor functions. Consists of 4 layers.

The ancient layer is responsible for elementary responses (for example, aggression) characteristic of humans and animals.

The old layer is involved in the formation of attachment and laying the foundations of altruism. Thanks to the layer we are happy or angry.

The intermediate layer is a formation of a transitional type, since the modification of old formations into new ones is carried out gradually. Ensures the activity of the new and old cortex.

The neocortex concentrates information from subcortical structures and the brainstem. Thanks to it, living beings think, talk, remember, and create.

5 cerebral lobes

The occipital lobe is the central section of the visual analyzer. Provides visual pattern recognition.

Parietal lobe:

controls movements;
orients in time and space;
provides perception of information from skin receptors.

Thanks to the temporal lobe, living things perceive a variety of sounds.

The frontal lobe regulates voluntary processes, movements, motor speech, abstract thinking, writing, self-criticism, and coordinates the work of other areas of the cortex.

The insular lobe is responsible for the formation of consciousness, the formation of an emotional response and the support of homeostasis.

Interaction with other structures

The brain matures unevenly during ontogenesis. At birth, unconditioned reflexes are formed. As the individual matures, conditioned reflexes develop.

The parts of the brain are anatomically and functionally interconnected. The trunk, together with the cortex, is involved in the preparation and implementation of various forms of behavior.

The interaction of the thalamus, limbic system, hippocampus helps to reproduce the image of events: sounds, smells, place, time, spatial location, emotional coloring. The connections of the thalamus with areas of the temporal lobe of the cortex contribute to the recognition of familiar places and objects.

The thalamus, hypothalamus, and cortex have mutual connections with the medulla oblongata. Thus, the medulla oblongata contributes to the assessment of receptor activity and the normalization of the activity of the musculoskeletal system.

Cooperation of the reticular formation of the trunk and cortex causes excitation or inhibition of the latter. The cooperation of the reticular formation of the medulla oblongata and the hypothalamus ensures the functioning of the vasomotor center.

Having examined the structure and purpose, we are one step closer to understanding a living entity.