The limbic system is a functional association of brain structures involved in the organization of emotional and motivational behavior, such as food, sexual, defensive instincts. This system is involved in organizing the wake-sleep cycle.

The limbic system, as a phylogenetically ancient formation, exerts a regulatory influence on the cerebral cortex and subcortical structures, establishing the necessary correspondence between their activity levels.

Morphofunctional organization.

The structures of the limbic system include 3 complexes.

The first complex is the ancient cortex (preperiform, periamygdala, diagonal cortex), olfactory bulbs, olfactory tubercle, and transparent septum.

The second complex of structures of the limbic system is the old cortex, which includes the hippocampus, dentate gyrus, and cingulate gyrus.

The third complex of the limbic system is the subcortical structures (almond-shaped bodies, nuclei of the septum pellucidum, anterior thalamic nucleus, mastoid bodies).

In addition to the above structures, the limbic system also includes the hypothalamus, the reticular formation of the midbrain.

Picture 1.

A feature of the limbic system is that between its structures there are simple two-way connections and complex paths that form many closed circles. Such an organization creates the conditions for a long-term circulation of the same excitation in the system and, thereby, for the preservation of a single state in it and the imposition of this state on other systems of the brain.

At present, connections between brain structures are well known, organizing circles that have their own functional specifics. These include the circle of Peipes (hippocampus a mastoid bodies a anterior nuclei of the thalamus a cortex of the cingulate gyrus a parahippocampal gyrus a hippocampus). This circle has to do with memory and learning processes.

The other circle (the amygdala, the hypothalamus, the mesencephalic structures, and the amygdala) regulates aggressive-defensive, feeding, and sexual behaviors.

Figure 2.

A - Peipets circle; B - circle through the tonsil; GT/MT, mammillary bodies of the hypothalamus; SM - midbrain (limbic region).

It is believed that figurative (iconic) memory is formed by the cortico-limbic-thalamo-cortical circle.

Circles of different functional purposes connect the limbic system with many structures of the central nervous system, which allows the latter to realize functions, the specificity of which is determined by the included additional structure.

For example, the inclusion of the caudate nucleus in one of the circles of the limbic system determines its participation in the organization of the inhibitory processes of higher nervous activity.

A large number of connections in the limbic system, a kind of circular interaction of its structures create favorable conditions for the reverberation of excitation in short and long circles. This, on the one hand, ensures the functional interaction of parts of the limbic system, on the other hand, creates conditions for memorization.

The abundance of connections of the limbic system with the structures of the central nervous system makes it difficult to identify brain functions in which it would not take part. Thus, the limbic system is related to the regulation of the level of reaction of the autonomous, somatic systems during emotional and motivational activity, the regulation of the level of attention, perception, and reproduction of emotionally significant information. The limbic system determines the choice and implementation of adaptive forms of behavior, the dynamics of innate forms of behavior, the maintenance of homeostasis, and generative processes. Finally, it ensures the creation of an emotional background, the formation and implementation of the processes of higher nervous activity.

It should be noted that the ancient and old cortex of the limbic system is directly related to the olfactory function. In turn, the olfactory analyzer, as the oldest of the analyzers, is a non-specific activator of all types of activity of the cerebral cortex.

Some authors call the limbic system the visceral brain, that is, the structure of the central nervous system involved in the regulation of the activity of internal organs. Indeed, the amygdala, the septum pellucidum, and the olfactory brain, when stimulated, change the activity of the body's vegetative systems in accordance with environmental conditions. This became possible due to the establishment of morphological and functional connections with younger brain formations that ensure the interaction of exteroceptive, interoceptive systems and the temporal cortex.

The most polyfunctional formations of the limbic system are the hippocampus and amygdala. The physiology of these structures is the most studied.

More on the limbic system of the brain:

1. The structure of the autonomic and limbic nervous system and their functions

The limbic system of the brain is part of the higher nervous system responsible for many bodily functions. The peculiarity of this part of the brain is that it represents a set of structures. This explains its versatility. What structure does this part of the brain have and how dangerous are violations in its work?

This is a kind of set of nervous structures that are interconnected. In total, the system includes about 12 "subdivisions", although it was initially believed that this part of the brain is responsible exclusively for the sense of smell.

Undoubtedly, the human brain has a complex structure, but do not forget that all structures have a certain relationship with each other. Those "divisions" that are part of this system are "on the verge". From the point of view of neurology and anatomy, such a term suggests that the nerve structures have a connection with the cerebral cortex.

The connections between neurons in this part of the brain are dense, having a ring structure. It is also considered a feature.

The history of the system

The first descriptions concerning this part of the brain appeared in 1952, they were inaccurate. But as civilization progressed and developed, it was possible to correct the information and get an accurate idea of ​​​​the system and its functioning.

It was originally said that the main and only function of this part of the brain is to process information. In general, the description is correct, but not accurate. Since it was assumed that a person receives information by analyzing smells.

The olfactory ability, the assessment of the information received and the connection with the cerebral cortex - that's all that the discoverer of the system, P. MacLean, managed to establish. He described a number of structures that formed a single whole and were "on the verge", that is, in close proximity to the cerebral cortex. The location of the nerve structures influenced the name of the system.

Initially, the doctor assumed that several nerve structures connected in the limbic system of the brain, forming dense neural connections. Later it was possible to obtain more complete information.

With the development of medicine, it was possible to establish that the structure is responsible not only for the sense of smell, but also for memory, both short-term and long-term.

System structure

It is believed that this part of the brain has a special, "ancient" structure, since it is connected with the cortical part of the main organ, located on the inner hemispheres.

The system is responsible for vegetative functions, it includes the following parts:

1. Belt gyrus.
2. Hippocampus.
3. Almond-shaped nuclei, they are also called hemispheres.
4. Pear-shaped gyrus.

Tight neural connections receive impulses from the following parts of the human brain:

• hypothalamus;
• pituitary;
• subcortical nuclei;
• thalamus;
• hippocampus.

In animal studies, it was found that stimulation of various parts of this system leads to changes in behavior:

1. Aggression appears, defensive functions become aggravated.
2. Irritation intensifies, social function changes.

First of all, emotions suffer, as well as memory. But at the same time, memories remain with a person.

Since the structure of this part of the brain is complex, a description is more common that says that it is a "bundle" of nerve structures that forms a system. Impulses are transmitted from the cerebral cortex, and not only. Various parts of this organ are involved in the "bundle".

Functionality of the limbic system

This part of the autonomic nervous system, according to physicians, performs many functions. Through experiments, it was possible to prove that disruptions in the work of interconnected structures lead to problems with vital organs.

Let us describe in detail the functions of this part of the brain:

• responsible for memory and perception of information, for the ability to learn and cognize;
• regulates the work and analyzes the information received from the olfactory organs;
• participates in the organization of the simplest motivational and informational activities;
• responsible for the socialization of a person, in particular, communication and the emotional component;
• participates in the ability to form research activities.

Through communication with the hypothalamus, the cerebral cortex, neurons receive impulses that affect the functioning of vital organs. They also act through the connection with the pituitary gland on the human hormonal background.

It should be noted that the system is involved in the formation of food and sexual instincts. But this participation is considered indirect, not direct.

What else is the system responsible for, and what functions does it perform:

1. It is believed that neural connections form a bundle: wakefulness - sleep.
2. Regulates metabolic processes in the body, including the water-salt balance.
3. Helps to adapt to external stimuli.

It is believed that the structure of the system is such that it allows the brain not only to analyze the information received, but also to perceive commands and give an adequate response. This makes it possible to judge the system's ability to influence the perception and analysis of information received from outside. And this means that the system in cases of change helps a person to adapt to environmental factors. This feature is called adaptation.

Significant functionality allows us to state that a set of structures is involved in the work of various organs responsible for the life support of the body.

Violations and their consequences

If they occur, then violations affect the entire body. In most cases, this situation is the result of:

• the development of infectious diseases affecting the nervous system;
• serious poisoning leading to severe intoxication;
• prolonged and excessive consumption of alcoholic beverages;
• taking certain medications in case of an overdose;
• development of psychological disorders;
• receiving serious head injuries.

As a result of such adverse circumstances, the following changes occur in the body:

1. There are memory problems. Often the patient cannot build a logical chain of events or link them together. At the same time, he has memories, but it is difficult for him to analyze the events.
2. There are problems with the sense of smell, the work of the organs of vision and hearing is disturbed. Problems can be local in nature, up to the development of blindness or deafness. A person may complain that he does not feel anything (smell, taste).
3. Violations affect fine motor skills, affect the correction of movements. The emotional component suffers the most. A person's behavior changes, he begins to show aggression, but more often such people suffer from mood swings.
4. There are problems with sleep (perhaps the most common violation). Similar problems are common, but you will have to pay attention to the presence of other manifestations.

However, other functions of the body can also “suffer”, violations affect the work of the organs of the digestive system, the hormonal background. It is difficult to say what violations will appear in the work of the body and what they will produce.

List of possible complications:

• auditory and visual hallucinations, less often taste;
• loss of orientation in space;
• frequent mood changes with the development of depressive conditions;
• confusion;
• inability to perceive and analyze information;
• development of epileptic seizures (in special cases).

Violations can be of a different nature, ranging from problems in the work of the intestines and stomach, ending with failures in the immune, cardiovascular and endocrine systems.

Interaction with the neocortex

The neocortex is called the "new cortex" that covers the entire brain like a cloak. The interconnection of the system lies in the fact that the neural connections that are "on the verge" and the new cortex form a connection, by transmitting impulses.

Receiving "signals", the brain begins to function, and this activity affects not the functional part, but the emotional one.

Since the limbic system is responsible for the emotional component, connecting through a neural connection with the new cortex makes a person “himself.

neocortex

It is quite difficult to understand what classifies this term, its meaning will become clearer if the word is translated from Latin, literally - this is a new bark. But other things are also allowed.
interpretation of the term "chosen bark", but it is considered inaccurate. This is a part of the human brain, which envelops the entire organ, like a cloak, forming a kind of “cap” that participates in neural processes and performs certain functions.

History of occurrence

The term has been known for a long time, but the lack of information has been compensated relatively recently.

The theory explaining the functionality of the neocortex was developed in Menlo Park. She explained the algorithm of work, and the theory was presented in the form of a computer presentation. This presentation helped to understand how the neocortex functions and was a real breakthrough.

The essence of the algorithm and the presented theory:

1. It unites all the human senses into a single whole.
2. Neurons have memory and fold into large connections, a kind of causal relationship.

What does it consist of

This part of the brain consists of three types of neurons that form connections with other parts of the body.

The composition includes:

• the first and, perhaps, the largest group, accounting for 70 percent or more of all neurons, are pyramidal;
• at the level of 15-20% there is a group of stellate neurons;
• spindle neurons account for only about 5%, this group is the smallest.

What functions does

There is an opinion that the brain performs many functions, which is true, but what role is assigned to the new cortex in this system?

To put it simply, without going into scientific terms, without a neocortex, a person may well exist, perform the usual functions: eat, multiply, get food. But his life will be subject to instincts akin to animals.

But when the new cortex “turns on” to work, a thinking appears that distinguishes humans from primates.

The neocortex performs the following functions:

1. Responsible for the mental and intellectual abilities of the individual.
2. Influences his creative development.
3. It affects the emotional component, allowing a person to experience feelings.
4. And also under the influence of this part of the brain was fine motor skills.

Simply put, without a new cortex, a person would not be able to write, draw, play music, perceive and analyze information. His movements would be rough, sloppy, automatic.

You can use an example to consider the activity of the new cortex:

• in the brain, in a specific part of it, an impulse is “born”;
• it gradually reaches the muscles of the larynx and tongue;
• a sound is heard, a song appears.

Approximately according to this algorithm, the neocortex "works". Under his control is all mental activity that is responsible for the individual characteristics of a person.

Understanding the structure of the limbic system of the human brain and comparing it with the neocortex, one should not forget that the first term is the ancient cortex, and the second is the new cortex. The relationship between these parts of the organ is determined even by terminology.

Since the main organ in the human body is the brain, its structure is a priori considered complex. The neocortex and the ancient cortex are just part of the system responsible for the functioning of the body and the performance of its functions.

The limbic system of the brain:

- the widest set, which is a morphofunctional association of systems. They are located in different parts of the brain.

Consider the functions and structure of the limbic system in the diagram below.

System structure

The limbic system includes:

• limbic and paralimbic formations
• anterior and medial nuclei of the thalamus
• medial and basal parts of the striatum
• hypothalamus
• the oldest subcrustal and mantle parts
• cingulate gyrus
• dentate gyrus
• hippocampus (seahorse)
• septum (partition)
• amygdala bodies.

There are 4 main structures of the limbic system in the diencephalon:

Then we have the hypothalamus, which is a vital part of the limbic system that is responsible for the production of several chemical messengers called hormones. These hormones control body water levels, sleep cycles, body temperature, and food intake. The hypothalamus is located under the thalamus.

The flexural gyrus, meanwhile, serves as a pathway that relays messages between the inner and outer parts of the limbic system. The amygdala is one of two almond-shaped clusters of nerve cells in the temporal lobe of the brain. Both amygdala are responsible for preparing the body for emergencies, such as being scared, and for storing memories of events for future recognition. The amygdala helps in the development of memories, especially those associated with emotional events and emergencies.

• habenular nuclei (leash nuclei)
• thalamus
• hypothalamus
• mastoid bodies.

main functions of the limbic system

Connection with emotions

The limbic system is responsible for the following activities:

• sensual
• motivational
• vegetative
• endocrine

Instincts can also be added here:

Michelds are also associated with the development of emotions of fear and can be the cause of extreme expressions of fear, as in the case of panic. In addition, the amygdala plays an important role in pleasure and sexual arousal and may vary with a person's sexual activity and maturity.

Components of the limbic system

The hippocampus is another section of the temporal lobe, which is responsible for converting short-term memories into long-term memories. The hippocampus is thought to work with the amygdala for memory storage, and damage to the hippocampus can lead to amnesia.

• food
• sexual
• defensive

The limbic system is responsible for regulating the wake-sleep process. It develops biological motivations. They predetermine complex chains of efforts to be made. These efforts lead to the satisfaction of the above vital needs. Physiologists define them as the most complex unconditioned reflexes or instinctive behavior. For clarity, we can recall the behavior of a newborn baby when breastfeeding. It is a system of coordinated processes. With the growth and development of the child, his instincts are increasingly influenced by consciousness, which develops in the course of study and education.

Finally, we have the basal ganglia, which are the collection of nerve cell bodies that are responsible for coordinating muscle movement in posture. In particular, the basal ganglia help block unwanted movements from occurring and communicate directly with the brain for coordination.

Speculation about the development of the limbic system

It is assumed that the limbic system developed from primitive mammals during human evolution. Therefore, many of the functions of the limbic system deal with instincts and not with the study of behavior. Scholars debate whether this system should be considered a single unit biologically, as many of the original ideas that were used to develop the concept are considered obsolete. While they do not dispute the functions of the individual parts, many do not agree on whether the paths associated with these primitive functions are related.

Interaction with the neocortex

The limbic system and neocortex are tightly and inextricably interconnected with each other, and with the autonomic nervous system. On this basis, it connects two of the most important activities of the brain - memory and feelings. As a rule, the limbic system and emotions are tied together.

However, the limbic system is still discussed in many traditional biology and physiology courses as part of the nervous system. The limbic system structures are involved in many of our emotions and motivations, especially those related to survival. Such emotions include fear, anger, and emotions associated with sexual behavior. The limbic system is also connected to feelings of pleasure that are associated with our survival, such as those experienced from food and sex.

Functions of the limbic system

Certain structures of the limbic system are also involved in memory. The two large structures of the limbic system play an important role in memory. The amygdala is responsible for determining which memories are stored and where the memories are stored. This definition is thought to be based on how much of an emotional response an event elicits. The hippocampus sends memories to the appropriate part of the brain hemisphere for long-term storage and retrieves them when needed. Damage to this area of ​​the brain can lead to an inability to form new memories.

Deprivation of a part of the system leads to psychological inertia. The urge leads to psychological hyperactivity. Strengthening the activity of the amygdala triggers ways to provoke anger. These methods are regulated by the hippocampus. The system triggers eating behavior and arouses a sense of danger. These behaviors are regulated by both the limbic system and hormones. Hormones, in turn, are produced by the hypothalamus. This combination largely affects the vital activity through the regulation of the functioning of the autonomic nervous system. Its meaning is hugely called the visceral brain. Determines the sensory-hormonal activity of the animal. Such activity is practically not subject to brain regulation either in an animal, or even more so in humans. This shows the relationship between emotions and the limbic system.

The part known as "also" is included in the limbic system. The thalamus is involved in sensory perception and regulation of motor functions. It connects areas that are involved in sensory perception and movement with other parts of the brain that also play a role in sensation and movement. The hypothalamus is a very small but important component of the diencephalon. It plays an important role in regulation, body temperature, and many other vital activities.

Almond-shaped mass of nuclei involved in emotional reactions, hormonal secretions and memory. Myggdala is responsible for the harnessing of fear, or the associative learning process by which we learn to be afraid of something. a fold in the brain associated with sensory input to emotions and the regulation of aggressive behavior. - arches, bands of axons that connect the hippocampus to the hypothalamus. - a tiny noob that acts as a memory indexer - sends memories to the appropriate part of the brain hemisphere for long-term storage and retrieves them when needed. - about the size of pearls, this structure directs many important functions. The hypothalamus is also an important emotional center, controlling the molecules that make you feel excited, angry, or unhappy. - receives sensory information from the olfactory bulb and is involved in the identification of odors. - a large, double-lobed mass of cells that transmit sensory signals in and out. It wakes you up in the morning and gives you an adrenaline rush. . Thus, the limbic system is responsible for controlling various functions in the body.

System functions

The main function of the limbic system is to coordinate actions with memory and its mechanisms. Short-term memory is usually associated with the hippocampus. Long-term memory - with the neocortex. The manifestation of personal skill and knowledge from the neocortex occurs through the limbic system. For this, sensual-hormonal provocation of the brain is used. This provocation brings up all the information from the neocortex.

Some of these functions include interpreting emotional responses, storing memories, and regulating. More recently, Paul McLean, taking the basic foundations of Papez's proposal, created the demonative limbic system and added new structures to the schema: the orbitofrontal and medial-frontal cortex, the paraftopacambic gyrus, and important subcortical groupings such as the amygdala, medial thalamic nucleus, septal region, prosencephalic basal nuclei and several brain stems.

The main areas associated with emotions. It is important to emphasize that all these structures are intensely connected to each other, and none of them is responsible for any particular emotional state. However, some of them contribute more than others to certain emotions. Below we consider, one by one, the most well-known structures of the limbic system.

The limbic system also performs the following significant function - the verbal memory of incidents and the experience gained, skills, and knowledge. All this looks like a complex of effector structures.

In the works of specialists, the system and functions of the limbic system are depicted as an "anatomical emotional ring". All aggregates are connected to each other and other parts of the brain. Connections with the hypothalamus are especially multifaceted.

Damage or stimulation of the medial dorsal and anterior nuclei of the thalamus is associated with changes in emotional reactivity. However, the importance of these nuclei in regulating emotional behavior is not due to the thalamus itself, but to the connection of these nuclei to other structures in the limbic system. The medial dorsal nucleus connects with the cortical zones of the prefrontal region and with the hypothalamus. The anterior nuclei connect to the mammillary bodies, and through them, through the plunger, to the hippocampus and dentate gyrus, thus participating in the Papez circuit.

It defines:

• sensual mood of a person
• his motivation to work
• behavior
• processes of acquiring knowledge and memorization.

Violations and their consequences

In case of violation of the limbic system or a defect in these sets, amnesia progresses in patients. However, it should not be defined as a place where certain information is stored. It combines all the separate parts of memory into generalized skills and incidents that are easy to reproduce. Disturbance of the limbic system does not destroy individual fragments of memories. These damages destroy their conscious repetition. In this case, various pieces of information are preserved and serve as a guarantee for procedural memory. Patients with Korsakov's syndrome can learn some other new knowledge for themselves. However, they will not know how and what exactly they learned.

This structure has extensive connections with other proencephalic areas and mesencephaly. Lesions in the hypothalamic nuclei interfere with several autonomic functions and some of the so-called motivated behaviors such as thermal regulation, sexuality, alertness, hunger, and thirst. The hypothalamus is believed to play a role in emotions. In particular, its lateral parts seem to be associated with pleasure and rage, while the median part seems to be associated with disgust, displeasure, and a tendency to uncontrollable and loud laughter.

Defects in its activities lead to:

• brain injury
• neuroinfections and intoxications
• vascular pathologies
• endogenous psychoses and neuroses.

It all depends on how significant the defeat was, as well as the limitations. Quite real:

• epileptic convulsive states
• automatisms
• changes in consciousness and mood
• derealization and depersonalization
• auditory hallucinations
• taste hallucinations
• olfactory hallucinations.

It is no coincidence that with the predominant defeat of the hippocampus by alcohol, a person suffers from memory in relation to recent incidents. Patients undergoing treatment for alcoholism in the hospital suffer from the following: they do not remember what they ate for lunch today and dined at all, or not, and when they last took medication. At the same time, they perfectly remember the events that took place in their lives for a long time.

The role of the limbic system in the formation of motivations, emotions, memory organization

However, in general terms, the hypothalamus is more associated with the expression of emotions than with the genesis of affective states. When the physical symptoms of emotions appear, the threat they pose returns through the hypothalamus to the limbic centers and therefore to the anterior frontal nuclei, increasing anxiety. This negative feedback mechanism can be strong enough to create a panic situation. As will be seen later, knowledge of this phenomenon is very important for clinical and therapeutic reasons.

Already scientifically substantiated - the limbic system (more precisely, the amygdala and the transparent septum) is responsible for processing certain information. This information is taken from the olfactory organs. At first, the following was stated - this system is capable of exclusively olfactory function. But over time, it became clear: it is also well developed in animals without smell. Everyone knows the importance of biogenic amines for leading a full life and activity:

Humans show the largest network of connections between the prefrontal area and traditional limbic structures. Perhaps, therefore, among all species, they represent the greatest variety of feelings and emotions. Although some signs of attachment can be perceived in birds, the limbic system only began to develop, in fact, after the first mammals, it is practically non-existent in reptiles, amphibians and all other previous species.

Paul McLean uses to say that "it's very hard to imagine a lonely and more emotionally empty creature than a crocodile." Two behaviors with affective connotations that have appeared in mammals deserve special attention because of their peculiarity.

• dopamine
• norepinephrine
• serotonin.

The limbic system has them in huge quantities. The manifestation of nervous and mental ailments is associated with the destruction of their balance.

The structure and functions of the limbic system are largely unknown. Conducting new research in this area will make it possible to determine its real place among other parts of the brain and will allow our practitioners to treat diseases of the central nervous system with new methods.

The more a mammal develops, the more accentuated these behaviors are. Ablation of important parts of the limbic system of any animal causes it to completely lose both maternal affection and lunar interest. And the evolution of mammals leads us to humanity. Of course, our hominid ancestor could already distinguish between the sensations he experienced on occasion, such as being in his cave, polishing a stone or bone, running after a weak animal, running away from a stronger one, hunting a female of his own kind, etc. P.

Cytoarchitectonics of the limbic system cortex

With the development of language, specific names were given to these sensations, allowing their definition and communication with other members of the group. Because there is an important subjective component that is difficult to convey, even today there is no consensus on the best terminology to be used to refer to many of these sensations in particular.

(average rating: 5,00 out of 5)

A set of nervous structures and their connections located in the mediobasal part, involved in the control of autonomic functions and emotional, instinctive behavior, as well as influencing the change in the phases of sleep and wakefulness.

Non-Emotional Functions of the Limbic System

Therefore, the words "affect", "emotion" and "feeling" are used interchangeably and imprecisely, almost as synonyms. However, we believe that each of these words deserves a precise definition, for the sake of their etymology and because of the physical and mental reactions they evoke.

Curiously, there is a worldwide tendency to regard only positive experiences as affecting. Opposite emotions and feelings can be used to refer to both positive and negative phenomena: “she has good feelings; I had painful emotions." According to Nobre de Melo, denominations influence, in general, events experienced by emotions or feelings. Emotions, as their etymology shows, show reactions to those emotional states that, due to their intensity, turn to some kind of action.

The limbic system is the most ancient part of the cerebral cortex, located on the inside of the cerebral hemispheres. It includes: hippocampus, cingulate gyrus, amygdala nuclei, piriform gyrus. Limbic formations belong to the highest integrative centers for the regulation of the autonomic functions of the body. The neurons of the limbic system receive impulses from the cortex, subcortical nuclei, thalamus, hypothalamus, reticular formation and all internal organs. A characteristic property of the limbic system is the presence of well-defined circular neural connections that unite its various structures. Among the structures responsible for memory and learning, the main role is played by the hippocampus and the associated posterior frontal cortex. Their activity is important for the transition of short-term memory to long-term memory. The limbic system is involved in afferent synthesis, in the control of the electrical activity of the brain, regulates metabolic processes and provides a number of autonomic reactions. Irritation of various sections of this system in an animal is accompanied by manifestations of defensive behavior and changes in the activity of internal organs. The limbic system is also involved in the formation of behavioral responses in animals. It contains the cortical section of the olfactory analyzer.

Great Circle of Peipes:

• hippocampus;
• vault;
• mamillary bodies;
• mamillary-thalamic bundle Wikd "Azira;
• thalamus;
• gyrus.

Small circle of Nauta:

• amygdala;
• end strip;
• partition.

Limbic system and its functions

Consists of phylogenetically old parts of the forebrain. In the name (limbus- edge) reflects the peculiarity of its location in the form of a ring between the new cortex and the final part of the brain stem. The limbic system includes a number of functionally integrated structures of the middle, diencephalon, and telencephalon. These are the cingulate, parahippocampal and dentate gyrus, the hippocampus, the olfactory bulb, the olfactory tract, and adjacent areas of the cortex. In addition, the limbic system includes the amygdala, anterior and septal thalamic nuclei, hypothalamus, and mamillary bodies (Fig. 1).

The limbic system has multiple afferent and efferent connections with other brain structures. Its structures interact with each other. The functions of the limbic system are realized on the basis of the integrative processes taking place in it. At the same time, more or less defined functions are inherent in individual structures of the limbic system.

Rice. 1. The most important connections between the structures of the limbic system and the brainstem: a - the circle of Paipez, b - the circle through the amygdala; MT - mammillary bodies

The main functions of the limbic system:

• Emotional-motivational behavior (with fear, aggression, hunger, thirst), which may be accompanied by emotionally colored motor reactions
• Participation in the organization of complex behaviors, such as instincts (food, sexual, defensive)
• Participation in orienting reflexes: reaction of alertness, attention
• Participation in the formation of memory and the dynamics of learning (the development of individual behavioral experience)
• Regulation of biological rhythms, in particular, changes in the phases of sleep and wakefulness
• Participation in maintaining homeostasis by regulating autonomic functions

cingulate gyrus

Neurons cingulate gyrus receive afferent signals from the association areas of the frontal, parietal and temporal cortex. The axons of its efferent neurons follow the neurons of the associative cortex of the frontal lobe, the hipiocampus, the septal nuclei, the amygdala, which are connected with the hypothalamus.

One of the functions of the cingulate gyrus is its participation in the formation of behavioral responses. So, when its anterior part is stimulated, aggressive behavior occurs in animals, and after bilateral removal, the animals become quiet, submissive, asocial - they lose interest in other individuals of the group, not trying to establish contact with them.

The cingulate gyrus can exert regulatory influences on the functions of internal organs and striated muscles. Its electrical stimulation is accompanied by a decrease in the frequency of breathing, heart contractions, a decrease in blood pressure, increased motility and secretion of the gastrointestinal tract, pupil dilation, and a decrease in muscle tone.

It is possible that the effects of the cingulate gyrus on the behavior of animals and the functions of internal organs are indirect and mediated by connections of the cingulate gyrus through the cortex of the frontal lobe, hippocampus, amygdala and septal nuclei with the hypothalamus and brainstem structures.

It is possible that the cingulate gyrus is related to the formation of pain sensations. People who underwent a cingulate gyrus dissection for medical reasons experienced a reduction in pain.

It has been established that the neural networks of the anterior part of the cingulate gyrus are involved in the operation of the brain error detector. Its function is to identify erroneous actions, the progress of which deviates from the program of their execution and actions, at the completion of which the parameters of the final results were not achieved. Error detector signals are used to trigger mechanisms for correcting erroneous actions.

Amygdala

Amygdala located in the temporal lobe of the brain, and its neurons form several subgroups of nuclei, the neurons of which interact with each other and other brain structures. Among these nuclear groups are the corticomesial and basolateral subgroups of the nuclei.

The neurons of the corticomesial nuclei of the amygdala receive afferent signals from the neurons of the olfactory bulb, hypothalamus, nuclei of the thalamus, septal nuclei, gustatory nuclei of the diencephalon, and pathways of pain sensitivity of the pons, along which signals from large receptive fields of the skin and internal organs arrive at the amygdala neurons. Taking into account these connections, it is assumed that the corticomedial group of tonsil nuclei is involved in the control of the implementation of the vegetative functions of the body.

The neurons of the basolateral nuclei of the amygdala receive sensory signals from the neurons of the thalamus, afferent signals about the semantic (conscious) content of signals from the prefrontal cortex of the frontal lobe, the temporal lobe of the brain and the cingulate gyrus.

The neurons of the basolateral nuclei are associated with the thalamus, the prefrontal cortex of the cerebral hemispheres, and the ventral striatum of the basal ganglia; therefore, it is assumed that the nuclei of the basolateral group of the tonsils are involved in the implementation of the functions of the frontal and temporal lobes of the brain.

Amygdala neurons send efferent signals along axons predominantly to the same brain structures from which they received afferent connections. Among them are the hypothalamus, the mediodorsal nucleus of the thalamus, the prefrontal cortex, the visual areas of the temporal cortex, the hippocampus, and the ventral striatum.

The nature of the functions performed by the amygdala is judged by the consequences of its destruction or by the effects of its irritation in higher animals. Thus, the bilateral destruction of the tonsils in monkeys causes a loss of aggressiveness, a decrease in emotions and defensive reactions. Monkeys with removed tonsils are kept alone, do not seek to make contact with other animals. In diseases of the tonsils, there is a disconnect between emotions and emotional reactions. Patients may experience and express great concern for any reason, but at this time the heart rate, blood pressure and other autonomic reactions are not changed. It is assumed that the removal of the tonsils, accompanied by a rupture of its connections with the cortex, leads to a disruption in the processes of normal integration of the semantic and emotional components of efferent signals in the cortex.

Electrical stimulation of the tonsils is accompanied by anxiety, hallucinations, past experiences, and SNS and ANS reactions. The nature of these reactions depends on the localization of irritation. When the nuclei of the cortico-medial group are irritated, reactions from the digestive organs prevail: salivation, chewing movements, bowel movements, urination, and when the nuclei of the basolateral group are irritated, reactions of alertness, raising the head, pupil dilation, search. With strong irritation, animals can develop states of rage or, conversely, fear.

In the formation of emotions, an important role belongs to the presence of closed circles of circulation of nerve impulses between the formations of the limbic system. A special role in this is played by the so-called limbic circle of Paipez (hippocampus - fornix - hypothalamus - mamillary bodies - thalamus - cingulate gyrus - parahippocampal gyrus - hippocampus). The streams of nerve impulses circulating along this circular neural circuit are sometimes called the "stream of emotions."

Another circle (almond - hypothalamus - midbrain - amygdala) is important in the regulation of aggressive-defensive, sexual and nutritional behavioral reactions and emotions.

The tonsils are one of the structures of the CNS, on the neurons of which there is the highest density of sex hormone receptors, which explains one of the changes in the behavior of animals after bilateral destruction of the tonsils - the development of hypersexuality.

Experimental data obtained on animals indicate that one of the important functions of the tonsils is their participation in establishing associative links between the nature of the stimulus and its significance: the expectation of pleasure (reward) or punishment for the actions performed. The neural networks of the tonsils, ventral striatum, thalamus, and prefrontal cortex are involved in the implementation of this function.

Hippocampal structures

hippocampus along with the dentate gyrus subiculun) and the olfactory cortex forms a single functional hippocampal structure of the limbic system, located in the medial part of the temporal lobe of the brain. There are numerous bilateral links between the components of this structure.

The dentate gyrus receives its main afferent signals from the olfactory cortex and sends them to the hippocampus. In turn, the olfactory cortex, as the main gateway for receiving afferent signals, receives them from various associative areas of the cerebral cortex, the hippocampal and cingulate gyrus. The hippocampus receives already processed visual signals from the extrastriate areas of the cortex, auditory signals from the temporal lobe, somatosensory signals from the postcentral gyrus, and information from polysensory associative areas of the cortex.

The hippocampal structures also receive signals from other areas of the brain - the stem nuclei, the raphe nucleus, and the bluish spot. These signals perform a predominantly modulatory function in relation to the activity of hippocampal neurons, adapting it to the degree of attention and motivations that are crucial for the processes of memorization and learning.

The efferent connections of the hippocampus are organized in such a way that they follow mainly those areas of the brain with which the hippocampus is connected by afferent connections. Thus, the efferent signals of the hippocampus go mainly to the association areas of the temporal and frontal lobes of the brain. To perform their functions, the hippocampal structures need a constant exchange of information with the cortex and other brain structures.

One of the consequences of a bilateral disease of the medial part of the temporal lobe is the development of amnesia - memory loss with a subsequent decrease in intelligence. At the same time, the most severe memory impairments are observed when all hippocampal structures are damaged, and less pronounced - when only the hippocampus is damaged. From these observations, it was concluded that the hippocampal structures are part of the structures of the brain, including the medial halamus, cholinergic neuronal groups of the base of the frontal lobes, the amygdala, which play a key role in the mechanisms of memory and learning.

A special role in the implementation of memory mechanisms in the hippocampus is played by the unique property of its neurons to maintain a state of excitation and synaptic signal transmission for a long time after they are activated by any influences (this property is called post-tetanic potentiation). Post-tetanic potentiation, which ensures long-term circulation of information signals in closed neural circuits of the limbic system, is one of the key processes in the mechanisms of long-term memory formation.

Hippocampal structures play an important role in learning new information and storing it in memory. Information about earlier events is stored in memory after damage to this structure. At the same time, hippocampal structures play a role in the mechanisms of declarative or specific memory for events and facts. The mechanisms of non-declarative memory (memory for skills and faces) are more involved in the basal ganglia, the cerebellum, the motor areas of the cortex, and the temporal cortex.

Thus, the structures of the limbic system are involved in the implementation of such complex brain functions as behavior, emotions, learning, memory. The functions of the brain are organized in such a way that the more complex the function, the more extensive the neural networks involved in its organization. From this it is obvious that the limbic system is only a part of the structures of the central nervous system that are important in the mechanisms of complex brain functions, and contributes to their implementation.

So, in the formation of emotions as states that reflect our subjective attitude to current or past events, one can distinguish mental (experience), somatic (gestures, facial expressions) and vegetative (vegetative reactions) components. The degree of manifestation of these components of emotions depends on the greater or lesser involvement in the emotional reactions of the brain structures with the participation of which they are realized. This is largely determined by which group of nuclei and structures of the limbic system is activated to the greatest extent. The limbic system acts in the organization of emotions as a kind of conductor, enhancing or weakening the severity of one or another component of an emotional reaction.

Involvement in the responses of the structures of the limbic system associated with the cerebral cortex enhances the mental component of emotion in them, and the involvement of structures associated with the hypothalamus and the hypothalamus itself as part of the limbic system enhances the autonomic component of the emotional reaction. At the same time, the function of the limbic system in the organization of emotions in humans is under the influence of the cortex of the frontal lobe of the brain, which has a corrective effect on the functions of the limbic system. It inhibits the manifestation of excessive emotional reactions associated with the satisfaction of the simplest biological needs and, apparently, contributes to the emergence of emotions associated with the implementation of social relationships and creativity.

The structures of the limbic system, built between the parts of the brain that are directly involved in the formation of higher mental, somatic and vegetative functions, ensure their coordinated implementation, maintenance of homeostasis and behavioral responses aimed at preserving the life of the individual and species.

The limbic system occupies a separate place in the complex human nervous system. It consists of a whole complex of subsystems, the work of which allows you to develop and maintain life.

In the middle of the last century, the term "limbic system" meant some formations at the edge of the brain. With the study of medicine, the number of formations included in the drugs increased.

The limbic system (LS) is a set of nerve connections and their structures located in the mediobasal part of the hemispheres that regulate emotional behavior, autonomic functions and instinctive reflexes. This part of the brain is also responsible for the phases of sleep and wakefulness.

Structure of the limbic system

The LS consists mainly of thirteen main formations. Take, for example, Almond-shaped kernels. These two identical areas of the brain, similar to an almond fruit, are located in the temple area, in different hemispheres. The tonsils form emotions and also play an important role in decision making and remembering information. The negative effect on the tonsils affects the activity of the heart, the functions of peristalsis, the production of hormones and the secretion of the stomach.

From experiments on animals it follows that the removal of some parts of the amygdala leads to uncertainty and anxiety.

In humans, on the contrary, electrical stimulation of these areas causes aggression and a nervous breakdown.

Belt gyrus. This cortical portion of the LS runs along the lateral walls of the sulcus that separates the left and right hemispheres. Anterior perforated substance. This is the section of the hemisphere, located below and stretching posteriorly from the olfactory triangle. Blood vessels pass through it. Next come the midbrain and piriformis gyrus. Parahippocampal gyrus. Transverse temporal gyri. They are located inside the lateral groove.

Hippocampus and hypothalamus

Hippocampus. This part is responsible for memory consolidation (transition from short-term to long-term), the implementation of emotions and the generation of theta rhythm with increased attention. Inside there is a dentate gyrus, smoothly turning into a tape.

Hypothalamus. In science, there are no sufficiently clear boundaries that define this zone. But it is generally accepted that the hypothalamus is a small area in the diencephalon, just below the region of the thalamus. Despite its small size, its neurons form 30-50 groups of nuclei that regulate the secretion of various hormones. Then comes the mastoid body.

Group of olfactory formations

Olfactory bulb. It looks like a small thickening and is located along the edges of the longitudinal fissure of the brain under the temples. There are several of these bulbs. They are located next to each other and are closely connected with the brain by nerve tissues. The olfactory receptor of the bulb needs only one molecule of a substance with a smell to form a complete sensation. Olfactory tract. Olfactory triangle.

These groups intersect with almost all departments of the central nervous system. Neuroendocrine connections deserve close attention. They are the link between the nervous and endocrine systems.

How the system works

Human LS is a kind of chain based on the principle of a vicious circle of functioning structures. The stability of neurons maintains nervous excitation in cells.

LS neurons receive signals from the cerebral cortex, hypothalamus, thalamus, subcortical nuclei and from all internal organs. The ring-shaped system allows information to be quickly transmitted from one part of the brain to another. The drug controls the electrical activity of the brain and vegetative reactions, and also regulates the metabolic process.

LS performs a number of vital functions:

• communicative activity;
• water-salt exchange;
• sleep regulation;
• smell;
• intellectual development;
• control of hunger;
• thermoregulation;
• emotions and behavior pattern;
• coordinated work of internal organs.

The functions of the LS do not end with the above. This system is still being carefully studied, and new details are being discovered over and over again.

This system helps the body to respond correctly to irritating factors and maintains internal balance. Previously, it was believed that the LS is able to process information coming only from the olfactory organs. Now it has become known that limbic connections analyze the signals of all the senses: visual, auditory, sensory, gustatory. In addition, thanks to drugs, a person adapts more easily in society and gets used to rapidly changing circumstances.

Pathology and symptoms

With disorders of the visceral brain, the first thing that suffers is memory. Although the LS does not archive the events and knowledge acquired by a person, when it is violated, it can be difficult to remember what you previously knew as two times two. Memories often become fragmented and abrupt. The events that took place before the defeat are easily reproduced; what happened later is more difficult to retell, especially to clarify on what day or at what hour it happened.

In addition to the above, the result of pathology often becomes:

• gastrointestinal disorders;
• weakening of the immune system;
• development of diabetes insipidus;
• Bad mood;
• tearfulness;
• insomnia;
• clouding of consciousness;
• hallucinations;
• stupor and even coma are not excluded.

The following factors lead to violations:

• infection of the nervous system;
• complications in the vascular system;
• head injury;
• psychical deviations;
• toxic and alcoholic poisoning.

The sense organs also suffer after dysfunction. This can manifest itself in different directions. Vision.

When the outer areas of the cortex of the occipital lobes are affected, the ability to recognize objects or people is lost, the patient perceives only individual elements, trying to remember where he could see it.

It happens that the object is recognized, but the name is not, or is confused, so the patient may well say “train” on a pencil, not suspecting that this is a completely different word. Hearing. With the defeat of the secondary zones of the temporal gyri of Heschl, there is an inability to recognize phenomena by characteristic sounds, for example, the sound of wind or rain. Taste and smell. The ability to identify objects by smell and taste is lost. sensitive function. The affected person cannot classify objects by touch (an anomaly called astereognosis) and correctly assess the state of his body (autopagnosia).

The Mystery of God and the Science of the Brain [Neurobiology of Faith and Religious Experience] Andrew Newberg

Emotional Brain: The Limbic System