Limbic system the brain is a special complex. It consists of several structures. In this article we will look in more detail at what the limbic system is and what tasks it performs.
Structure
The main part of the complex includes brain formations that belong to the new, old and ancient cortex. They are located mainly on the medial surface of the hemispheres. In addition, the complex includes numerous subcortical formations, structures of the diencephalon, telencephalon and midbrain. They take part in the formation of visceral, emotional and motivational reactions.
Morphologically, in higher mammals, the limbic system, the functions of which will be discussed below, includes sections of the old cortex (hipocampus, cingulate, gyrus), a number of formations of the new cortex (frontal and temporal zones and the intermediate frontotemporal section). The complex also includes such subcortical structures as the caudate nucleus, globus pallidus, putamen, septum, amygdala, nonspecific nuclei in the thalamus, and the reticular formation in the midbrain.
Meaning
At the initial stage of development of vertebrates, the limbic system contributed to ensuring all the most important reactions of the body: food, sexual, orientation and others, formed on the basis of a distant ancient sense - smell. It was this that acted as an integrating factor of various integral functions. The sense of smell united the structures of the midbrain, telencephalon and diencephalon into a single complex. Some formations that the limbic system includes, based on descending and ascending paths form closed structures.
Stimulation of the complex
It has been experimentally proven that during stimulation of certain areas, which include the limbic system, the emotional reactions of animals manifest themselves predominantly in the form of anger (aggression) or fear (flight). Mixed forms are also observed. In this case, the behavior includes defensive reactions. Unlike motivations, the emergence of emotions occurs in response to spontaneous changes in the environment. This reaction fulfills a tactical task. This determines their optionality and transience. Long-term unmotivated changes in emotional behavior can be considered a consequence of an organic disease or occur under the influence of antipsychotics.
Motivational reactions
IN various departments In the limbic complex, centers of “displeasure and pleasure” are opened, which are combined into systems of “punishment” and “reward”. In the process of stimulating a complex of “punishments,” behavior is similar to what is observed during pain or fear. When exposed to the “reward” area of animals, there is a resumption of irritation and its implementation independently, if such an opportunity is presented. Presumably, the effects of “rewards” are not directly related to the regulation of biological motivation or the inhibition of negative emotions. They probably represent a nonspecific type of positive reinforcement mechanism. It, in turn, is connected to various motivational structures and contributes to the direction of behavior based on the “good-bad” principle.
Visceral reactions
These manifestations, as a rule, are a specific component of the corresponding form of behavior. Thus, under the influence of the hunger center in the lateral zones of the hypothalamus, there is an increase in salivation, increased secretory activity and gastrointestinal motility. When sexual response is stimulated, ejaculation and erection occur. Against the background of various types of emotional and motivational behavior, changes are observed in the frequency of heart contraction, changes in breathing, pressure indicators, the level of catecholamines and the secretion of ACTH, other mediators and hormones.
Integrative activity
To understand the principles by which the limbic system operates, the idea of the cyclical circulation of excitation processes along a closed network of formations has been put forward. This network includes, in particular, the mammillary bodies, the hippocampus, the cingulate gyrus, the anterior nuclei in the thalamus, and the fornix - the “Papes circle.” Then the cycle resumes. This “transit” principle of the formation of functions performed by the limbic complex is confirmed by some facts. So, for example, food reactions can be caused by stimulating the lateral nucleus in the hypothalamus, the preoptic zone and a number of other formations. However, despite the multiplicity of functional localization, key pacemaker mechanisms have been established, the disabling of which leads to the complete loss of a certain function.
Importance of Neurochemistry
Today there is a certain problem in consolidating structures into a separate functional system. This issue is resolved from the perspective of neurochemistry. It has been established that many formations that the limbic system includes contain special terminals and cells. They secrete several types of biologically active compounds. The most studied among them are monoaminergic neurons. They form three systems: serotonergic, noradrenergic and dopaminergic. The neurochemical affinity of a number of structures of the limbic system largely determines the level of their participation in one form or another of behavior. Disturbances in the complex's activities appear against the background various pathologies, intoxication, injuries, vascular diseases, neuroses, endogenous psychoses.
In this article we will talk about the limbic system, the neocortex, their history, origin and main functions.
Limbic system
The limbic system of the brain is a set of complex neuroregulatory structures of the brain. This system is not limited to just a few functions - it performs a huge number of tasks that are essential for humans. The purpose of the limbus is the regulation of higher mental functions and special processes of higher nervous activity, ranging from simple charm and wakefulness to cultural emotions, memory and sleep.
History of origin
The limbic system of the brain formed long before the neocortex began to form. This oldest hormonal-instinctive structure of the brain, which is responsible for the survival of the subject. Over a long period of evolution, 3 main goals of the system for survival can be formed:
- Dominance is a manifestation of superiority in a variety of ways
- Food - Subject's nutrition
- Reproduction - transferring your genome to the next generation
Because man has animal roots, the human brain has a limbic system. Initially, Homo sapiens possessed only affects that influenced the physiological state of the body. Over time, communication developed using the type of scream (vocalization). Individuals who were able to convey their state through emotions survived. Over time, the emotional perception of reality was increasingly formed. This evolutionary layering allowed people to unite into groups, groups into tribes, tribes into settlements, and the latter into entire nations. The limbic system was first discovered by American researcher Paul McLean back in 1952.
System structure
Anatomically, the limbus includes areas of the paleocortex (ancient cortex), archicortex (old cortex), part of the neocortex (new cortex) and some subcortical structures (caudate nucleus, amygdala, globus pallidus). Names listed various types cortex denotes their formation at the indicated time of evolution.
Weight specialists in the field of neurobiology, they studied the question of which structures belong to the limbic system. The latter includes many structures:
In addition, the system is closely related to the reticular formation system (the structure responsible for brain activation and wakefulness). The anatomy of the limbic complex is based on the gradual layering of one part onto another. So, the cingulate gyrus lies on top, and then descending:
- corpus callosum;
- vault;
- mamillary body;
- amygdala;
- hippocampus
A distinctive feature of the visceral brain is its rich connection with other structures, consisting of complex pathways and two-way connections. Such a branched system of branches forms a complex of closed circles, which creates conditions for prolonged circulation of excitation in the limbus.
Functionality of the limbic system
The visceral brain actively receives and processes information from the surrounding world. What is the limbic system responsible for? Limbus- one of those structures that works in real time, allowing the body to effectively adapt to environmental conditions.
The human limbic system in the brain performs the following functions:
- Formation of emotions, feelings and experiences. Through the prism of emotions, a person subjectively evaluates objects and environmental phenomena.
- Memory. This function is carried out by the hippocampus, located in the structure of the limbic system. Mnestic processes are ensured by reverberation processes - a circular movement of excitation in the closed neural circuits of the seahorse.
- Selecting and correcting a model of appropriate behavior.
- Training, retraining, fear and aggression;
- Development of spatial skills.
- Defensive and foraging behavior.
- Expressiveness of speech.
- Acquisition and maintenance of various phobias.
- Function of the olfactory system.
- Reaction of caution, preparation for action.
- Regulation of sexual and social behavior. There is a concept of emotional intelligence - the ability to recognize the emotions of others.
At expressing emotions a reaction occurs, which manifests itself in the form of: changes blood pressure, skin temperature, breathing rate, pupil reaction, sweating, reaction hormonal mechanisms and much more.
Perhaps there is a question among women about how to turn on the limbic system in men. However answer simple: no way. For all men, the limbus works in to the fullest(except for patients). This is justified by evolutionary processes, when a woman in almost all time periods of history was engaged in raising a child, which includes a deep emotional return, and, consequently, a deep development of the emotional brain. Unfortunately, men can no longer achieve the development of limbus at the level of women.
The development of the limbic system in an infant largely depends on the type of upbringing and the general attitude towards it. A stern look and a cold smile do not contribute to the development of the limbic complex, unlike a tight hug and a sincere smile.
Interaction with the neocortex
The neocortex and limbic system are tightly connected through many pathways. Thanks to this unification, these two structures form one whole of the human mental sphere: they connect the mental component with the emotional one. The neocortex acts as a regulator of animal instincts: before committing any action spontaneously caused by emotions, human thought, as a rule, undergoes a series of cultural and moral inspections. In addition to controlling emotions, the neocortex has an auxiliary effect. The feeling of hunger arises in the depths of the limbic system, and the higher cortical centers that regulate behavior search for food.
The father of psychoanalysis, Sigmund Freud, did not ignore such brain structures in his time. The psychologist argued that any neurosis is formed under the yoke of suppression of sexual and aggressive instincts. Of course, at the time of his work there was no data on the limbus, but the great scientist guessed about similar brain devices. Thus, the more cultural and moral layers (super ego - neocortex) an individual had, the more his primary animal instincts (id - limbic system) are suppressed.
Violations and their consequences
Based on the fact that the limbic system is responsible for many functions, this very many can be susceptible to various damages. The limbus, like other structures of the brain, can be subject to injury and other harmful factors, which include tumors with hemorrhages.
Syndromes of damage to the limbic system are rich in number, the main ones are:
Dementia– dementia. The development of diseases such as Alzheimer's and Pick's syndrome is associated with atrophy of the limbic complex systems, and especially in the hippocampus.
Epilepsy. Organic disorders of the hippocampus lead to the development of epilepsy.
Pathological anxiety and phobias. Disturbance in the activity of the amygdala leads to a mediator imbalance, which, in turn, is accompanied by a disorder of emotions, which includes anxiety. A phobia is an irrational fear of a harmless object. In addition, an imbalance of neurotransmitters provokes depression and mania.
Autism. At its core, autism is a deep and serious maladjustment in society. The inability of the limbic system to recognize the emotions of other people leads to serious consequences.
Reticular formation(or reticular formation) is a nonspecific formation of the limbic system responsible for the activation of consciousness. After deep sleep, people wake up thanks to the work of this structure. In cases of damage human brain is subject to various disorders of loss of consciousness, including absence and syncope.
Neocortex
The neocortex is a part of the brain found in higher mammals. The rudiments of the neocortex are also observed in lower animals that suck milk, but they do not reach high development. In humans, the isocortex is the lion's part of the general cerebral cortex, having an average thickness of 4 millimeters. The area of the neocortex reaches 220 thousand square meters. mm.
History of origin
IN this moment neocortex is the highest stage of human evolution. Scientists were able to study the first manifestations of the neobark in representatives of reptiles. The last animals in the chain of development that did not have a new cortex were birds. And only a person is developed.
Evolution is a complex and long process. Every species of creature goes through a harsh evolutionary process. If an animal species was unable to adapt to a changing external environment, the species lost its existence. Why does a person was able to adapt and survive to this day?
Being in favorable living conditions (warm climate and protein foods), human descendants (before the Neanderthals) had no choice but to eat and reproduce (thanks to the developed limbic system). Because of this, the mass of the brain, by the standards of the duration of evolution, gained a critical mass in a short period of time (several million years). By the way, the brain mass in those days was 20% greater than that of a modern person.
However, all good things come to an end sooner or later. With a change in climate, descendants needed to change their place of residence, and with it, start looking for food. Having a huge brain, descendants began to use it to find food, and then for social involvement, because. It turned out that by uniting into groups according to certain behavioral criteria, it was easier to survive. For example, in a group where everyone shared food with other members of the group, there was a greater chance of survival (Someone was good at picking berries, someone was good at hunting, etc.).
From this moment it began separate evolution in the brain, separate from the evolution of the whole body. Since then appearance the person has not changed much, but the composition of the brain is radically different.
What does it consist of?
New crust cerebral hemispheres- this is a cluster nerve cells, forming a complex . Anatomically, there are 4 types of cortex, depending on its location - , occipital, . Histologically, the cortex consists of six balls of cells:
- Molecular ball;
- external granular;
- pyramidal neurons;
- internal granular;
- ganglion layer;
- multiform cells.
What functions does it perform?
The human neocortex is classified into three functional areas:
- Sensory. This zone is responsible for higher processing of received stimuli from the external environment. So, ice becomes cold when information about the temperature arrives in the parietal region - on the other hand, there is no cold on the finger, but only an electrical impulse.
- Association zone. This area of the cortex is responsible for information communication between the motor cortex and the sensitive one.
- Motor area. All conscious movements are formed in this part of the brain.
In addition to such functions, the neocortex provides higher mental activity: intelligence, speech, memory and behavior.
Conclusion
To summarize, we can highlight the following:
- Thanks to two main, fundamentally different, brain structures, a person has duality of consciousness. For each action, two different thoughts are formed in the brain:
- “I want” - limbic system (instinctive behavior). The limbic system occupies 10% of the total brain mass, low energy consumption
- “We must” - neocortex ( social behavior). Neocortex occupies up to 80% of total brain mass, high energy consumption and limited metabolic rate
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 us to develop and support life.
In the middle of the last century, the concept of “limbic system” meant certain formations at the edge of the brain. As medicine was studied, the number of entities included in the medicine 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 sleep and wakefulness phases.
Structure of the limbic system
The LS consists mainly of thirteen main entities. Take, for example, the amygdala nuclei. These two identical almond-shaped areas of the brain are located in the temple area, in different hemispheres. The amygdala forms emotions and also plays an important role in decision making and remembering information. Negative influence 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 almond leads to uncertainty and anxiety.
In humans, on the contrary, electrical stimulation of these areas causes aggression and nervous breakdown.
Cingulate gyrus. This cortical part of the LS runs along the lateral walls of the groove that separates the left and right hemisphere. Anterior perforated substance. This is the part of the hemisphere located below and extending posteriorly from the olfactory triangle. They pass through it blood vessels. Next come the midbrain and piriform gyrus. Parahippocampal gyrus. Transverse temporal gyri. Located inside the lateral groove.
Hippocampus and hypothalamus
Hippocampus This part is responsible for the consolidation of memory (the transition from short-term to long-term), the realization of emotions and the generation of the theta rhythm with increased attention. Inside there is a dentate gyrus, smoothly turning into a ribbon gyrus.
Hypothalamus. Science does not have clear enough boundaries defining this zone. But it is generally accepted that the hypothalamus is a small area in diencephalon, just below the thalamic region. Despite small size, its neurons form 30–50 groups of nuclei that regulate secretion various hormones. Next comes the mastoid body.
Group of olfactory formations
Olfactory bulb. It looks like a slight 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 to the brain by nerve tissue. The olfactory receptor of the bulb only needs one molecule of a substance with an odor to create a complete sensation. Olfactory tract. Olfactory triangle.
These groups overlap with almost all parts of the central nervous system. Neuroendocrine connections deserve close attention. They are the connecting link between the nervous and endocrine systems.
How the system works
The human psyche is a kind of chain based on the principle vicious circle 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 transferred from one part of the brain to another. LS controls electrical activity brain and autonomic reactions, and also regulates the metabolic process.
The drug performs a number of vital functions:
- communication activities;
- water-salt metabolism;
- sleep regulation;
- sense of smell;
- intellectual development;
- control of hunger;
- thermoregulation;
- emotions and behavior patterns;
- coordinated work of internal organs.
The functions of the drug 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 respond correctly to irritating factors and maintains internal balance. Previously, it was believed that the drug was capable of processing information coming only from the olfactory organs. It has now become known that limbic connections analyze signals from all senses: visual, auditory, sensory, gustatory. In addition, thanks to drugs, a person more easily adapts to 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 LS does not archive events and knowledge acquired by a person, when it is violated, it can be difficult to remember what was previously known as twice two. Often memories become scattered and abrupt. Events that occurred before the defeat are easily reproduced; what happened later is more difficult to retell, especially to clarify on what day or at what time it happened.
In addition to the above, pathology often results in:
- gastrointestinal disorders;
- weakened immunity;
- 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 nervous system;
- complications on the vascular system;
- head injuries;
- psychical deviations;
- toxic and alcohol poisoning.
The sense organs also suffer after dysfunction. This can manifest itself in different directions. Vision.
When the outer areas of the occipital lobe cortex 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 an object is recognized, but the name is not, or is confused, so the patient may well say “train” to a pencil, not suspecting that it is a completely different word. Hearing. When the secondary zones of Heschl's temporal gyri are damaged, there is an inability to recognize phenomena by characteristic sounds, such as the sound of wind or rain. Taste and smell. The ability to identify objects by smell and taste is lost. Sensitive function. The victim cannot classify objects by touch (an anomaly called astereognosis) and correctly assess the state of his body (autotopagnosia).
– the broadest totality, which represents a morphofunctional association of systems. They are in various parts brain
Let's look at 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
- oldest subcortical and mantle parts
- cingulate gyrus
- dentate gyrus
- hippocampus (seahorse)
- septum (septum)
- amygdala.
The diencephalon contains 4 main structures of the limbic system:
- habenular nuclei (lead nuclei)
- thalamus
- hypothalamus
- mastoid bodies.
main functions of the limbic system
Connecting with Emotions
The limbic system is responsible for the following activities:
- sensual
- motivational
- vegetative
- endocrine
You can also add instincts here:
- food
- sexual
- defensive
The limbic system is responsible for regulating the wakefulness-sleep process. It develops biological motivations. They predetermine complex chains of effort. These efforts lead to the satisfaction of the above vital needs. Physiologists define them as the most difficult unconditioned reflexes or instinctive behavior. For clarity, we can recall the behavior of a newborn baby when breastfeeding. This is a system of coordinated processes. With the growth and development of a child, his instincts are increasingly influenced by consciousness, which develops as he studies and is raised.
Interaction with the neocortex
The limbic system and neocortex are tightly and inextricably interconnected with each other and the autonomic nervous system. On this basis, it connects two of the most important activities of the brain - memory and feelings. Typically, the limbic system and emotions are linked together.
Deprivation of part of the system leads to psychological inertia. The urge leads to psychological hyperactivity. Increased activity of the amygdala activates methods for provoking anger. These methods are regulated by the hippocampus. The system operates eating behavior and awakens a sense of danger. These behaviors are regulated by both the limbic system and hormones. Hormones are in turn produced by the hypothalamus. This combination significantly influences life through the regulation of the functioning of the autonomic nervous system. Its significance is called the visceral brain. Determines the sensory-hormonal activity of the animal. Such activity is practically not subject to brain regulation either in animals, or even less so in humans. This demonstrates the relationship between emotions and the limbic system.
System functions
The main function of the limbic system is to coordinate actions with memory and its mechanisms. Short-term memory is usually combined with the hippocampus. Long-term memory comes from the neocortex. The manifestation of personal skills and knowledge from the neocortex occurs through the limbic system. For this purpose, sensory-hormonal stimulation of the brain is used. This provocation brings up all the information from the neocortex.
The limbic system also performs the following significant function - verbal memory of incidents and experiences gained, skills, as well as 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 connect with each other and other parts of the brain. The connections with the hypothalamus are especially multifaceted.
It defines:
- human sensual mood
- his motivation for action
- behavior
- processes of acquiring knowledge and remembering.
Violations and their consequences
If the limbic system is disturbed or there is a defect in these complexes, amnesia progresses in patients. However, it should not be defined as a place of storage certain information. It connects all the separate parts of memory into generalized skills and incidents that are easy to reproduce. Disruption 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 stored and serve as a guarantee for procedural memory. Patients with Korsakoff's syndrome can learn some other new knowledge. However, they will not know how and what exactly they learned.
Defects in its activities result from:
- brain injury
- neuroinfections and intoxications
- vascular pathologies
- endogenous psychoses and neuroses.
It all depends on how significant the defeat was, as well as the restrictions. 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 when the hippocampus is predominantly damaged by alcohol, a person’s memory for recent incidents suffers. Patients undergoing treatment for alcoholism in hospital suffer from the following: they do not remember what they ate for lunch today and whether they had lunch at all or not, and when was the last time they took medications. At the same time, they perfectly remember events that took place in their lives long ago.
It has already been scientifically substantiated - the limbic system (more precisely, the amygdala and the transparent septum) is responsible for processing certain information. This information was received 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 the sense of smell. Everyone knows about the importance of biogenic amines for leading a full life and activity:
- dopamine
- norepinephrine
- serotonin.
The limbic system has them in huge quantities. The manifestation of nervous and mental illnesses is associated with the destruction of their balance.
2. Self-regulation of autonomic functions
3. The role of the limbic system in the formation of motivations, emotions, memory organization
Conclusion
References
Introduction
In each of the two hemispheres of the brain there are six lobes: the frontal lobe, the parietal lobe, temporal lobe, occipital lobe, central (or insular) lobe and limbic lobe. A set of formations located predominantly on the inferomedial surfaces of the cerebral hemispheres, closely interconnected with the hypothalamus and overlying structures, was first designated as an independent formation (limbic lobe) in 1878 by the French anatomist Paul Broca (1824-1880). Then only the marginal zones of the cortex, located in the form of a bilateral ring on the inner border of the neocortex (Latin: limbus - edge), were classified as the limbic lobe. These are the cingulate and hippocampal gyri, as well as other areas of the cortex located next to the fibers coming from the olfactory bulb. These zones separated the cerebral cortex from the brain stem and hypothalamus.
At first it was believed that the limbic lobe performed only the function of smell and therefore it was also called the olfactory brain. Subsequently, it was found that the limbic lobe, together with a number of other neighboring brain structures, perform many other functions. These include coordination (organization of interaction) of many mental (for example, motivations, emotions) and physical functions, coordination of visceral systems and propulsion systems. In this regard, this set of formations was designated by the physiological term - limbic system.
1. The concept and significance of the limbic system in nervous regulation
The occurrence of emotions is associated with the activity of the limbic system, which includes some subcortical formations and areas of the cortex. The cortical sections of the limbic system, representing its highest section, are located on the lower and inner surfaces of the cerebral hemispheres (cingulate gyrus, hippocampus, etc.). The subcortical structures of the limbic system include the hypothalamus, some nuclei of the thalamus, midbrain and reticular formation. Between all these formations there are close direct and feedback connections that form the “limbic ring”.
The limbic system is involved in a wide variety of activities of the body. It forms positive and negative emotions with all their motor, autonomic and endocrine components (changes in breathing, heartbeat blood pressure, gland activity internal secretion, skeletal and facial muscles, etc.). Depends on her emotional coloring mental processes and changes in motor activity. It creates motivation for behavior (a certain predisposition). The emergence of emotions has an “evaluative influence” on the activity of specific systems, since, by reinforcing certain methods of action, ways of solving assigned tasks, they ensure the selective nature of behavior in situations with many choices.
The limbic system is involved in the formation of indicative and conditioned reflexes. Thanks to the centers of the limbic system, defensive and food conditioned reflexes can be produced even without the participation of other parts of the cortex. With lesions of this system, strengthening of conditioned reflexes becomes difficult, memory processes are disrupted, selectivity of reactions is lost and their excessive strengthening is noted (excessively increased motor activity, etc.). It is known that the so-called psychotropic substances, changing the normal mental activity of a person, act specifically on the structures of the limbic system.
Electrical stimulation of various parts of the limbic system through implanted electrodes (in experiments on animals and in the clinic during the treatment of patients) revealed the presence of pleasure centers that form positive emotions, and centers of displeasure that form negative emotions. Isolated irritation of such points in the deep structures of the human brain caused the appearance of feelings of “causeless joy,” “pointless melancholy,” and “unaccountable fear.”
In special experiments with self-irritation on rats, the animal was taught to close a circuit by pressing its paw on a pedal and produce electrical stimulation of its own brain through implanted electrodes. When the electrodes are localized in the centers of negative emotions (some areas of the thalamus), the animal tries to avoid closing the circuit, and when they are located in the centers of positive emotions (hypothalamus, midbrain) pressing the pedal with the paw followed almost continuously, reaching up to 8 thousand irritations in 1 hour.
Great role emotional reactions in sports (positive emotions when performing physical exercises - “muscle joy”, joy of victory and negative ones - dissatisfaction sporting result and etc.). Positive emotions can significantly increase, and negative emotions can significantly decrease, a person’s performance. The great stress that accompanies sports activity, especially during competitions, also creates emotional stress - the so-called emotional stress. On the nature of reactions in the body emotional stress the success of an athlete’s motor activity depends.
The regulation of the activity of internal organs is carried out by the nervous system through its special department - the autonomic nervous system.
All functions of the body can be divided into somatic, or animal (from the Latin animal - animal), associated with activity skeletal muscles, - organization of posture and movement in space, and vegetative (from the Latin vegetativus - plant), associated with the activity of internal organs - the processes of breathing, blood circulation, digestion, excretion, metabolism, growth and reproduction. This division is conditional, since vegetative processes also inherent in the motor system (for example, metabolism, etc.); motor activity is inextricably linked with changes in breathing, blood circulation, etc.
Stimulation of various body receptors and reflex responses of nerve centers can cause changes in both somatic and autonomic functions, i.e. afferent and central departments these reflex arcs are common. Only their efferent sections are different.
The totality of efferent nerve cells of the spinal cord and brain, as well as cells of special nodes (ganglia) innervating internal organs, is called the autonomic nervous system. Consequently, this system is the efferent part of the nervous system, through which the central nervous system controls the activities of the internal organs.
A characteristic feature of the efferent pathways included in reflex arcs autonomic reflexes, is their two-neuron structure. From the body of the first efferent neuron, which is located in the central nervous system (in the spinal, medulla oblongata or midbrain), a long axon extends, forming a prenodal (or preganglionic) fiber. In the autonomic ganglia - clusters of cell bodies outside the central nervous system - excitation switches to the second efferent neuron, from which a postnodal (or postganglionic) fiber departs to the innervated organ.
The autonomic nervous system is divided into 2 sections - sympathetic and parasympathetic. The efferent pathways of the sympathetic nervous system begin in the thoracic and lumbar regions spinal cord from neurons of its lateral horns. The transfer of excitation from the prenodal sympathetic fibers to the postnodal ones occurs in the ganglia of the border sympathetic trunks with the participation of the mediator acetylcholine, and the transfer of excitation from the postnodal fibers to the innervated organs - with the participation of the mediator adrenaline, or sympathin. The efferent pathways of the parasympathetic nervous system begin in the brain from some nuclei of the midbrain and medulla oblongata and from neurons of the sacral spinal cord. Parasympathetic ganglia are located in close proximity to or within the innervated organs. The conduction of excitation at the synapses of the parasympathetic pathway occurs with the participation of the mediator acetylcholine.
The autonomic nervous system, regulating the activity of internal organs, increasing the metabolism of skeletal muscles, improving their blood supply, increasing the functional state nerve centers etc., contributes to the implementation of the functions of the somatic and nervous system, which ensures the active adaptive activity of the body in the external environment (reception external signals, their processing, motor activity aimed at protecting the body, searching for food, in humans - motor acts associated with household, work, sports activities, etc.). The transmission of nervous influences in the somatic nervous system occurs at high speed (thick somatic fibers have high excitability and a conduction speed of 50-140 m/sec). Somatic effects on individual parts musculoskeletal system characterized by high selectivity. the autonomic nervous system is involved in these adaptive reactions body, especially under extreme stress (stress).
Another significant aspect of the activity of the autonomic nervous system is its huge role in maintaining the constancy of the internal environment of the body.
Constancy physiological indicators can be provided in various ways. For example, the constancy of blood pressure is maintained by changes in the activity of the heart, pro. light of blood vessels, the amount of circulating blood, its redistribution in the body, etc. In homeostatic reactions, along with nervous influences, transmitted along vegetative fibers, humoral influences are important. All these influences, unlike somatic ones, are transmitted in the body much more slowly and more diffusely. Thin vegetative nerve fibers are characterized by low excitability and low speed of excitation conduction (in prenodal fibers the conduction speed is 3-20 m/sec, and in postnodal fibers it is 0.5-3 m/sec).
