The human limbic system: structure and functions

The limbic system, also called the visceral brain, rhinencephalon, thyme cephalon, contains a whole complex of structures of different parts of the brain: the middle, intermediate, final, which participate in the organization of motivational, visceral and emotional reactions of the body.

The limbic system of the brain has a very complex structure, it unites such sections of the old cortex as the hippocampus, limbic and girdle gyrus; Sections of the new cortex: frontal, temporal divisions and frontotemporal intermediate zone; Subcortical structures: caudate nucleus, pale sphere, shell, septum, amygdala, hypothalamus, nonspecific nuclei of thalamus, reticular formation of midbrain. All subcortical structures are very closely related to the basic structures of the cerebral cortex. The structures of the system are localized, mainly in the cerebral hemispheres.

The limbic system, whose functions at the initial stage of the evolution of the animal world were formed on the basis of olfaction, provides many vital reactions of the organism, such as the orienting, sex and food. The sense of smell not only acted as the main integrating factor, but also united the structures of the brain into a single integrated complex. Therefore, in higher vertebrates, including humans, the structures of the limbic system, constructed on the basis of descending and ascending paths, have a closed system of functioning.

The limbic system controls many of the most important processes occurring in the body - regulation of the water-salt balance, maintaining a constant body temperature, and behavioral reactions, in particular, food, aimed at obtaining energy and nutrients. It determines the emotional behavior of a person, sexual behavior, sleep and wakefulness, learning and remembering. This system determines and manages the motivation of behavior, ensures the goal-directedness of all actions. As a result, the adaptation of the organism to changes in environmental conditions is constantly improving. And, first of all, this concerns changes in the social and social environment, since man is a purely social being.

The limbic system also provides one more important function - a verbal or declarative memory, carrying information about any events, available knowledge or acquired skills and experience. In clinical practice, it was found that in cases of impaired function or damage to limbic structures, amnesia develops in patients. But scientists argue that the limbic system is not a repository of information, because fragments of memory are dispersed throughout the associative cortex. A limbic system only functionally unites them and makes them available for reproduction. If limbic structures are disturbed, memory is not erased, its fragments remain and are preserved, but only its conscious reproduction fails. Therefore, almost all people with a limbic system lesion are able to instantly master many motor or perceptual skills and abilities, but they can not remember where they could previously learn this.

Violations of the limbic system can cause brain injuries, neuroinfections and intoxications, vascular pathologies, endogenous psychoses and neuroses. Depending on the extent of the lesion or its location, epilepsy convulsions, automatisms, changes in consciousness and mood, derealization and depersonalization, as well as auditory, taste and olfactory hallucinations may occur.