The limbic system, also called the visceral brain, rinencephalon, thimencephalon, contains a whole complex of structures of different parts of the brain: middle, intermediate, final, which are involved in the organization of motivational, visceral and emotional reactions of the body.
The limbic system of the brain has a very complex structure, it combines such parts of the old cortex as the hippocampus, limbic and cingulate gyrus; sections of the new cortex: frontal, temporal and frontotemporal intermediate zone; subcortical structures: caudate nucleus, pale ball, shell, septum, amygdala, hypothalamus, non-specific nuclei of the thalamus, reticular formation of the midbrain. All subcortical structures are very closely connected with the main structures of the cerebral cortex. System structures 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 smell, provides many vital reactions of the body, such as orientational, sexual and food. The sense of smell not only acted as the main integrating factor, but also combined the structure of the brain into a single integrated complex. Therefore, in higher vertebrates, including humans, the structures of the limbic system, built on the basis of the descending and ascending paths, have a closed system of functioning.
The limbic system controls many of the most important processes that occur in the body - the regulation of water-salt balance, maintaining a constant body temperature, as well as 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 processes. This system defines and controls the motivation of behavior, ensures the focus of all actions. As a result, the adaptation of the body to changes in environmental conditions is constantly being improved. And first of all, this concerns changes in the social and social environment, since a person is a purely social being.
The limbic system also provides another important function - verbal or declarative memory, which carries information about any events, existing knowledge or acquired skills and experience. In clinical practice, it was found that with impaired function or damage to limbic structures, patients develop amnesia. But scientists argue that the limbic system is not a repository of information, because fragments of memory are scattered throughout the associative cortex. And the limbic system only integrates them functionally and makes them available for playback. When limbic structures are violated, memory is not erased, its fragments remain and are saved, but only its conscious reproduction fails. Therefore, almost all people with a lesion of the limbic system are able to instantly master many motor or perceptual skills, but they cannot remember where they could learn this before.
Dysfunctions of the limbic system can cause brain injuries, neuroinfection and intoxication, vascular pathologies, endogenous psychoses and neuroses. Epilepsy convulsive states, automatisms, changes in consciousness and mood, derealization and depersonalization, as well as auditory, gustatory and olfactory hallucinations, may occur depending on the volume of the lesion or its localization.