Limbic system

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The limbic system is a developmentally old area of ​​the brain that is located between the neocortex (part of the cerebral cortex) and the brain stem. It is the center of all emotions, controls our expressions of anger, fear and joy and influences sexual behavior, vegetative functions of the organism and memory and retentiveness. Read everything you need to know about the limbic system: function, structure and the relationship between the limbic system and emotions!

What is the Limbic System?

The limbic system is an area of ​​brain areas that wrap around the basal ganglia and the thalamus like a ring (the word limbic is derived from the Latin word limbus = hem). It contains parts of the frontal, parietal and temporal lobes of the cerebrum.

Our limbic system is divided into three areas:

Cortical and subcortical gray areas

This area includes the hippocampus, gray matter on the surface of the bar, the olfactory cortex in the hippocampi gyrus, the cingulate gyrus, the amygdala and septum nuclei (subcortical nucleus in the basal forebrain).

Intramural fiber strands

The intramural fiber strands connect the above-mentioned areas with one another. These include the cingulum (medullary nerve fibers that lie on the bar and run to the cingulate gyrus and hippocampal gyrus), the striae longitudinales (part of the hippocampus), Broca's diagonal ligament (core area in the forebrain that projects to the hippocampus) and a fiber train between the hippocampus and the entorhinal area (in the hippocampal gyrus).

Extramural connections

The extramural connections link the limbic system with core areas of the mid- and diencephalon. These include the fornix (the roof of the third ventricle in the endbrain below the bar), the striae terminales (nerve fibers coming from the amygdala that run to the hypothalamus and the brain stem) and fibers of the tonsil nucleus with connections to the hypothalamus.

A second area of ​​the extramural connections is the circle of neurons: Individual fornix fibers run from the hippocampus to the thalamic nuclei, where, after switching over other areas, they reach the hippocampus.

A third group of extramural connections establishes contact with the midbrain - this area is also called the mesolimbic system. The connection from the mesolimbic system to the neuron circuit described above is established via neuron circuits.

A fourth area establishes connections with the reticular formation. These run over the fornix, the basal olfactory bundle, tonsil and septum nuclei, the preoptic region, striae medullares (fibers of the brain stem on the wall of the fourth ventricle) and areas of the diencephalon to the formatio reticularis (gray and white matter that extends from the brain stem to the spinal cord pulls).

What is the function of the limbic system?

Our limbic system regulates affect and drive behavior towards the environment. All incoming sensory information is coordinated in the limbic system and finds its emotional response here. The sense of smell, for example, is particularly closely linked to the limbic system. Vital vegetative functions such as breathing, sleep-wake rhythm and motivation are also controlled by our limbic system.

Learning processes are only possible if the content that is to be saved is also given attention. To be able to save knowledge about events in the right context and to be able to retrieve them again, to remember (long-term memory), to be able to report on previous experiences and the ability to find one's way in a new environment, to be able to orientate oneself - all these functions are only possible via our limbic system.

The amygdala evaluates memory traces (memories) with emotions within the limbic system.

Where is the limbic system located?

The limbic system is a collection of different areas of the brain that are closely connected to one another. It is located between the diencephalon and the two cerebral hemispheres. The limbic system is like a ring around the basal ganglia and thalamus.

What problems can the limbic system cause?

If our limbic system is damaged, memories can only be evaluated neutrally, without their emotional content. Affected patients become indifferent and social behavior is undifferentiated.

Defects in the limbic system hinder the storage of memory contents and memories. Diseases such as Korsakoff's syndrome after alcohol abuse or Alzheimer's disease are partly a result of disorders in the limbic system. The circuits that lead to areas of the brain that enable transmission to the cerebral cortex are disrupted here. Memory disorders, post-traumatic stress disorders, depression and phobias can also often be traced back to damage to the limbic system.

In schizophrenia, decreased activity of the frontal lobe can often be demonstrated, which is associated with dysfunction of the limbic system.

Our limbic system can develop tumors, bleeding and foci of inflammation. The possible consequences are urgent sexual acts and aggressiveness (unrestrained outbursts of anger) without an adequate cause.

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