Limbic system
The limbic system is a functional unit of the brain that serves the processing of emotions and the development of instinctive behavior. The limbic system also be awarded academic performance. The view, certain features (such as the shoots) to refer only to the limbic system and to be regarded as functionally separated from the rest of the brain, is now considered outdated. Other cortical and non- cortical structures of the brain exert a tremendous influence on the limbic system. The emergence of emotion and instinctive behavior so always needs to be seen as an interplay of many brain shares and may not be awarded to the limbic system alone.
The limbic system is also responsible for the release of endorphins, so endogenous opioids.
History
The term was introduced in 1878 by Paul Broca, who defined a " limbic lobe ". The name " limbic " comes from the Latin limbus ( " seam " ), since the associated structures form a double ring around the basal ganglia and the thalamus. Paul MacLean coined in 1952 the term " limbic system " and also ordered the amygdala, this functional structure to.
The first functional theory was developed in 1937 by James W. Papez, called the Papez circuit. Since the 1990s, however, the concept of the limbic system is in increasing criticism:
- Authors such as Rolf Kötter and Niels Meyer ( 1992) point out that there is no independent and generally accepted definition criterion - whether anatomical or functional - which could be true for all counted to the limbic system areas. In response to this criticism, other authors have proposed the concept of extended limbic system, which also includes parts of the cerebral cortex and brain stem, or defended the concept as fuzzy limbic system ( Isaacson ).
- Other scientists who conduct research on the neural basis of emotion (eg, Joseph LeDoux ), may raise concerns that emotions are not a monolithic phenomenon, but that very different neural substrates underlie, for example, the fear or the craving. So neuroscience describes the limbic system as an emotional power center in the brain.
Anatomy
The structures of the limbic system form a double ring around the basal ganglia and the thalamus. It is formed from phylogenetically old shares of the cerebral cortex ( paleopallium and Archipallium, also Allocortex ) and subcortical structures that lie medial to the hemispheres.
The limbic system is divided into the following anatomical structures (incomplete selection):
- Hippocampus
- Fornix
- Mammillary
- Cingulate gyrus
- Amygdaloid body ( amygdala, amygdala )
- Anterioventrales nuclei of the thalamus
- Parahippocampal gyrus
- Septum pellucidum
Each of these components has important functional connections to the control centers in other brain regions. The connections with the mesencephalon are also called mesolimbic system.
Disorders of the limbic system
Some diseases can be attributed to disturbances of the limbic system and the amygdala, so presumably the inability to assess emotional situations; Memory disorders; Post-traumatic stress disorder; narcolepsy; autism; depression; Phobias and the Urbach - Wiethe syndrome.
To the limbic system, since many structures are, it is difficult, this " functional unit " of the assets of individual diseases or disorders. Diseases can have many different causes, whose origins are possibly accepted limited to specific parts of the limbic system.
- Alzheimer's disease
The hippocampus - as part of the limbic system - is one of the first areas that are affected by Alzheimer's disease. Other brain changes associated with the disease, then focus largely on the neocortex and the limbic cortex.
- Bipolar Disorder
Among the causes of bipolar disorder and a change of function of the limbic system is counted.
- Schizophrenia
Among the biological factors of schizophrenia is often recognized by reduced activity of the frontal brain using positron emission tomography, the hypofrontality - this is in turn associated with limbic dysfunction with impaired regulation of emotion and anxiety.