Locus caeruleus
The locus caeruleus (from the Latin locus 'place' and caeruleus 'sky blue') is a core area in the area of the dorsal bridge hood of the metencephalon of the brain . It has a black pigmentation that shimmers through bluish on the surface of the brain. Other terms used synonymously are Locus coeruleus or Nucleus caeruleus ( TA ).
anatomy
The core area is located in the bridge hood ( tegmentum pontis ) of the hindbrain , embedded in the formatio reticularis , under the floor of the anterior diamond-shaped pit and extends caudally to the lower (rear) hill ( colliculi inferiores or caudales ) of the four- hill plate of the midbrain down to about at the level of the confluence of the cerebral aqueduct with the fourth ventricle . Neurophysiologically , this structure is an important part of the system of noradrenergic neurons and represents their largest accumulation in the central nervous system.
One of the tasks of the monoaminergic neuron group in the caeruleus nucleus is presumably to influence mental orientation in the sense of directed attention . Sensory excitations switched via the locus caeruleus are responded to with a release of norepinephrine as a transmitter , which reaches various other brain regions and covers large parts of the brain.
Reach ascending fibers, next to the thalamus and hypothalamus in the diencephalon , in particular fractions of the so-called limbic system - such as the hippocampus , amygdala and septal nuclei ( septal nuclei ) - and projecting beyond almost the entire neocortex . Descending efferents move to various nuclei in the lower brain stem and next to it in the anterior cord to segments of the spinal cord .
For the locus caeruleus, several sections can be subdivided, in addition to the well-defined large central nucleus, an anterior ( anterior ) and a posterior ( posterior ) (sub) nucleus. The nucleus subcaeruleus is mostly understood neuroanatomically as a separate structure.
The most important connections of the Locus caeruleus system are summarized as
- the dorsal (tegmental) noradrenergic path
- the dorsal periventricular route
The former accompanies the medial forebrain bundle ( Fasciculus medialis telencephali ) through the caudal and lateral hypothalamus to the basal forebrain and the neocortex. The second projects into the dorsal thalamus and some hypothalamic centers.
Clinical relevance
The locus caeruleus is involved in numerous diseases , for example in Parkinson's disease , Down's syndrome and Alzheimer's disease .
The locus caeruleus also plays a role in the development of physical dependencies. Opiates and alcohol, for example, dampen its activity. In acute opiate withdrawal, on the other hand, there is overactivity and the symptoms are similar to those of a stress reaction, which also explains the effectiveness of α2 receptor agonists (e.g. clonidine ).
Web links
Individual evidence
- ↑ Strahlendorf, HK and JC Strahlendorf (1983). "Ethanol suppression of locus coeruleus neurons: relevancy to the fetal alcohol syndrome." Neurobehavioral Toxicology and Teratology 5 (2): 221-224.
- ↑ Lüdecke, Sachsse, Faure. Addiction - attachment - trauma. Schattauer GmbH; 2010. pp. 115-116.
- ↑ Aktories, Förstermann, Hofmann, Starke. General and special pharmacology and toxicology. Munich: Urban & Fischer; 9th edition.