Nucleus (CNS)

In neuroanatomy, the nucleus ( Latin nucleus "core"; plural nuclei ), nucleus , nucleus or core area is a collection of nerve cell bodies ( perikaryen or somata ) that lies within the central nervous system and is surrounded by white matter . The nuclei here together with the cortex of the cerebrum and cerebellum form the gray matter ( substantia grisea ).

While the individual nuclei in the brain are often clearly distinguishable from one another, these groups in the spinal cord , which are made up of functionally related cell bodies, are not clearly separated by white matter. Together they form a butterfly shape in the spinal cord cross-section. The nuclei, which extend over several spinal cord sections, are also referred to as nuclear columns ( Columnae ).

Aggregations of nerve cell bodies outside the CNS are called ganglia .

Deviating from the rule of referring to accumulations of nerve cell bodies in the peripheral nervous system as ganglia, but in the central nervous system as nuclei, the term basal ganglia (basal ganglia) is traditionally used for certain subcortical nuclei in the telencephalon .

Important nuclei in the mammalian brain

Endbrain

In the endbrain ( telencephalon ), the basal nuclei ( basal ganglia ) are located medially at the base of a cerebral hemisphere under the mantle of the cerebral cortex and medullary bed . Their functional meaning and relationship to one another has not yet been finally clarified. You are u. a. a switching point of the so-called extrapyramidal motor system and important for involuntary expressive movements. The basal nuclei include:

Nucleus caudatus (tail nucleus ): bulges into the lateral ventricles

Striatum : with putamen and caudate nucleus

Putamen and globus pallidus are sometimes grouped together as the nucleus lentiformis (lens body), but this is considered out of date, since the putamen and the nucleus caudatus belong together phylogenetically.

The claustrum (front wall) lies to the side of the basal nuclei, directly under the cerebral cortex. The amygdala ( corpus amygdaloideum , tonsil body) is located medial to the temporal lobe and is part of the limbic system .

Diencephalon

In the diencephalon ( diencephalon ), a distinction is non-specific and specific nuclei in the thalamus and the geniculate in metathalamus . There are over 100 core groups in the thalamus alone. In the nuclei of the hypothalamus , effector hormones , liberins and statins and neuropeptides are formed.

Corpus geniculatum laterale (lateral knee hump): It is part of the visual pathway . Here ends the optic nerve ( optic nerve ), the information to the visual cortex forwarded.
Corpus geniculatum mediale (medial knee hump): It is an important switching station for the auditory pathway on the way to the auditory cortex .
Nuclei habenulares : in the habenulae
Nucleus infundibularis : in the pituitary stalk
Nuclei mamillares : in the corpus mamillare
Paraventricular nucleus : The nerve cells produce the hormone oxytocin , which is then transported axonally to the neurohypophysis .
Nucleus preopticus : in front of the optic nerve junction
Nucleus suprachiasmaticus : It is the most important clock for the internal clock and works closely with the pineal gland .
Nucleus supraopticus : The nerve cells produce the hormone vasopressin , which is then transported axially to the neurohypophysis .
Nucleus ventralis posterior : Specific thalamic nucleus for haptic perception .
Nucleus ventralis anterolateralis : Specific thalamic nucleus for the control of movement sequences.

Midbrain

The midbrain ( mesencephalon ) includes :

Nuclei motorii of the 3rd ( Nucleus nervi oculomotorii ) and 4th ( Nucleus nervi trochlearis ) cranial nerves

Nucleus pretectalis : switching from descending tracts of the visual cortex to the parasympathetic nucleus of the ocular motor nerve ( oculomotor nerve ).

Nucleus parasympathicus ( Edinger-Westphal-Kern ): origin of the parasympathetic fibers of the nervus oculomotorius, center of the eye motor function

Ruber nucleus : most important component of the extrapyramidal system , starting point of the rubrospinal tract

Substantia nigra : see extrapyramidal motor system

Nucleus mesencephalicus nervi trigemini : here are the perikaryen proprioceptive neurons of the 5th cranial nerve (including the temporomandibular joint and muscle tone)

Hindbrain

In the hindbrain ( metencephalon ) are among others:

Nucleus dentatus : in the cerebellum , connection to the nucleus ruber

Nucleus emboliformis : in the cerebellum, connection to the nucleus ruber

Nucleus fastigii : in the cerebellum, connection to equilibrium nuclei
Nucleus globosus : in the cerebellum, connection to the nucleus ruber
Nuclei pontis (bridge cores): Switching station for the pathways between the cerebrum and the cerebellum
Nuclei motorii : nuclei in the pons for the motor parts of the 5th , 6th and 7th cranial nerves
Nucleus (sensorius) principalis nervi trigemini : receives somatosensitive fibers of the 5th cranial nerve (epicritical sense of touch of the facial region)

Nucleus caeruleus , also Locus coeruleus : the largest core area of pigmented noradrenergic neurons that influence directed attention

Nuclei corporis trapezoidei ( trapezoidal cores ): origin of the lateral longitudinal bundle

Nuclei cochleares (snail cores): first switching of the auditory pathway, in some mammals in the medullary brain

Nuclei vestibulares (equilibrium nuclei ): first switching of the vestibular nerve and thus the equilibrium pathway, in some mammals in the medullary brain

Medullary brain

In the medullary brain ( myelencephalon or medulla oblongata ) are among others:

Nuclei cochleares (snail cores): first switching of the auditory pathway, in some mammals also in the hindbrain

Nuclei vestibulares (vestibular or equilibrium nuclei ): first switching of the vestibular nerve and thus the equilibrium pathway, in some mammals also in the hindbrain

Nuclei raphes (raphe nuclei): involved in the attenuation of pain sensations

Nuclei tractus solitarii : receive primary viscera afferents of the 7th , 9th and 10th cranial nerves, etc. a. Flavor fibers

Nuclei parasympathici : origin of the parasympathetic fibers of the 7th , 9th and 10th cranial nerves

Nucleus ambiguus : motor core for the palate, throat and larynx muscles

Nuclei motorii of the 9th , 10th , 11th and 12th cranial nerves
Nucleus nervi hypoglossi : the nucleus of origin for the tongue muscles

Nucleus olivaris (olive): connection to the cerebellum and spinal cord , interconnection of the auditory pathway

Nucleus spinalis nervi trigemini : receives somatosensitive fibers of the 5th cranial nerve (protopathic sensation of pressure, temperature, pain, itching, tickling)

Nucleus cuneatus : switching of the sensitive pathways from the upper / front extremity

Nucleus gracilis : switching of the sensitive tracts of the lower / rear half of the body

Nuclei in the spinal cord

Nucleus intermediolateralis : in the gray matter, origin of the sympathetic nerve fibers in the thoracic and lumbar cord
Motor nuclei (core column): in the anterior / ventral horn of the gray matter, origin of the motor fibers of the spinal cord nerves