A cranial nerve nucleus is a collection of

neuron A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...

s (

gray matter Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries. Grey matter is distinguis ...

) in the

brain stem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

that is associated with one or more of the

cranial nerves Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...

Axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action po ...

s carrying information to and from the cranial nerves form a

synapse In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from ...

first at these nuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they are associated with. All the nuclei except that of the

trochlear nerve The trochlear nerve (), ( lit. ''pulley-like'' nerve) also known as the fourth cranial nerve, cranial nerve IV, or CN IV, is a cranial nerve that innervates just one muscle: the superior oblique muscle of the eye, which operates through the pul ...

(CN IV) supply nerves of the same side of the body.

Structure

Motor and sensory

In general, motor nuclei are closer to the front (

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...

), and sensory nuclei and neurons are closer to the back (

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

). This arrangement mirrors the arrangement of tracts in the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

. * Close to the midline are the motor efferent nuclei, such as the

oculomotor nucleus The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. From ...

, which control skeletal muscle. Just lateral to this are the autonomic (or visceral) efferent nuclei. * There is a separation, called the

sulcus limitans The sulcus limitans is found in the fourth ventricle of the brain. It separates the cranial nerve motor nuclei (medial) from the sensory nuclei (lateral).Nolte, John. The Human Brain 6th ed. p.685. Mosby Inc. It can also be located by searching ...

, and lateral to this are the sensory nuclei. Near the sulcus limitans are the visceral afferent nuclei, namely the

solitary tract nucleus In the human brainstem, the solitary nucleus, also called nucleus of the solitary tract, nucleus solitarius, and nucleus tractus solitarii, (SN or NTS) is a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column ...

. * More lateral, but also less posterior, are the

general somatic afferent The general somatic afferent fibers (GSA, or somatic sensory fibers) afferent fibers arise from neurons in sensory ganglia and are found in all the spinal nerves, except occasionally the first cervical, and conduct impulses of pain, touch and tempe ...

nuclei. This is the

trigeminal nucleus The sensory trigeminal nerve nuclei are the largest of the cranial nerve nuclei, and extend through the whole of the midbrain, pons and medulla, and into the high cervical spinal cord. The nucleus is divided into three parts, from rostral to caud ...

. Back at the dorsal surface of the brainstem, and more lateral are the

special somatic afferent Special somatic afferent fibers (SSA) are the afferent nerve fibers that carry information from the special senses of vision, hearing and balance. The cranial nerves containing SSA fibers are the optic nerve (II) and the vestibulocochlear nerve (VI ...

s, this handles sensation such as balance. * Another area, not on the dorsum of the brainstem, is where the special visceral efferents nuclei reside. These formed from the

pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arch ...

es, in the embryo. This area is a bit below the autonomic motor nuclei, and includes the

nucleus ambiguus The nucleus ambiguus ("ambiguous nucleus" in English) is a group of large motor neurons, situated deep in the medullary reticular formation named by Jacob Clarke. The nucleus ambiguus contains the cell bodies of neurons that innervate the muscles ...

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of tas ...

nucleus, as well as the motor part of the

trigeminal nerve In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewin ...

nucleus.

Location

This list documents nuclei by the part of the brain they are found in: *

Red nucleus The red nucleus or nucleus ruber is a structure in the rostral midbrain involved in motor coordination. The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. ...

- motor, extrapyramidal *

Trochlear nucleus The nucleus of the trochlear nerve () is located in the midbrain, at an intercollicular level between the superior colliculus and inferior colliculus. It is a motor nucleus, and so is located near the midline, embedded within the medial longitudina ...

(IV) - motor *

Oculomotor nucleus The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. From ...

(III) - motor * Edinger-Westphal nucleus (III) - visceromotor *

Cochlear nuclei The cochlear nuclear (CN) complex comprises two cranial nerve nuclei in the human brainstem, the ventral cochlear nucleus (VCN) and the dorsal cochlear nucleus (DCN). The ventral cochlear nucleus is unlayered whereas the dorsal cochlear nucleus ...

(VIII) - sensory **

Dorsal cochlear nucleus The dorsal cochlear nucleus (DCN, also known as the "tuberculum acusticum"), is a cortex-like structure on the dorso-lateral surface of the brainstem. Along with the ventral cochlear nucleus (VCN), it forms the cochlear nucleus (CN), where all au ...

Ventral cochlear nucleus In the ventral cochlear nucleus (VCN), auditory nerve fibers enter the brain via the nerve root in the VCN. The ventral cochlear nucleus is divided into the anterior ventral (anteroventral) cochlear nucleus (AVCN) and the posterior ventral (poster ...

Vestibular nuclei The vestibular nuclei (VN) are the cranial nuclei for the vestibular nerve located in the brainstem. In Terminologia Anatomica they are grouped in both the pons and the medulla in the brainstem. Structure Path The fibers of the vestibular nerve ...

(VIII) - sensory *

Salivary nuclei The salivatory nuclei are the superior salivatory nucleus, and the inferior salivatory nucleus that innervate the salivary glands. They are located in the pontine tegmentum in the brainstem. They both are examples of cranial nerve nuclei. The sup ...

- visceromotor ** Inferior salivary nucleus (IX) **

Superior salivary nucleus The salivatory nuclei are the superior salivatory nucleus, and the inferior salivatory nucleus that innervate the salivary glands. They are located in the pontine tegmentum in the brainstem. They both are examples of cranial nerve nuclei. The sup ...

(VII) *

Facial nucleus The facial motor nucleus is a nucleus (neuroanatomy), collection of neurons in the brainstem that belong to the facial nerve (cranial nerve VII). These lower motor neurons innervate the muscles of facial expression and the stapedius. Structure Th ...

(VII) - motor *

Abducens nucleus The abducens nucleus is the originating nucleus from which the abducens nerve (VI) emerges—a cranial nerve nucleus. This nucleus is located beneath the fourth ventricle in the Anatomical terms of location, caudal portion of the pons, Anatomical t ...

(VI) - motor *

Trigeminal motor nucleus The trigeminal motor nucleus contains motor neurons that innervate muscles of the first branchial arch, namely the muscles of mastication, the tensor tympani, tensor veli palatini, mylohyoid, and anterior belly of the digastric. This nucleus is l ...

(V) - motor *

Main trigeminal nucleus The principal sensory nucleus of trigeminal nerve (or chief sensory nucleus of V, main trigeminal sensory nucleus) is a group of second-order neurons which have cell bodies in the caudal pons. It receives information about discriminative sensation ...

(V) - sensory (fine touch and vibration) Medulla oblongata - posterior - low mag

Hypoglossal nucleus The hypoglossal nucleus is a cranial nerve nucleus, found within the medulla oblongata, medulla. Being a motor nucleus, it is close to the midline. In the Medulla oblongata#Anatomy, open medulla, it is visible as what is known as the ''hypoglossal ...

(XII) - motor * Dorsal motor nucleus of vagus nerve (X) - visceromotor *

Nucleus ambiguus The nucleus ambiguus ("ambiguous nucleus" in English) is a group of large motor neurons, situated deep in the medullary reticular formation named by Jacob Clarke. The nucleus ambiguus contains the cell bodies of neurons that innervate the muscles ...

(IX, X, XI) - motor *

Solitary nucleus In the human brainstem, the solitary nucleus, also called nucleus of the solitary tract, nucleus solitarius, and nucleus tractus solitarii, (SN or NTS) is a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column ...

(VII, IX, X) - sensory *

Spinal trigeminal nucleus The spinal trigeminal nucleus is a nucleus in the medulla that receives information about deep/crude touch, pain, and temperature from the ipsilateral face. In addition to the trigeminal nerve (CN V), the facial (CN VII), glossopharyngeal (CN IX), ...

(V) - sensory (crude touch, temperature and pain) *

Inferior olivary nucleus The inferior olivary nucleus (ION), is a structure found in the medulla oblongata underneath the superior olivary nucleus.Gado, Thomas A. Woolsey; Joseph Hanaway; Mokhtar H. (2003). The brain atlas a visual guide to the human central nervous syste ...

afferent fibres to cerebellum

Location

References

Lennart Heimer Lennart Heimer (11 March 1930 – 12 March 2007), was a Swedish-American neuroscientist and professor at the Massachusetts Institute of Technology and the University of Virginia. He was most noted for mapping circuits of the brain in the limbic lobe ...

, ''The Human Brain'',

Additional images

File:Gray697.png, Nuclei of origin of cranial motor nerves schematically represented; lateral view. File:Gray698.png, Primary terminal nuclei of the afferent (sensory) cranial nerves schematically represented; lateral view. File:Brain stem sagittal section.svg, Brain stem sagittal section

External links

*
Slides at Colorado College
{{Authority control Brainstem