inferior olivary nucleus

in·fe·ri·or ol·i·var·y nu·cle·us

a large aggregate of small densely packed nerve cells consisting of medial and dorsal accessory olivary nuclei and a principal olivary nucleus that is arranged in folded laminae shaped like a purse with the opening (hilum) directed medially. It corresponds in position to the oliva, projects to all parts of the contralateral half of the cerebellar cortex by way of the olivocerebellar tract, and is the only source of cerebellar climbing fibers. Its afferent connections include fibers from the spinal cord, dentate nucleus, and motor cortex, but its major input appears to be the central tegmental tract originating from multiple nuclei at midbrain levels. Synonym(s): nucleus olivaris inferior

in·fe·ri·or ol·i·var·y nu·cle·us

(in-fēr'ē-ŏr ol'i-var-ē nū'klē-ŭs) A large aggregate of small densely packed nerve cells arranged in folded laminae shaped like a purse with the opening (hilum) directed medially. It corresponds in position to the oliva, projects to all parts of the contralateral half of the cerebellar cortex by way of the olivocerebellar tract, and is the only source of cerebellar climbing fibers. Its afferent connections include fibers from the spinal cord, the dentate nucleus and motor cortex, but its major input appears to be the central tegmental tract originating from multiple nuclei at midbrain levels.

nucleus

(noo'kle-us, nu') (noo'kle-i?, nu') plural.nuclei [L., nucleus, kernel] 1. A central point about which things are clustered.2. The organelle in a eukaryotic cell that contains the chromosomes. Synonym: cell nucleus3. In the central nervous system, a group of neuronal cell bodies that are clustered together and form a coherent demarcated mass in stained brain sections. 4. Atomic nucleus.

nucleus abducens

A nucleus of the somatic motor column in the hindbrain. It lies in the floor of the fourth ventricle near the midline, and it is the origin of the abducens nerve (CN VI).

accessory olivary nucleus

Accessory olive.

nucleus accumbens

A limbic nucleus that sits at the ventral head of the striatum, contiguous with the caudate and putamen and adjacent to the olfactory tubercle. The nucleus accumbens is part of the ventral striatum nuclei. Synapses in the nucleus accumbens use dopamine as their neurotransmitter. Increasing the activity of these synapses (i.e., increasing the level of dopamine in the nucleus) leads to a rewarding or pleasurable sensation. This is thought to partly explain the addictive effect of those drugs, such as cocaine and amphetamine, that increase the level of dopamine in the nucleus accumbens.

nucleus ambiguus

A long, thin nucleus of the branchial motor column in the medulla. It is the origin of motor axons in both the glossopharyngeal and vagus nerves, and its axons innervate the muscles of swallowing and vocalization.

amygdaloid nucleus

Amygdala (2).

angular nucleus

The superior vestibular nucleus. Synonym: Bechterew's nucleus See: vestibular nucleus

anterior thalamic nucleus

The most rostral of the thalamic nuclei. The anterior thalamic nucleus is the only thalamic nucleus that is directly part of the limbic circuitry. This nucleus receives axons from the mammillary body via the mammillothalamic tract, from the hippocampus via the fornix, and from cholinergic nuclei in the basal forebrain. The anterior thalamic nucleus sends axons to medial cerebral cortices: the cingulate gyrus, the anterior limbic area, and the parahippocampal gyrus. See: limbic system for illus

anterior olfactory nucleus

The neurons clustered along the olfactory tract. Some axons from the mitral cells in the olfactory bulb synapse on anterior olfactory neurons, and anterior olfactory neurons contribute axons to the olfactory tract. The anterior olfactory nucleus, which is distinct in most mammals, is sparse in primates.

arcuate nucleus

A hypothalamic nucleus in the ventral wall of the third ventricle near the pituitary stalk. The arcuate nucleus produces inhibiting and releasing factors (adrenocorticotrophic hormone, beta-lipotrophic hormone, and beta-endorphin) for pituitary hormones. Synonym: infundibular nucleus

atomic nucleus

In chemistry, the heavy, positively charged, central part of an atom, which contains protons, neutrons, and most of the atomic mass. Synonym: nucleus (4)

auditory nucleus

A group of neuron cell bodies where the auditory nerves arise.

basal nucleus

Nucleus basalis of Meynert.

nucleus basalis

Nucleus basalis of Meynert.

nucleus basalis of Meynert

See: Meynert, Theodor H.

bed nucleus of the stria terminalis

Any of the many small clusters of neurons on which some axons of the stria terminalis synapse. The bed nuclei lie lateral to the columns of the fornix and dorsal to the anterior commissure.

nucleus of Burdach

See: Burdach, Karl

caudal pontine reticular nucleus

Nucleus reticularis pontis caudalis. See: reticular formation

caudate nucleus

A large basal ganglion nucleus shaped like a tadpole. With its interconnected neighbor, the putamen, the caudate forms a single functional nucleus called the striatum. The caudate lies deep in the cerebral hemisphere; its head forms the base of the anterior horn of the lateral ventricle, and its tail follows the ventricle as it arches over the thalamus and curves down and outward to become the inferior horn of the lateral ventricle, inside the temporal lobe of the cerebral hemisphere. The tip of the tail of the caudate ends alongside the caudal end of the amygdala, and many axons that originate in the amygdala synapse in the caudate and other parts of the striatum. Synonym: nucleus caudatus; intraventricular nucleus

nucleus caudatus

Caudate nucleus.

cell nucleus

Nucleus (2).

central cervical nucleus

A short column of secondary sensory neurons near the midline of the dorsal horn of spinal segments C1-C4. Inputs to the central cervical nucleus include direct dorsal root ganglion axons, and outputs from this nucleus cross the midline and run to the cerebellum.

central nucleus of the thalamus

A group of nuclei in the middle part of the thalamus. Synonym: centromedian nucleus

centromedian nucleus

Central nucleus of the thalamus.

cerebellar nucleus

One of the four deep (i.e., below the cerebellar cortex) nuclei of each half of the cerebellum (from lateral to medial): the dentate, the emboliform, the globose, and the fastigial nuclei.

cervical nucleus

The central or the lateral cervical nucleus.

cochlear nucleus

See: dorsal cochlear nucleus; ventral cochlear nucleus

cranial nerve nucleus

Any of the nuclei of the twelve pairs of nerves that carry signals directly to or from the brain.

cuneate nucleus

A secondary sensory nucleus lateral to the gracile nucleus in the caudal hindbrain near the junction with the spinal cord. Axons of the fasciculus cuneatus in the dorsal columns synapse in this nucleus, and neurons in the nucleus send their axons in the contralateral medial lemniscus to synapse in the ventral posterior lateral (VPL) nucleus of the thalamus. The cuneate nucleus is a waystation for discriminative somatic sensory information from the arm, shoulder, and neck.

cuneiform nucleus

A nucleus in the midbrain reticular formation lying directly under the superior and inferior colliculi. Axons from the cuneiform nucleus project widely, caudally as far as the hindbrain and rostrally as far as the the diencephalon. See: reticular formation

nucleus of Darkschewitsch

A midbrain nucleus in the ventrolateral periaqueductal gray matter, dorsal to the interstitial nucleus of Cajal and rostral to the oculomotor nucleus. The nucleus of Darkschewitsch is one of the accessory oculomotor (preoculomotor) nuclei, which are composed of interneurons concerned with eye movements and reflex gaze coordination and which receive axons from the MLF.

Deiter nucleus

The lateral vestibular nucleus. See: vestibular nucleus

dentate nucleus

The largest and most lateral of the four pairs of deep cerebellar nuclei; in cross-sections it has a serpentine shape. The nucleus receives axons from the cerebellar cortex and from the brainstem, and it sends axons to the red nucleus and the thalamus via the superior cerebellar peduncle.

nucleus of the diagonal band

A collection of large cholinergic neurons intermingled with the diagonal band, an axon tract interconnecting the septal area of the cerebral hemispheres with the substantia innominata. The nucleus of the diagonal band has reciprocal connections with the hippocampus. Like the large cholinergic neurons in the nucleus basalis, the neurons in the nucleus of the diagonal band degenerate if the brain develops Alzheimer's disease.

diploid nucleus

A cell nucleus that contains double the normal number of chromosomes.

dorsal cochlear nucleus

A nucleus of the special sensory column in the hindbrain. It forms a bump (the acoustic tubercle) on the lateral edge of the floor of the fourth ventricle. Axons of the primary sensory cells in the spiral ganglion (in the cochlea of the inner ear) run in the vestibulocochlear nerve (CN VIII) and synapse in the dorsal and ventral cochlear nuclei. About half of the axons from neurons in the cochlear nuclei cross the midline in a tract called the trapezoid body and then join the uncrossed axons from the contralateral cochlear nuclei. Together, these axons ascend in a tract called the lateral lemniscus to synapse in the inferior colliculus in the midbrain.

dorsal nucleus of the lateral lemniscus

One of the two distinguishable nuclei clustered in the upper (rostral) end of the lateral lemniscus near the inferior colliculi. These nuclei are part of the auditory circuitry.

dorsal motor nucleus of the vagus

A nucleus of the visceral motor column in the hindbrain; it lies in the floor of the fourth ventricle lateral to the hypoglossal nucleus. The dorsal motor nucleus of the vagus is the origin of preganglionic parasympathetic axons via which the vagus nerve (CN X) modulates secretory activity in the gastrointestinal system. Synonym: nucleus of the vagus; dorsal nucleus of the vagus

dorsal raphe nucleus

A midbrain nucleus that lies in the midline in the tegmentum, below the periaqueductal gray. It sends serotonergic axons to the striatum via the medial forebrain bundle, and it receives axons from the interpeduncular nucleus. See: raphe nucleus

dorsal nucleus of the vagus

Dorsal motor nucleus of the vagus.

dorsal nucleus of the spinal cord

A column of gray matter lying at the base of the dorsal horn of the gray matter and extending from the seventh cervical to the third lumbar segments. These cells give rise to fibers of the dorsal spinocerebellar tract. Synonym: Clarke's column

dorsolateral septal nucleus

One of the four major septal nuclei.

ectoblastic nucleus

A nucleus in the cells of the epiblast.

Edinger-Westphal nucleus

See: Edinger-Westphal nucleus

emboliform nucleus

A deep nucleus of the cerebellum, lying between the dentate and globose nuclei. Synonym: anterior interposed nucleus; nucleus interpositus anterior

external cuneate nucleus

A secondary sensory nucleus in the caudal hindbrain lying along the lateral edge of the cuneate nucleus. It receives proprioceptive information from the upper half of the body, it is the source of the cuneocerebellar tract, and it is the homologue of the nucleus called "Clarke column", which receives proprioceptive information from the lower half of the body. Synonym: accessory cuneate nucleus; lateral cuneate nucleus

facial motor nucleus

A nucleus of the branchial motor column in the pontine region of the hindbrain. This nucleus is a column of cholinergic neurons in the ventrolateral tegmentum. It is the origin of motor axons in the facial nerve (CN VII), which innervate the muscles of facial expression.

fastigial nucleus

The most medial of the four pairs of deep cerebellar nuclei. The fastigial nucleus receives inputs from the vestibular nuclei and from the medial cerebellar cortex. Outputs from the fastigial nucleus synapse in the vestibular nuclei and the medial part of the hindbrain reticular formation. Synonym: nucleus fastigii

fertilization nucleus

A nucleus produced by the joining of the male and female nuclei in the fertilization of the ovum.

free nucleus

A cell nucleus that is no longer surrounded by the other intracellular components.

nucleus funiculi gracilis

An elongated mass of gray matter in the dorsal pyramid of the medulla oblongata of the brain. Synonym: postpyramidal nucleus

germinal nucleus

A cell nucleus resulting from the union of male and female pronuclei.

gigantocellular reticular nucleus

Nucleus reticularis gigantocellularis.

globose nucleus

A deep nucleus of the cerebellum, lying between the emboliform and fastigial nuclei. Synonym: posterior interposed nucleus

gonad nucleus

Micronucleus (2).

gracile nucleus

A secondary sensory nucleus medial to the cuneate nucleus in the caudal hindbrain near the junction with the spinal cord. Axons of the fasciculus gracilis in dorsal columns synapse in this nucleus, and neurons in the nucleus send their axons in the contralateral medial lemniscus to synapse in the ventral posterior lateral (VPL) nucleus of the thalamus. The gracile nucleus is a way station for discriminative somatic sensory information from the leg and trunk. Synonym: nucleus gracilis

nucleus gracilis

Gracile nucleus.

gustatory nucleus

A nucleus of the visceral sensory column in the hindbrain; it comprises the rostral third of the nucleus of the solitary tract. The gustatory nucleus receives axons carrying sensory information from the taste buds via three cranial nerves, the facial (CN VII), the glossopharyngeal (CN IX), and the vagus (CN X). Axons from the gustatory nucleus synapse in the semilunar nucleus, a component of the ventromedial subdivision of the ventral posterior nucleus of the thalamus.

habenular nucleus

A small set of nuclei in the limbic system found just rostral to the pineal gland in the roof of the third ventricle. The habenula receives axons from the limbic forebrain via a compact tract, the stria medullaris. In turn, the habenula sends a compact bundle of axons, the fasciculus retroflexus (habenulo-interpeduncular tract), to innervate the interpeduncular nuclei of the midbrain. See: limbic system for illus

haploid nucleus

A cell nucleus with half the normal number of chromosomes, as in germ cells (ova and sperm) following the normal reduction divisions in gametogenesis.

hypoglossal nucleus

A nucleus of the somatic motor column, found near the midline in the caudal hindbrain. It innervates all the muscles in the tongue and is the origin of the hypoglossal nerve (CN XII)

hypothalamic nucleus

A set of nuclei in the ventral diencephalon on either side of the lower recess of the third ventricle. These nuclei (a) regulate the preganglionic motor neurons of the sympathetic and parasympathetic nervous systems, (b) control the secretions of the anterior lobe of the pituitary gland, (c) secrete hormones (e.g., oxytocin and vasopressin) through the posterior lobe of the pituitary gland, and (d) modulate the limbic system (e.g., via the mammillary bodies). See: limbic system for illus

inferior olivary nucleus

Inferior olive.

nucleus of the inferior colliculus

A three-part nucleus forming the caudal pair of bulges -- the inferior colliculi -- in the tectum of the midbrain. This nucleus is an auditory relay center: the cochlear and other hindbrain auditory nuclei send information rostrally in the lateral lemniscus, axons of the lateral lemniscus synapse in the inferior colliculus, and axons originating in the inferior colliculus take the brachium of the inferior colliculus rostrally to synapse in the medial geniculate body of the thalamus.

inferior salivatory nucleus

A nucleus of the visceral motor column in the pontine hindbrain just rostral to the medulla. This nucleus is the origin of the preganglionic parasympathetic axons of the glossopharyngeal nerve (CN IX) that synapse in the otic ganglion and regulate secretions of the parotid gland.

inferior vestibular nucleus

One of the four vestibular nuclei in the special sensory column in the hindbrain. It is lateral to the medial vestibular nucleus. It lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum.

infundibular nucleus

Arcuate nucleus.

nucleus intercalatus

A reticular nucleus inside the floor of the fourth ventricle, between the hypoglossal nucleus and the dorsal motor nucleus of the vagus.

interpeduncular nucleus

A ventral nucleus of the midbrain tegmentum lying between the left and right substantia nigrae, which cap the two cerebral peduncles. The interpeduncular nucleus receives axons from the habenula (via the habenulo-interpeduncular tract), and it sends axons dorsally, to the midbrain raphe nuclei. See: limbic system for illus

interphase nucleus

The nucleus of a cell in interphase; typically, the nuclear membrane is visible and undisrupted, and the chromatin is not condensed.

interstitial nucleus of Cajal

A midbrain nucleus found both interspersed among and lateral to the medial longitudinal fasciculus (MLF), just rostral to the oculomotor nucleus. The interstitial nucleus of Cajal is one of the accessory oculomotor (preoculomotor) nuclei, which are composed of interneurons concerned with eye movements and reflex gaze coordination and which receive axons from the MLF.

intraventricular nucleus

Caudate nucleus.

lateral cuneate nucleus

external cuneate nucleus.

lateral geniculate nucleus

The visual relay nucleus of the thalamus. It is a set of nuclei located on the bottom rear edges of the thalamus, lateral to the medial geniculate nucleus. Axons from the retinal ganglion cells of the retina reach the lateral geniculate via the optic nerve and optic tract and then synapse in topographic order. The outflow axons from the lateral geniculate neurons run in the optic radiation and synapse in the primary visual cortex in the occipital hemisphere, again maintaining their topographic organization.

nucleus of the lateral lemniscus

The dorsal or the ventral nucleus of the lateral lemniscus. See: lateral lemniscus under lemniscus

lateral posterior nucleus of the thalamus

A nucleus that lies dorsal to the ventral posterior nucleus. See: thalamic nucleus

lateral reticular nucleus

A reticular nucleus found in the caudal hindbrain. This nucleus receives axons from the spinal cord (via the spinoreticular tract) and from the red nucleus, and it sends axons to the cerebellum.

lateral septal nucleus

A member of the ventral group of nuclei in the septal region of each cerebral hemisphere. The lateral septal nucleus, a part of the limbic system, receives axons from the hippocampus and the hypothalamus and also monoaminergic axons from the brainstem. It sends axons to the hypothalamus, habenula, thalamus, and midbrain. See: limbic system for illus

lateral vestibular nucleus

One of the four vestibular nuclei in the special sensory column in the hindbrain. The lateral vestibular nucleus extends rostrally, beginning near the front end of the inferior vestibular nucleus. It lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum and to all levels of the ipsilateral spinal cord via the vestibulospinal tract. Synonym: Deiter nucleus

lentiform nucleus

The putamen and the globus pallidus considered together. This is an artificial grouping of basal ganglia nuclei determined purely by physical appearance.

nucleus lentis

The core or inner dense section of the crystalline lens.

mammillary nucleus

The lateral, intermediate, or medial mammillary nucleus. See: limbic system for illus

masticatory nucleus

Motor nucleus of the trigeminal nerve (CN V).

medial geniculate nucleus

The auditory relay nucleus of the thalamus. It is on the back undersurface of the thalamus, above the cerebral peduncle. It receives auditory axons from the inferior colliculus, and it sends axons to the auditory cortex (superior temporal gyrus of Heschl [area 41]) in which the neurons are organized according to auditory pitch.

medial mammillary nucleus

The largest of the three mammillary nuclei -- the medial, intermediate, and lateral mammillary nuclei. The medial mammillary nucleus is spherical and nearly fills the mammilary body. The mammillary nuclei -- members of the limbic system -- receive axons from the hippocampus (via the fornix) and the midbrain tementum (via a tract called the mammillary peduncle), and they send axons to the anterior nucleus of the thalamus (via the mammillothalamic tract) and the midbrain tegmentum (via the mammillotegmental tract). See: limbic system for illus

medial septal nucleus

A nucleus alongside the diagonal band in the septal region of each cerebral hemisphere. This nucleus sends axons to and receives axons from the hippocampus, among other brain structures.

medial vestibular nucleus

One of the four vestibular nuclei in the special sensory column in the hindbrain. The medial vestibular nucleus is medial to the inferior vestibular nucleus. It lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum and to the spinal cord via the MLF.

median raphe nucleus

A midline reticular nucleus in the caudal midbrain or rostral pontine tegmentum. This nucleus receives axons from the interpeduncular nucleus, and it sends serotonergic axons to the forebrain limbic areas and to the cerebral cortex via the medial forebrain bundle. Synonym: superior central nucleus

mediodorsalis nucleus of the thalamus

Dorsomedial nucleus of the thalamus

mesencephalic trigeminal nucleus

A nucleus of the general somatic sensory column in the midbrain and rostral hindbrain. It lies in the lateral edge of the gray matter, extending from the cerebral aqueduct to the rostral fourth ventricle. The large unipolar neurons of this nucleus are like dorsal root ganglion neurons, and the mesencephalic trigeminal nucleus contains the only primary sensory neurons found inside the central nervous system. The afferent fibers of this nucleus follow the motor root of the trigeminal nerve (CN V3) to the mouth from which they carry pressure, proprioceptive, stretch, and kinesthetic information; the efferent fibers synapse in the trigeminal motor nucleus.

nucleus of Meynert

Nucleus basalis of Meynert.

mother nucleus

A cell nucleus that divides into two or more parts to form daughter nuclei.

motor nucleus

A nucleus participating in the formation or the execution of the output programs of the central nervous system.

motor nucleus of the trigeminal nerve

Trigeminal motor nucleus. Synonym: masticatory nucleus

noradrenergic nucleus

A nucleus with neurons that use norepinehrine as their neurotransmitter, e.g., the locus coeruleus.

oculomotor nucleus

A nucleus in the grey matter below the cerebral aqueduct in the midbrain at the rostral end of the somatic motor column. It is the origin of the axons that innervate four extraocular eye muscles -- the medial, the inferior, and the superior rectus muscles and the inferior oblique muscle -- via the oculomotor nerve (CN III).

olivary nucleus

The inferior or the superior olive. See: olive

nucleus of origin

When referring to an axon in the central nervous system, the nucleus that contains the neuronal cell body of that axon.

parabigeminal nucleus

Scattered clusters of neurons in the lateral-most edge of the midbrain below (ventral to) the inferior colliculus. The parabigeminal nuclei are satellites of the superior colliculi, and they receive axons from and send axons to the ipsilateral and contralateral superior colliculi.

paramedian reticular nucleus

One of the three major groups of reticular nuclei in the caudal hindbrain.

paraventricular nucleus

A large-celled nucleus beneath the ependymal layer lining the third ventricle in the supraoptic region of the hypothalamus. Axons of the paraventricular nucleus, along with axons from the neighboring supraoptic n., form the supraopticohypophyseal tract. The axons of this tract regulate water balance in the body, secreting vasopressin, the antidiuretic hormone, from their terminals in the posterior lobe of the pituitary gland. Its cells also seem to stimulate the sensation of thirst. Finally, the supraoptic and paraventricular nuclei produce oxytocin, which causes uterine muscle contraction and milk secretion. See: hypothalamic nucleus

phrenic nucleus

A column of motor neurons in the center of the ventral horn of spinal cord segments C3-C7. Axons from this nucleus innervate the muscles of the diaphragm.

pontine nucleus

Any of the neurons interspersed with the corticospinal axons in the ventral pontine hindbrain. The inputs to the pontine nuclei are mainly axons from sesnory and motor areas of the cerebral cortex; the outputs are axons that cross the midline and ascend into the cerebellum via the middle cerebellar peduncle (brachium pontis).

pontine reticular nucleus

Nucleus reticularis pontis.

nucleus of the posterior commissure

Any of the small midbrain nuclei interspersed in the axons of the posterior commissure just rostral to the oculomotor nucleus. The nuclei of the posterior commissure are members of the accessory oculomotor (preoculomotor) nuclei, which are composed of interneurons concerned with eye movements and reflex gaze coordination and which receive axons from the MLF.

posterior interposed nucleus

globose nucleus.

postpyramidal nucleus

Nucleus funiculi gracilis.

preoptic nucleus

A pair of hypothalamic nuclei (medial and lateral) in the most anterior sector -- the preoptic region -- of the wall of the third ventricle. Various parts of these nuclei appear to inhibit arousal during sleep, influence temperature regulation, influence the perception of thirst, regulate the release of gonadotropins from the anterior pituitary (adenohypophysis), and influence sexual behaviors.

nucleus prepositus

A motor processing nucleus in the midline gray matter of the rostral hindbrain. It contains interneurons that coordinate signals destined for the oculomotor, trochlear, and abducens nuclei, i.e., the motor nuclei of the extraocular eye muscles.

pretectal nucleus

One of the motor processing nuclei in the region of the midbrain immediately rostral to the superior colliculus. The nuclei in this region coordinate the output signals for the pupillary light reflex.

principal sensory trigeminal nucleus

The most rostral nucleus of the general somatic sensory column, a long collection of sensory nuclei that extends through the entire hindbrain as a continuation of the dorsal horn nuclei of the spinal cord. The principal sensory trigeminal nucleus receives axons from the trigeminal nerve (CN V) carrying touch, two-point discrimination, and pressure signals from the face and mouth. Like the spinal trigeminal nucleus, the principal sensory trigeminal nucleus sends axons to the ventral posterior nucleus of the thalamus via the medial lemniscus and the spinothalamic tract. In addition, the principal sensory trigeminal nucleus sends axons to the ventral posterior nucleus in a separate tract called the dorsal trigeminal tract.

nucleus proprius

The column of cells comprised by the middle third of the dorsal horn of the spinal cord, Rexed's lamina 4. Neurons in this layer receive dorsal root ganglion cell axons carrying pain and temperature information; many of these neurons send their axons across the midline to join the contralateral spinothalamic tract.

nucleus pulposus

The center cushioning gelatinous mass lying within an intervertebral disk. It is the remnant of the notochord.

pyramidal nucleus

A band of gray matter near the olivary nucleus in the medulla.

raphe nucleus

Any of a set of midline reticular nuclei in the midbrain and hindbrain tegmentum that send serotonergic axons widely throughout the forebrain brain via the medial forebrain bundle. Raphe nuclei appear to regulate sleep and aggressive behavior and to influence pain perception.

nucleus raphe magnus

A raphe nucleus in the rostral medulla.

red nucleus

A pinkish-colored spherical nucleus in the midbrain tegmentum. The red nucleus, a part of the motor system, receives axons from the deep cerebellar nuclei via the superior cerebellar peduncle (brachium conjunctivum) and from the motor areas of the cerebral cortex. It sends axons to the contralateral spinal cord via the rubrospinal tract. Synonym: nucleus ruber

reproductive nucleus

Micronucleus (2).

reticular nucleus

A column of neurons in the spinal cord, brainstem, and thalamus

nucleus reticularis gigantocellularis

A segment of the reticular formation found at the level of the inferior olive in the hindbrain and containing large neurons. Its descending axons contribute to the reticulospinal tract, and activation of this nucleus inhibits motor neuron activity in the spinal cord, e.g., during sleep.

nucleus reticularis lateralis

Lateral reticular nucleus.

nucleus reticularis magnocellularis

Nucleus reticularis gigantocellularis.

nucleus reticularis pontis

Any of the reticular nuclei in the rostral hindbrain, e.g., the nucleus reticularis pontis caudalis.

nucleus reticularis pontis caudalis

A rostral extension of the gigantocellular reticular nucleus of the hindbrain. The nucleus reticularis pontis caudalis sends reticulospinal axons caudally into the spinal cord via the MLF and sends ascending axons as far rostrally as the thalamus via the central tegmental tract.

nucleus reticularis ventralis

A reticular nucleus found in the caudal hindbrain.

reticulotegmental nucleus

A reticular nucleus found at the pontine level of the hindbrain. It receives axons from the cerebral cortex and the cerebellum, and it sends axons to the cerebellum.

nucleus ruber

Red nucleus.

salivatory nucleus

A two-part visceral motor nucleus comprising the superior and the inferior salivatory nuclei.

segmentation nucleus

The cell nucleus of a zygote formed by fusion of the male and female pronuclei.

sensory nucleus

A nucleus participating in the reception or the interpretation of input to the central nervous system.

sensory nucleus of the trigeminal nerve

The principal sensory trigeminal nucleus, the spinal trigeminal nucleus, or the mesencephalic trigeminal nucleus.

septal nucleus

The dorsal, ventral, medial, or caudal septal nucleus. The septal area is the subcallosal area plus the paraterminal gyrus, i.e., the anterior and medial region of the cerebral hemispheres above the lamina terminalis and below (and including) the septum pellucidum. The septal nuclei receive inputs from the hippocampus (via the fornix) and the hypothalamus; the septal nuclei project to the hypothalamus, the habenula, the thalamus, and via the medial forebrain bundle, to the midbrain tegmentum. See: limbic system for illus

sexually dimorphic nucleus

A central nervous system nucleus that has different characteristics (e.g., size or number of cells) in males than in females. One well-studied sexually dimorphic nucleus is found in the preoptic region of the hypothalamus.

solitary nucleus

Nucleus of the solitary tract.

nucleus of the solitary tract

The only brainstem nucleus of the visceral sensory column. It runs the length of the caudal hindbrain in the lateral subventricular gray matter alongside the solitary tract. At the caudal end of the hindbrain, the right and left nuclei of the solitary tract merge in the midline, just dorsal to the central canal, forming the commissural nucleus. The facial (CN VII), the glossopharyngeal (CN IX), and the vagus (CN X) nerves provide the main inputs to the nucleus, bringing information about taste, blood pressure, and blood chemistry. The nucleus then sends information throughout the hindbrain to reflex centers controlling cardiovascular, respiratory, and gastrointestinal homeostasis; the nucleus is also an important source of input to the hypothalamus. Synonym: solitary nucleus

sperm nucleus

The head of the spermatozoon.

spinal accessory nucleus

A branchial motor column nucleus that extends caudally from the end of the nucleus ambiguus into the ventral horn of spinal cord segments C1-C4. Axons of the neurons in the spinal accessory nucleus leave the spinal cord through lateral (not ventral) rootlets and collect into a thin nerve that runs up along the side of the cord and into the skull through the foramen magnum. There, this nerve joins with rootlets from the nucleus ambiguus to form the spinal accessory nerve (CN XI).

spinal trigeminal nucleus

A nucleus of the general somatic sensory column that extends through the entire hindbrain as a continuation of the dorsal horn nuclei of the spinal cord; rostrally the spinal trigeminal nucleus merges into the principal sensory trigeminal nucleus. The spinal trigeminal nucleus receives axons, from the trigeminal nerve (CN V) and other cranial nerves, carrying pain and temperature signals from the face and mouth. This nucleus sends axons to the ventral posterior nucleus of the thalamus via the medial lemniscus and the spinothalamic tract. Synonym: trigeminal spinal nucleus

subcoeruleus nucleus

A reticular nucleus in the pontine hindbrain. Activation of this nucleus appears to be one step in initiating normal REM sleep.

subthalamic nucleus

A basal ganglia nucleus that is found under the thalamus in the base of the diencephalon; it lies between the thalamus and the cerebral peduncle, just rostral to the substantia nigra. The subthalamic nucleus is a satellite of the globus pallidus with which it has reciprocal connections. Lesions of the subthalamic nucleus on one side of the brain produce hemiballismus.

superior central nucleus

Median raphe nucleus.

superior olivary nucleus

Superior olive.

superior salivatory nucleus

A nucleus of the visceral motor column in the pontine hindbrain just rostral to the medulla. This nucleus is the origin of those preganglionic parasympathetic axons of the intermediate nerve (a component of the facial nerve (CN VII)) that synapse in the pterygopalatine ganglion to regulate secretions of the lacrimal and mucosal glands of the nose and mouth and the submandibular ganglion to regulate secretions of the sublingual and submandibular salivary glands.

superior vestibular nucleus

The smallest and most rostral of the four vestibular nuclei, which lie in the special sensory column in the hindbrain. The superior vestibular nucleus lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum.

suprachiasmatic nucleus

A small hypothalamic nucleus lying at the base of the third ventricle, directly above the optic chiasm. This nucleus generates the brain's circadian rhythm. To entrain its rhythm with the natural day-night cycle, the nucleus is innervated by optic axons via the accessory optic tract; it also receives axons from the lateral geniculate nucleus of the thalamus, and serotonergic axons from the midbrain raphe nuclei. The suprachiasmatic nucleus sends most of its axons to the paraventricular nucleus of the hypothalamus.

supraoptic nucleus

A large-celled nucleus of the hypothalamus lying above the rostral ends of the optic tracts and lateral to the optic chiasm. See: paraventricular nucleus

target nucleus

When referring to an axon in the central nervous system, the nucleus that contains the neuronal cell body (or its dendrites) on which that axon synapses.

nucleus of termination

Any of the clusters of cells in the brain and medulla in which fibers of a nerve or nerve tract terminate.

thalamic nucleus

Any of the more than 27 nuclei of the thalamus. The thalamic nuclei are named according to their position in the thalamus, and the medial and dorsal nuclei are separated from the lateral and ventral nuclei by a partitioning layer of axons, called the internal medullary lamina. The thalamic nuclei filter and modify the signals that the nervous system sends to the cerebral cortices. Thalamic nuclei can be divided into five groups by their patterns of connectivity: (a) The nuclei in the base of the thalamus -- the ventroposterior (also called, ventrobasal), the lateral geniculate, and the medial geniculate nuclei -- receive all the sensory information from the body, except olfaction, and send information to the primary sensory areas of the cerebral cortices. (b) The ventral anterior and ventral lateral nuclei (the VA-VL complex) receive motor programs from the globus pallidus (of the basal ganglia) and the cerebellum and send information to the motor areas of the cerebral cortices. (c) The dorsomedial nucleus, the lateral posterior and lateral dorsal nuclei, and the pulvinar nucleus receive information from the association areas of the cerebral cortices and from noncortical regions of the brain and send information back to the association cortices. (d) The anterior nucleus -- part of the limbic circuitry -- receives information from the mammillary body and from the fornix and sends information to the cingulate gyrus of the cerebral cortex. (e) The small nuclei in the internal medullary lamina (intralaminar nuclei) and the nuclei along the midline of the thalamus receive information from the cerbral cortices, the cererebellum, the reticular formation, and elsewhere and send information widely throughout the cerebral cortices.

thoracic nucleus

A column of large neurons in the posterior gray column of the spinal cord. These cells give rise to the dorsal spinocerebellar tract on the same side.

nucleus of the tractus solitarius

Nucleus of the solitary tract. See: tractus solitarius under tractus

nucleus of the trapezoid body

Clusters of neurons in the trapezoid body in the hindbrain. Some axons crossing the midline through the trapezoid body synapse locally on these neurons.

trigeminal mesencephalic nucleus

Mesencephalic trigeminal nucleus.

trigeminal motor nucleus

A nucleus of the branchial motor column in the rostral hindbrain. It is found in the ventral pontine tegmentum between the spinal trigeminal nucleus and the superior olive. It is the origin of motor axons in the mandibular division of the trigeminal nerve (CN V3), and its axons innervate the muscles of mastication and the tensor tympani (a middle ear muscle).

trigeminal sensory nucleus

The mesencephalic trigeminal nucleus, the principal sensory trigeminal nucleus, or the spinal trigeminal nucleus.

trigeminal spinal nucleus

spinal trigeminal nucleus.

trochlear nucleus

A nucleus of the somatic motor column in the hindbrain. It is a small midbrain nucleus sitting atop the MLF just caudal to the oculomotor nucleus, and it is the origin of the trochlear nerve (CN VI).

tuberal nucleus

The lateral, medial, anterior, or posterior tuberal nucleus in the hypothalamus.

tuberomammillary nucleus

A hypothalamic nucleus found just lateral to the medial mammillary nucleus. It is characterized by histaminergic axons that widely and diffusely innervate the entire brain. Neurons of this nucleus fire regularly when a person is awake and rarely during sleep. Stimulation of the tuberomammillary nucleus raises blood pressure and heart rate.

nucleus of the vagus

The dorsal motor nucleus of the vagus.

ventral cochlear nucleus

A nucleus of the special sensory column in the hindbrain; it forms a bulge around the entering cochlear nerve. Axons of the primary sensory cells in the spiral ganglion (in the cochlea of the inner ear) run in the vestibulocochlear nerve (CN VIII) and synapse in the dorsal and ventral cochlear nuclei. About half of the axons from neurons in the cochlear nuclei cross the midline in a tract called the trapezoid body and join the uncrossed axons from the contralateral cochlear nuclei. Together, these axons ascend in a tract called the lateral lemniscus to synapse in the inferior colliculus in the midbrain.

ventral nucleus of the lateral lemniscus

One of the two distinguishable nuclei clustered in the upper (rostral) end of the lateral lemniscus near the inferior colliculi. These nuclei are part of the auditory circuitry.

ventral posterior nucleus of the thalamus

The ventral posterior lateral or the ventral posterior medial nucleus of the thalamus. Synonym: ventrobasal nucleus of the thalamus

ventral posterior lateral nucleus of the thalamus

One of the two major divisions of the ventral posterior nucleus, the somatic sensory relay nucleus of the thalamus. The ventral posterior lateral nucleus is the target of the medial lemniscus (touch and position sense from the body) and of many spinothalamic tract axons, and it sends axons to the sensory areas of the cerebral cortices.

ventral posterior medial nucleus of the thalamus

Abbreviation: VPM
One of the two major divisions of the ventral posterior nucleus, the somatic sensory relay nucleus of the thalamus. The ventral posterior medial nucleus is the target of the trigeminal lemniscus (somatic sensory information from the face and intraoral regions), and it sends axons to the sensory areas of the cerebral cortices.

ventral nucleus of the thalamus

The ventral anterior, ventral lateral, entral posterior medial, or ventral posterior lateral nucleus.

ventrobasal nucleus of the thalamus

Ventral posterior nucleus of the thalamus.

vesicular nucleus

A cell nucleus having a deeply staining membrane and a pale center.

vestibular nucleus

The inferior, lateral, medial, or superior vestibular nucleus.

vitelline nucleus

A cell nucleus formed by union of male and female pronuclei within the vitellus. It is a part of the cytoplasm of an ovum in which the initial process of accumulation of food supplies is probably located. Synonym: yolk nucleus

yolk nucleus

Vitelline nucleus.

单词	inferior olivary nucleus
释义	DictionarySeenucleus inferior olivary nucleus in·fe·ri·or ol·i·var·y nu·cle·us a large aggregate of small densely packed nerve cells consisting of medial and dorsal accessory olivary nuclei and a principal olivary nucleus that is arranged in folded laminae shaped like a purse with the opening (hilum) directed medially. It corresponds in position to the oliva, projects to all parts of the contralateral half of the cerebellar cortex by way of the olivocerebellar tract, and is the only source of cerebellar climbing fibers. Its afferent connections include fibers from the spinal cord, dentate nucleus, and motor cortex, but its major input appears to be the central tegmental tract originating from multiple nuclei at midbrain levels. Synonym(s): nucleus olivaris inferior in·fe·ri·or ol·i·var·y nu·cle·us (in-fēr'ē-ŏr ol'i-var-ē nū'klē-ŭs) A large aggregate of small densely packed nerve cells arranged in folded laminae shaped like a purse with the opening (hilum) directed medially. It corresponds in position to the oliva, projects to all parts of the contralateral half of the cerebellar cortex by way of the olivocerebellar tract, and is the only source of cerebellar climbing fibers. Its afferent connections include fibers from the spinal cord, the dentate nucleus and motor cortex, but its major input appears to be the central tegmental tract originating from multiple nuclei at midbrain levels. nucleus (noo'kle-us, nu') (noo'kle-i?, nu') plural.nuclei [L., nucleus, kernel] 1. A central point about which things are clustered.2. The organelle in a eukaryotic cell that contains the chromosomes. Synonym: cell nucleus3. In the central nervous system, a group of neuronal cell bodies that are clustered together and form a coherent demarcated mass in stained brain sections. 4. Atomic nucleus. nucleus abducens A nucleus of the somatic motor column in the hindbrain. It lies in the floor of the fourth ventricle near the midline, and it is the origin of the abducens nerve (CN VI). accessory olivary nucleus Accessory olive. nucleus accumbens A limbic nucleus that sits at the ventral head of the striatum, contiguous with the caudate and putamen and adjacent to the olfactory tubercle. The nucleus accumbens is part of the ventral striatum nuclei. Synapses in the nucleus accumbens use dopamine as their neurotransmitter. Increasing the activity of these synapses (i.e., increasing the level of dopamine in the nucleus) leads to a rewarding or pleasurable sensation. This is thought to partly explain the addictive effect of those drugs, such as cocaine and amphetamine, that increase the level of dopamine in the nucleus accumbens. nucleus ambiguus A long, thin nucleus of the branchial motor column in the medulla. It is the origin of motor axons in both the glossopharyngeal and vagus nerves, and its axons innervate the muscles of swallowing and vocalization. amygdaloid nucleus Amygdala (2). angular nucleus The superior vestibular nucleus. Synonym: Bechterew's nucleus See: vestibular nucleus anterior thalamic nucleus The most rostral of the thalamic nuclei. The anterior thalamic nucleus is the only thalamic nucleus that is directly part of the limbic circuitry. This nucleus receives axons from the mammillary body via the mammillothalamic tract, from the hippocampus via the fornix, and from cholinergic nuclei in the basal forebrain. The anterior thalamic nucleus sends axons to medial cerebral cortices: the cingulate gyrus, the anterior limbic area, and the parahippocampal gyrus. See: limbic system for illus anterior olfactory nucleus The neurons clustered along the olfactory tract. Some axons from the mitral cells in the olfactory bulb synapse on anterior olfactory neurons, and anterior olfactory neurons contribute axons to the olfactory tract. The anterior olfactory nucleus, which is distinct in most mammals, is sparse in primates. arcuate nucleus A hypothalamic nucleus in the ventral wall of the third ventricle near the pituitary stalk. The arcuate nucleus produces inhibiting and releasing factors (adrenocorticotrophic hormone, beta-lipotrophic hormone, and beta-endorphin) for pituitary hormones. Synonym: infundibular nucleus atomic nucleus In chemistry, the heavy, positively charged, central part of an atom, which contains protons, neutrons, and most of the atomic mass. Synonym: nucleus (4) auditory nucleus A group of neuron cell bodies where the auditory nerves arise. basal nucleus Nucleus basalis of Meynert. nucleus basalis Nucleus basalis of Meynert. nucleus basalis of Meynert See: Meynert, Theodor H. bed nucleus of the stria terminalis Any of the many small clusters of neurons on which some axons of the stria terminalis synapse. The bed nuclei lie lateral to the columns of the fornix and dorsal to the anterior commissure. nucleus of Burdach See: Burdach, Karl caudal pontine reticular nucleus Nucleus reticularis pontis caudalis. See: reticular formation caudate nucleus A large basal ganglion nucleus shaped like a tadpole. With its interconnected neighbor, the putamen, the caudate forms a single functional nucleus called the striatum. The caudate lies deep in the cerebral hemisphere; its head forms the base of the anterior horn of the lateral ventricle, and its tail follows the ventricle as it arches over the thalamus and curves down and outward to become the inferior horn of the lateral ventricle, inside the temporal lobe of the cerebral hemisphere. The tip of the tail of the caudate ends alongside the caudal end of the amygdala, and many axons that originate in the amygdala synapse in the caudate and other parts of the striatum. Synonym: nucleus caudatus; intraventricular nucleus nucleus caudatus Caudate nucleus. cell nucleus Nucleus (2). central cervical nucleus A short column of secondary sensory neurons near the midline of the dorsal horn of spinal segments C1-C4. Inputs to the central cervical nucleus include direct dorsal root ganglion axons, and outputs from this nucleus cross the midline and run to the cerebellum. central nucleus of the thalamus A group of nuclei in the middle part of the thalamus. Synonym: centromedian nucleus centromedian nucleus Central nucleus of the thalamus. cerebellar nucleus One of the four deep (i.e., below the cerebellar cortex) nuclei of each half of the cerebellum (from lateral to medial): the dentate, the emboliform, the globose, and the fastigial nuclei. cervical nucleus The central or the lateral cervical nucleus. cochlear nucleus See: dorsal cochlear nucleus; ventral cochlear nucleus cranial nerve nucleus Any of the nuclei of the twelve pairs of nerves that carry signals directly to or from the brain. cuneate nucleus A secondary sensory nucleus lateral to the gracile nucleus in the caudal hindbrain near the junction with the spinal cord. Axons of the fasciculus cuneatus in the dorsal columns synapse in this nucleus, and neurons in the nucleus send their axons in the contralateral medial lemniscus to synapse in the ventral posterior lateral (VPL) nucleus of the thalamus. The cuneate nucleus is a waystation for discriminative somatic sensory information from the arm, shoulder, and neck. cuneiform nucleus A nucleus in the midbrain reticular formation lying directly under the superior and inferior colliculi. Axons from the cuneiform nucleus project widely, caudally as far as the hindbrain and rostrally as far as the the diencephalon. See: reticular formation nucleus of Darkschewitsch A midbrain nucleus in the ventrolateral periaqueductal gray matter, dorsal to the interstitial nucleus of Cajal and rostral to the oculomotor nucleus. The nucleus of Darkschewitsch is one of the accessory oculomotor (preoculomotor) nuclei, which are composed of interneurons concerned with eye movements and reflex gaze coordination and which receive axons from the MLF. Deiter nucleus The lateral vestibular nucleus. See: vestibular nucleus dentate nucleus The largest and most lateral of the four pairs of deep cerebellar nuclei; in cross-sections it has a serpentine shape. The nucleus receives axons from the cerebellar cortex and from the brainstem, and it sends axons to the red nucleus and the thalamus via the superior cerebellar peduncle. nucleus of the diagonal band A collection of large cholinergic neurons intermingled with the diagonal band, an axon tract interconnecting the septal area of the cerebral hemispheres with the substantia innominata. The nucleus of the diagonal band has reciprocal connections with the hippocampus. Like the large cholinergic neurons in the nucleus basalis, the neurons in the nucleus of the diagonal band degenerate if the brain develops Alzheimer's disease. diploid nucleus A cell nucleus that contains double the normal number of chromosomes. dorsal cochlear nucleus A nucleus of the special sensory column in the hindbrain. It forms a bump (the acoustic tubercle) on the lateral edge of the floor of the fourth ventricle. Axons of the primary sensory cells in the spiral ganglion (in the cochlea of the inner ear) run in the vestibulocochlear nerve (CN VIII) and synapse in the dorsal and ventral cochlear nuclei. About half of the axons from neurons in the cochlear nuclei cross the midline in a tract called the trapezoid body and then join the uncrossed axons from the contralateral cochlear nuclei. Together, these axons ascend in a tract called the lateral lemniscus to synapse in the inferior colliculus in the midbrain. dorsal nucleus of the lateral lemniscus One of the two distinguishable nuclei clustered in the upper (rostral) end of the lateral lemniscus near the inferior colliculi. These nuclei are part of the auditory circuitry. dorsal motor nucleus of the vagus A nucleus of the visceral motor column in the hindbrain; it lies in the floor of the fourth ventricle lateral to the hypoglossal nucleus. The dorsal motor nucleus of the vagus is the origin of preganglionic parasympathetic axons via which the vagus nerve (CN X) modulates secretory activity in the gastrointestinal system. Synonym: nucleus of the vagus; dorsal nucleus of the vagus dorsal raphe nucleus A midbrain nucleus that lies in the midline in the tegmentum, below the periaqueductal gray. It sends serotonergic axons to the striatum via the medial forebrain bundle, and it receives axons from the interpeduncular nucleus. See: raphe nucleus dorsal nucleus of the vagus Dorsal motor nucleus of the vagus. dorsal nucleus of the spinal cord A column of gray matter lying at the base of the dorsal horn of the gray matter and extending from the seventh cervical to the third lumbar segments. These cells give rise to fibers of the dorsal spinocerebellar tract. Synonym: Clarke's column dorsolateral septal nucleus One of the four major septal nuclei. ectoblastic nucleus A nucleus in the cells of the epiblast. Edinger-Westphal nucleus See: Edinger-Westphal nucleus emboliform nucleus A deep nucleus of the cerebellum, lying between the dentate and globose nuclei. Synonym: anterior interposed nucleus; nucleus interpositus anterior external cuneate nucleus A secondary sensory nucleus in the caudal hindbrain lying along the lateral edge of the cuneate nucleus. It receives proprioceptive information from the upper half of the body, it is the source of the cuneocerebellar tract, and it is the homologue of the nucleus called "Clarke column", which receives proprioceptive information from the lower half of the body. Synonym: accessory cuneate nucleus; lateral cuneate nucleus facial motor nucleus A nucleus of the branchial motor column in the pontine region of the hindbrain. This nucleus is a column of cholinergic neurons in the ventrolateral tegmentum. It is the origin of motor axons in the facial nerve (CN VII), which innervate the muscles of facial expression. fastigial nucleus The most medial of the four pairs of deep cerebellar nuclei. The fastigial nucleus receives inputs from the vestibular nuclei and from the medial cerebellar cortex. Outputs from the fastigial nucleus synapse in the vestibular nuclei and the medial part of the hindbrain reticular formation. Synonym: nucleus fastigii fertilization nucleus A nucleus produced by the joining of the male and female nuclei in the fertilization of the ovum. free nucleus A cell nucleus that is no longer surrounded by the other intracellular components. nucleus funiculi gracilis An elongated mass of gray matter in the dorsal pyramid of the medulla oblongata of the brain. Synonym: postpyramidal nucleus germinal nucleus A cell nucleus resulting from the union of male and female pronuclei. gigantocellular reticular nucleus Nucleus reticularis gigantocellularis. globose nucleus A deep nucleus of the cerebellum, lying between the emboliform and fastigial nuclei. Synonym: posterior interposed nucleus gonad nucleus Micronucleus (2). gracile nucleus A secondary sensory nucleus medial to the cuneate nucleus in the caudal hindbrain near the junction with the spinal cord. Axons of the fasciculus gracilis in dorsal columns synapse in this nucleus, and neurons in the nucleus send their axons in the contralateral medial lemniscus to synapse in the ventral posterior lateral (VPL) nucleus of the thalamus. The gracile nucleus is a way station for discriminative somatic sensory information from the leg and trunk. Synonym: nucleus gracilis nucleus gracilis Gracile nucleus. gustatory nucleus A nucleus of the visceral sensory column in the hindbrain; it comprises the rostral third of the nucleus of the solitary tract. The gustatory nucleus receives axons carrying sensory information from the taste buds via three cranial nerves, the facial (CN VII), the glossopharyngeal (CN IX), and the vagus (CN X). Axons from the gustatory nucleus synapse in the semilunar nucleus, a component of the ventromedial subdivision of the ventral posterior nucleus of the thalamus. habenular nucleus A small set of nuclei in the limbic system found just rostral to the pineal gland in the roof of the third ventricle. The habenula receives axons from the limbic forebrain via a compact tract, the stria medullaris. In turn, the habenula sends a compact bundle of axons, the fasciculus retroflexus (habenulo-interpeduncular tract), to innervate the interpeduncular nuclei of the midbrain. See: limbic system for illus haploid nucleus A cell nucleus with half the normal number of chromosomes, as in germ cells (ova and sperm) following the normal reduction divisions in gametogenesis. hypoglossal nucleus A nucleus of the somatic motor column, found near the midline in the caudal hindbrain. It innervates all the muscles in the tongue and is the origin of the hypoglossal nerve (CN XII) hypothalamic nucleus A set of nuclei in the ventral diencephalon on either side of the lower recess of the third ventricle. These nuclei (a) regulate the preganglionic motor neurons of the sympathetic and parasympathetic nervous systems, (b) control the secretions of the anterior lobe of the pituitary gland, (c) secrete hormones (e.g., oxytocin and vasopressin) through the posterior lobe of the pituitary gland, and (d) modulate the limbic system (e.g., via the mammillary bodies). See: limbic system for illus inferior olivary nucleus Inferior olive. nucleus of the inferior colliculus A three-part nucleus forming the caudal pair of bulges -- the inferior colliculi -- in the tectum of the midbrain. This nucleus is an auditory relay center: the cochlear and other hindbrain auditory nuclei send information rostrally in the lateral lemniscus, axons of the lateral lemniscus synapse in the inferior colliculus, and axons originating in the inferior colliculus take the brachium of the inferior colliculus rostrally to synapse in the medial geniculate body of the thalamus. inferior salivatory nucleus A nucleus of the visceral motor column in the pontine hindbrain just rostral to the medulla. This nucleus is the origin of the preganglionic parasympathetic axons of the glossopharyngeal nerve (CN IX) that synapse in the otic ganglion and regulate secretions of the parotid gland. inferior vestibular nucleus One of the four vestibular nuclei in the special sensory column in the hindbrain. It is lateral to the medial vestibular nucleus. It lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum. infundibular nucleus Arcuate nucleus. nucleus intercalatus A reticular nucleus inside the floor of the fourth ventricle, between the hypoglossal nucleus and the dorsal motor nucleus of the vagus. interpeduncular nucleus A ventral nucleus of the midbrain tegmentum lying between the left and right substantia nigrae, which cap the two cerebral peduncles. The interpeduncular nucleus receives axons from the habenula (via the habenulo-interpeduncular tract), and it sends axons dorsally, to the midbrain raphe nuclei. See: limbic system for illus interphase nucleus The nucleus of a cell in interphase; typically, the nuclear membrane is visible and undisrupted, and the chromatin is not condensed. interstitial nucleus of Cajal A midbrain nucleus found both interspersed among and lateral to the medial longitudinal fasciculus (MLF), just rostral to the oculomotor nucleus. The interstitial nucleus of Cajal is one of the accessory oculomotor (preoculomotor) nuclei, which are composed of interneurons concerned with eye movements and reflex gaze coordination and which receive axons from the MLF. intraventricular nucleus Caudate nucleus. lateral cuneate nucleus external cuneate nucleus. lateral geniculate nucleus The visual relay nucleus of the thalamus. It is a set of nuclei located on the bottom rear edges of the thalamus, lateral to the medial geniculate nucleus. Axons from the retinal ganglion cells of the retina reach the lateral geniculate via the optic nerve and optic tract and then synapse in topographic order. The outflow axons from the lateral geniculate neurons run in the optic radiation and synapse in the primary visual cortex in the occipital hemisphere, again maintaining their topographic organization. nucleus of the lateral lemniscus The dorsal or the ventral nucleus of the lateral lemniscus. See: lateral lemniscus under lemniscus lateral posterior nucleus of the thalamus A nucleus that lies dorsal to the ventral posterior nucleus. See: thalamic nucleus lateral reticular nucleus A reticular nucleus found in the caudal hindbrain. This nucleus receives axons from the spinal cord (via the spinoreticular tract) and from the red nucleus, and it sends axons to the cerebellum. lateral septal nucleus A member of the ventral group of nuclei in the septal region of each cerebral hemisphere. The lateral septal nucleus, a part of the limbic system, receives axons from the hippocampus and the hypothalamus and also monoaminergic axons from the brainstem. It sends axons to the hypothalamus, habenula, thalamus, and midbrain. See: limbic system for illus lateral vestibular nucleus One of the four vestibular nuclei in the special sensory column in the hindbrain. The lateral vestibular nucleus extends rostrally, beginning near the front end of the inferior vestibular nucleus. It lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum and to all levels of the ipsilateral spinal cord via the vestibulospinal tract. Synonym: Deiter nucleus lentiform nucleus The putamen and the globus pallidus considered together. This is an artificial grouping of basal ganglia nuclei determined purely by physical appearance. nucleus lentis The core or inner dense section of the crystalline lens. mammillary nucleus The lateral, intermediate, or medial mammillary nucleus. See: limbic system for illus masticatory nucleus Motor nucleus of the trigeminal nerve (CN V). medial geniculate nucleus The auditory relay nucleus of the thalamus. It is on the back undersurface of the thalamus, above the cerebral peduncle. It receives auditory axons from the inferior colliculus, and it sends axons to the auditory cortex (superior temporal gyrus of Heschl [area 41]) in which the neurons are organized according to auditory pitch. medial mammillary nucleus The largest of the three mammillary nuclei -- the medial, intermediate, and lateral mammillary nuclei. The medial mammillary nucleus is spherical and nearly fills the mammilary body. The mammillary nuclei -- members of the limbic system -- receive axons from the hippocampus (via the fornix) and the midbrain tementum (via a tract called the mammillary peduncle), and they send axons to the anterior nucleus of the thalamus (via the mammillothalamic tract) and the midbrain tegmentum (via the mammillotegmental tract). See: limbic system for illus medial septal nucleus A nucleus alongside the diagonal band in the septal region of each cerebral hemisphere. This nucleus sends axons to and receives axons from the hippocampus, among other brain structures. medial vestibular nucleus One of the four vestibular nuclei in the special sensory column in the hindbrain. The medial vestibular nucleus is medial to the inferior vestibular nucleus. It lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum and to the spinal cord via the MLF. median raphe nucleus A midline reticular nucleus in the caudal midbrain or rostral pontine tegmentum. This nucleus receives axons from the interpeduncular nucleus, and it sends serotonergic axons to the forebrain limbic areas and to the cerebral cortex via the medial forebrain bundle. Synonym: superior central nucleus mediodorsalis nucleus of the thalamus Dorsomedial nucleus of the thalamus mesencephalic trigeminal nucleus A nucleus of the general somatic sensory column in the midbrain and rostral hindbrain. It lies in the lateral edge of the gray matter, extending from the cerebral aqueduct to the rostral fourth ventricle. The large unipolar neurons of this nucleus are like dorsal root ganglion neurons, and the mesencephalic trigeminal nucleus contains the only primary sensory neurons found inside the central nervous system. The afferent fibers of this nucleus follow the motor root of the trigeminal nerve (CN V3) to the mouth from which they carry pressure, proprioceptive, stretch, and kinesthetic information; the efferent fibers synapse in the trigeminal motor nucleus. nucleus of Meynert Nucleus basalis of Meynert. mother nucleus A cell nucleus that divides into two or more parts to form daughter nuclei. motor nucleus A nucleus participating in the formation or the execution of the output programs of the central nervous system. motor nucleus of the trigeminal nerve Trigeminal motor nucleus. Synonym: masticatory nucleus noradrenergic nucleus A nucleus with neurons that use norepinehrine as their neurotransmitter, e.g., the locus coeruleus. oculomotor nucleus A nucleus in the grey matter below the cerebral aqueduct in the midbrain at the rostral end of the somatic motor column. It is the origin of the axons that innervate four extraocular eye muscles -- the medial, the inferior, and the superior rectus muscles and the inferior oblique muscle -- via the oculomotor nerve (CN III). olivary nucleus The inferior or the superior olive. See: olive nucleus of origin When referring to an axon in the central nervous system, the nucleus that contains the neuronal cell body of that axon. parabigeminal nucleus Scattered clusters of neurons in the lateral-most edge of the midbrain below (ventral to) the inferior colliculus. The parabigeminal nuclei are satellites of the superior colliculi, and they receive axons from and send axons to the ipsilateral and contralateral superior colliculi. paramedian reticular nucleus One of the three major groups of reticular nuclei in the caudal hindbrain. paraventricular nucleus A large-celled nucleus beneath the ependymal layer lining the third ventricle in the supraoptic region of the hypothalamus. Axons of the paraventricular nucleus, along with axons from the neighboring supraoptic n., form the supraopticohypophyseal tract. The axons of this tract regulate water balance in the body, secreting vasopressin, the antidiuretic hormone, from their terminals in the posterior lobe of the pituitary gland. Its cells also seem to stimulate the sensation of thirst. Finally, the supraoptic and paraventricular nuclei produce oxytocin, which causes uterine muscle contraction and milk secretion. See: hypothalamic nucleus phrenic nucleus A column of motor neurons in the center of the ventral horn of spinal cord segments C3-C7. Axons from this nucleus innervate the muscles of the diaphragm. pontine nucleus Any of the neurons interspersed with the corticospinal axons in the ventral pontine hindbrain. The inputs to the pontine nuclei are mainly axons from sesnory and motor areas of the cerebral cortex; the outputs are axons that cross the midline and ascend into the cerebellum via the middle cerebellar peduncle (brachium pontis). pontine reticular nucleus Nucleus reticularis pontis. nucleus of the posterior commissure Any of the small midbrain nuclei interspersed in the axons of the posterior commissure just rostral to the oculomotor nucleus. The nuclei of the posterior commissure are members of the accessory oculomotor (preoculomotor) nuclei, which are composed of interneurons concerned with eye movements and reflex gaze coordination and which receive axons from the MLF. posterior interposed nucleus globose nucleus. postpyramidal nucleus Nucleus funiculi gracilis. preoptic nucleus A pair of hypothalamic nuclei (medial and lateral) in the most anterior sector -- the preoptic region -- of the wall of the third ventricle. Various parts of these nuclei appear to inhibit arousal during sleep, influence temperature regulation, influence the perception of thirst, regulate the release of gonadotropins from the anterior pituitary (adenohypophysis), and influence sexual behaviors. nucleus prepositus A motor processing nucleus in the midline gray matter of the rostral hindbrain. It contains interneurons that coordinate signals destined for the oculomotor, trochlear, and abducens nuclei, i.e., the motor nuclei of the extraocular eye muscles. pretectal nucleus One of the motor processing nuclei in the region of the midbrain immediately rostral to the superior colliculus. The nuclei in this region coordinate the output signals for the pupillary light reflex. principal sensory trigeminal nucleus The most rostral nucleus of the general somatic sensory column, a long collection of sensory nuclei that extends through the entire hindbrain as a continuation of the dorsal horn nuclei of the spinal cord. The principal sensory trigeminal nucleus receives axons from the trigeminal nerve (CN V) carrying touch, two-point discrimination, and pressure signals from the face and mouth. Like the spinal trigeminal nucleus, the principal sensory trigeminal nucleus sends axons to the ventral posterior nucleus of the thalamus via the medial lemniscus and the spinothalamic tract. In addition, the principal sensory trigeminal nucleus sends axons to the ventral posterior nucleus in a separate tract called the dorsal trigeminal tract. nucleus proprius The column of cells comprised by the middle third of the dorsal horn of the spinal cord, Rexed's lamina 4. Neurons in this layer receive dorsal root ganglion cell axons carrying pain and temperature information; many of these neurons send their axons across the midline to join the contralateral spinothalamic tract. nucleus pulposus The center cushioning gelatinous mass lying within an intervertebral disk. It is the remnant of the notochord. pyramidal nucleus A band of gray matter near the olivary nucleus in the medulla. raphe nucleus Any of a set of midline reticular nuclei in the midbrain and hindbrain tegmentum that send serotonergic axons widely throughout the forebrain brain via the medial forebrain bundle. Raphe nuclei appear to regulate sleep and aggressive behavior and to influence pain perception. nucleus raphe magnus A raphe nucleus in the rostral medulla. red nucleus A pinkish-colored spherical nucleus in the midbrain tegmentum. The red nucleus, a part of the motor system, receives axons from the deep cerebellar nuclei via the superior cerebellar peduncle (brachium conjunctivum) and from the motor areas of the cerebral cortex. It sends axons to the contralateral spinal cord via the rubrospinal tract. Synonym: nucleus ruber reproductive nucleus Micronucleus (2). reticular nucleus A column of neurons in the spinal cord, brainstem, and thalamus nucleus reticularis gigantocellularis A segment of the reticular formation found at the level of the inferior olive in the hindbrain and containing large neurons. Its descending axons contribute to the reticulospinal tract, and activation of this nucleus inhibits motor neuron activity in the spinal cord, e.g., during sleep. nucleus reticularis lateralis Lateral reticular nucleus. nucleus reticularis magnocellularis Nucleus reticularis gigantocellularis. nucleus reticularis pontis Any of the reticular nuclei in the rostral hindbrain, e.g., the nucleus reticularis pontis caudalis. nucleus reticularis pontis caudalis A rostral extension of the gigantocellular reticular nucleus of the hindbrain. The nucleus reticularis pontis caudalis sends reticulospinal axons caudally into the spinal cord via the MLF and sends ascending axons as far rostrally as the thalamus via the central tegmental tract. nucleus reticularis ventralis A reticular nucleus found in the caudal hindbrain. reticulotegmental nucleus A reticular nucleus found at the pontine level of the hindbrain. It receives axons from the cerebral cortex and the cerebellum, and it sends axons to the cerebellum. nucleus ruber Red nucleus. salivatory nucleus A two-part visceral motor nucleus comprising the superior and the inferior salivatory nuclei. segmentation nucleus The cell nucleus of a zygote formed by fusion of the male and female pronuclei. sensory nucleus A nucleus participating in the reception or the interpretation of input to the central nervous system. sensory nucleus of the trigeminal nerve The principal sensory trigeminal nucleus, the spinal trigeminal nucleus, or the mesencephalic trigeminal nucleus. septal nucleus The dorsal, ventral, medial, or caudal septal nucleus. The septal area is the subcallosal area plus the paraterminal gyrus, i.e., the anterior and medial region of the cerebral hemispheres above the lamina terminalis and below (and including) the septum pellucidum. The septal nuclei receive inputs from the hippocampus (via the fornix) and the hypothalamus; the septal nuclei project to the hypothalamus, the habenula, the thalamus, and via the medial forebrain bundle, to the midbrain tegmentum. See: limbic system for illus sexually dimorphic nucleus A central nervous system nucleus that has different characteristics (e.g., size or number of cells) in males than in females. One well-studied sexually dimorphic nucleus is found in the preoptic region of the hypothalamus. solitary nucleus Nucleus of the solitary tract. nucleus of the solitary tract The only brainstem nucleus of the visceral sensory column. It runs the length of the caudal hindbrain in the lateral subventricular gray matter alongside the solitary tract. At the caudal end of the hindbrain, the right and left nuclei of the solitary tract merge in the midline, just dorsal to the central canal, forming the commissural nucleus. The facial (CN VII), the glossopharyngeal (CN IX), and the vagus (CN X) nerves provide the main inputs to the nucleus, bringing information about taste, blood pressure, and blood chemistry. The nucleus then sends information throughout the hindbrain to reflex centers controlling cardiovascular, respiratory, and gastrointestinal homeostasis; the nucleus is also an important source of input to the hypothalamus. Synonym: solitary nucleus sperm nucleus The head of the spermatozoon. spinal accessory nucleus A branchial motor column nucleus that extends caudally from the end of the nucleus ambiguus into the ventral horn of spinal cord segments C1-C4. Axons of the neurons in the spinal accessory nucleus leave the spinal cord through lateral (not ventral) rootlets and collect into a thin nerve that runs up along the side of the cord and into the skull through the foramen magnum. There, this nerve joins with rootlets from the nucleus ambiguus to form the spinal accessory nerve (CN XI). spinal trigeminal nucleus A nucleus of the general somatic sensory column that extends through the entire hindbrain as a continuation of the dorsal horn nuclei of the spinal cord; rostrally the spinal trigeminal nucleus merges into the principal sensory trigeminal nucleus. The spinal trigeminal nucleus receives axons, from the trigeminal nerve (CN V) and other cranial nerves, carrying pain and temperature signals from the face and mouth. This nucleus sends axons to the ventral posterior nucleus of the thalamus via the medial lemniscus and the spinothalamic tract. Synonym: trigeminal spinal nucleus subcoeruleus nucleus A reticular nucleus in the pontine hindbrain. Activation of this nucleus appears to be one step in initiating normal REM sleep. subthalamic nucleus A basal ganglia nucleus that is found under the thalamus in the base of the diencephalon; it lies between the thalamus and the cerebral peduncle, just rostral to the substantia nigra. The subthalamic nucleus is a satellite of the globus pallidus with which it has reciprocal connections. Lesions of the subthalamic nucleus on one side of the brain produce hemiballismus. superior central nucleus Median raphe nucleus. superior olivary nucleus Superior olive. superior salivatory nucleus A nucleus of the visceral motor column in the pontine hindbrain just rostral to the medulla. This nucleus is the origin of those preganglionic parasympathetic axons of the intermediate nerve (a component of the facial nerve (CN VII)) that synapse in the pterygopalatine ganglion to regulate secretions of the lacrimal and mucosal glands of the nose and mouth and the submandibular ganglion to regulate secretions of the sublingual and submandibular salivary glands. superior vestibular nucleus The smallest and most rostral of the four vestibular nuclei, which lie in the special sensory column in the hindbrain. The superior vestibular nucleus lies in the floor of the fourth ventricle near the lateral edge, it receives axons from the vestibular ganglia (via the vestibulocochlear nerve (CN VIII)) and from the deep cerebellar nuclei, and it sends axons to the cerebellum. suprachiasmatic nucleus A small hypothalamic nucleus lying at the base of the third ventricle, directly above the optic chiasm. This nucleus generates the brain's circadian rhythm. To entrain its rhythm with the natural day-night cycle, the nucleus is innervated by optic axons via the accessory optic tract; it also receives axons from the lateral geniculate nucleus of the thalamus, and serotonergic axons from the midbrain raphe nuclei. The suprachiasmatic nucleus sends most of its axons to the paraventricular nucleus of the hypothalamus. supraoptic nucleus A large-celled nucleus of the hypothalamus lying above the rostral ends of the optic tracts and lateral to the optic chiasm. See: paraventricular nucleus target nucleus When referring to an axon in the central nervous system, the nucleus that contains the neuronal cell body (or its dendrites) on which that axon synapses. nucleus of termination Any of the clusters of cells in the brain and medulla in which fibers of a nerve or nerve tract terminate. thalamic nucleus Any of the more than 27 nuclei of the thalamus. The thalamic nuclei are named according to their position in the thalamus, and the medial and dorsal nuclei are separated from the lateral and ventral nuclei by a partitioning layer of axons, called the internal medullary lamina. The thalamic nuclei filter and modify the signals that the nervous system sends to the cerebral cortices. Thalamic nuclei can be divided into five groups by their patterns of connectivity: (a) The nuclei in the base of the thalamus -- the ventroposterior (also called, ventrobasal), the lateral geniculate, and the medial geniculate nuclei -- receive all the sensory information from the body, except olfaction, and send information to the primary sensory areas of the cerebral cortices. (b) The ventral anterior and ventral lateral nuclei (the VA-VL complex) receive motor programs from the globus pallidus (of the basal ganglia) and the cerebellum and send information to the motor areas of the cerebral cortices. (c) The dorsomedial nucleus, the lateral posterior and lateral dorsal nuclei, and the pulvinar nucleus receive information from the association areas of the cerebral cortices and from noncortical regions of the brain and send information back to the association cortices. (d) The anterior nucleus -- part of the limbic circuitry -- receives information from the mammillary body and from the fornix and sends information to the cingulate gyrus of the cerebral cortex. (e) The small nuclei in the internal medullary lamina (intralaminar nuclei) and the nuclei along the midline of the thalamus receive information from the cerbral cortices, the cererebellum, the reticular formation, and elsewhere and send information widely throughout the cerebral cortices. thoracic nucleus A column of large neurons in the posterior gray column of the spinal cord. These cells give rise to the dorsal spinocerebellar tract on the same side. nucleus of the tractus solitarius Nucleus of the solitary tract. See: tractus solitarius under tractus nucleus of the trapezoid body Clusters of neurons in the trapezoid body in the hindbrain. Some axons crossing the midline through the trapezoid body synapse locally on these neurons. trigeminal mesencephalic nucleus Mesencephalic trigeminal nucleus. trigeminal motor nucleus A nucleus of the branchial motor column in the rostral hindbrain. It is found in the ventral pontine tegmentum between the spinal trigeminal nucleus and the superior olive. It is the origin of motor axons in the mandibular division of the trigeminal nerve (CN V3), and its axons innervate the muscles of mastication and the tensor tympani (a middle ear muscle). trigeminal sensory nucleus The mesencephalic trigeminal nucleus, the principal sensory trigeminal nucleus, or the spinal trigeminal nucleus. trigeminal spinal nucleus spinal trigeminal nucleus. trochlear nucleus A nucleus of the somatic motor column in the hindbrain. It is a small midbrain nucleus sitting atop the MLF just caudal to the oculomotor nucleus, and it is the origin of the trochlear nerve (CN VI). tuberal nucleus The lateral, medial, anterior, or posterior tuberal nucleus in the hypothalamus. tuberomammillary nucleus A hypothalamic nucleus found just lateral to the medial mammillary nucleus. It is characterized by histaminergic axons that widely and diffusely innervate the entire brain. Neurons of this nucleus fire regularly when a person is awake and rarely during sleep. Stimulation of the tuberomammillary nucleus raises blood pressure and heart rate. nucleus of the vagus The dorsal motor nucleus of the vagus. ventral cochlear nucleus A nucleus of the special sensory column in the hindbrain; it forms a bulge around the entering cochlear nerve. Axons of the primary sensory cells in the spiral ganglion (in the cochlea of the inner ear) run in the vestibulocochlear nerve (CN VIII) and synapse in the dorsal and ventral cochlear nuclei. About half of the axons from neurons in the cochlear nuclei cross the midline in a tract called the trapezoid body and join the uncrossed axons from the contralateral cochlear nuclei. Together, these axons ascend in a tract called the lateral lemniscus to synapse in the inferior colliculus in the midbrain. ventral nucleus of the lateral lemniscus One of the two distinguishable nuclei clustered in the upper (rostral) end of the lateral lemniscus near the inferior colliculi. These nuclei are part of the auditory circuitry. ventral posterior nucleus of the thalamus The ventral posterior lateral or the ventral posterior medial nucleus of the thalamus. Synonym: ventrobasal nucleus of the thalamus ventral posterior lateral nucleus of the thalamus One of the two major divisions of the ventral posterior nucleus, the somatic sensory relay nucleus of the thalamus. The ventral posterior lateral nucleus is the target of the medial lemniscus (touch and position sense from the body) and of many spinothalamic tract axons, and it sends axons to the sensory areas of the cerebral cortices. ventral posterior medial nucleus of the thalamus Abbreviation: VPM One of the two major divisions of the ventral posterior nucleus, the somatic sensory relay nucleus of the thalamus. The ventral posterior medial nucleus is the target of the trigeminal lemniscus (somatic sensory information from the face and intraoral regions), and it sends axons to the sensory areas of the cerebral cortices. ventral nucleus of the thalamus The ventral anterior, ventral lateral, entral posterior medial, or ventral posterior lateral nucleus. ventrobasal nucleus of the thalamus Ventral posterior nucleus of the thalamus. vesicular nucleus A cell nucleus having a deeply staining membrane and a pale center. vestibular nucleus The inferior, lateral, medial, or superior vestibular nucleus. vitelline nucleus A cell nucleus formed by union of male and female pronuclei within the vitellus. It is a part of the cytoplasm of an ovum in which the initial process of accumulation of food supplies is probably located. Synonym: yolk nucleus yolk nucleus Vitelline nucleus. See ION See IDL On the Net
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