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See basal ganglion.
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 nucleus
3. 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.
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 nucleusAccessory olive.
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.
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 nucleusAmygdala (2).
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.
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
In chemistry, the heavy, positively charged, central part of an atom, which contains protons, neutrons, and most of the atomic mass.Synonym: nucleus (4)
A group of neuron cell bodies where the auditory nerves arise.
basal nucleusNucleus basalis of Meynert.
nucleus basalisNucleus basalis of Meynert.
nucleus basalis of MeynertSee: 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 BurdachSee: Burdach, Karl
caudal pontine reticular nucleus
Nucleus reticularis pontis caudalis.See: reticular formation
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 caudatusCaudate nucleus.
cell nucleusNucleus (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 nucleusCentral nucleus of the thalamus.
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.
The central or the lateral cervical nucleus.
cochlear nucleusSee: 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.
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.
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.
The lateral vestibular nucleus.See: vestibular 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.
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 vagusDorsal 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.
A nucleus in the cells of the epiblast.
Edinger-Westphal nucleusSee: Edinger-Westphal 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.
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
A nucleus produced by the joining of the male and female nuclei in the fertilization of the ovum.
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
A cell nucleus resulting from the union of male and female pronuclei.
gigantocellular reticular nucleus
Nucleus reticularis gigantocellularis.
A deep nucleus of the cerebellum, lying between the emboliform and fastigial nuclei.Synonym: posterior interposed nucleus
gonad nucleusMicronucleus (2).
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 gracilisGracile 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.
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
A cell nucleus with half the normal number of chromosomes, as in germ cells (ova and sperm) following the normal reduction divisions in gametogenesis.
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)
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 nucleusInferior 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 nucleusArcuate nucleus.
A reticular nucleus inside the floor of the fourth ventricle, between the hypoglossal nucleus and the dorsal motor nucleus of the vagus.
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
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 nucleusCaudate nucleus.
lateral cuneate nucleusexternal 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
The putamen and the globus pallidus considered together. This is an artificial grouping of basal ganglia nuclei determined purely by physical appearance.
The core or inner dense section of the crystalline lens.
The lateral, intermediate, or medial mammillary nucleus.See: limbic system for illus
masticatory nucleusMotor 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.
A cell nucleus that divides into two or more parts to form daughter nuclei.
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
A nucleus with neurons that use norepinehrine as their neurotransmitter, e.g., the locus coeruleus.
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).
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.
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.
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
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.
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 nucleusNucleus 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 nucleusglobose nucleus.
postpyramidal nucleusNucleus funiculi gracilis.
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.
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.
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.
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.
The center cushioning gelatinous mass lying within an intervertebral disk. It is the remnant of the notochord.
A band of gray matter near the olivary nucleus in the medulla.
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.
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 nucleusMicronucleus (2).
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.
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 ruberRed nucleus.
A two-part visceral motor nucleus comprising the superior and the inferior salivatory nuclei.
The cell nucleus of a zygote formed by fusion of the male and female pronuclei.
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.
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.
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
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
A reticular nucleus in the pontine hindbrain. Activation of this nucleus appears to be one step in initiating normal REM sleep.
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 nucleusSuperior 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.
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.
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
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.
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.
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 nucleusMesencephalic 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 nucleusspinal trigeminal 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).
The lateral, medial, anterior, or posterior tuberal nucleus in the hypothalamus.
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 thalamusAbbreviation: 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.
A cell nucleus having a deeply staining membrane and a pale center.
The inferior, lateral, medial, or superior vestibular 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 nucleusVitelline nucleus.
pl. nuclei [L.]
1. cell nucleus; a spheroid body within a cell, contained in a double membrane, the nuclear envelope, and containing the chromosomes and one or more nucleoli. The contents are collectively referred to as nucleoplasm. The chromosomes contain deoxyribonucleic acid (DNA), which is the genetic material that codes for the structure of all the proteins of the cell.
2. a mass of gray matter in the central nervous system, especially such a mass marking the central termination of a cranial nerve.
3. in organic chemistry, the combination of atoms forming the central element or basic framework of the molecule of a specific compound or class of compounds.
4. the dense core of an atom; called also atomic nucleus. It is made of protons and neutrons held together by the strong nuclear force. Traveling in orbit around the nucleus is a cloud of negatively charged particles called electrons. The number of protons in the atomic nucleus gives a substance its identity as a particular element (2).
located in the floor of the fourth ventricle; its axons constitute the abducent nerve.
the nucleus of origin of motor fibers of the glossopharyngeal, vagus and accessory nerves that supply the striated muscle of the pharynx and larynx. Found in the medulla oblongata.
arcuate nucleus, nucleus arcuati
small irregular areas of gray substance on the ventromedial aspect of the pyramid of the medulla oblongata.
large brain nuclei, the caudate and lentiform nuclei, which combine with the white matter to form the corpus striatum. Important in the regulation of motor function.
caudate nucleus, nucleus caudatus
an elongated, arched gray mass closely related to the lateral ventricle throughout its entire extent, which, together with the putamen, forms the neostriatum.
central nervous system nucleus
aggregations of neurons within the brain.
there are a number of them; they are surrounded by the medulla oblongata caudal to the cerebellum.
cochlear nucleus (dorsal and ventral)
the nuclei of termination of sensory fibers of the cochlear part of the vestibulocochlear (eighth cranial) nerve, which partly encircle the inferior cerebellar peduncle at the junction of the medulla oblongata and pons.
cranial nerve nucleus
aggregations of cell bodies associated with the cranial nerves, which in general are organized as continuations of the four gray matter components of the spinal cord plus three others which appear in the medulla oblongata developed for innervation of the organs in the head.
medial and lateral nuclei are situated in the medulla oblongata.
dentate nucleus, nucleus dentatus
the largest of the deep cerebellar nuclei lying in the white matter of the cerebellum.
located in the midbrain and a center for coordination of oculomotor activity.
in the medulla oblongata and the origin of the facial nerve.
located in the medulla oblongata.
the gray matter of the habenula.
located in the medulla oblongata, the origin of the hypoglossal nerve.
lateral geniculate nucleus
concerned in the transmission of visual stimuli.
lenticular nucleus, lentiform nucleus
the part of the corpus striatum just lateral to the internal capsule, comprising the putamen and globus pallidus.
medial geniculate nucleus
a nucleus within the thalamus; involved in transmission of auditory stimuli.
any collection of cells in the central nervous system giving origin to a motor nerve.
the cells of the midbrain which make up the origin of the oculomotor nerve.
olivary nucleus, nucleus olivaris
1. a folded band of gray matter enclosing a white core and producing the elevation (olive) on the medulla oblongata.
2. olive (2).
nucleus of origin
any collection of nerve cells giving origin to the fibers, or a part of the fibers, of a peripheral nerve.
paraventricular nucleus, nucleus paraventricularis
a band of cells in the wall of the third ventricle in the supraoptic part of the hypothalamus; many of its cells are neurosecretory in function and project to the neurohypophysis, where they secrete oxytocin (and, to a lesser extent, antidiuretic hormone).
pontine nucleus, nucleus pontis
groups of nerve cell bodies in the part of the pyramidal tract within the ventral part of the pons, upon which the fibers of the corticopontine tract synapse, and whose axons in turn cross to the opposite side and form the middle cerebellar peduncle.
pulpy nucleus, nucleus pulposus
a semifluid mass of fine white and elastic fibers forming the center of an intervertebral disk. It serves to distribute pressure over the vertebral body. It shows early age changes, may calcify and herniate through the fibrous rings that enclose it to cause disk disease.
an oval mass of gray matter (pink in fresh specimens) in the anterior part of the tegmentum and extending into the posterior part of the hypothalamus; one of the important relay stations in the extrapyramidal motor pathway of the CNS; origin of the rubrospinal tract in the cord; called also nucleus ruber.
see red nucleus (above).
groups of preganglionic parasympathetic neurons concerned with salivary secretion organized into a rostral nucleus, of the facial nerve, and the caudal nucleus, of the glossopharyngeal nerve.
the nucleus of termination of the afferent (sensory) fibers of a peripheral nerve.
supraoptic nucleus, nucleus supraopticus
one just above the lateral part of the optic chiasm; many of its cells are neurosecretory in function and project to the neurohypophysis, where they secrete antidiuretic hormone (ADH) and, to a lesser extent, oxytocin; other cells are osmoreceptors that stimulate ADH release in response to increased osmotic pressure.
several nuclear masses of the reticular formations of the pons and midbrain, especially of the latter, where they are in close approximation to the superior cerebellar peduncles.
thoracic nucleus, nucleus thoracicus
a column of cells in the dorsal gray column of the spinal cord, extending from the seventh or eighth cervical segments to the second or third lumbar level.
trapezoid body nucleus
a relay station in the auditory pathways.
there are three sensory nuclei and one motor nucleus of the trigeminal nerve found in the brainstem; the sensory nuclei comprise the mesencephalic nucleus, the nucleus of the descending tract, and the principal sensory nucleus, but none is exclusive to the trigeminal nerve, all of them receiving sensory inputs from other cranial nerves.
source of the trochlear nerve; located in the tegmentum of the midbrain.
source of the vagus nerve.
vestibular nucleus, nucleus vestibularis
the four cellular masses (superior, lateral, medial and inferior) in the floor of the fourth ventricle, in which the branches of the eighth cranial (vestibulocochlear) nerve terminate.