| nucleus filiformis | A triangular group of large magnocellular neurons in the periventricular zone of the anterior half of the hypothalamus. The cells of the nucleus are similar to those of the supraoptic nucleus; the axons of about 20% of their number join in the formation of the supraopticohypophysial tract and are functionally associated with the posterior lobe of the hypophysis; they project fibres to the brainstem nuclei (dorsal motor nucleus and solitary nucleus) and to the intermediolateral cell column of the spinal cord at thoracic, lumbar, and spinal levels; similar descending autonomic fibres arise from the lateral and posterior hypothalamic nuclei. Synonym: nucleus paraventricularis, filiform nucleus, nucleus filiformis. (05 Mar 2000) |
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| nucleus funiculi cuneati | The larger Burdach's nucleus; one of the three nuclei of the posterior column of the spinal cord; located near the dorsal surface of the medulla oblongata at and below the level of the obex, the nucleus receives posterior root fibres corresponding to the sensory innervation of the arm and hand of the same side; together with its medial companion, the gracile nucleus, it is the major source of origin of the medial lemniscus. Synonym: nucleus cuneatus, Burdach's nucleus, nucleus funiculi cuneati, nucleus of cuneate fasciculus. (05 Mar 2000) |
| nucleus funiculi gracilis | The medial one of the three nuclei of the dorsal column, the remaining two being the cuneate nucleus and the accessory cuneate nucleus, which corresponds to the clava; it receives dorsal-root fibres conveying sensory innervation of the leg, and lower trunk, and projects, by way of the medial lemniscus, to the ventral nucleus posterior nucleus of the thalamus. Synonym: nucleus gracilis, nucleus fasciculi gracilis, nucleus funiculi gracilis, nucleus of Goll. (05 Mar 2000) |
| nucleus gelatinosus | The soft fibrocartilage central portion of the intervertebral disk; regarded as a derivative of the notochord. Synonym: gelatinous nucleus, nucleus gelatinosus, vertebral pulp. (05 Mar 2000) |
| nucleus gigantocellularis medullae oblongatae | One of the three major nuclei of the reticular formation of the brainstem. Synonym: nucleus gigantocellularis medullae oblongatae. (05 Mar 2000) |
| nucleus globosus | A group of two or three small masses of gray substance in the white central core of the cerebellum, medial to the emboliform nucleus; receives axons of Purkinje cells of the intermediate area of the cerebellar cortex; axons of these cells exit the cerebellum via the superior cerebellar peduncle. Synonym: nucleus globosus, spherical nucleus. (05 Mar 2000) |
| nucleus gracilis | The medial one of the three nuclei of the dorsal column, the remaining two being the cuneate nucleus and the accessory cuneate nucleus, which corresponds to the clava; it receives dorsal-root fibres conveying sensory innervation of the leg, and lower trunk, and projects, by way of the medial lemniscus, to the ventral nucleus posterior nucleus of the thalamus. Synonym: nucleus gracilis, nucleus fasciculi gracilis, nucleus funiculi gracilis, nucleus of Goll. (05 Mar 2000) |
| nucleus habenulae | The gray matter of the habenula, composed of a small-celled medial and a larger-celled lateral habenular nucleus; both nuclei receive fibres from basal forebrain regions (septum, basal nucleus, lateral preoptic nucleus); the lateral habenular nucleus receives an additional projection from the medial segment of the globus pallidus. Both nuclei project by way of the retroflex fasciculus to the interpeduncular nucleus and a medial zone of the midbrain tegmentum. Synonym: nucleus habenulae, ganglion habenulae. (05 Mar 2000) |
| nucleus intercalatus | A small collection of nerve cells in the medulla oblongata lying lateral to the hypoglossal nucleus. Synonym: nucleus intercalatus, Staderini's nucleus. (05 Mar 2000) |
| nucleus intermediolateralis | The cell column that forms the lateral horn of the spinal cord's gray matter. Extending from the first thoracic through the second lumbar segment, the column contains the autonomic motor neurons that give rise to the preganglionic fibres of the sympathetic system. Synonym: intermediolateral cell column of spinal cord, nucleus intermediolateralis. (05 Mar 2000) |
| nucleus intermediomedialis | A small group of scattered visceral motor neurons immediately ventral to the thoracic nucleus in the thoracic and upper two lumbar segments of the spinal cord; considered to receive visceral afferent fibres at all spinal levels. Synonym: nucleus intermediomedialis. (05 Mar 2000) |
| nucleus interpeduncularis | A median, unpaired, ovoid cell group at the base of the midbrain tegmentum between the cerebral peduncles; it receives the retroflex fasciculus from the habenula, and projects to the raphe region (raphe nuclei) and periaqueductal gray substance of the midbrain. Synonym: nucleus interpeduncularis, ganglion isthmi, Gudden's ganglion, intercrural ganglion, interpeduncular ganglion. (05 Mar 2000) |
| nucleus interpositus | Collective term denoting the combined globosus nuclei and emboliform nuclei of the cerebellum; more correctly used as interposed nuclei as it identifies two cell groups. Synonym: nucleus interpositus. (05 Mar 2000) |
| nucleus interstitialis | A group of widely spaced, medium-sized neurons in the dorsomedial region of the upper mesencephalic tegmentum, immediately lateral to the nucleus of Darkschewitsch; together with the latter, the interstitial nucleus is closely associated with the medial longitudinal fasciculus, via which it receives fibres from the vestibular nuclei and projects crossed fibres via the posterior commissure to the oculomotor nucleus; also projects fibres to all spinal levels. It is believed to be involved in the integration of head and eye movements, particularly eye movements of a vertical or oblique nature. Synonym: nucleus interstitialis, interstitial nucleus of Cajal. (05 Mar 2000) |
| nucleus lateralis medullae oblongatae | A group of cells in the medulla oblongata, located between the inferior olive and the descending trigeminal nucleus, receiving fibres from the spinal cord and motor cortex and projecting to the cerebellum. Synonym: nucleus lateralis medullae oblongatae, lateral reticular nucleus. (05 Mar 2000) |