Lexic.us

Definition of Nucleus niger

1. Noun. A layer of deeply pigmented grey matter in the midbrain; associated with the striate body; is involved in metabolic disturbances associated with Parkinson's disease and with Huntington's disease.

Medical Definition of Nucleus niger

1. A large cell mass, crescentic on transverse section, extending forward over the dorsal surface of the crus cerebri from the rostral border of the pons into the subthalamic region; it is composed of a dorsal stratum of closely spaced pigmented (i.e., melanin-containing) cells, the pars compacta, and a larger ventral region of widely scattered cells, the pars reticulata; the pars compacta in particular includes numerous cells that project forward to the striatum (caudate nucleus and putamen) and contain dopamine, which acts as the transmitter substance at their synaptic endings; other, apparently non-dopaminergic cells of the substantia nigra project to a rostral part of the ventral nucleus of thalmus, the middle layers of the superior colliculus and to restricted parts of the reticular formation of the midbrain; the nigrostriatal projection is reciprocated by a massive striatonigral fibre system with multiple neurotransmitters, chief among which is gamma-aminobutyric acid (GABA); substantia n. Receives smaller afferent projections from the subthalamic nucleus, the lateral segment of the globus pallidus, the dorsal nucleus of the raphe and the pedunculopontine nucleus of the midbrain. The pars reticulata forms part of the output system for the striate body. The substantia n. Is involved in the metabolic disturbances associated with Parkinson's disease and Huntington's disease. Synonym: locus niger, nucleus niger, Soemmerring's ganglion. (05 Mar 2000)

Lexicographical Neighbors of Nucleus Niger

Literary usage of Nucleus niger

Below you will find example usage of this term as found in modern and/or classical literature:

1. Dictionary of Philosophy and Psychology: Including Many of the Principal by James Mark Baldwin (1901)
"A mass of nerve cells in the caudal part of the thalamus near the nucleus ruber and closely associated with the nucleus niger, which replaces it in the pes ..."

2. Dictionary of Philosophy and Psychology: Including Many of the Principal by James Mark Baldwin (1901)
"A mass of nerve cells in the caudal part of the thalamus near the nucleus rubor and closely associated with the nucleus niger, which replaces it in the pes ..."

3. Kirkes' Handbook of physiology by William Senhouse Kirkes (1905)
"... or nucleus niger or substantia nigra. The tegmentum situated dorsally ends for the most part in the neighborhood of the optic thalamus and the parts ..."

4. Kirkes': Handbook of Physiology by William Senhouse Kirkes, William Hayden Rockwell, Charles Loomis Dana (1902)
"Separating these two parts, is a mass of gray matter of the shape of a lens, called the locus or nucleus niger or substantia nigra. ..."

5. Syllabus of lectures on physiology by William Howard Bigler (1903)
"Separating these two portions is a central nucleus containing pigment; the locus or nucleus niger, or substantia nigra. The crura transmit both motor ..."

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