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substantia nigra (nucleus niger, Soemmerring's ganglion)
Structure:
- the substantia nigra is a nucleus of the midbrain, crescentic on transverse section extending from the rostral border of the pons into the subthalamic region
- it contains a dorsal stratum of closely spaced pigmented, melanin-containing cells, the pars compacta, & a larger ventral region of widely scattered cells, the pars reticulata
Afferents:
1) the pars compacta contains dopaminergic neurons which project to the striatum (caudate & putamen)
2) other non dopaminergic neurons project to the rostral part of the ventral nucleus of the thalamus
3) the pars reticulata forms part of the output system for the striatum
Efferents:
1) the nigrostriatal system is reciprocated by a massive striatonigral fiber system with multiple neurotransmitters, but chiefly GABA
2) smaller afferent projections are received from
a) subthalamic nucleus
b) the lateral segment of the globus pallidus
c) the dorsal nucleus of the raphe
d) the pedunculopontine nucleus of the midbrain
Related
nigrostiatal system/tract
General
CNS nucleus
References
- Stedman's Medical Dictionary 26th ed, Williams &
Wilkins, Baltimore, 1995
- Stedman's Medical Dictionary 27th ed, Williams &
Wilkins, Baltimore, 1999
Component-of
mesencephalon (midbrain)
Components
pars compacta
pars reticulata
Images
images related to substantia nigra