Substantia nigra

Last revised by Francis Deng ◉ on 10 May 2022

Citation, DOI, disclosures and article data

Citation:

Jones J, Deng F, Sam R, et al. Substantia nigra. Reference article, Radiopaedia.org (Accessed on 23 Mar 2025) https://doi.org/10.53347/rID-5813

DOI:

https://doi.org/10.53347/rID-5813

Permalink:

https://radiopaedia.org/articles/5813

rID:

5813

Article created:

23 Mar 2009, Jeremy Jones ◉

Disclosures:

At the time the article was created Jeremy Jones had no recorded disclosures.

View Jeremy Jones's current disclosures

Last revised:

10 May 2022, Francis Deng ◉

Disclosures:

At the time the article was last revised Francis Deng had no financial relationships to ineligible companies to disclose.

View Francis Deng's current disclosures

Revisions:

13 times, by 10 contributors - see full revision history and disclosures

Systems:

Central Nervous System

Sections:

Anatomy

Tags:

anatomy rewrite

Synonyms:

Substantiae nigrae
Substantia nigras

The substantia nigra (plural: substantiae nigrae) is one of the brainstem nuclei and part of the extrapyramidal system. While other nuclei such as the red nucleus are small and contained within an axial slice at the superior colliculi (see figure), the substantia nigra is seen in axial slices at both superior and inferior colliculi.

It is an important relay station in the motor system. It consists of a compact part (dark, containing melanin) and a reticular part (reddish, containing iron). Most of its axons are projected diffusely to other brain areas and not arranged into tracts. Numerous axonal tracts terminate in the substantia nigra:

caudate nucleus (striatonigral fibers)
anterior cerebral cortex (corticonigral fibers)
putamen
precentral cortex

Nigrosomes

Nigrosomes are small clusters of dopaminergic cells measuring up to a few millimeters in size within the substantia nigra that exhibit calbindin D28K negativity on immunohistochemistry. Five nigrasomes have been described with the largest labeled as nigrosome-1 positioned in the caudal, medio-lateral portion of the substantia nigra. Nigrasome-1 contains the largest proportion of neurons affected in Parkinson disease ³.

Radiographic features

High resolution T2*/SWI weighted MRI is able to identify the distribution of normal signal within healthy and diseased substantia nigra both at 7 T and 3 T field strength. The healthy nigrosome-1 produces a swallow tail appearance on axial imaging. Absence of the normal swallow tail appearance of nigrosome-1 is reported to be a reliable sign of Parkinson disease ³.