neuromelanin
A dark pigment found in specific brain regions, particularly substantia nigra neurons, whose loss indicates neurodegeneration.
Full Definition
Neuromelanin is a dark, insoluble pigment polymer found primarily in dopaminergic neurons of the substantia nigra and noradrenergic neurons of the locus coeruleus. In neuropathological examination, the progressive loss of neuromelanin-containing neurons serves as a key diagnostic marker for Parkinson's disease and other neurodegenerative conditions. The pigment accumulates with age and can be visualized in unstained tissue sections, making it valuable for assessing neuronal populations in postmortem brain analysis.
Usage
Usage note: Distinguished from general melanin found in skin and hair; specifically refers to brain pigment.
In Context
- "The neuromelanin-containing neurons showed marked depletion in the ventrolateral substantia nigra." — Neuropathology report
- "Neuromelanin pigmentation was reduced by approximately 60% compared to age-matched controls." — Research findings