substantia nigra

Scientific Latin, from substantia (“substance”) + nigra (“black”).

substantia nigra (plural substantiae nigrae or substantia nigras)

1. (anatomy) A brain structure located in the mesencephalon (midbrain) that plays an important role in reward, addiction, and movement, damage to which occurs in Parkinson's and Parkinsonian patients. [from 19th c.]
   • 1997, Roy Porter, The Greatest Benefit to Mankind, Folio Society, published 2016, page 551:

     Their location was established in the 1950s as the substantia nigra, a layer of grey matter in the midbrain.

• SN

• (midbrain brain structure): pars compacta, pars reticulata