<Tr> <Th> TA </Th> <Td> A14. 1.06. 111 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terms of neuroanatomy (edit on Wikidata) </Td> </Tr> <P> The substantia nigra is a basal ganglia structure located in the midbrain that plays an important role in reward and movement . Substantia nigra is Latin for "black substance", reflecting the fact that parts of the substantia nigra appear darker than neighboring areas due to high levels of neuromelanin in dopaminergic neurons . It was discovered in 1784 by Félix Vicq - d'Azyr, and Samuel Thomas von Sömmerring alluded to this structure in 1791 . Parkinson's disease is characterized by the death of dopaminergic neurons in the substantia nigra pars compacta . </P> <P> Although the substantia nigra appears as a continuous band in brain sections, anatomical studies have found that it actually consists of two parts with very different connections and functions: the pars compacta and the pars reticulata . This classification was first proposed by Sano in 1910 . The pars compacta serves mainly as an input to the basal ganglia circuit, supplying the striatum with dopamine . The pars reticulata, though, serves mainly as an output, conveying signals from the basal ganglia to numerous other brain structures . </P>

In parkinson's disease which part of the brain shows depigmentation