Primate Basal Ganglia System - Substantia Nigra Compacta (SNc) and Nearby Dopaminergic Elements

Substantia Nigra Compacta (SNc) and Nearby Dopaminergic Elements

In strict sense, the pars compacta is a part of the core of basal ganglia core since it directly receives synapses from striatal axons through the striatopallidonigral bundle. The long ventral dendrites of the pars compacta indeed plunge deep in the pars reticulata where they receive synapses from the bundle. However, its constitution, physiology and mediator contrast with the rest of the nigra. This explains why it is analysed here between the elements of the core and the regulators. Ageing leads to the blackening of its cell bodies, by deposit of melanin, visible by naked eye. This is the origin of the name of the ensemble, first "locus niger" (Vicq d'Azyr), meaning black place, and then "substantia nigra" (Sömmering), meaning black substance.