 This has two parts—an input area called the pars compacta and an output area the pars reticulata.The dopaminergic neurons are found mainly in the pars compacta (cell group A8) and nearby (group A9).In humans, the projection of dopaminergic neurons from the substantia nigra pars compacta to the dorsal striatum, termed the "nigrostriatal pathway", plays a significant role in the control of motor function and in learning new motor skills.