The tissue of the central nervous system comprises two classes of cells that may be broadly classified as neurons and glia. Neurons are the anatomic, functional, and trophic units of the brain. Despite great variability in size and shape, all neurons share common morphologic features; the key elements of a highly complex communication network. Neurons, which have a dynamic polarization, serves as the major signaling unit of the nervous system. Human Dopaminergic Neuronal Precursor Cells of the midbrain are the main source of dopamine (DA) in the mammalian central nervous system. Their loss is related with one of the most prominent human neurological disorders, Parkinson’s disease (PD). Although their numbers are few, these dopaminergic neurons play an important role in the control of multiple brain functions; including voluntary movement and a broad array of behavioral processes such as mood, reward, addiction, and stress.