The present invention is related to the discovery of a novel class of neural progenitor cells, which proliferate in response to platelet derived growth factor (PDGF) and differentiate into neurons and oligodendrocytes but not astrocytes. Progeny of the progenitor cells can be obtained by culturing brain tissue in PDGF without serum, epidermal growth factor (EGF), fibroblast growth factor 2, or transforming growth factor alpha. Upon subculturing into EGF-containing media, these progeny cells can proliferate and form neurospheres, whereas PDGF has no such effect.