An isolated population of human neuronal progenitor cells having both developmental and neuron specific markers, with a purity greater than about 90%, wherein at least 90% of the isolated population of human neural progenitor cells express pax6 and nestin, and also express at least one of NeuN and Tuj1, wherein further differentiation of said neuronal progenitor cells produces less than about 5% astrocytes, expressing glial fibrillary acidic protein (GFAP).