Regulation of the early development of the nervous system by growth factors.

Development of the nervous system, although patterned by intrinsic genetic expression, appears to be dependent on growth factors for many of the differentiation steps that generate the wide variety of neurons and glia found in the both the central and peripheral nervous system. By using in vitro assays, including clonal analysis, the precise function of the various growth factors and the differentiation potential of the various neural populations has begun to be described. This review discusses some of the recent findings and examines how neuronal differentiation may result from the interaction of several growth factors.