REGULATION OF THE EARLY DEVELOPMENT OF THE NERVOUS-SYSTEM BY GROWTH-FACTORS

Development of the nervous system, although patterned by intrinsic gen etic expression, appears to be dependent on growth factors for many of the differentiation steps that generate the wide variety of neurons a nd glia found in the both the central and peripheral nervous system. B y using in vitro assays, including clonal analysis, the precise functi on 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 differ entiation may result from the interaction of several growth factors.