Neurotrophic factors includes nerve growth factors (NGF) family, glial cell line-derived neurotrophic factors (GDNF) family and other neurotrophic factors. NGF, BDNF, NT-3, NT-4/5 and NT-6 constitute NGF family (the neurotrophins), which may enhance both survival and differentiation of neurons from the EGF-responsive hippocampal and the subventricular zone neural stem cells. GDNF family includes GDNF, NTN, PSP and ART, whose major role is in peripheral neurodevelopment. This family enhance proliferation and survival of enteric neural crest precursor cells and is critical for the development of peripheral sensory nerve. Other growth factors such as bFGF and EGF can enhance proliferation and survival of neural stem cell. CNTF and LIF are critical for differentiation of neural stem cells.