iPSC differentiation flow chart describing differentiation protocols, from somatic cells through iPSC derivation and differentiation to neural, neuronal, and glial lineages. Growth factors driving differentiation are shown in black, and blue indicates exogenously expressed factors used in direct reprogramming protocols (31–33, 38, 40, 44, 49, 59, 64, 75, 93, 94, 135–150). Abbreviations: CNTF, ciliary neurotrophic factor; d, days of growth factor–driven differentiation; EGF, epidermal growth factor; FGF, fibroblast growth factor; FGF8, fibroblast growth factor 8; GSK3βi, glycogen synthase kinase-3β inhibitor; iPSC, induced pluripotent stem cell; RA, retinoic acid; SHH, sonic hedgehog; SMAD, intracellular proteins that transduce extracellular signals from TGFβ signaling; WNT, family of Wnt signaling pathways; WNTi, inhibitors of Wnt signaling pathways.