English: Schematic depiction of an in vitro culture system used to isolate NCSCs. The neural tube is isolated from a rodent or avian embryo at a developmental stage before in vivo neural crest cell delamination. After plating the neural tube onto a substrate-coated plastic dish, NCSCs emigrate from the dorsal part of the neural tube to form a so-called neural crest explant. Subsequently, these cells can be trypsinized and plated as single cells at clonal density in a media supplemented with specific growth factors. In such an in vitro system, addition of fetal calf serum and/or chicken embryo extract results in mixed clones composed of several neural crest-derived lineages. In contrast, addition of instructive growth factors leads to the generation of specific lineages at the expense of other possible fates. For instance, TGF-β promotes a non-neural fate when added to a single NCSC. BMP2 promotes autonomic neurogenesis by upregulating the expression of the basic helix-loop-helix (bHLH) transcription factor Mash-1. NRG isoforms promote gliogenesis, while –at least in the mouse– canonical Wnt signaling induces sensory neurogenesis. Instructive growth factors for other fates, such as melanocytes and chondrocytes, have not been identified to date.