Abstract
Embryonic chick neural tubes containing neural crest cells were cultured in vitro on tissue culture plastic and collagen. Two parameters, the time of onset of cell migration from the neural tube and the rate of movement of the cell front away from the neural tube explant, were determined. On collagen, cell migration consistently began after four to six h in vitro, about five h prior to the onset of cell migration on tissue culture plastic. The identity of the migrating cells as neural crest cells is established by their eventual differentiation into melanocytes. Ablation experiments reveal that collagen also causes the early onset of migration of cells not of neural crest origin. These results provide in vitro support for the idea that extracellular materials may alter cell migratory behaviour in morphogenesis.