Fig. 4. Filopodial contact is important for neural crest migration through the rostral somite. (A-D) A cell positioned midway in a chain extends filopodia into the caudal somite and touches a cell in a chain in a different axial level. The cell maintains filopodial contact with its chain neighbors and returns to its original chain. (E-H) A cell attempts to extend a filopodium into the caudal somite but all connections are lost with its neighbors in the chain. This cell roams in a disoriented, undirected manner through the rostral and caudal somite. Scale bars: 30 µm in A-D; 30 µm in E-H. cs, caudal somite; D, dorsal; DRG, dorsal root ganglia; SG, sympathetic ganglia; V, ventral.