A spatial and temporal analysis of dorsal root and sympathetic ganglion formation in the avian embryo

The present study explores the formation of the dorsal root and sympathetic ganglia in the trunk of the avian embryo. Particular emphasis was given to the timing of gangliogenesis and the relative positions of the neural crest-derived ganglia with respect to the somites. Observation that both dorsal root and sympathetic ganglia form in register with the rostral portion of somite suggests that cues localized at these axial levels, perhaps within the rostral somite, may influence the position where neural crest cells condense to form ganglia. Molecules other than N-CAM may play an important role in the aggregation of some neuronal populations.