Yip J W
Brain Res. 1987 Mar;429(1):155-9. doi: 10.1016/0165-3806(87)90149-0.
The patterns of preganglionic projections in the avian sympathetic system are highly specific. Preganglionic axons arising from the T1 spinal segment, for example, project predominantly in the rostral direction, whereas T4 preganglionic axons project predominantly in the caudal direction. Moreover, each ganglion receives projections from a distinct set of spinal cord segments. These patterns are established during embryonic life and are correct from the outset. In this study, I have examined the patterns of preganglionic projections in embryos deprived of their target ganglia through removal of the neural crest prior to its migration to form the sympathetic ganglia. My results indicate that preganglionic axons of target-deprived embryos still project in the proper directions and terminate in the presumptive target regions. Target cues are thus not required for the guidance of preganglionic axons.
鸟类交感神经系统中节前投射的模式具有高度特异性。例如，起源于胸1脊髓节段的节前轴突主要向头侧投射，而胸4节前轴突主要向尾侧投射。此外，每个神经节接收来自一组特定脊髓节段的投射。这些模式在胚胎期建立，并且从一开始就是正确的。在本研究中，我通过在神经嵴迁移形成交感神经节之前将其去除，检查了缺乏靶神经节的胚胎中节前投射的模式。我的结果表明，缺乏靶标的胚胎的节前轴突仍沿正确方向投射并终止于假定的靶标区域。因此，节前轴突的导向不需要靶标线索。
