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ZFIN ID: ZDB-PUB-961014-272
Pathway selection by growth cones of identified motoneurones in live zebra fish embryos
Eisen, J.S., Myers, P.Z., and Westerfield, M.
Date: 1986
Source: Nature   320(6059): 269-271 (Journal)
Registered Authors: Eisen, Judith S., Myers, Paul Z., Westerfield, Monte
Keywords: none
MeSH Terms:
  • Animals
  • Axons/physiology
  • Axons/ultrastructure
  • Fishes/embryology*
  • Fluorescent Dyes
  • Motor Neurons/physiology*
  • Motor Neurons/ultrastructure
  • Muscles/embryology
  • Muscles/innervation*
  • Neural Pathways/embryology
  • Neural Pathways/ultrastructure
  • Photomicrography
  • Spinal Cord/embryology
  • Spinal Cord/ultrastructure
PubMed: 3960108 Full text @ Nature
How is the adult pattern of connections between motoneurones and the muscles that they innervate established during vertebrate development? Populations of motoneurones are thought to follow one of two patterns of development: (1) motor axons initially follow stereotyped pathways and project to appropriate regions of the developing muscle or (2) motor axons initially project to some regions that are incorrect, the inappropriate projections being eliminated subsequently. Here we observed individually identified motoneurones in live zebra fish embryos as they formed growth cones and as their growth cones navigated towards their targets. We report that from axogenesis, each motor axon followed a stereotyped pathway and projected only to the specific region of the muscle appropriate for its adult function. In addition, the peripheral arbor established by each motoneurone was restricted to a stereotyped region of its own segment and did not overlap with the peripheral arbor of the other motoneurones in that segment. We conclude that the highly stereotyped pattern of innervation seen in the adult is due to initial selection of the appropriate athway, rather than elimination of incorrect projections.