Motoneuron axon guidance: development of specific projections to two muscles in the embryonic chick limb.
In the embryonic chick limb, multiple mechanisms are believed to be responsible for a precise guidance of motoneuron axons to their appropriate targets from the earliest stages of axon outgrowth. In this report, I discuss one of these guidance mechanisms; a mechanism which appears to depend on a prelabeling of motoneurons prior to axon outgrowth. By focusing on the development of axonal projections to two specific muscles, I review the evidence that motoneurons destined for each muscle actively recognize environmental cues, and discuss recent experiments designed to identify the source of these cues.
Lance-Jones
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Department of Neurobiology, Anatomy and Cell Science, University of Pittsburgh School of Medicine, Pa.
D000818:Animals; D001369:Axons / Q000502:physiology*; D002642:Chick Embryo / Q000254:growth & development*; D005121:Extremities / Q000196:embryology* / Q000294:innervation; D009046:Motor Neurons / Q000502:physiology*; D009132:Muscles / Q000196:embryology* / Q000294:innervation