These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Adjacent pioneer commissural interneuron growth cones switch from contact avoidance to axon fasciculation after midline crossing.
    Author: Moon MS, Gomez TM.
    Journal: Dev Biol; 2005 Dec 15; 288(2):474-86. PubMed ID: 16293241.
    Abstract:
    Commissural interneurons (CI) of the vertebrate spinal cord are guided ventrally toward the floor plate, but subsequently cross the midline and select a longitudinal fascicle at specific dorsal-ventral (D-V) positions. We examined at high resolution the detailed behaviors of individual pathfinding CI growth cones on the ipsilateral and contralateral sides of the spinal cord of living Xenopus embryos. We find that pre-crossing CI growth cones exhibit distinct pathfinding behaviors compared to post-crossing axons and that the behavioral switch occurs immediately upon crossing to the contralateral side. Groups of pioneer commissural axons typically extend simultaneously toward the ventral midline following discrete paths with separation between adjacent commissurals apparently maintained through contact inhibition. In contrast, shortly after crossing the midline, commissural axons turn longitudinally and begin to fasciculate with other crossed CIs. However, growth cones of crossed commissurals often select their final D-V longitudinal track through a series of rapid step-like dorsal adjustments that may be due to differential fasciculation with longitudinal axons. Together, our results suggest that guidance of commissural axons is controlled in part through interactions among CIs that switch rapidly from avoidance to fasciculation after midline crossing.
    [Abstract] [Full Text] [Related] [New Search]