title: Getting into shape: optimal ligand gradients for axonal guidance.
abstract: During neural development, neurons from downstream, presynaptic regions of the nervous system (such as the retina) send spatially patterned axonal projections to upstream, target regions (the tectum or superior colliculus). A servomechanism model has been proposed to explain the pattern and time-course of axonal growth between these two regions [Honda, H., 1998. Topographic mapping in the retinotectal projection by means of complementary ligand and receptor gradients: a computer simulation study. J. Theor. Biol., 192, 235-246]. Here, we show that a modification of this model incorporating a different criterion for axonal decision-making, called the local optimum rule, is guaranteed to converge to a topographic map under a wide range of conditions encountered during neural development. A theoretical investigation of these conditions leads to new hypotheses regarding map formation.
authors.affiliation: Département de physiologie, Université de Montréal, Canada. jean-philippe.thivierge@umontreal.ca
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Thivierge
authors.forename: Evan
authors.initials: E
authors.lastname: Balaban
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D002465:Cell Movement; D003198:Computer Simulation; D006801:Humans; D008024:Ligands; D008954:Models, Biological; D008959:Models, Neurological; D008962:Models, Theoretical; D009415:Nerve Net; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000378:metabolism; D015398:Signal Transduction; D049490:Systems Biology
chemical_list: D008024:Ligands