a multi-component model of the developing retinocollicular pathway incorporating axonal and synaptic growth的多组分的模型开发retinocollicular通路将轴突和突触的生长.pdfVIP

A Multi-Component Model of the Developing Retinocollicular Pathway Incorporating Axonal and Synaptic Growth 1,2 1 2 Keith B. Godfrey *, Stephen J. Eglen , Nicholas V. Swindale 1 Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom, 2 Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada Abstract During development, neurons extend axons to different brain areas and produce stereotypical patterns of connections. The mechanisms underlying this process have been intensively studied in the visual system, where retinal neurons form retinotopic maps in the thalamus and superior colliculus. The mechanisms active in map formation include molecular guidance cues, trophic factor release, spontaneous neural activity, spike-timing dependent plasticity (STDP), synapse creation and retraction, and axon growth, branching and retraction. To investigate how these mechanisms interact, a multi- component model of the developing retinocollicular pathway was produced based on phenomenological approximations of each of these mechanisms. Core assumptions of the model were that the probabilities of axonal branching and synaptic growth are highest where the combined influences of chemoaffinity and trophic factor cues are highest, and that activity- dependent release of trophic factors acts to stabilize synapses. Based on these behaviors, model axons produced morphologically realistic growth patterns and projected to retinotopically correct locations in the colliculus. Findings of the model include that STDP, gradient detection by axonal growth cones and lateral connectivity among coll