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The development of nerve connections involves competition among axons for survival promoting factors, or neurotrophins, which are released by the axons’ target cells. We have extended our model of axonal competition (van Ooyen and Willshaw, Proc. R. Soc. B. 266 (1999) 883–892) to study the influence of the target's dendritic tree on competition. We show that spatial separation of innervating axons on the target's dendrites mitigates competition and permits the coexistence of axons. The model accounts for the finding that in many types of neurons a positive correlation exists between the size of the dendritic tree and the number of innervating axons surviving into adulthood (Hume and Purves, Nature 293 (1981) 469–471; Purves and Hume, J. Neurosci. 1 (1981) 441–452). Our results emphasize the importance of postsynaptic dendritic morphology in the development of specific patterns of nerve connections. |
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