van Ooyen A, Willshaw D J
Institute for Adaptive and Neural Computation, Division of Informatics, 2 Buccleuch Place, Edinburgh EH8 9LW, U.K.
J Theor Biol. 1999 Feb 21;196(4):495-511. doi: 10.1006/jtbi.1998.0849.
In the normal development of connections between motor neurons and muscle fibres, an initial stage of polyneuronal innervation is followed by withdrawal of connections until each muscle fibre is innervated by a single axon. However, polyneuronal innervation has been found to persist after prolonged nerve conduction block, in spite of the resumption of normal neuromuscular activity. Here we analyse in detail a model proposed for the withdrawal of nerve connections in developing muscle, based on competition between nerve terminals. The model combines competition for a pre-synaptic resource with competition for a post-synaptic resource. Using bifurcation and phase space analysis, we show that polyneuronal innervation, as well as mononeuronal innervation, can be stable. The model accounts for the development of mononeuronal innervation and for persistent polyneuronal innervation after prolonged nerve conduction block, which appears as a consequence of the general competitive interactions operating during normal development.
在运动神经元与肌纤维之间连接的正常发育过程中，最初会经历多神经元支配阶段，随后连接逐渐减少，直到每条肌纤维仅由单个轴突支配。然而，尽管神经肌肉活动已恢复正常，但在长时间神经传导阻滞之后，多神经元支配仍会持续存在。在此，我们详细分析了一个基于神经末梢之间竞争而提出的、用于解释发育中肌肉神经连接消退的模型。该模型将对突触前资源的竞争与对突触后资源的竞争结合在一起。通过分岔和相空间分析，我们表明多神经元支配以及单神经元支配都可以是稳定的。该模型解释了单神经元支配的发育过程以及长时间神经传导阻滞之后多神经元支配持续存在的现象，而这一现象似乎是正常发育过程中普遍存在的竞争相互作用所导致的结果。
