Stollberg J
Békésy Laboratory of Neurobiology, University of Hawaii at Manoa, Honolulu 96822, USA.
J Neurobiol. 1995 Feb;26(2):273-82. doi: 10.1002/neu.480260211.
Synapse elimination at the vertebrate neuromuscular junction reduces a polyinnervated population of muscle fibers to a monoinnervated state. The function of this developmental phenomenon (if any) is unproven. A theoretical analysis of Hebbian (correlation) rules connecting presynaptic and postsynaptic activity and synaptic strength at the neuromuscular junction is presented. The following points are demonstrated: (1) Correlational competition leads to the reduction of polyinnervation to a stable monoinnervated state; (2) the competition gives rise to the size principle over a wide range of the plausible parameter space; (3) over a significant subrange, the competition selectively eliminates topographically incorrect synapses; and (4) in cases in which topographic projection errors overwhelm the system, both error correction and the development of the size principle are disrupted. Correlational competition may explain contradictory experimental results concerning the effects of stimulating or silencing subpopulations of motor neurons. It may also explain an otherwise puzzling instance of a breakdown in the size principle seen in humans undergoing neural regeneration. Taken together, these findings suggest a novel hypothesis for the function of synapse elimination at the neuromuscular junction: the establishment of the size principle.
脊椎动物神经肌肉接头处的突触消除将多神经支配的肌纤维群体减少到单神经支配状态。这种发育现象的功能（如果有）尚未得到证实。本文对连接神经肌肉接头处突触前和突触后活动及突触强度的赫布（相关性）规则进行了理论分析。证明了以下几点：（1）相关性竞争导致多神经支配减少到稳定的单神经支配状态；（2）这种竞争在广泛的合理参数空间范围内产生了大小原则；（3）在相当大的子范围内，竞争选择性地消除了地形学上不正确的突触；（4）在地形投射误差使系统不堪重负的情况下，误差校正和大小原则的发展都会受到干扰。相关性竞争可能解释了关于刺激或沉默运动神经元亚群效应的相互矛盾的实验结果。它也可能解释了在经历神经再生的人类中出现的大小原则崩溃这一令人费解的现象。综上所述，这些发现为神经肌肉接头处突触消除的功能提出了一个新的假设：大小原则的建立。
