标题： 轴突生长和突触竞争的简单规则生成现实的连接长度和填充分数 显示英文标题

标题： A simple rule for axon outgrowth and synaptic competition generates realistic connection lengths and filling fractions

摘要： 神经元在细胞和介观层面的连接似乎非常特定，并被认为是由高度特定的发育机制产生的。 然而，在系统之间存在一些共享的连接特征，这些系统差异很大，如秀丽隐杆线虫或大鼠视觉皮层中单个神经元形成的网络，以及小鼠、猕猴和人类大脑皮层区域的介观电路。 在所有这些系统中，连接长度分布具有非常相似的形状，有一个初始的大峰和一个长而平的尾部，代表了长距离连接与主要短距离连接的混合。 此外，并非所有潜在可能的突触都会形成，只有部分轴突（称为填充分数）会与空间邻近的神经元建立突触。 我们探讨了这些连接模式中哪些方面可以通过随机轴突生长来简单解释。 我们发现，远离胞体的随机轴突生长已经可以再现已知的连接距离分布。 我们还观察到，实验观察到的填充分数可以通过目标神经元处可用空间的竞争产生——这是一种与以往解释显著不同的模型。 这些发现可能作为连接发展的基准模型，可以通过更具体的机制进一步完善。 显示英文摘要

摘要： Neural connectivity at the cellular and mesoscopic level appears very specific and is presumed to arise from highly specific developmental mechanisms. However, there are general shared features of connectivity in systems as different as the networks formed by individual neurons in Caenorhabditis elegans or in rat visual cortex and the mesoscopic circuitry of cortical areas in the mouse, macaque, and human brain. In all these systems, connection length distributions have very similar shapes, with an initial large peak and a long flat tail representing the admixture of long-distance connections to mostly short-distance connections. Furthermore, not all potentially possible synapses are formed, and only a fraction of axons (called filling fraction) establish synapses with spatially neighboring neurons. We explored what aspects of these connectivity patterns can be explained simply by random axonal outgrowth. We found that random axonal growth away from the soma can already reproduce the known distance distribution of connections. We also observed that experimentally observed filling fractions can be generated by competition for available space at the target neurons--a model markedly different from previous explanations. These findings may serve as a baseline model for the development of connectivity that can be further refined by more specific mechanisms.