Optimal Degrees of Synaptic Connectivity.
Optimal Degrees of Synaptic Connectivity.
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DOI：
10.1016/j.neuron.2017.01.030
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发表时间：
2017-03-08
期刊：
影响因子：
16.2
通讯作者：
Abbott LF
中科院分区：
文献类型：
--
作者：
Litwin-Kumar A;Harris KD;Axel R;Sompolinsky H;Abbott LF
突触连接在不同的神经元类型中有很大的差异。小脑颗粒细胞接受的输入比它们所支配的浦肯野细胞少五个数量级，而包括昆虫蘑菇体在内的小脑样回路也表现出很大的连通性差异。相比之下，大脑皮层中每个神经元的输入数量更均匀和大。我们研究了由神经元群体形成的表示的维度如何取决于它们各自接收到多少输入以及这对学习关联意味着什么。我们的理论预测，小脑颗粒细胞和果蝇Kenyon细胞表示的尺寸是最大化的突触连接的程度相匹配的解剖学上观察到的，表明稀疏的连接有时上级密集的连接。然而，当输入突触受到监督的可塑性时，密集的布线变得有利，这表明一组突触表现出的可塑性类型是连接密度的主要决定因素。
Synaptic connectivity varies widely across neuronal types. Cerebellar granule cells receive five orders of magnitude fewer inputs than the Purkinje cells they innervate, and cerebellum-like circuits including the insect mushroom body also exhibit large divergences in connectivity. In contrast, the number of inputs per neuron in cerebral cortex is more uniform and large. We investigate how the dimension of a representation formed by a population of neurons depends on how many inputs they each receive and what this implies for learning associations. Our theory predicts that the dimensions of the cerebellar granule-cell and Drosophila Kenyon-cell representations are maximized at degrees of synaptic connectivity that match those observed anatomically, showing that sparse connectivity is sometimes superior to dense connectivity. When input synapses are subject to supervised plasticity, however, dense wiring becomes advantageous, suggesting that the type of plasticity exhibited by a set of synapses is a major determinant of connection density.