Katz Yael, Menon Vilas, Nicholson Daniel A, Geinisman Yuri, Kath William L, Spruston Nelson
Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA.
Neuron. 2009 Jul 30;63(2):171-7. doi: 10.1016/j.neuron.2009.06.023.
Competing models have been proposed to explain how neurons integrate the thousands of inputs distributed throughout their dendritic trees. In a simple global integration model, inputs from all locations sum in the axon. In a two-stage integration model, inputs contribute directly to dendritic spikes, and outputs from multiple branches sum in the axon. These two models yield opposite predictions of how synapses at different dendritic locations should be scaled if they are to contribute equally to neuronal output. We used serial-section electron microscopy to reconstruct individual apical oblique dendritic branches of CA1 pyramidal neurons and observe a synapse distribution consistent with the two-stage integration model. Computational modeling suggests that the observed synapse distribution enhances the contribution of each dendritic branch to neuronal output.
人们提出了相互竞争的模型来解释神经元如何整合分布在其整个树突树中的数千个输入。在一个简单的全局整合模型中，来自所有位置的输入在轴突中求和。在一个两阶段整合模型中，输入直接促成树突棘，多个分支的输出在轴突中求和。如果不同树突位置的突触要对神经元输出做出同等贡献，这两种模型对突触应如何缩放产生了相反的预测。我们使用连续切片电子显微镜来重建CA1锥体神经元的单个顶端斜向树突分支，并观察到与两阶段整合模型一致的突触分布。计算模型表明，观察到的突触分布增强了每个树突分支对神经元输出的贡献。
