A quantitative map of the circuit of cat primary visual cortex
A quantitative map of the circuit of cat primary visual cortex
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DOI：
10.1523/jneurosci.1400-04.2004
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发表时间：
2004-09-29
影响因子：
5.3
通讯作者：
Martin, KAC
中科院分区：
文献类型：
--
作者：
Binzegger, T;Douglas, RJ;Martin, KAC
我们通过估计不同神经元类型之间投射的“权重”，对猫区域 17 中形成的回路进行了定量描述。为了实现这一目标，我们在体内细胞内记录过程中对 39 个单个神经元和用辣根过氧化物酶标记的丘脑传入神经进行了三维重建。这些神经元作为不同类型的代表，并提供有关树突树和突触纽扣的层状分布以及给定类型神经元形成的突触数量的形态测量数据。对文献的广泛搜索提供了不同神经元类型的数量及其在皮质层中的分布的估计。应用不同细胞类型之间的突触与这些细胞类型对给定层中的神经纤维贡献的纽扣和树突成比例的简化，我们能够估计六层神经元之间形成的突触的可能来源和数量。预测的突触图在数量上接近于对多刺星状细胞的兴奋性和抑制性输入的主要来源的实验电子显微镜研究得出的估计，多刺星状细胞形成了第 4 层传入的主要目标。整个皮质回路的图显示，“强”兴奋性投射很少，但有很多“弱”兴奋性投射，每个兴奋性投射可能只涉及单个神经元兴奋性突触总数的几个百分比。
We developed a quantitative description of the circuits formed in cat area 17 by estimating the "weight" of the projections between different neuronal types. To achieve this, we made three-dimensional reconstructions of 39 single neurons and thalamic afferents labeled with horseradish peroxidase during intracellular recordings in vivo. These neurons served as representatives of the different types and provided the morphometrical data about the laminar distribution of the dendritic trees and synaptic boutons and the number of synapses formed by a given type of neuron. Extensive searches of the literature provided the estimates of numbers of the different neuronal types and their distribution across the cortical layers. Applying the simplification that synapses between different cell types are made in proportion to the boutons and dendrites that those cell types contribute to the neuropil in a given layer, we were able to estimate the probable source and number of synapses made between neurons in the six layers. The predicted synaptic maps were quantitatively close to the estimates derived from the experimental electron microscopic studies for the case of the main sources of excitatory and inhibitory input to the spiny stellate cells, which form a major target of layer 4 afferents. The map of the whole cortical circuit shows that there are very few "strong" but many "weak" excitatory projections, each of which may involve only a few percentage of the total complement of excitatory synapses of a single neuron.