PDF(Pubmed)
Abstract：
The highly complex structure of the brain requires an approach that can unravel its connectivity. Using volume electron microscopy and a dedicated software we can trace and measure all nerve fibers present within different samples of brain tissue. With this software tool, individual dendrites and axons are traced, obtaining a simplified \"skeleton\" of each fiber, which is linked to its corresponding synaptic contacts. The result is an intricate meshwork of axons and dendrites interconnected by a cloud of synaptic junctions. To test this methodology, we apply it to the stratum radiatum of the hippocampus and layers 1 and 3 of the somatosensory cortex of the mouse. We find that nerve fibers are densely packed in the neuropil, reaching up to 9 kilometers per cubic mm. We obtain the number of synapses, the number and lengths of dendrites and axons, the linear densities of synapses established by dendrites and axons, and their location on dendritic spines and shafts. The quantitative data obtained through this method enable us to identify subtle traits and differences in the synaptic organization of the samples, which might have been overlooked in a qualitative analysis.
摘要：
大脑高度复杂的结构需要一种可以解开其连通性的方法。使用体积电子显微镜和专用软件，我们可以跟踪和测量不同脑组织样本中存在的所有神经纤维。有了这个软件工具，个体树突和轴突被追踪,获得每根光纤的简化“骨架”，连接到其相应的突触接触。结果是由突触连接云互连的轴突和树突的复杂网格。为了测试这种方法，我们将其应用于海马的辐射层以及小鼠体感皮层的1层和3层。我们发现神经纤维密集地堆积在神经纤维中，达到每立方毫米9公里。我们获得了突触的数量，树突和轴突的数量和长度，由树突和轴突建立的突触的线性密度，以及它们在树突棘和轴上的位置。通过这种方法获得的定量数据使我们能够识别样本突触组织的细微特征和差异，这在定性分析中可能被忽略了。
