MouseLight Neuron AA0138

A vast neural tracing effort by a team of Janelia scientists has upped the number of fully-traced neurons in the mouse brain by a factor of 10. Researchers can now download and browse the data in three dimensions. Inside the mouse brain, individual neurons zigzag across hemispheres, embroider branching patterns and, researchers have now discovered, can even spool out spindly fibers up to 45 centimeters long.Scientists can see and explore these wandering neural traces in 3-D in the most detailed map of mouse brain wiring yet created. The map reconstructs the shape and position of more than 300 of the 70 million neurons in the mouse brain. Previous efforts to trace the path of individual neurons had topped out in the dozens. The selectively-labeled neurons were mapped in an iterative process with two-photon microscopy. The brain is sliced in 200-micron sections and a few dozen neurons are labeled at a time and imaged. Each brain imaged yields about 50 terabytes of data, each containing mapped neurons which can be browsed via the NeuronBrowser application. Researchers interested in the complete raw data set should contact Janelia to discuss obtaining it via hardware transfer.

贾内利亚研究所（Janelia）的科研团队开展了大规模神经示踪研究，将小鼠大脑中已完全示踪的神经元数量提升了10倍。如今研究人员可下载并三维浏览该数据集。在小鼠大脑中，单个神经元会在左右脑半球间蜿蜒穿行，编织出繁复的分支形态；研究人员此次还发现，它们甚至能延伸出长达45厘米的细长纤维。这是目前已构建的最精细的小鼠大脑连接图谱，科学家可通过三维方式查看并探索这些蜿蜒分布的神经示踪结果。该图谱重建了小鼠大脑7000万个神经元中超过300个的形态与位置信息，而此前的单个神经元示踪研究最多仅能完成数十个神经元的示踪。研究人员采用双光子显微镜（two-photon microscopy）通过迭代成像流程完成了该批选择性标记神经元的图谱绘制。实验中将小鼠大脑切成200微米厚的切片，每次对数十个神经元进行标记并成像。每枚成像的大脑样本可产生约50太字节（terabytes）的数据，其中包含已完成图谱绘制的神经元信息，研究人员可通过NeuronBrowser应用程序进行浏览。若研究人员需要完整的原始数据集，可联系贾内利亚研究所沟通通过硬件传输的方式获取。