MouseLight Neuron AA0173

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（Janelia）科研团队开展的大规模神经示踪研究，将小鼠大脑中已完成全示踪的神经元数量提升了10倍。研究人员如今可下载并以三维形式浏览该数据集。
在小鼠大脑中，单个神经元会在大脑半球间蜿蜒穿行，形成精致的分支结构；研究人员此次还发现，这类神经元甚至可伸出长达45厘米的纤细纤维。
科学家们可在这一迄今最精细的小鼠大脑连接图谱中，以三维视角观察并探索这些蜿蜒的神经示踪痕迹。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，而此前的单神经元示踪研究最多仅能完成数十个神经元的示踪。
研究团队采用双光子显微镜（two-photon microscopy）技术，通过迭代流程对选择性标记的神经元进行成像测绘。具体流程为：将小鼠大脑切割为200微米厚的脑切片，每次对数十个神经元进行标记并成像。每一个被成像的大脑可产生约50太字节（terabytes，TB）的数据，其中包含已测绘的神经元，研究人员可通过神经元浏览器（NeuronBrowser）应用程序进行浏览。若有研究人员需要完整的原始数据集，可联系贾内利亚（Janelia）商讨通过硬件传输的方式获取。