为了在神经细胞通路水平阐明脑疾病的发生发展机制，更加精细的脑结构图谱成为一种迫切的需求，并已成为当前的研究热点之一。本项目拟将在国际上首次利用肽型DNA载体对鼠脑神经元进行稀疏、高亮度标记，并结合荧光显微光学切片层析成像系统，在全脑尺度亚微米水平获得不同脑区多种神经元的单个细胞完整三维树突、轴突及其长程投射的高分辨图谱。在此基础上，进一步结合病毒追踪技术，尝试构建这些稀疏标记神经元的跨一级突触神经回路网络结构的高分辨图谱，从而为理解单个神经细胞在复杂脑区回路的连接机制奠定基础，并为破译大脑复杂神经回路，获得高分辨精细脑结构图谱提供方法学上的可能。本项目建立的基于肽型DNA载体的新型鼠脑神经元标记策略将在神经生物学研究领域有着广泛的应用前景。

The study of distributions of neurites (e.g., dendrites and axons) of neural circuits in the brain is essential to understanding the relation between the structure and function of the brain. In this proposal, we will develop a new method based on peptide-based DNA delivery system to label neurons in mice sparsely and brightly. By combining this novel labeling method and an automated fluorescence micro-optical sectioning tomography system, we will obtain brain-wide dendrites, axons and long-distance axonal projections of single neurons in different brain regions at a one-micron voxel resolution. To the best of our knowledge, the mouse neuron labeling method presented in this proposal will be the first peptide-based labeling method for mouse neurons in vivo. We anticipate that this convenience and safe labeling method will be helpful tools for sparse neuronal labeling in vivo. Our results will provide useful guide to understand both local and long-distance neural circuits that are related to brain functions down to the neurite level.