1 Imaging Microglia Surveillance during Sleep-wake Cycles in Freely Behaving Mice Xiaochun Gu 2,3,6 *, Lifeng Zhang 6 , Zhong Zhao 5,6 , Huaqiang Fang 6 , Ting Zhao 7 , Shenghong Ju 2 , Xueli Chen 6 , Weizheng Gao 4 , Xiaoyu Qian 4 , Xianhua Wang 1,6 , Jue Zhang 4 , Heping Cheng 1,6 * 1 National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing 100871, China 2 Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, China 3 Key Laboratory of Developmental Genes and Human Diseases, Department of Histology Embryology, Medical School, Southeast University, Nanjing 210009, China 4 Academy of Advanced Interdisciplinary Study, College of Engineering, Peking University, Beijing 100871, China 5 Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China. 6 Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing 211899, China 7 Nanjing Raygenitm Biotech Co., Ltd, Nanjing 211899, China *Address correspondence to: chengp@pku.edu.cn , xiaochun.gu@seu.edu.cn . CC-BY-NC-ND 4.0 International license perpetuity. It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted February 4, 2023. ; https://doi.org/10.1101/2023.02.03.527083 doi: bioRxiv preprint