1Department of Radiology, Xuanwu hospital, Capital Medical University, Beijing, China, People's Republic of, 2Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences, Beijing, China, People's Republic of, 3Department of Neurology, Xuanwu hospital, Capital Medical University, Beijing, China, People's Republic of, 4Department of Nuclear Medicine, Xuanwu hospital, Capital Medical University, Beijing, China, People's Republic of