Xiao-Chun Chen, Xiao-Li Li, Feng Bai, Yan-Juan Wang, Di Wu, Fang-Fang Wu, Qing-Guo Ren, Zhijun Zhang, Xiang Tang, Binbin Nie, Lin Xu, Li-Hua Gu, and Xin-Yang Qi
// Xiang Tang 1,* , Di Wu 1,* , Li-Hua Gu 1 , Bin-Bin Nie 2 , Xin-Yang Qi 1 , Yan-Juan Wang 1 , Fang-Fang Wu 1 , Xiao-Li Li 1 , Feng Bai 1 , Xiao-Chun Chen 3 , Lin Xu 4,5 , Qing-Guo Ren 1 and Zhi-Jun Zhang 1 1 Department of Neurology, Affiliated ZhongDa Hospital, Neuropsychiatric Institute, School of Medicine, Southeast University, Nanjing, Jiangsu, China 2 Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China 3 Department of Neurology and Geriatrics, Fujian Institute of Geriatrics, Fujian Medical University Union Hospital, Fuzhou, Fujian, China 4 Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China 5 Graduate School of Chinese Academy of Sciences, Beijing, China * These authors have contributed equally to this work Correspondence to: Zhi-Jun Zhang, email: // Qing-Guo Ren, email: // Keywords : Alzheimer’s disease, 5XFAD mice, cognition, neuroimaging, manganese enhanced MRI, Pathology Section Received : March 25, 2016 Accepted : July 19, 2016 Published : August 17, 2016 Abstract Dysfunction of neuronal activity is a major and early contributor to cognitive impairment in Alzheimer’s disease (AD). To investigate neuronal activity alterations at early stage of AD, we encompassed behavioral testing and in vivo manganese-enhanced magnetic resonance imaging (MEMRI) in 5XFAD mice at early ages (1-, 2-, 3- and 5-month). The 5XFAD model over-express human amyloid precursor protein (APP) and presenilin 1 (PS1) harboring five familial AD mutations, which have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-β. In the Morris water maze, 5XFAD mice showed longer escape latency and poorer memory retention. In the MEMRI, 5XFAD mice showed increased signal intensity in the brain regions involved in spatial cognition, including the entorhinal cortex, the hippocampus, the retrosplenial cortex and the caudate putamen. Of note, the observed alterations in spatial cognition were associated with increased MEMRI signal intensity. These findings indicate that aberrant increased basal neuronal activity may contribute to the spatial cognitive function impairment at early stage of AD, and may further suggest the potential use of MEMRI to predict cognitive impairments. Early intervention that targets aberrant neuronal activity may be crucial to prevent cognitive impairment.