title: Disrupted functional brain connectivity and its association to structural connectivity in amnestic mild cognitive impairment and Alzheimer's disease.
abstract: Although anomalies in the topological architecture of whole-brain connectivity have been found to be associated with Alzheimer's disease (AD), our understanding about the progression of AD in a functional connectivity (FC) perspective is still rudimentary and few study has explored the function-structure relations in brain networks of AD patients. By using resting-state functional MRI (fMRI), this study firstly investigated organizational alternations in FC networks in 12 AD patients, 15 amnestic mild cognitive impairment (aMCI) patients, and 14 age-matched healthy aging subjects and found that all three groups exhibit economical small-world network properties. Nonetheless, we found a decline of the optimal architecture in the progression of AD, represented by a more localized modular organization with less efficient local information transfer. Our results also show that aMCI forms a boundary between normal aging and AD and represents a functional continuum between healthy aging and the earliest signs of dementia. Moreover, we revealed a dissociated relationship between the overall FC and structural connectivity (SC) in AD patients. In this study, diffusion tensor imaging tractography was used to map the structural network of the same individuals. The decreased FC-SC coupling may be indicative of more stringent and less dynamic brain function in AD patients. Our findings provided insightful implications for understanding the pathophysiological mechanisms of brain dysfunctions in aMCI and AD patients and demonstrated that functional disorders can be characterized by multimodal neuroimaging-based metrics.
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), Center for Life Sciences, National University of Singapore, Singapore; School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Qihua
authors.initials: Q
authors.lastname: Yin
authors.affiliation: Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Fang
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Yan
authors.affiliation: Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), Center for Life Sciences, National University of Singapore, Singapore.
authors.forename: Anastasios
authors.initials: A
authors.lastname: Bezerianos
authors.affiliation: Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Huidong
authors.initials: H
authors.lastname: Tang
authors.affiliation: Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Miao
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Sun
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology / Q000502:physiology; D000544:Alzheimer Disease / Q000473:pathology / Q000503:physiopathology*; D000647:Amnesia / Q000473:pathology / Q000503:physiopathology*; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D060825:Cognitive Dysfunction / Q000473:pathology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology*; D059906:Neuroimaging; D009483:Neuropsychological Tests