title: Detection of PCC functional connectivity characteristics in resting-state fMRI in mild Alzheimer's disease.
abstract: Resting-state networks dissociate in the early stage of Alzheimer's disease (AD). The posterior cingulate cortex (PCC) in AD brain is vulnerable to isolation from the rest of brain. However, it remains unclear how this functional connectivity is related to PCC changes. We employed resting-state functional MRI (fMRI) to examine brain regions with a functional connection to PCC in a mild AD group compared with matched control subjects. PCC connectivity was gathered by investigating synchronic low frequency fMRI signal fluctuations with a temporal correlation method. We found asymmetric PCC-left hippocampus, right dorsal-lateral prefrontal cortex and right thalamus connectivity disruption. In addition, some other regions such as the bilateral visual cortex, the infero-temporal cortex, the posterior orbital frontal cortex, the ventral medial prefrontal cortex and the precuneus showed decreased functional connectivity to the PCC. There were also some regions, primarily in the left frontal-parietal cortices, that showed increased connectivity. These regions included the medial prefrontal cortex, bilateral dorsal-lateral prefrontal cortex, the left basal ganglia and the left primary motor cortex. Impairments to memory, high vision-related functions and olfaction in AD can be explained by a disruption to the functional connection of resting-state networks. The results of increased connectivity may support the compensatory-recruitment hypothesis. Our findings suggest that the characteristics of resting-state functional connectivity could plausibly provide an early imaging biomarker for AD.
authors.affiliation: Department of Radiology, Zhong-Da Hospital, Southeast University, Nanjing 210009, China.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Zhang
authors.forename: Shi-Jie
authors.initials: SJ
authors.lastname: Wang
authors.forename: Jiong
authors.initials: J
authors.lastname: Xing
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Zhan-Long
authors.initials: ZL
authors.lastname: Ma
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Gao-Jun
authors.initials: GJ
authors.lastname: Teng
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D000704:Analysis of Variance; D001931:Brain Mapping; D016022:Case-Control Studies; D005260:Female; D007839:Functional Laterality; D006179:Gyrus Cinguli / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D016555:Matched-Pair Analysis; D009415:Nerve Net / Q000502:physiology* / Q000503:physiopathology; D009434:Neural Pathways / Q000502:physiology* / Q000503:physiopathology; D012016:Reference Values; D012146:Rest / Q000502:physiology*; D012720:Severity of Illness Index; D013997:Time Factors