title: Altered inter-subregion connectivity of the default mode network in relapsing remitting multiple sclerosis: a functional and structural connectivity study.
abstract: OBJECTIVE
  Little is known about the interactions between the default mode network (DMN) subregions in relapsing-remitting multiple sclerosis (RRMS). This study used diffusion tensor imaging (DTI) and resting-state functional MRI (rs-fMRI) to examine alterations of long white matter tracts in paired DMN subregions and their functional connectivity in RRMS patients.
  
  
  METHODS
  Twenty-four RRMS patients and 24 healthy subjects participated in this study. The fiber connections derived from DTI tractography and the temporal correlation coefficient derived from rs-fMRI were combined to examine the inter-subregion structural-functional connectivity (SC-FC) within the DMN and its correlations with clinical markers.
  
  
  RESULTS
  Compared with healthy subjects, the RRMS patients showed the following: 1) significantly decreased SC and increased FC in the pair-wise subregions; 2) two significant correlations in SC-FC coupling patterns, including the positive correlation between slightly increased FC value and long white matter tract damage in the PCC/PCUN-MPFC connection, and the negative correlations between significantly increased FC values and long white matter tract damage in the PCC/PCUN-bilateral mTL connections; 3) SC alterations [log(N track) of the PCC/PCUN-left IPL, RD value of the MPFC-left IPL, FA value of the PCC/PCUN-left mTL connections] correlated with EDSS, increases in the RD value of MPFC-left IPL connection was positively correlated to the MFIS; and decreases in the FA value of PCC/PCUN-right IPL connection was negatively correlated with the PASAT; 4) decreased SC (FA value of the MPFC-left IPL, track volume of the PCC/PCUN-MPFC, and log(N track) of PCC/PCUN-left mTL connections) was positively correlated with brain atrophy.
  
  
  CONCLUSIONS
  In the connections of paired DMN subregions, we observed decreased SC and increased FC in RRMS patients. The relationship between MS-related structural abnormalities and clinical markers suggests that the disruption of this long-distance "inter-subregion" connectivity (white matter) may significantly impact the integrity of the network's function.
authors.affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China; Jiangxi Province Medical Imaging Research Institute, Nanchang, Jiangxi Province, China.
authors.forename: Fuqing
authors.initials: F
authors.lastname: Zhou
authors.affiliation: Department of Oncology, The Second Hospital of Nanchang, Nanchang, Jiangxi Province, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuang
authors.affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China; Jiangxi Province Medical Imaging Research Institute, Nanchang, Jiangxi Province, China.
authors.forename: Honghan
authors.initials: H
authors.lastname: Gong
authors.affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Neurology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wan
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000473:pathology* / Q000503:physiopathology*; D009415:Nerve Net / Q000473:pathology* / Q000503:physiopathology*; D012146:Rest; D066127:White Matter / Q000473:pathology / Q000503:physiopathology; D055815:Young Adult