Altered inter-subregion connectivity of the default mode network in relapsing remitting multiple sclerosis: a functional and structural connectivity study

PLoS One. 2014 Jul 7;9(7):e101198. doi: 10.1371/journal.pone.0101198. eCollection 2014.

Abstract

Background and purpose: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / pathology*
  • Brain / physiopathology*
  • Diffusion Tensor Imaging
  • Female
  • Humans
  • Linear Models
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Multiple Sclerosis, Relapsing-Remitting / pathology*
  • Multiple Sclerosis, Relapsing-Remitting / physiopathology*
  • Nerve Net / pathology*
  • Nerve Net / physiopathology*
  • Rest
  • White Matter / pathology
  • White Matter / physiopathology
  • Young Adult

Grants and funding

This work was supported by the National Science Foundation of China (Grant No. 81101041 for FZ, Grant No. 81060116 for HG, and Grant No. 81260217 for HG), JiangXi Province science and technology support program (Grant No. 20111BBG70028-1 for FZ), Hong Kong Scholars Program (Grant No. XJ2012026 for FZ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.