Synchronization within, and interactions between, the default mode and dorsal attention networks in relapsing-remitting multiple sclerosis

Abstract

Background and purpose

The effects of the interactions between the default mode network (DMN) and the dorsal attention network (DAN), which present anticorrelated behaviors, in relapsing-remitting multiple sclerosis (RRMS) are poorly understood. This study used resting-state functional connectivity (FC) and the Granger causality test (GCT) to examine changes in the undirected and effective functional network connectivity (FNC) between the two networks during the remitting phase in RRMS patients.

Patients and methods

Thirty-three patients experiencing a clinically diagnosed remitting phase of RRMS and 33 well-matched healthy control subjects participated in this study. First, an independent component (IC) analysis was performed to preprocess the functional magnetic resonance imaging data and select resting-state networks. Then, an FNC analysis and the GCT were combined to examine the temporal correlations between the ICs of the DMN and DAN and to identify correlations with clinical markers.

Results

Compared with the healthy subjects, the RRMS patients in the remitting phase showed the following: 1) significantly decreased FC within the DAN in the postcentral gyrus and decreased FC within the DMN in several regions except the parahippocampal gyrus, where increased FC was observed; 2) a relatively stable interaction between the two anticorrelated networks as well as a driving connectivity from the DAN to DMN (IC15); and 3) significantly positive correlations between the connectivity coefficient of the right superior temporal gyrus and the Modified Fatigue Impact Scale score (ρ = 0.379, p = 0.036).

Conclusion

Adaptive mechanisms that maintain stable interactions might occur between the DMN and DAN during the remitting phase in RRMS patients.

Keywords:

• default mode network
• dorsal attention network
• multiple sclerosis
• resting-state functional MRI
• Granger causality test
• anticorrelation

Acknowledgments

This study was supported by the National Science Foundation of China (grant no 81101041 and 81560284), the Natural Science Foundation of Jiangxi, People’s Republic of China (grant no 20161BAB205245 and 2017BAB215048), and the Distinguished Young Scholars of Jiangxi Province (grant no 2017BCB23089). The authors thank their patients and volunteers for participating in this study. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Author contributions

All authors contributed toward data analysis, drafting and revising the paper and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.