Research Paper Volume 12, Issue 7 pp 5907—5919

Increased intrinsic default-mode network activity as a compensatory mechanism in aMCI: a resting-state functional connectivity MRI study

Jiali Liang 1, *, , Yunfei Li 2, *, , Hao Liu 3, , Sisi Zhang 4, , Meimei Wang 4, , Yonghua Chu 1, , Jianping Ye 1, , Qian Xi 5, , Xiaohu Zhao 2, ,

  • 1 Department of Clinical Engineering, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang, China
  • 2 Department of Imaging, The Fifth People’s Hospital of Shanghai, Fudan University, Shanghai 200240, China
  • 3 Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
  • 4 Department of Imaging, Shanghai Tongji Hospital, Tongji University School of Medicine, Tongji University, Shanghai 200065, China
  • 5 Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
* Equal contribution

received: October 1, 2019 ; accepted: March 24, 2020 ; published: April 1, 2020 ;

https://doi.org/10.18632/aging.102986
How to Cite

Copyright © 2020 Liang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Numerous studies have investigated the differences in the mean functional connectivity (FC) strength between amnestic mild cognitive impairment (aMCI) patients and normal subjects using resting-state functional magnetic resonance imaging. However, whether the mean FC is increased, decreased or unchanged in aMCI patients compared to normal controls remains unclear. Two factors might lead to inconsistent results: the determination of regions of interest and the reliability of the FC.

We explored differences in FC and the degree centrality (Dc) constructed by the bootstrap method, between and within networks (default-mode network (DN), frontoparietal control network (CN), dorsal attention network (AN)), and resulting from a hierarchical-clustering algorithm.

The mean FC within the DN and CN was significantly increased (P < 0.05, uncorrected) in patients. Significant increases (P < 0.05, uncorrected) in the mean FC were found in patients between DN and CN and between DN and AN. Five pairs of FC (false discovery rate corrected) and the Dc of six regions (Bonferroni corrected) displayed a significant increase in patients. Lower cognitive ability was significantly associated with a greater increase in the Dc of the left superior temporal sulcus.

Our results demonstrate that the early dysfunctions in aMCI disease are mainly compensatory impairments.

Abbreviations

FC: functional connectivity; aMCI: amnestic mild cognitive impairment; fMRI: functional magnetic resonance imaging; ROI: regions of interest; Dc: degree centrality; DN: default-mode network; CN: control network; AN: attention network; MMSE: Mini Mental State Examination; FDR: false discovery rate; STS: superior temporal sulcus; AD: Alzheimer’s disease; BOLD: blood oxygen level-dependent; NC: normal control; PCu: precuneus; CI: confidence interval; EPI: echo planar imaging; TR: repetition time; TE: echo time; FA: flip angle; TI: inversion time; GM: gray matter; WM: white matter; CSF: cerebrospinal fluid; FD: framewise displace; MNI: Montreal Neurological Institute; FWHM: full width at half maximum; amPFC: anterior medial prefrontal cortex; dmPFC: dorsal medial prefrontal cortex; IFG: inferior frontal gyrus; pIPL: posterior inferior parietal lobule; SFG: superior frontal gyrus; TPJ: temporal parietal junction; vmPFC: ventral medial prefrontal cortex; MT: middle temporal motion complex; SPL: superior parietal lobule; aIPL: anterior inferior parietal lobule; daCC: dorsal anterior cingulated cortex; msPFC: medial superior prefrontal cortex; rlPFC: rostrolateral prefrontal cortex; aTL: anterior temporal lobe; HF: hippocampal formation; pCC: posterior cingulated cortex; FEF: frontal eye fields; iPCS: inferior precentral sulcus; SOG: superior occipital gyrus; aINS: anterior insula; dlPFC: dorsolateral prefrontal cortex; MFG(BA6): middle frontal gyrus BA6; MFG(BA9): middle frontal gyrus BA9.