Alterations of brain local functional connectivity in amnestic mild cognitive impairment

Dan Zheng,Jian Guo Zhong,Pan Wen Zhao,Ping Lei Pan,Zhong Quan Yi,Wei Xia,Zhen Yu Dai,Hua Liang Li,Hai Cun Shi

doi:10.1186/s40035-018-0134-8

Abstract

BackgroundResting-state functional magnetic resonance imaging studies using a regional homogeneity (ReHo) method have reported that amnestic mild cognitive impairment (aMCI) was associated with abnormalities in local functional connectivity. However, their results were not conclusive.MethodsSeed-based d Mapping was used to conduct a coordinate-based meta-analysis to identify consistent ReHo alterations in aMCI.ResultsWe identified 10 studies with 11 datasets suitable for inclusion, including 378 patients with aMCI and 435 healthy controls. This meta-analysis identified significant ReHo alterations in patients with aMCI relative to healthy controls, mainly within the default mode network (DMN) (bilateral posterior cingulate cortex [PCC], right angular gyrus, bilateral middle temporal gyri, and left parahippocampal gyrus/hippocampus), executive control network (right superior parietal lobule and dorsolateral prefrontal cortex), visual network (right lingual gyrus and left middle occipital gyrus), and sensorimotor network (right paracentral lobule/supplementary motor area, right postcentral gyrus and left posterior insula). Significant heterogeneity of ReHo alterations in the bilateral PCC, left parahippocampal gyrus/hippocampus, and right superior parietal lobule/angular gyrus was observed. Exploratory meta-regression analyses indicated that general cognitive function, gender distribution, age, and education level partially contributed to this heterogeneity.ConclusionsThis study provides provisional evidence that aMCI is associated with abnormal ReHo within the DMN, executive control network, visual network, and sensorimotor network. These local functional connectivity alterations suggest coexistence of functional deficits and compensation in these networks. These findings contribute to the modeling of brain functional connectomes and to a better understanding of the neural substrates of aMCI. Confounding factors merit much attention and warrant future investigations.

Highlights

Resting-state functional magnetic resonance imaging studies using a regional homogeneity (ReHo) method have reported that amnestic mild cognitive impairment was associated with abnormalities in local functional connectivity
Study selection was according to the following inclusion criteria: 1) Patients enrollment met the diagnostic criteria for amnestic mild cognitive impairment (aMCI); 2) the study employed Resting-state functional magnetic resonance imaging (rs-fMRI) to measure ReHo differences between patients with aMCI and matched healthy controls; 3) the study utilized a voxel-based statistical analysis at the whole-brain level; 4) three-dimensional stereotactic coordinates in either Talairach or Montreal Neurological Institute (MNI) space were explicitly reported; and 5) the study was an original article that was peer-reviewed and published in an English-language journal
No significant differences were observed between the aMCI samples and Healthy control (HC) groups regarding mean age or education level (SMD = − 0.26; 95% Confidence interval (CI) = − 0.57 to 0.037, z = 1.72, p = 0.086)

Summary

Introduction

Resting-state functional magnetic resonance imaging studies using a regional homogeneity (ReHo) method have reported that amnestic mild cognitive impairment (aMCI) was associated with abnormalities in local functional connectivity. Many rs-fMRI studies have reported aberrant ReHo in patients with aMCI relative to healthy controls. ReHo alterations have been observed to correlate with cognitive and memory impairment in patients with aMCI [11,12,13,14]. ReHo alterations in the posterior cingulate cortex (PCC)/precuneus in patients with aMCI relative to healthy controls have been controversial.

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