Relationship between Amyloid-β Deposition and the Coupling between Structural and Functional Brain Networks in Patients with Mild Cognitive Impairment and Alzheimer's Disease.

Hui Zhang,Edward S Hui,Henry K F Mak,Peng Cao

doi:10.3390/brainsci11111535

Hui Zhang, Edward S Hui + Show 2 more

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https://doi.org/10.3390/brainsci11111535

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Abstract

Previous studies have demonstrated that the accumulation of amyloid-β (Aβ) pathologies has distinctive stage-specific effects on the structural and functional brain networks along the Alzheimer’s disease (AD) continuum. A more comprehensive account of both types of brain network may provide a better characterization of the stage-specific effects of Aβ pathologies. A potential candidate for this joint characterization is the coupling between the structural and functional brain networks (SC-FC coupling). We therefore investigated the effect of Aβ accumulation on global SC-FC coupling in patients with mild cognitive impairment (MCI), AD, and healthy controls. Patients with MCI were dichotomized according to their level of Aβ pathology seen in 18F-flutemetamol PET-CT scans—namely, Aβ-negative and Aβ-positive. Our results show that there was no difference in global SC-FC coupling between different cohorts. During the prodromal AD stage, there was a significant negative correlation between the level of Aβ pathology and the global SC-FC coupling of MCI patients with positive Aβ, but no significant correlation for MCI patients with negative Aβ. During the AD dementia stage, the correlation between Aβ pathology and global SC-FC coupling in patients with AD was positive. Our results suggest that Aβ pathology has distinctive stage-specific effects on global coupling between the structural and functional brain networks along the AD continuum.

Highlights

Alzheimer’s disease (AD), a chronic disease characterized by progressive memory loss and the deterioration of other cognitive functions, is one of the most common forms of dementia and results in death within 3 to 9 years after diagnosis [1]
Our results suggest that Aβ pathology has distinctive stage-specific effects on global coupling between the structural and functional brain networks along the AD continuum
We have previously shown that the majority of mild cognitive impairment (MCI) patients can be distinguished from AD patients based on 18 F-flutemetamol PET-CT scans with high efficacy [20]

Summary

Introduction

Alzheimer’s disease (AD), a chronic disease characterized by progressive memory loss and the deterioration of other cognitive functions, is one of the most common forms of dementia and results in death within 3 to 9 years after diagnosis [1]. Amyloid-β initially accumulates in the medial frontal and parietal cortices [3,4], while tau accumulates in the medial temporal lobe [5] These pathological hallmarks of AD follow stage-dependent changes along the AD continuum [6]. It is of note that previous studies have focused on investigating the effect of AD pathologies on the structural or functional brain network alone Considering these two types of brain connections are tightly coupled, whereby static anatomical connections facilitate and constrain the dynamic functional interactions between different brain regions [12,13,14], whether AD neuropathologies exhibit stage-dependent effects on the interplay between these two types of brain connections warrants further investigation

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