Aberrant Brain Spontaneous Activity and Synchronization in Type 2 Diabetes Mellitus Subjects Without Mild Cognitive Impairment.

Yifan Li,Yue Feng,Chunhong Qin,Mingrui Li,Xin Tan,Shijun Qiu,Yi Liang,Xiaomeng Ma,Haoming Huang,Yuna Chen

doi:10.3389/fnins.2021.749730

Abstract

Objective: We aimed to explore whether the percent amplitude of fluctuation (PerAF) measurement could provide supplementary information for amplitude of low-frequency fluctuation (ALFF) about spontaneous activity alteration in type 2 diabetes mellitus (T2DM) subjects without mild cognitive impairment (MCI). Then we further evaluated the synchronization through the method of functional connectivity (FC) to better demonstrate brain changes in a more comprehensive manner in T2DM.Methods: Thirty T2DM subjects without MCI and thirty well-matched healthy subjects were recruited in this study. Subjects’ clinical data, neuropsychological test results, and resting-state functional magnetic resonance imaging (rs-fMRI) data were acquired. Voxel-based group difference comparisons between PerAF and ALFF were conducted. Then, seed-based FC between the recognized brain regions based on PerAF and ALFF and the rest of the whole brain was performed.Results: Compared with healthy group, T2DM group had significantly decreased PerAF in the bilateral middle occipital gyrus and the right calcarine, increased ALFF in the right orbital inferior frontal gyrus and decreased ALFF in the right calcarine. Seed-based FC analysis showed that the right middle occipital gyrus of T2DM subjects exhibited significantly decreased FC with the right caudate nucleus and right putamen. According to the partial correlation analyses, hemoglobin A1c (HbA1c) and immediate memory scores on the auditory verbal learning test (AVLT) were negatively correlated in the T2DM group. However, we found that total cholesterol was positively correlated with symbol digit test (SDT) scores.Conclusion: PerAF and ALFF may have different sensitivities in detecting the abnormal spontaneous brain activity in T2DM subjects. We suggest PerAF values may add supplementary information and indicate additional potential neuronal spontaneous activity in T2DM subjects without MCI, which may provide new insights into the neuroimaging mechanisms underlying early diabetes-associated cognitive decline.

Highlights

Type 2 diabetes mellitus (T2DM) can lead to cognitive impairment, which mainly presents as memory deterioration, slowed information processing speed and executive function (Cui et al, 2014) and can even progress to dementia
Intergroup comparison showed that compared with healthy controls (HCs), T2DM subjects had significantly increased amplitude of low-frequency fluctuation (ALFF) in the right orbital inferior frontal gyrus, decreased ALFF in the right calcarine (Table 2 and Figure 1A), and decreased percent amplitude of fluctuation (PerAF) in the bilateral middle occipital gyrus and the right calcarine (Table 2 and Figure 1B)
Seed-based functional connectivity (FC) analysis showed that compared with HCs, T2DM subjects exhibited significantly decreased FC between the right middle occipital gyrus and the right basal ganglia, which contains the right caudate nucleus and right putamen (Table 3 and Figure 2)

Summary

Introduction

Type 2 diabetes mellitus (T2DM) can lead to cognitive impairment, which mainly presents as memory deterioration, slowed information processing speed and executive function (Cui et al, 2014) and can even progress to dementia. Compared to healthy aging people, T2DM subjects are more prone to accelerated cognitive decline (Xiong et al, 2020). Many cognitive functions gradually decline before significant mild cognitive impairment (MCI) occurs (Ma et al, 2015; Yang et al, 2018; Li et al, 2020). We studied early neural spontaneous activity before MCI to determine the neural mechanisms of cognitive changes and investigate the imaging biomarkers of early cognitive decline in T2DM subjects

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Discussion

Conclusion