Functional Connectivity Abnormalities of Brain Regions With Structural Deficits in Primary Insomnia Patients.

Dongdong Xie,Kai Yuan,Chang Liu,XianFu Wang,Ting Xue,Bo Liu,He Qin,Yifu Hao,Dahua Yu,Fang Dong

doi:10.3389/fnins.2020.00566

Abstract

ObjectivesThe present study examined the abnormal resting state functional connections (RSFCs) in structural deficit brain regions of primary insomnia (PI) patients.MethodsThirty-three PI patients and 38 well-matched healthy controls participated in our study. We used voxel-based morphometry and RSFC to study functional connectivity abnormalities of brain regions with structural deficits in PI patients.ResultsPI patients showed decreased gray matter (GM) volume in the left dorsolateral prefrontal cortex, left orbitofrontal cortex (OFC), bilateral middle frontal gyrus (MFC), right inferior frontal gyrus (IFG), and left inferior temporal gyrus. Gray matter volume in the right MFC negatively correlated with Self-Rating Scale of Sleep (SRSS) scores, and GM volume in the right IFG negatively correlated with SRSS and Insomnia Severity Index (ISI) scores. Therefore, the right MFC and right IFG were selected as regions of interest for RSFC analysis. PI patients had weakened RSFC between the right inferior parietal gyrus (IPC) and the right MFC compared to the healthy controls and between the left OFC and right IFG. The RSFC between the right MFC and right IPC negatively correlated with SRSS scores. The RSFC between the right IFG and left OFC negatively correlated with SRSS, ISI, SAS, and SDS scores.ConclusionsThe present study found structural changes in the right MFC and right IFG accompanied by RSFC changes. This finding may provide novel insights into the neural mechanisms of PI via combining structural and functional modality information.

Highlights

As one of the most common health problems in people and in clinical practice (Lichstein et al, 2003), primary insomnia (PI) generally manifests as difficulties in the onset and maintenance of sleep (Morin et al, 2011)
The volume of gray matter (GM) in several brain regions was decreased in PI patients, i.e., the left dorsolateral prefrontal cortex (DLPFC), left orbitofrontal cortex (OFC), bilateral MFC, right inferior frontal gyrus (IFG), and left inferior temporal gyrus (p < 0.05, familywise error (FWE) corrected; Figure 1)
The GM volume in the right MFC negatively correlated with the SelfRating Scale of Sleep (SRSS) score (Figure 2A), and GM volume in the right IFG negatively correlated with the SRSS score (Figure 2B) and Insomnia Severity Index (ISI) score (Figure 2C)

Summary

Introduction

As one of the most common health problems in people and in clinical practice (Lichstein et al, 2003), primary insomnia (PI) generally manifests as difficulties in the onset and maintenance of sleep (Morin et al, 2011). Over the past few decades, many neuroimaging studies investigated the neural mechanism of PI and found extensive structural and functional changes in several brain regions. Many structural neuroimaging studies used voxel-based morphometry (VBM) analysis to reveal PI-related brain tissue injury (Yeon et al, 2013), and multiple brain regions showed abnormal gray matter (GM) volume. Resting state functional connectivity (RSFC) is primarily used to examine spontaneous neuronal activity in the human brain, which may provide new insights into the neurological mechanism of abnormal behavior in PI patients (Dijk et al, 2010; Friston, 2011). Most previous studies focused on the difference in RSFC between PI patients and healthy subjects, but few studies investigated the RSFC in brain structural defect regions of PI patients in the whole brain

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