Altered Brain Functional Asymmetry in Patients With Major Depressive Disorder Related to Gastrointestinal Symptoms

Xiaoya Fu,Jingping Zhao,Feng Liu,Jindong Chen,Huabing Li,Yudan Ding,Wenbin Guo

doi:10.3389/fnins.2021.797598

Abstract

ObjectiveDisrupted brain functional asymmetry has been reported in major depressive disorder (MDD). The comorbidity may be a crucial factor to this functional asymmetry. It is quite common that gastrointestinal (GI) symptoms are comorbid with MDD, but limited evidence focuses on the effect of GI comorbidity on the neuropathology of MDD from a functional lateralization perspective.MethodsResting-state functional magnetic resonance imaging was obtained in 28 healthy controls (HCs), 35 MDD patients with GI symptoms (GI-MDD patients), and 17 patients with MDD without GI symptoms (nGI-MDD patients). The parameter of asymmetry (PAS) was used to analyze the imaging data and evaluate the changes of functional asymmetry.ResultsThe GI-MDD patients showed increased PAS scores in the left inferior frontal gyrus (IFG) and superior medial prefrontal cortex (MPFC) and decreased PAS scores in the right postcentral gyrus in comparison with nGI-MDD patients. The PAS scores of the left IFG and left superior MPFC were correlated with the severity of GI problems and could be applied to distinguish GI-MDD patients from nGI-MDD patients with an accuracy, a sensitivity, and a specificity of 92.31, 100, and 76.47%, respectively. Furthermore, GI-MDD and nGI-MDD patients both displayed increased PAS scores in the PCC/precuneus.ConclusionsThis study revealed the influence of concomitant GI symptoms on functional asymmetry in MDD patients. Increased PAS scores of the left IFG and superior MPFC might represent an unbalanced regulation of brain over GI function and had the potential to be regarded as distinctive features related to functional GI symptoms in MDD.

Highlights

Hemispheric asymmetry is widespread in various species and of great significance for human perception, emotion, cognition, and behavior (Güntürkün et al, 2020)
This study investigated the effect of GI symptoms on functional asymmetry in first-episode, treatment-naive major depressive disorder (MDD) patients
The parameter of asymmetry (PAS) scores of the left inferior frontal gyrus (IFG) and left superior medial prefrontal cortex (MPFC) were correlated with the severity of GI problems and, more importantly, they could better meet the requirment of discrimination between GI-MDD and nGI-MDD patients

Summary

Introduction

Hemispheric asymmetry is widespread in various species and of great significance for human perception, emotion, cognition, and behavior (Güntürkün et al, 2020). The right-left asymmetry in the process of emotional information sparks an interest to researchers. The results of neuroimaging studies suggested that brain functional lateralization in the emotional process might be region-specific (Wager et al, 2003; Beraha et al, 2012). A meta-analysis of electroencephalograph (EEG) studies reported a link of depression to altered resting frontal asymmetry with a moderate effect (Thibodeau et al, 2006). The psychosocial risk, especially maternal depression, showed an association to greater right-sided resting frontal EEG asymmetry in children (Peltola et al, 2014). These findings indicate that the anomalous hemispheric asymmetry may be of great importance for clinical diagnosis and treatment of depression. Bruder et al (2017) reviewed electrophysiological and functional magnetic resonance imaging (fMRI) evidence of brain asymmetry in depression and revealed abnormalities in brain asymmetry and lateralized responses to emotional stimuli, but the comorbidity might be a confound factor to suppress or enhance the alteration of brain asymmetry

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