Identify changes of brain regional homogeneity in bipolar disorder and unipolar depression using resting-state FMRI.

Min-Jie Liang,Xiao-Ling Yang,Jin Fang,Quan Zhou,Wen-Li Chen,Kan-Rong Yang,Zheng Huang,Kewei Chen

doi:10.1371/journal.pone.0079999

Abstract

BackgroundTo identify changes in brain activation patterns in bipolar disorder (BD) and unipolar depression (UD) patients.Methodology/Principal FindingsResting-state fMRI scans of 16 healthy controls, 17 BD and 16 UD patients were obtained. T-test of normalized regional homogeneity (ReHo) was performed in a voxel-by-voxel manner. A combined threshold of á = 0.05, minimum cluster volume of V = 10503 mm3 (389 voxels) were used to determine ReHo differences between groups. In UD group, fMRI revealed ReHo increases in the left middle occipital lobe, right inferior parietal lobule, right precuneus and left convolution; and ReHo decreases in the left parahippocampalgyrus, right precentralgyrus, left postcentralgyrus, left precentralgyrus and left cingulated. In BD group, ReHo increases in the right insular cortex, left middle frontal gyrus, left precuneus, left occipital lobe, left parietal, left superior frontal gyrus and left thalamus; and ReHo decreases in the right anterior lobe of cerebellum, pons, right precentralgyrus, left postcentralgyrus, left inferior frontal gyrus, and right cingulate. There were some overlaps in ReHo profiles between UD and BD groups, but a marked difference was seen in the thalamus of BD.Conclusions/SignificanceThe resting-state fMRI and ReHo mapping are a promising tool to assist the detection of functional deficits and distinguish clinical and pathophysiological signs of BD and UD.

Highlights

Bipolar disorder (BD) is a common psychiatric condition and the sixth leading cause of disability that affects 1.5–3.0% of the population worldwide [1,2]
Group characteristics and psychological data Due to excessive head movement during scanning, imaging data from 2 unipolar depression (UD) and 3 bipolar disorder (BD) patients were excluded and a total of 49 participants were included in this study
It has been demonstrated that in the absence of any stimulus the network exhibits temporally coherent low-frequency fluctuations of the blood oxygen level-dependent (BOLD) signal [49,50]. Such functional connectivity studies need to select a Regions of interest (ROI) for examining relationships among connected regions

Summary

Introduction

Bipolar disorder (BD) is a common psychiatric condition and the sixth leading cause of disability that affects 1.5–3.0% of the population worldwide [1,2]. According to the Diagnostic and Statistical Manual of Mental Disorders (DSMIV) it might be easy to make diagnosis when BD patient is in the manic and hypomanic state [3], but BD patients who are mainly in depressive episodes without a history of mania are often misdiagnosed [4]. These patients are often treated as having recurrent unipolar depression (UD), which can lead to inadequate treatment, increased medical costs and poor outcomes [5,6,7]. To identify changes in brain activation patterns in bipolar disorder (BD) and unipolar depression (UD) patients

Methods

Results

Conclusion