Amplitude of Low-Frequency Oscillations in First-Episode, Treatment-Naive Patients with Major Depressive Disorder: A Resting-State Functional MRI Study

Yunai Su,Carles Soriano-Mas,Wenji Dai,Xiaodong Wang,Yunlong Tan,Zhen Jin,Tianmei Si,Wei Chen,Gang Wang,Yawei Zeng,Li Wang,Xin Yu

doi:10.1371/journal.pone.0048658

Abstract

BackgroundResting-state fMRI is a novel approach to measure spontaneous brain activity in patients with major depressive disorder (MDD). Although most resting-state fMRI studies have focused on the examination of temporal correlations between low-frequency oscillations (LFOs), few studies have explored the amplitude of these LFOs in MDD. In this study, we applied the approaches of amplitude of low-frequency fluctuation (ALFF) and fractional ALFF to examine the amplitude of LFOs in MDD.Methodology/Principal FindingsA total of 36 subjects, 18 first-episode, treatment-naive patients with MDD matched with 18 healthy controls (HCs) completed the fMRI scans. Compared with HCs, MDD patients showed increased ALFF in the right fusiform gyrus and the right anterior and posterior lobes of the cerebellum but decreased ALFF in the left inferior temporal gyrus, bilateral inferior parietal lobule, and right lingual gyrus. The fALFF in patients was significantly increased in the right precentral gyrus, right inferior temporal gyrus, bilateral fusiform gyrus, and bilateral anterior and posterior lobes of the cerebellum but was decreased in the left dorsolateral prefrontal cortex, bilateral medial orbitofrontal cortex, bilateral middle temporal gyrus, left inferior temporal gyrus, and right inferior parietal lobule. After taking gray matter (GM) volume as a covariate, the results still remained.Conclusions/SignificanceThese findings indicate that MDD patients have altered LFO amplitude in a number of regions distributed over the frontal, temporal, parietal, and occipital cortices and the cerebellum. These aberrant regions may be related to the disturbances of multiple emotion- and cognition-related networks observed in MDD and the apparent heterogeneity in depressive symptom domains. Such brain functional alteration of MDD may contribute to further understanding of MDD-related network imbalances demonstrated in previous fMRI studies.

Highlights

Major depressive disorder (MDD) is highly prevalent and constitutes a pressing public health problem, with a yearly increase in morbidity and a high risk of mortality [1]
There were no significant differences between major depressive disorder (MDD) patients and healthy controls in gender, age, years of education, or handedness
FALFF values of any region and the total HRSD scores before and after the gray matter (GM) correction. Using both the amplitude of low-frequency fluctuation (ALFF) and fALFF measures, the current study examined resting-state cerebral function in a cohort of firstepisode, treatment-naive patients with MDD

Summary

Introduction

Major depressive disorder (MDD) is highly prevalent and constitutes a pressing public health problem, with a yearly increase in morbidity and a high risk of mortality [1]. Using a series of approaches, such as independent component analysis (ICA), seed-based methods and graph theory analysis, several fMRI studies have been conducted to examine the alterations of network connectivity in MDD patients at rest [4,5,6,7,8,9]. Overall, these approaches have led to the proposal that MDD is associated with the dysregulation of various neural networks. We applied the approaches of amplitude of low-frequency fluctuation (ALFF) and fractional ALFF to examine the amplitude of LFOs in MDD

Methods

Results

Conclusion