title: First-episode medication-naive major depressive disorder is associated with altered resting brain function in the affective network.
abstract: BACKGROUND
  Major depressive disorder (MDD) has been associated with abnormal structure and function of the brain's affective network, including the amygdala and orbitofrontal cortex (OFC). However, it is unclear if alterations of resting-state function in this affective network are present at the initial onset of MDD.
  
  
  OBJECTIVE
  To examine resting-state function of the brain's affective network in first-episode, medication-naive patients with MDD compared to healthy controls (HCs).
  
  
  METHODS
  Resting-state functional magnetic resonance imaging (rs-fMRI) was performed on 32 first-episode, medication-naive young adult patients with MDD and 35 matched HCs. The amplitude of low-frequency fluctuations (ALFF) of the blood oxygen level-dependent (BOLD) signal and amygdala-seeded functional connectivity (FC) were investigated.
  
  
  RESULTS
  Compared to HC, MDD patients showed reduced ALFF in the bilateral OFC and increased ALFF in the bilateral temporal lobe extending to the insular and left fusiform cortices. Enhanced anti-correlation of activity between the left amygdala seed and the left OFC was found in MDD patients but not in HCs.
  
  
  CONCLUSIONS
  Reduced ALFF in the OFC suggests hypo-functioning of emotion regulation in the affective network. Enhanced anti-correlation of activity between the amygdala and OFC may reflect dysfunction of the amygdala-OFC network and additionally represent a pathological process of MDD.
authors.affiliation: The Medical Psychological Institute of the Second Xiangya Hospital, Central South University, Changsha, Hunan, China ; Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Xiaocui
authors.initials: X
authors.lastname: Zhang
authors.affiliation: The Medical Psychological Institute of the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Xueling
authors.initials: X
authors.lastname: Zhu
authors.affiliation: The Medical Psychological Institute of the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.affiliation: The Medical Psychological Institute of the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Xiongzhao
authors.initials: X
authors.lastname: Zhu
authors.affiliation: School of Psychology, South China Normal University, Guangzhou, Guangdong, China.
authors.forename: Mingtian
authors.initials: M
authors.lastname: Zhong
authors.affiliation: The Medical Psychological Institute of the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Jinyao
authors.initials: J
authors.lastname: Yi
authors.affiliation: Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America ; Department of Psychology, Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Hengyi
authors.initials: H
authors.lastname: Rao
authors.affiliation: The Medical Psychological Institute of the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Shuqiao
authors.initials: S
authors.lastname: Yao
mesh_terms: D000293:Adolescent; D000342:Affective Symptoms / Q000473:pathology / Q000503:physiopathology*; D000679:Amygdala / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000473:pathology / Q000503:physiopathology*; D004644:Emotions; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D012146:Rest; D013702:Temporal Lobe / Q000473:pathology / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D010100:Oxygen