title: Altered baseline brain activities before food intake in obese men: a resting state fMRI study.
abstract: Obesity as a chronic disease has become a global epidemic. However, why obese individuals eat more still remains unclear. Recent functional neuroimaging studies have found abnormal brain activations in obese people. In the present study, we used resting state functional MRI to observe spontaneous blood-oxygen-level dependent (BOLD) signal fluctuations during both hunger and satiety states in 20 lean and 20 obese men. Using a regional homogeneity (ReHo) analysis method, we measured temporal homogeneity of the regional BOLD signals. We found that, before food intake, obese men had significantly increased synchronicity of activity in the left putamen relative to lean men. Decreased synchronicity of activity was found in the orbitofrontal cortex (OFC) and medial prefrontal cortex(MPFC) in the obese subjects. And, the ratings of hunger of the obese subjects were higher than those of the lean subjects before food intake. After food intake, we did not find the significant differences between the obese men and the lean men. In all participations, synchronicity of activity increased from the fasted to the satiated state in the OFC. The results indicated that OFC plays an important role in feeding behavior, and OFC signaling may be disordered in obesity. Obese men show less inhibitory control during fasting state. This study has provided strong evidence supporting the hypothesis that there is a hypo-functioning reward circuitry in obese individuals, in which the frontal cortex may fail to inhibit the striatum, and consequently lead to overeating and obesity.
authors.affiliation: Department of Anatomy, Tianjin Medical University, Tianjin, China; Clinical Affective Neuroimaging Laboratory, Department of Psychiatry, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Anatomy, Tianjin Medical University, Tianjin, China. Electronic address: tiandr@tijmu.edu.cn.
authors.forename: Derun
authors.initials: D
authors.lastname: Tian
authors.affiliation: Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Chunshui
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Anatomy, Tianjin Medical University, Tianjin, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Tian
authors.affiliation: School of Life Sciences and Technology, Xidian University, Xi'an, China; Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Center for Cognition and Brain Disorders, The Affiliated Hospital at Hangzhou Normal University, Hangzhou, China.
authors.forename: Karen M
authors.initials: KM
authors.lastname: von Deneen
authors.affiliation: Center for Cognition and Brain Disorders, The Affiliated Hospital at Hangzhou Normal University, Hangzhou, China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zang
authors.affiliation: Clinical Affective Neuroimaging Laboratory, Department of Psychiatry, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Walter
authors.affiliation: Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA; College of Engineering, Department of Biomedical Engineering, Peking University, Beijing, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D004435:Eating; D006801:Humans; D006815:Hunger; D008279:Magnetic Resonance Imaging; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D012527:Satiation; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Food intake; Functional magnetic resonance imaging; Obesity; Regional homogeneity; Resting state