Anterior cingulate volumes associated with trait impulsivity in individuals with bipolar disorder |
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Authors: | Koji Matsuo Mark A Nicoletti Marco A M Peluso John P Hatch Kiyotaka Nemoto Yoshifumi Watanabe Fabiano G Nery E Serap Monkul Giovana B Zunta-Soares Charles L Bowden Jair C Soares |
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Affiliation: | Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA;, Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University of Graduate School of Medicine, Yamaguchi, Japan;, Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA;, Section of Psychiatric Epidemiology, Department of Psychiatry, University of São Paulo, São Paulo, Brazil;, Department of Orthodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA;, Division of Psychiatry, Tsukuba University Hospital, Tsukuba, Japan;, Bipolar Disorder Research Program (PROMAN), Institute of Psychiatry, Department of Psychiatry, University of São Paulo Medical School, São Paulo, Brazil |
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Abstract: | Objective: Impulsivity is associated with the clinical outcome and likelihood of risky behaviors among bipolar disorder (BD) patients. Our previous study showed an inverse relationship between impulsivity and orbitofrontal cortex (OFC) volume in healthy subjects. We hypothesized that BD patients would show an inverse relationship between impulsivity and volumes of the OFC, anterior cingulate cortex (ACC), medial prefrontal cortex, and amygdala, which have been implicated in the pathophysiology of BD. Methods: Sixty-three BD patients were studied (mean ± SD age = 38.2 ± 11.5 years; 79% female). The Barratt Impulsiveness Scale (BIS), version 11A, was used to assess trait impulsivity. Images were processed using SPM2 and an optimized voxel-based morphometry protocol. We examined the correlations between BIS scores and the gray matter (GM) and white matter (WM) volumes of the prespecified regions. Results: Left rostral ACC GM volume was inversely correlated with the BIS total score ( t = 3.95, pcorrected = 0.003) and the BIS motor score ( t = 5.22, pcorrected < 0.001). In contrast to our hypothesis, OFC volumes were not significantly associated with impulsivity in BD. No WM volume of any structure was significantly correlated with impulsivity. No statistical association between any clinical variable and the rostral ACC GM volumes reached significance. Conclusions: Based on our previous findings and the current results, impulsivity may have a different neural representation in BD and healthy subjects, and the ACC may be involved in the pathophysiology of abnormal impulsivity regulation in BD patients. |
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Keywords: | anterior cingulate bipolar disorder impulsive behavior magnetic resonance imaging voxel-based morphometry |
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