A voxel-based morphometry study of frontal gray matter correlates of impulsivity

Authors

  • Koji Matsuo,

    1. Department of Psychiatry, the University of Texas Health Science Center at San Antonio, Texas
    2. Devision of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
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  • Mark Nicoletti,

    1. Department of Psychiatry, University of North Carolina at Chapel Hill, North Carolina
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  • Kiyotaka Nemoto,

    1. Department of Psychiatry, University of Tsukuba, Ibaraki, Japan
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  • John P. Hatch,

    1. Department of Psychiatry, the University of Texas Health Science Center at San Antonio, Texas
    2. Department of Orthodontics, The University of Texas Health Science Center at San Antonio, Texas
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  • Marco A.M. Peluso,

    1. Section of Psychiatric Epidemiology, Department of Psychiatry, University of São Paulo, São Paulo, Brazil
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  • Fabiano G. Nery,

    1. Department of Psychiatry, the University of Texas Health Science Center at San Antonio, Texas
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  • Jair C. Soares

    Corresponding author
    1. Department of Psychiatry, University of North Carolina at Chapel Hill, North Carolina
    2. Center of Excellence for Research and Treatment of Bipolar Disorders (CERT-BD), Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina
    • Center of Excellence for Research and Treatment of Bipolar Disorder (CERT-BD), Department of Psychiatry, Campus Box 7160, University of North Carolina, Chapel Hill, North Carolina 27599-7160
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  • These findings were presented in part at the annual meeting of the Society of Biological Psychiatry, May 19–21, 2006, Toronto, Canada.

Abstract

Impulsivity is a personality trait exhibited by healthy individuals, but excessive impulsivity is associated with some mental disorders. Lesion and functional neuroimaging studies indicate that the ventromedial prefrontal region (VMPFC), including the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC) and medial prefrontal cortex, and the amygdala may modulate impulsivity and aggression. However, no morphometric study has examined the association between VMPFC and impulsivity. We hypothesized that healthy subjects with high impulsivity would have smaller volumes in these brain regions compared with those with low impulsivity. Sixty-two healthy subjects were studied (age 35.4 ± 12.1 years) using a 1.5-T MRI system. The Barratt impulsiveness scale (BIS) was used to assess impulsivity. Images were processed using an optimized voxel-based morphometry (VBM) protocol. We calculated the correlations between BIS scale scores and the gray matter (GM) and white matter (WM) volumes of VMPFC and amygdala. GM volumes of the left and right OFC were inversely correlated with the BIS total score (P = 0.04 and 0.02, respectively). Left ACC GM volumes had a tendency to be inversely correlated with the BIS total score (P = 0.05). Right OFC GM volumes were inversely correlated with BIS nonplanning impulsivity, and left OFC GM volumes were inversely correlated with motor impulsivity. There were no significant WM volume correlations with impulsivity. The results of this morphometry study indicate that small OFC volume relate to high impulsivity and extend the prior finding that the VMPFC is involved in the circuit modulating impulsivity. Hum Brain Mapp 2009. © 2008 Wiley-Liss, Inc.

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