Reduced gray matter volume in ventral prefrontal cortex but not amygdala in bipolar disorder: Significant effects of gender and trait anxiety

Almeida, Jorge R.C.; Akkal, Dalila; Hassel, Stefanie; Travis, Michael J.; Banihashemi, Layla; Kerr, Natalie; Kupfer, David J.; Phillips, Mary L.

doi:10.1016/j.pscychresns.2008.02.001

« Previous Next »Psychiatry Research: Neuroimaging
Volume 171, Issue 1 , Pages 54-68, 30 January 2009

Reduced gray matter volume in ventral prefrontal cortex but not amygdala in bipolar disorder: Significant effects of gender and trait anxiety

Jorge R.C. Almeida
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Psychiatry, University of São Paulo Medical School, São Paulo, Brazil
Dalila Akkal
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
Stefanie Hassel
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
Michael J. Travis
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
Layla Banihashemi
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
Natalie Kerr
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
David J. Kupfer
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
Mary L. Phillips
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Division of Psychological Medicine, Institute of Psychiatry and GKT School of Medicine, De Crespigny Park, London, SE5 8AF, UK
- Corresponding author. Western Psychiatric Institute and Clinic, 3811 O'Hara Street, Pittsburgh, PA 15213-2593, USA. Tel.: +1 412 383 8206.

Received 9 October 2007; received in revised form 2 February 2008; accepted 3 February 2008.

Abstract

Neuroimaging studies in bipolar disorder report gray matter volume (GMV) abnormalities in neural regions implicated in emotion regulation. This includes a reduction in ventral/orbital medial prefrontal cortex (OMPFC) GMV and, inconsistently, increases in amygdala GMV. We aimed to examine OMPFC and amygdala GMV in bipolar disorder type 1 patients (BPI) versus healthy control participants (HC), and the potential confounding effects of gender, clinical and illness history variables and psychotropic medication upon any group differences that were demonstrated in OMPFC and amygdala GMV. Images were acquired from 27 BPI (17 euthymic, 10 depressed) and 28 age- and gender-matched HC in a 3T Siemens scanner. Data were analyzed with SPM5 using voxel-based morphometry (VBM) to assess main effects of diagnostic group and gender upon whole brain (WB) GMV. Post-hoc analyses were subsequently performed using SPSS to examine the extent to which clinical and illness history variables and psychotropic medication contributed to GMV abnormalities in BPI in a priori and non-a priori regions has demonstrated by the above VBM analyses. BPI showed reduced GMV in bilateral posteromedial rectal gyrus (PMRG), but no abnormalities in amygdala GMV. BPI also showed reduced GMV in two non-a priori regions: left parahippocampal gyrus and left putamen. For left PMRG GMV, there was a significant group by gender by trait anxiety interaction. GMV was significantly reduced in male low-trait anxiety BPI versus male low-trait anxiety HC, and in high- versus low-trait anxiety male BPI. Our results show that in BPI there were significant effects of gender and trait-anxiety, with male BPI and those high in trait-anxiety showing reduced left PMRG GMV. PMRG is part of medial prefrontal network implicated in visceromotor and emotion regulation.

Keywords: Bipolar 1 disorder, Voxel-based morphometry, Gender, Neuroimage