An emotional Stroop functional MRI study of euthymic bipolar disorder

Authors

  • Gin S Malhi,

    1. School of Psychiatry, University of New South Wales, Sydney
    2. Neuroscience Research Group, Mayne Clinical Research Imaging Centre, Prince of Wales Medical Research Institute, Sydney
    3. Mood Disorders Unit, Black Dog Institute, Sydney
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  • Jim Lagopoulos,

    1. School of Psychiatry, University of New South Wales, Sydney
    2. Neuroscience Research Group, Mayne Clinical Research Imaging Centre, Prince of Wales Medical Research Institute, Sydney
    3. Mood Disorders Unit, Black Dog Institute, Sydney
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  • Perminder S Sachdev,

    1. School of Psychiatry, University of New South Wales, Sydney
    2. Mood Disorders Unit, Black Dog Institute, Sydney
    3. Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, NSW
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  • Belinda Ivanovski,

    1. School of Psychiatry, University of New South Wales, Sydney
    2. Mood Disorders Unit, Black Dog Institute, Sydney
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  • Ron Shnier

    1. Diagnostic Imaging, Mayne Group, Melbourne, Victoria, Australia
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Dr Gin S Malhi, Mayne Clinical Research Imaging Centre, Prince of Wales Medical Research Institute, Barker Street, Randwick, NSW 2052, Australia.
Fax: +61-2-9382-8208;
e-mail: g.malhi@unsw.edu.au

Abstract

Objective:  To identify the brain regions associated with emotional processing in euthymic bipolar patients.

Methods:  The study examined 12 euthymic bipolar patients using functional magnetic resonance imaging (fMRI) while performing an emotional Stroop (eStroop) task. The task comprised emotionally valent and neutral words presented in alternating blocks that was designed to implicitly induce affect. In conjunction with fMRI, galvanic skin responses (GSR) were measured to monitor arousal.

Results:  Euthymic bipolar patients had diminished activation in response to the affective stimuli in both cortical and subcortical brain regions when compared with healthy subjects. In particular, patients had less activation in the left ventral prefrontal cortex suggesting a potential trait deficit. Patients were slower to react than healthy controls, but did not differ with respect to accuracy.

Conclusions:  Euthymic bipolar patients are perhaps constrained in their ability to engage affective processing. Diminished ventral prefrontal cortex activation corroborates previous reports of a potential trait deficit, suggesting that ‘all is not well in euthymia’, although the effects of medication cannot be overlooked.

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