title: Abnormal FMRI brain activation in euthymic bipolar disorder patients during a counting Stroop interference task.
abstract: BACKGROUND
  Bipolar disorder is characterized by disturbed mood homeostasis accompanied by cognitive impairments that appear to persist during euthymia. Cognitive probes, coupled with neuroimaging, provide an approach toward clarifying the neurophysiology of bipolar disorder.
  
  
  METHODS
  Sixteen patients with euthymic bipolar disorder and 16 healthy subjects underwent functional magnetic resonance imaging (fMRI) while performing a counting Stroop interference task and a control condition. Task performance was correlated with regional brain activation differences between groups, and the effect on brain activation of receiving versus not receiving medications was evaluated.
  
  
  RESULTS
  Bipolar patients exhibited impaired task performance relative to the healthy subjects. In addition, the two groups demonstrated significantly different patterns of brain activation during the interference task. Healthy subjects exhibited relatively increased activation in temporal cortical regions, middle frontal gyrus, putamen, and midline cerebellum. Bipolar subjects exhibited relatively greater activation in the medial occipital cortex. The groups demonstrated different associations between task performance and fMRI activation in these brain regions. No differences in activation in these regions were observed between patients who were versus those who were not receiving medications; however, patients receiving medications exhibited greater activation in the anterior cingulate and dorsolateral prefrontal cortex.
  
  
  CONCLUSIONS
  These differences suggest that patients with euthymic bipolar disorder fail to activate brain regions associated with performance of an interference task, which may contribute to impaired task performance. Medications do not explain these differences but may influence activation of brain regions primarily associated with performing an interference task.
authors.affiliation: Center for Imaging Research, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0583, USA. stephen.strakowski@uc.edu
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Strakowski
authors.forename: Caleb M
authors.initials: CM
authors.lastname: Adler
authors.forename: Scott K
authors.initials: SK
authors.lastname: Holland
authors.forename: Neil P
authors.initials: NP
authors.lastname: Mills
authors.forename: Melissa P
authors.initials: MP
authors.lastname: DelBello
authors.forename: James C
authors.initials: JC
authors.lastname: Eliassen
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000503:physiopathology* / Q000523:psychology; D001921:Brain / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales; D013647:Task Performance and Analysis