title: Frontal-amygdala connectivity alterations during emotion downregulation in bipolar I disorder.
abstract: BACKGROUND
  The symptoms of bipolar disorder suggest dysfunction of emotion regulatory networks. In healthy control populations, downregulation of emotional responses activates the ventral lateral prefrontal cortex (vlPFC) and dampens amygdala activation. This study investigated frontal and limbic function and connectivity during emotion downregulation in euthymic subjects with bipolar I disorder (BPI) and healthy control subjects.
  
  
  METHODS
  Thirty BPI and 26 control subjects underwent functional magnetic resonance imaging scanning while performing an emotion processing task with passive viewing and emotion downregulation conditions. Contrasts were made for each group comparing the downregulation and passive viewing conditions, and these were entered into a between-group random effects analysis to assess group differences in activation. Psychophysiological interaction analyses were conducted to test for significant group differences in functional connectivity between the amygdala and inhibitory frontal regions (i.e., vlPFC).
  
  
  RESULTS
  Control subjects showed the expected robust bilateral activation of frontal and limbic regions during passive viewing and emotion downregulation tasks. Between-group analyses revealed similar activation of BPI and control subjects during passive viewing but significantly decreased activation in bilateral vlPFC, bilateral anterior and posterior cingulate, medial frontal gyrus, and bilateral dorsal lateral prefrontal cortex during emotion downregulation in subjects with BPI. Connectivity analysis demonstrated that control subjects had significantly greater negative functional connectivity between the left amygdala and bilateral vlPFC compared with subjects with BPI.
  
  
  CONCLUSIONS
  This study provides evidence that dysfunction in the neural networks responsible for emotion regulation, including the prefrontal cortex, cingulate, and subcortical structures, are present in BPI subjects, even while euthymic.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at University of California, Los Angeles, California, USA.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Townsend
authors.forename: Salvatore J
authors.initials: SJ
authors.lastname: Torrisi
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Lieberman
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Sugar
authors.forename: Susan Y
authors.initials: SY
authors.lastname: Bookheimer
authors.forename: Lori L
authors.initials: LL
authors.lastname: Altshuler
mesh_terms: D000328:Adult; D000679:Amygdala / Q000503:physiopathology*; D001714:Bipolar Disorder / Q000473:pathology* / Q000523:psychology; D016022:Case-Control Studies; D015536:Down-Regulation / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D059907:Functional Neuroimaging / Q000379:methods / Q000523:psychology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology; D011603:Psychophysiology / Q000706:statistics & numerical data