title: Emotional response inhibition in bipolar disorder: a functional magnetic resonance imaging study of trait- and state-related abnormalities.
abstract: BACKGROUND
  Impaired response inhibition and poor impulse control are hallmarks of the manic phase of bipolar disorder but are also present during depressive and, to a lesser degree, euthymic periods. The neural mechanisms underlying these impairments are poorly understood, including how mechanisms are related to bipolar trait or state effects.
  
  
  METHODS
  One-hundred four unmedicated participants with bipolar mania (BM) (n = 30), bipolar depression (BD) (n = 30), bipolar euthymia (BE) (n = 14), and healthy control subjects (n = 30) underwent functional magnetic resonance imaging during emotional and nonemotional go/no-go tasks. The go/no-go task requires participants to press a button for go stimuli, while inhibiting the response to no-go trials. In separate blocks, participants inhibited the response to happy faces, sad faces, or letters.
  
  
  RESULTS
  The BE group had higher insula activity during happy face inhibition and greater activity in left inferior frontal gyrus during sad face inhibition, demonstrating bipolar trait effects. Relative to the BE group, BD and BM groups demonstrated lower insula activity during inhibition of happy faces, though the depressed sample had lower activity than manic patients. The BD and BM groups had a greater response to inhibiting sad faces in emotion processing and regulation regions, including putamen, insula, and lateral prefrontal cortex. The manic group also had higher activity in insula and putamen during neutral letter inhibition.
  
  
  CONCLUSIONS
  These results suggest distinct trait- and state-related neural abnormalities during response inhibition in bipolar disorder, with implications for future research and treatment.
authors.affiliation: Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Tom A
authors.initials: TA
authors.lastname: Hummer
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Hulvershorn
authors.forename: Harish S
authors.initials: HS
authors.lastname: Karne
authors.forename: Abigail D
authors.initials: AD
authors.lastname: Gunn
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Amit
authors.initials: A
authors.lastname: Anand
mesh_terms: D000293:Adolescent; D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D004644:Emotions / Q000502:physiology*; D005149:Facial Expression; D059907:Functional Neuroimaging / Q000379:methods / Q000523:psychology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology*; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D014796:Visual Perception / Q000502:physiology