title: Differential brain network activity across mood states in bipolar disorder.
abstract: This study aimed to identify how the activity of large-scale brain networks differs between mood states in bipolar disorder. The authors measured spontaneous brain activity in subjects with bipolar disorder in mania and euthymia and compared these states to a healthy comparison population.
  
  
  
  23 subjects with bipolar disorder type I in a manic episode, 24 euthymic bipolar I subjects, and 23 matched healthy comparison (HC) subjects underwent resting state fMRI scans. Using an existing parcellation of the whole brain, we measured functional connectivity between brain regions and identified significant differences between groups.
  
  
  
  In unbiased whole-brain analyses, functional connectivity between parietal, occipital, and frontal nodes within the dorsal attention network (DAN) were significantly greater in mania than euthymia or HC subjects. In the default mode network (DMN), connectivity between dorsal frontal nodes and the rest of the DMN differentiated both mood state and diagnosis.
  
  
  
  The bipolar groups were separate cohorts rather than subjects imaged longitudinally across mood states.
  
  
  
  Bipolar mood states are associated with highly significant alterations in connectivity in two large-scale brain networks. These same networks also differentiate bipolar mania and euthymia from a HC population. State related changes in DAN and DMN connectivity suggest a circuit based pathology underlying cognitive dysfunction as well as activity/reactivity in bipolar mania. Altered activities in neural networks may be biomarkers of bipolar disorder diagnosis and mood state that are accessible to neuromodulation and are promising novel targets for scientific investigation and possible clinical intervention.
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, United States; Psychotic Disorders Division, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States. Electronic address: robrady@bidmc.harvard.edu.
authors.forename: Roscoe O
authors.initials: RO
authors.lastname: Brady
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Tandon
authors.affiliation: Psychotic Disorders Division, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States.
authors.forename: Grace A
authors.initials: GA
authors.lastname: Masters
authors.affiliation: Psychotic Disorders Division, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States.
authors.forename: Allison
authors.initials: A
authors.lastname: Margolis
authors.affiliation: Department of Psychiatry, Harvard Medical School, Boston, MA, United States; Program for Neuropsychiatric Research, McLean Hospital, Belmont, MA, United States.
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Cohen
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States.
authors.forename: Matcheri
authors.initials: M
authors.lastname: Keshavan
authors.affiliation: Psychotic Disorders Division, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States.
authors.forename: Dost
authors.initials: D
authors.lastname: Öngür
mesh_terms: D000328:Adult; D000339:Affect; D001288:Attention; D001714:Bipolar Disorder / Q000473:pathology* / Q000523:psychology; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D003527:Cyclothymic Disorder / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012146:Rest; D055815:Young Adult
keywords: Bipolar; Euthymia; Imaging; Mania; Network; fMRI