title: Default mode network abnormalities in bipolar disorder and schizophrenia.
abstract: The default-mode network (DMN) consists of a set of brain areas preferentially activated during internally focused tasks. We used functional magnetic resonance imaging (fMRI) to study the DMN in bipolar mania and acute schizophrenia. Participants comprised 17 patients with bipolar disorder (BD), 14 patients with schizophrenia (SZ) and 15 normal controls (NC), who underwent 10-min resting fMRI scans. The DMN was extracted using independent component analysis and template-matching; spatial extent and timecourse were examined. Both patient groups showed reduced DMN connectivity in the medial prefrontal cortex (mPFC) (BD: x=-2, y=54, z=-12; SZ: x=-2, y=22, z=18). BD subjects showed abnormal recruitment of parietal cortex (correlated with mania severity) while SZ subjects showed greater recruitment of the frontopolar cortex/basal ganglia. Both groups had significantly higher frequency fluctuations than controls. We found ventral mPFC abnormalities in BD and dorsal mPFC abnormalities in SZ. The higher frequency of BOLD signal oscillations observed in patients suggests abnormal functional organization of circuits in both disorders. Further studies are needed to determine how these abnormalities are related to specific symptoms of each condition.
authors.affiliation: McLean Hospital, Belmont, MA and Harvard Medical School, Boston, MA, United States. dongur@partners.org
authors.forename: Dost
authors.initials: D
authors.lastname: Ongür
authors.forename: Miriam
authors.initials: M
authors.lastname: Lundy
authors.forename: Ian
authors.initials: I
authors.lastname: Greenhouse
authors.forename: Ann K
authors.initials: AK
authors.lastname: Shinn
authors.forename: Vinod
authors.initials: V
authors.lastname: Menon
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Cohen
authors.forename: Perry F
authors.initials: PF
authors.lastname: Renshaw
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000473:pathology*; D001921:Brain / Q000098:blood supply / Q000473:pathology; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009415:Nerve Net / Q000098:blood supply; D012559:Schizophrenia / Q000473:pathology*; D013057:Spectrum Analysis; D055815:Young Adult