title: Differential abnormalities of functional connectivity of the amygdala and hippocampus in unipolar and bipolar affective disorders.
abstract: OBJECTIVE
  The amygdala and hippocampus - two structures intimately associated with mood and cognition - have been reported to exhibit altered neural activity or volume in affective disorders. We hypothesized the amygdala and hippocampus would show altered and differential patterns of connectivity in patients with bipolar (BPs) and unipolar (UPs) disorder compared to healthy volunteers.
  
  
  METHODS
  Thirty BPs, 34 UPs, and 66 healthy volunteers were imaged using F-18-fluorodeoxyglucose and positron emission tomography while performing an auditory continuous performance task (CPT). Normalized mean activity of the amygdala and hippocampus was correlated with the rest of the brain.
  
  
  RESULTS
  In BPs, the amygdalae displayed exaggerated positive metabolic correlations with prefrontal and ventral striatal areas, while the hippocampus showed a paucity of normal inter-relations compared to controls. In contrast, in UPs the amygdala was significantly negatively correlated with prefrontal and anterior cingulate cortex, while the hippocampus was significantly more positively correlated to these same prefrontal areas.
  
  
  CONCLUSIONS
  During a simple cognitive task, the functional connectivity of the amygdala and hippocampus, regions usually associated with emotion and memory regulation, was substantially different in affective illness compared to healthy controls whether or not there were baseline abnormalities in these areas. These striking differences in functional connectivity of amygdala and hippocampus should be further explored in ill and well states and using more specific emotion and cognitive evocative tasks.
authors: National Institute of Mental Health, NIH, Bethesda, MD, United States. Electronic address: bbenson@mail.nih.gov.
authors: Brenda E
authors: BE
authors: Benson
authors: Uniformed Services, Bethesda, MD, United States.
authors: Mark W
authors: MW
authors: Willis
authors: Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States.
authors: Terence A
authors: TA
authors: Ketter
authors: National Institute of Mental Health, NIH, Bethesda, MD, United States.
authors: Andrew
authors: A
authors: Speer
authors: Veterans Affairs Medical Center, Little Rock, AR, United States.
authors: Tim A
authors: TA
authors: Kimbrell
authors: Positron Emission Tomography Department, NIH, Bethesda, MD, United States.
authors: Peter
authors: P
authors: Herscovitch
authors: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, United States.
authors: Mark S
authors: MS
authors: George
authors: Biological Psychiatry Branch, NIMH, NIH, Bethesda, MD, United States; Bipolar Collaborative Network, Bethesda, MD, United States.
authors: Robert M
authors: RM
authors: Post
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000339:Affect; D000679:Amygdala / Q000473:pathology / Q000503:physiopathology*; D001714:Bipolar Disorder / Q000473:pathology / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000473:pathology / Q000503:physiopathology*; D004644:Emotions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006179:Gyrus Cinguli / Q000503:physiopathology; D006309:Hearing; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D017397:Prefrontal Cortex / Q000503:physiopathology; D012146:Rest; D013647:Task Performance and Analysis
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Amygdala; Functional connectivity; Hippocampus; Metabolism; Mood disorders; Neuroimaging