title: Functional connectivity in the cognitive control network and the default mode network in late-life depression.
abstract: BACKGROUND
  Abnormalities have been identified in the Cognitive Control Network (CCN) and the Default Mode Network (DMN) during episodes of late-life depression. This study examined whether functional connectivity at rest (FC) within these networks characterizes late-life depression and predicts antidepressant response.
  
  
  METHODS
  26 non-demented, non-MCI older adults were studied. Of these, 16 had major depression and 10 had no psychopathology. Depressed patients were treated with escitalopram (target dose 20 mg) for 12 weeks after a 2-week placebo phase. Resting state time series was determined prior to treatment. FC within the CCN was determined by placing seeds in the dACC and the DLPFC bilaterally. FC within the DMN was assessed from a seed placed in the posterior cingulate.
  
  
  RESULTS
  Low resting FC within the CCN and high resting FC within the DMN distinguished depressed from normal elderly subjects. Beyond this "double dissociation", low resting FC within the CCN predicted low remission rate and persistence of depressive symptoms and signs, apathy, and dysexecutive behavior after treatment with escitalopram. In contrast, resting FC within the DMN was correlated with pessimism but did not predict treatment response.
  
  
  CONCLUSIONS
  If confirmed, these findings may serve as a signature of the brain's functional topography characterizing late-life depression and sustaining its symptoms. By identifying the network abnormalities underlying biologically meaningful characteristics (apathy, dysexecutive behavior, pessimism) and sustaining late-life depression, these findings can provide a novel target on which new somatic and psychosocial treatments can be tested.
authors.affiliation: Weill Cornell Medical College, Weill-Cornell Institute of Geriatric Psychiatry, USA. gsalexop@med.cornell.edu
authors.forename: George S
authors.initials: GS
authors.lastname: Alexopoulos
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Hoptman
authors.forename: Dora
authors.initials: D
authors.lastname: Kanellopoulos
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Murphy
authors.forename: Kelvin O
authors.initials: KO
authors.lastname: Lim
authors.forename: Faith M
authors.initials: FM
authors.lastname: Gunning
mesh_terms: D000367:Age Factors; D000368:Aged; D001921:Brain / Q000503:physiopathology*; D015283:Citalopram / Q000627:therapeutic use; D003071:Cognition / Q000502:physiology; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D012146:Rest / Q000502:physiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use; D016037:Single-Blind Method
chemical_list: D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors