title: Functional brain-imaging correlates of negative affectivity and the onset of first-episode depression.
abstract: BACKGROUND
  The amygdala and subgenual anterior cingulate cortex (sACC) are key brain regions for the generation of negative affect. In this longitudinal fMRI study of adolescents we investigated how amygdala-sACC connectivity was correlated with negative affectivity (NA) both cross-sectionally and longitudinally, and examined its relationship to the onset of first-episode depression.
  
  
  METHODS
  Fifty-six adolescents who were part of a larger longitudinal study of adolescent development were included. They had no history of mental illness at the time of their baseline scan (mean age 16.5 years) and had a follow-up scan 2 years later (mean age 18.8 years). We used resting-state functional-connectivity MRI to investigate whether cross-sectional and change measures of amygdala-sACC connectivity were (i) correlated with NA and its change over time, and (ii) related to the onset of first-episode depression.
  
  
  RESULTS
  The magnitude of amygdala connectivity with sACC showed significant positive correlation with NA at both time-points. Further analysis confirmed that change in amygdala-sACC connectivity between assessments was correlated with change in NA. Eight participants developed a first episode of depression between the baseline and follow-up assessments: they showed increased amygdala-sACC connectivity at follow-up.
  
  
  CONCLUSIONS
  Amygdala-sACC connectivity is associated with NA in adolescence, with change in connectivity between these regions showing positive correlation with change in NA. Our observation that the onset of depression was associated with an increase in connectivity between the regions provides support for the neurobiological 'scar' hypothesis of depression.
authors.affiliation: Orygen Youth Health Research Centre, Centre for Youth Mental Health,The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: C G
authors.initials: CG
authors.lastname: Davey
authors.affiliation: Melbourne Neuropsychiatry Centre,Department of Psychiatry,The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: S
authors.initials: S
authors.lastname: Whittle
authors.affiliation: Melbourne Neuropsychiatry Centre,Department of Psychiatry,The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: B J
authors.initials: BJ
authors.lastname: Harrison
authors.affiliation: Melbourne School of Psychological Sciences, The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: J G
authors.initials: JG
authors.lastname: Simmons
authors.affiliation: Melbourne School of Psychological Sciences, The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: M L
authors.initials: ML
authors.lastname: Byrne
authors.affiliation: Melbourne School of Psychological Sciences, The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: O S
authors.initials: OS
authors.lastname: Schwartz
authors.affiliation: Melbourne School of Psychological Sciences, The University of Melbourne,Parkville,Victoria,Australia.
authors.forename: N B
authors.initials: NB
authors.lastname: Allen
mesh_terms: D000293:Adolescent; D000339:Affect; D000679:Amygdala / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000503:physiopathology*; D005260:Female; D059907:Functional Neuroimaging; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D010296:Parietal Lobe / Q000503:physiopathology; D011446:Prospective Studies; D055815:Young Adult
keywords: negative affectivity