title: Ventral striatum reactivity to reward and recent life stress interact to predict positive affect.
abstract: BACKGROUND
  Stressful life events are among the most reliable precipitants of major depressive disorder; yet, not everyone exposed to stress develops depression. It has been hypothesized that robust neural reactivity to reward and associated stable levels of positive affect (PA) may protect against major depressive disorder in the context of environmental adversity. However, little empirical data exist to confirm this postulation. Here, we test the hypothesis that individuals with relatively low ventral striatum (VS) reactivity to reward will show low PA levels in the context of recent life stress, while those with relatively high VS reactivity will be protected against these potentially depressogenic effects.
  
  
  METHODS
  Differential VS reactivity to positive feedback was assessed using blood oxygen level-dependent functional magnetic resonance imaging in a sample of 200 nonpatient young adults. Recent life stress, current depressive symptoms, and PA were assessed via self-report. Linear regression models were used to investigate the moderating effects of VS reactivity on the relationship between recent stress and state PA across participants.
  
  
  RESULTS
  Recent life stress interacted with VS reactivity to predict self-reported state PA, such that higher levels of life stress were associated with lower PA for participants with relatively low, but not for those with high, VS reactivity. These effects were independent of age, gender, race/ethnicity, trait PA, and early childhood trauma.
  
  
  CONCLUSIONS
  The current results provide empirical evidence for the potentially protective role of robust reward-related neural responsiveness against reductions in PA that may occur in the wake of life stress and possibly vulnerability to depression precipitated by stressful life events.
authors.affiliation: Department of Psychology and Neuroscience and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27705, USA. yuliya.nikolova@duke.edu
authors.forename: Yuliya S
authors.initials: YS
authors.lastname: Nikolova
authors.forename: Ryan
authors.initials: R
authors.lastname: Bogdan
authors.forename: Bartholomew D
authors.initials: BD
authors.lastname: Brigidi
authors.forename: Ahmad R
authors.initials: AR
authors.lastname: Hariri
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods / Q000523:psychology*; D003342:Corpus Striatum / Q000098:blood supply / Q000502:physiology*; D003865:Major Depressive Disorder / Q000503:physiopathology*; D005006:Ethnicity / Q000523:psychology; D005260:Female; D006801:Humans; D008016:Life Change Events; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology; D008297:Male; D012201:Reward; D057566:Self Report; D013315:Stress, Psychological / Q000503:physiopathology*