title: Serotonin transporter gene polymorphisms and brain function during emotional distraction from cognitive processing in posttraumatic stress disorder.
abstract: BACKGROUND
  Serotonergic system dysfunction has been implicated in posttraumatic stress disorder (PTSD). Genetic polymorphisms associated with serotonin signaling may predict differences in brain circuitry involved in emotion processing and deficits associated with PTSD. In healthy individuals, common functional polymorphisms in the serotonin transporter gene (SLC6A4) have been shown to modulate amygdala and prefrontal cortex (PFC) activity in response to salient emotional stimuli. Similar patterns of differential neural responses to emotional stimuli have been demonstrated in PTSD but genetic factors influencing these activations have yet to be examined.
  
  
  METHODS
  We investigated whether SLC6A4 promoter polymorphisms (5-HTTLPR, rs25531) and several downstream single nucleotide polymorphisms (SNPs) modulated activity of brain regions involved in the cognitive control of emotion in post-9/11 veterans with PTSD. We used functional MRI to examine neural activity in a PTSD group (n = 22) and a trauma-exposed control group (n = 20) in response to trauma-related images presented as task-irrelevant distractors during the active maintenance period of a delayed-response working memory task. Regions of interest were derived by contrasting activation for the most distracting and least distracting conditions across participants.
  
  
  RESULTS
  In patients with PTSD, when compared to trauma-exposed controls, rs16965628 (associated with serotonin transporter gene expression) modulated task-related ventrolateral PFC activation and 5-HTTLPR tended to modulate left amygdala activation. Subsequent to combat-related trauma, these SLC6A4 polymorphisms may bias serotonin signaling and the neural circuitry mediating cognitive control of emotion in patients with PTSD.
  
  
  CONCLUSIONS
  The SLC6A4 SNP rs16965628 and 5-HTTLPR are associated with a bias in neural responses to traumatic reminders and cognitive control of emotions in patients with PTSD. Functional MRI may help identify intermediate phenotypes and dimensions of PTSD that clarify the functional link between genes and disease phenotype, and also highlight features of PTSD that show more proximal influence of susceptibility genes compared to current clinical categorizations.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA. morey@biac.duke.edu
authors.forename: Rajendra A
authors.initials: RA
authors.lastname: Morey
authors.forename: Ahmad R
authors.initials: AR
authors.lastname: Hariri
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Gold
authors.forename: Michael A
authors.initials: MA
authors.lastname: Hauser
authors.forename: Heidi J
authors.initials: HJ
authors.lastname: Munger
authors.forename: Florin
authors.initials: F
authors.lastname: Dolcos
authors.forename: Gregory
authors.initials: G
authors.lastname: McCarthy
mesh_terms: D000679:Amygdala / Q000503:physiopathology; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D059907:Functional Neuroimaging / Q000379:methods / Q000523:psychology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000523:psychology; D008570:Memory, Short-Term / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D017397:Prefrontal Cortex / Q000503:physiopathology; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D047851:September 11 Terrorist Attacks / Q000523:psychology; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics / Q000502:physiology*; D013313:Stress Disorders, Post-Traumatic / Q000235:genetics* / Q000503:physiopathology* / Q000523:psychology; D014728:Veterans / Q000523:psychology; D014947:Wounds and Injuries / Q000503:physiopathology / Q000523:psychology
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins