title: Preferential recruitment of the basolateral amygdala during memory encoding of negative scenes in posttraumatic stress disorder.
abstract: BACKGROUND
  The vast majority of functional neuroimaging studies in posttraumatic stress disorder (PTSD) have examined the amygdala as a unitary structure. However, an emerging body of studies indicates that separable functions are subserved by discrete amygdala subregions. The basolateral subdivision (BLA), as compared with the centromedial amygdala (CMA), plays a unique role in learning and memory-based processes for threatening events, and alterations to the BLA have been implicated in the pathogenesis of PTSD. We assessed whether PTSD is associated with differential involvement of the BLA versus the CMA during successful encoding of emotionally charged events.
  
  
  METHODS
  Participants with PTSD (n=11) and a trauma-exposed comparison (TEC) group (n=11) viewed a series of photos that varied in valence (negative versus positive) and arousal (high versus low) while undergoing functional magnetic resonance imaging (fMRI). Subsequently, participants completed an old/new recognition memory test.
  
  
  RESULTS
  Using analytic methods based on probabilistic cytoarchitectonic mapping, PTSD was associated with greater activation of the BLA, as compared to the CMA, during successful encoding of negative scenes, a finding which was not observed in the TEC group. Moreover, this memory-related activity in the BLA independently predicted PTSD status. Contrary to hypotheses, there was no evidence of altered BLA activity during memory encoding of high arousing relative to low arousing scenes.
  
  
  CONCLUSIONS
  Task-related brain activation in PTSD does not appear to be consistent across the entire amygdala. Importantly, memory-related processing of negative information in PTSD is associated with preferential recruitment of the BLA.
authors.affiliation: Department of Clinical Health Psychology, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada. Electronic address: rpatel4@exchange.hsc.mb.ca.
authors.forename: Ronak
authors.initials: R
authors.lastname: Patel
authors.affiliation: Department of Psychology, Ryerson University, Toronto, Ontario, Canada.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Girard
authors.affiliation: Trauma Recovery Center, Cincinnati VAMC - Ft. Thomas Division, Cincinnati, OH, United States.
authors.forename: Nicole
authors.initials: N
authors.lastname: Pukay-Martin
authors.affiliation: Department of Psychology, Ryerson University, Toronto, Ontario, Canada.
authors.forename: Candice
authors.initials: C
authors.lastname: Monson
mesh_terms: D000328:Adult; D000679:Amygdala / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001143:Arousal / Q000502:physiology; D066272:Basolateral Nuclear Complex / Q000000981:diagnostic imaging / Q000503:physiopathology; D001931:Brain Mapping; D004644:Emotions / Q000502:physiology*; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D021641:Recognition, Psychology / Q000502:physiology; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D055815:Young Adult
keywords: Amygdala; Basolateral amygdala; Emotion; Memory; Posttraumatic stress disorder; fMRI