title: Altered Microstructural Caudate Integrity in Posttraumatic Stress Disorder but Not Traumatic Brain Injury.
abstract: OBJECTIVE
  Given the high prevalence and comorbidity of combat-related PTSD and TBI in Veterans, it is often difficult to disentangle the contributions of each disorder. Examining these pathologies separately may help to understand the neurobiological basis of memory impairment in PTSD and TBI independently of each other. Thus, we investigated whether a) PTSD and TBI are characterized by subcortical structural abnormalities by examining diffusion tensor imaging (DTI) metrics and volume and b) if these abnormalities were specific to PTSD versus TBI.
  
  
  METHODS
  We investigated whether individuals with PTSD or TBI display subcortical structural abnormalities in memory regions by examining DTI metrics and volume of the hippocampus and caudate in three groups of Veterans: Veterans with PTSD, Veterans with TBI, and Veterans with neither PTSD nor TBI (Veteran controls).
  
  
  RESULTS
  While our results demonstrated no macrostructural differences among the groups in these regions, there were significant alterations in microstructural DTI indices in the caudate for the PTSD group but not the TBI group compared to Veteran controls.
  
  
  CONCLUSIONS
  The result of increased mean, radial, and axial diffusivity, and decreased fractional anisotropy in the caudate in absence of significant volume atrophy in the PTSD group suggests the presence of subtle abnormalities evident only at a microstructural level. The caudate is thought to play a role in the physiopathology of PTSD, and the habit-like behavioral features of the disorder could be due to striatal-dependent habit learning mechanisms. Thus, DTI appears to be a vital tool to investigate subcortical pathology, greatly enhancing the ability to detect subtle brain changes in complex disorders.
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.
authors.forename: Dana
authors.initials: D
authors.lastname: Waltzman
authors.affiliation: Department of Radiology, Harvard University, Cambridge, United States of America.
authors.forename: Salil
authors.initials: S
authors.lastname: Soman
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.|Sierra Pacific Mental Illness Research Education and Clinical Center (MIRECC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Hantke
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.|Sierra Pacific Mental Illness Research Education and Clinical Center (MIRECC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.
authors.forename: J Kaci
authors.initials: JK
authors.lastname: Fairchild
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.|Psychology Service, Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Kinoshita
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Palo Alto, United States of America.|Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, United States of America.
authors.forename: Max
authors.initials: M
authors.lastname: Wintermark
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.
authors.forename: J Wesson
authors.initials: JW
authors.lastname: Ashford
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.
authors.forename: Jerome
authors.initials: J
authors.lastname: Yesavage
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.
authors.forename: Leanne
authors.initials: L
authors.lastname: Williams
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.|Defense Veterans Brain Injury Center (DVBIC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.
authors.forename: Maheen M
authors.initials: MM
authors.lastname: Adamson
authors.affiliation: War Related Illness and Injury Study Center (WRIISC), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, United States of America.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, United States of America.|Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, United States of America.
authors.forename: Ansgar J
authors.initials: AJ
authors.lastname: Furst
mesh_terms: D000328:Adult; D000368:Aged; D000070642:Brain Injuries, Traumatic / Q000000981:diagnostic imaging / Q000473:pathology*; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000473:pathology*; D003072:Cognition Disorders; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging / Q000473:pathology*; D014728:Veterans