title: Smaller amygdala volume and reduced anterior cingulate gray matter density associated with history of post-traumatic stress disorder.
abstract: Although post-traumatic stress disorder (PTSD) may be seen to represent a failure to extinguish learned fear, significant aspects of the pathophysiology relevant to this hypothesis remain unknown. Both the amygdala and hippocampus are necessary for fear extinction occur, and thus both regions may be abnormal in PTSD. Twenty-five people who experienced the Tokyo subway sarin attack in 1995, nine who later developed PTSD and 16 who did not, underwent magnetic resonance imaging (MRI) with manual tracing to determine bilateral amygdala and hippocampus volumes. At the time of scanning, one had PTSD and eight had a history of PTSD. Results indicated that the group with a history of PTSD had significantly smaller mean bilateral amygdala volume than did the group that did not develop PTSD. Furthermore, left amygdala volume showed a significant negative correlation with severity of PTSD symptomatology as well as reduced gray matter density in the left anterior cingulate cortex. To our knowledge, this is the first observation of an association between PTSD and amygdala volume. Furthermore the apparent interplay between amygdala and anterior cingulate cortex represents support at the level of gross brain morphology for the theory of PTSD as a failure of fear extinction.
authors.affiliation: Department of Psychology, Monash University, Clayton 3800, Victoria, Australia. mark.rogers@med.monash.edu.au
authors.forename: Mark A
authors.initials: MA
authors.lastname: Rogers
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yamasue
authors.forename: Osamu
authors.initials: O
authors.lastname: Abe
authors.forename: Haruyasu
authors.initials: H
authors.lastname: Yamada
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ohtani
authors.forename: Akira
authors.initials: A
authors.lastname: Iwanami
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Kato
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Kasai
mesh_terms: D000328:Adult; D000679:Amygdala / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008016:Life Change Events; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013313:Stress Disorders, Post-Traumatic / Q000473:pathology*