Theoretical neuroanatomic models of posttraumatic stress disorder (PTSD)
and the results of previous neuroimaging studies of PTSD highlight the potential
importance of the amygdala and medial prefrontal regions in this disorder.
However, the functional relationship between these brain regions in PTSD has
not been directly examined.
To examine the relationship between the amygdala and medial prefrontal
regions during symptom provocation in male combat veterans (MCVs) and female
nurse veterans (FNVs) with PTSD.
Academic medical center.
Volunteer sample of 17 (7 men and 10 women) Vietnam veterans with PTSD
(PTSD group) and 19 (9 men and 10 women) Vietnam veterans without PTSD (control
Main Outcome Measures
We used positron emission tomography and the script-driven imagery paradigm
to study regional cerebral blood flow (rCBF) during the recollection of personal
traumatic and neutral events. Psychophysiologic and emotional self-report
data also were obtained to confirm the intended effects of script-driven imagery.
The PTSD group exhibited rCBF decreases in medial frontal gyrus in the
traumatic vs neutral comparison. When this comparison was conducted separately
by subgroup, MCVs and FNVs with PTSD exhibited these medial frontal gyrus
decreases. Only MCVs exhibited rCBF increases in the left amygdala. However,
for both subgroups with PTSD, rCBF changes in medial frontal gyrus were inversely
correlated with rCBF changes in the left amygdala and the right amygdala/periamygdaloid
cortex. Furthermore, in the traumatic condition, for both subgroups with PTSD,
symptom severity was positively related to rCBF in the right amygdala and
negatively related to rCBF in medial frontal gyrus.
These results suggest a reciprocal relationship between medial prefrontal
cortex and amygdala function in PTSD and opposing associations between activity
in these regions and symptom severity consistent with current functional neuroanatomic
models of this disorder.