Functional connectivity of the prefrontal cortex and the amygdala in posttraumatic stress disorder.
BACKGROUND
Persistent, intrusive re-experiencing in posttraumatic stress disorder (PTSD) is commonly construed as a failure of cingulate inhibition (i.e., extinction) over a hyperresponsive amygdala, based primarily on animal research of fear conditioning and the finding of cingulate hypoperfusion in PTSD.


METHODS
We examined functional connectivity in patients with PTSD and healthy trauma survivors during repeated symptom provocation using H(2)O(15) positron emission tomography.


RESULTS
Memory retrieval networks (right prefrontal cortex, hippocampus, and visual cortex) were common to both groups. Networks supporting autonomic and emotional control and preparatory motor action (amygdala, anterior cingulate, subcallosal gyrus, and premotor cortex) differed between the two groups and became progressively disparate with successive presentations of the traumatic script. Patterns of effective connectivity demonstrated the predominance of direct influences of the amygdala on visual cortex, subcallosal gyrus, and anterior cingulate in PTSD but not in control subjects. There was little evidence for failure of inhibition of cingulate or subcallosal cortex over the amygdala.


CONCLUSIONS
These patterns might represent excessive influences of the amygdala over regions involved in autonomic, and higher-order visual memory processing in PTSD. The present data suggest that inferences of direct correspondence between animal studies and pathophysiology of PTSD should be made with caution.
Gilboa
Asaf
A
Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
Shalev
Arieh Y
AY
Laor
Lucian
L
Lester
Hava
H
Louzoun
Yoram
Y
Chisin
Roland
R
Bonne
Omer
O
D000328:Adult; D000679:Amygdala / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014055:Tomography, Emission-Computed; D014793:Visual Cortex / Q000503:physiopathology