Functional Connectivity with the Fear Circuitry in Combat-Related PTSD

Leslie Yan¹, Mariana Lazar¹, Clare Henn-Haase¹, Charles Marmar¹

Previous studies of posttraumatic stress disorder (PTSD)with neuroimaging and animal models have identified several brain structures of the fear circuitry to play critical roles in the neural mechanism of PTSD, including the amygdala, the anterior cingulate cortex and the insula; these structures are shown to be hyper-responsive in previous task-based neuroimaging studies during symptom provocation conditions. However the neural connectivity between these structures and other neural systems has not yet been systematically investigated, therefore the present study used resting state fMRI to study the functional connectivity with the above mentioned structures as seeds in combat veterans with (PTSD+) and without PTSD(PTSD-). Results demonstrated that PTSD subjects had decreased functional connectivity between the fear circuitry and prefrontal cortex compared to controls, and decreased functional connectivity between the insula and the default mode network.