Positive association between local brain hypercorrelations and posttraumatic stress disorder (PTSD) symptom severity

Previous studies have documented neural network anomalies in posttraumatic stress disorder (PTSD) characterized by hypercorrelated interactions across brain areas, relative to controls. Here we evaluated and compared local, intra-area(s), interactions by computing crosscorrelations derived from prewhitened resting-state 3T fMRI BOLD time series within 84 brain regions (35 cortical areas and 7 subcortical nuclei per hemisphere) in 15 veterans with PTSD and 21 healthy controls. We found that intra-area correlations were significantly higher in PTSD, as compared to controls, indicating a restriction in local network flexibility. PTSD symptom severity was positively and significantly associated with increased local correlations, most prominently in frontal and limbic areas.