Abnormal baseline brain activity in posttraumatic stress disorder: a resting-state functional magnetic resonance imaging study.

Little is known about how spontaneous brain activity during the resting state may be altered in posttraumatic stress disorder (PTSD) compared to traumatized individuals. In the current study, we used a measure of amplitude of low-frequency (0.01-0.08 Hz) fluctuation (ALFF) to investigate the regional baseline brain function of this disorder. Fifty-four medication-naive PTSD patients and seventy-two matched traumatized comparison subjects who experienced the Sichuan major earthquake participated in a functional magnetic resonance imaging (fMRI) scan. We analyzed the difference between the PTSD and comparison groups during a resting state using ALFF. PTSD patients showed decreased ALFF values in right lingual gyrus, cuneus, middle occipital gyrus, insula, and cerebellum, and increased ALFF values in right medial and middle frontal gyri, relative to traumatized individuals without PTSD. The ALFF value in the right medial frontal gyrus was positively correlated with severity of the disorder. Our findings show that abnormality of intrinsic brain activity exists under resting conditions in PTSD patients exposed to a major earthquake. Altered ALFF in predominantly right hemisphere cortical and subcortical regions and in cerebellum potentially contribute to the neural mechanisms underlying traumatic memory and symptoms in PTSD.