PET Mapping of Neurofunctional Changes in a Posttraumatic Stress Disorder Model

Posttraumatic stress disorder (PTSD) is an anxiety disorder that occurs after exposure to a traumatic event. This study aimed to investigate the neurobiologic changes before and after exposure-based therapy by PET in a rat model of PTSD.Serial (18)F-FDG PET imaging studies were performed under the control (tone presentation), fear-conditioning, and extinction retrieval phases. Neuroactivity marker c-Fos protein was used for immunostaining.Increased glucose metabolism was observed in the bilateral amygdala after fear-conditioning (P < 0.001) and in the right posterior insular cortex under extinction retrieval (P < 0.001) compared with the control phase. Increased c-Fos expression in the posterior insular cortex under extinction retrieval was positively correlated to the glucose metabolism (P < 0.01).Our results indicated that the amygdala plays a key role in fear memory formation and, most importantly, the insular cortex is related to the retrieval of extinction memory. (18)F-FDG PET may provide a promising in vivo approach for evaluating exposure-based therapy of PTSD.