PET mapping of neurofunctional changes in a posttraumatic stress disorder model

Abstract

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. Methods: Serial 18F-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. Results: Increased glucose metabolism was observed in the bilateral amygdala after fearconditioning (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 glucosemetabolism (P , 0.01). Conclusion: 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. 18F-FDG PET may provide a promising in vivo approach for evaluating exposurebased therapy of PTSD.