Structural and functional neuroimaging in PTSD: A neurobiological update

Advances in neuroimaging permit in vivo investigation of the structural and functional neurobiology of post-traumatic stress disorder (PTSD). Recent reviews of structural and functional neuroimaging in PTSD are discussed together with recent studies. The significance of the findings is limited by the disparate groupings of PTSD trauma exposures, making generalization difficult, and this, combined with the heterogeneity inherent in the existing diagnostic criteria, renders the often conflicting data confusing. There has been an emphasis on studies of cortical structures, without adequate consideration of neural circuit models implicating other brain structures. There has been a move towards investigating subsets of symptoms, such as hyperarousal and dissociation, particularly in functional imaging studies. Overall, neuroimaging research in PTSD faces challenges for the future. The key improvements lie in: the definition and classification of trauma exposures, as they are not all equivalent in nature or indeed comparable; the study of restricted phenotypic subsets of symptoms or endophenotypes, such as hyperarousal and dissociation which may have different neural substrates; adequate study designs for power and control of confounders; and more focused research based upon targeted investigation of neural networks putatively involved in the processing and re-experiencing of trauma.