Neuroimaging and neurocircuitry in post-traumatic stress disorder: what is currently known?

Neurobiologic, psychologic, and social factors interact jointly to create and perpetuate the symptoms of post-traumatic stress disorder (PTSD). The fear conditioning paradigm in animal research helped researchers gather preclinical evidence for the possible contribution of several brain areas to PTSD symptoms. In the past 10 years, highly sophisticated neuroimaging techniques made it possible for researchers to look at the brain of patients with PTSD and draw conclusions about the neurocircuitry underlying PTSD symptoms. In this article, the author will review the evidence from neuroimaging studies for the involvement of the following brain areas in PTSD neurocircuitry: the amygdala, the anterior cingulate cortex and subcallosal gyrus, the inferior frontal gyrus, the posterior cingulate cortex, and the hippocampus. Neuroimaging studies have shown these areas as altered in structure or function in patients with PTSD. The author also presents the normal functions that these areas subserve and, whenever possible based on the evidence, infer how their dysfunction may contribute importantly to the symptomatology of PTSD.