Hippocampus Function Predicts Severity of Post-Traumatic Stress Disorder

Astur, R. S., St. Germain, S. A., Tolin, D., Ford, J., Russell, D., & Stevens, M. (2006). Hippocampus Function Predicts Severity of Post-Traumatic Stress Disorder. CyberPsychology & Behavior, 9(2), 234-240. doi:10.1089/cpb.2006.9.234. Retrieved from EBSCOhost.

http://ezproxy.utm.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=20594237&site=ehost-live

            The numerous negative consequences of continual exposure to stressors have lead to quite the large body of stress research in the field of psychology. Within the area of neuropsychology, researchers are interested in finding specific areas of the brain that are affected by stress and what the consequences of these affected brain areas might be. The area of neuropsychology meshes with the area of clinical psychology in this particular article as researchers examine a clinical population to find effects of the disorder on the brain. Actually, the study more closely examines if researchers can look to specific structures in the brain to predict the severity of a later psychological disorder. In particular, Astur, St. Germain, Tolin, Ford, Russell, & Stevens (2006) examined the hippocampal formation in efforts to predict the seriousness of later symptoms of Posttraumatic Stress Disorder, which was measured using a clinical standard test called the Clinically Administered PTSD Scale for DSM IV. To do this, researchers separated participants with PTSD and controls of relatively the same age and instructed them to perform the virtual Morris water task. This task required participants to locate and “swim” (in a virtual environment) to a hidden or a visible platform. During the task involving the hidden platform, memory and therefore the hippocampus should be utilized. During the performance of this task, participants’ brain activity was analyzed using functional magnetic resonance imaging. Neither group outperformed the other regarding the Morris water task. Regarding the fMRI images, researchers found a strong negative correlation between brain activity in the hippocampus and severity of PTSD symptoms. In non-technical language, those with less activity in the hippocampal region had more severe PTSD symptoms. The researchers offered the explanation that the chronic stress of PTSD has caused damage to their hippocampus, and thus, the neural activity in this task is decreased. However, it cannot be the case that the hippocampus has been dramatically damaged, because those with PTSD can still successfully perform the task and do not show any global memory deficits. Another explanation lies in the Clinical test for PTSD symptoms. Within this test, those with higher scores in hyper-arousal also tended to have decreased hippocampus activity. Hyper-arousal may be explained by increased activity in the amygdala, which has been found to directly compete with activity in the hippocampus. Based on these results, it might be possible to predict the harshness of PTSD symptoms based on analysis of the activity within the hippocampus. This makes sense because PTSD is typically accompanied by poorer memory, which is centralized in the hippocampal area. Further implications for this research may extend to the prediction of those who may be at risk for PTSD after a traumatic experience. The research shows the possible valuable uses of the virtual Morris water task to assess hippocampal activity.