Magnetic Resonance Imaging Study of Hippocampus Structural Alterations in Posttraumatic Stress Disorder: A Brief Review (Translated Version) (Report‪)‬

Post-traumatic stress disorder (PTSD) is a psychiatric condition in which an individual presents with intrusion, lability of mood, emotional numbness and avoidance after exposure to severe traumatic events. Neuropsychological studies have shown that PTSD patients have impaired attention, working memory, and new learning (1); electroencephalography reveals that affected persons have heightened processing of trauma-related information, but weaker processing of neutral information. (2) These findings suggest possible structural and functional abnormalities in memory-related brain areas. The hippocampal formation, which plays an important role in memory processes, probably exerts significant effects in the pathogenesis of PTSD. The hippocampus, an important component of the brain limbic system, is the area that controls learning and memory. While playing a significant role in spatial learning and memory, it is also implicated in anxiety behaviours. (3,4) Moreover, functional and structural abnormalities of the hippocampus are believed to be associated with a number of psychiatric disorders. The hippocampus is also one of the brain structures that regulates stress responses. Studies with animals demonstrated that chronic stress may lead to changes in hippocampal structure in rats, including suppression of neurogenesis, neural dendritic atrophy and neuron loss. Changes in hippocampal structure and function are therefore considered to be causally inter-related to the development of many psychiatric diseases. (5) Researchers studying the brain structure of patients with PTSD have focused mainly on the hippocampal region. This paper aimed to present an organised and selected review / analysis of relevant published Chinese and English literature on this topic.