Magnetic resonance volumetry and spectroscopy of hippocampus and insula in relation to severe exposure of traumatic stress

Abstract

Severe and chronic stress affects the hippocampus, especially during development. However, studies concerning structural alterations of the hippocampus yielded a rather inconsistent picture. Moreover, further anxiety-relevant brain regions, such as the insula, might be implicated in the pathophysiology of posttraumatic stress disorder (PTSD). We combined magnetic resonance (MR) volumetric and spectroscopic analyses of hippocampus and insula in highly traumatized refugees without a history of alcohol/substance abuse or other comorbid diseases. No PTSD-related difference was apparent in the volumes or neurometabolite levels of bilateral hippocampus or insula. However, an association between left hippocampal N-acetyl-aspartate (NAA) and adverse childhood experiences indicated a potential detrimental effect of the early environment on hippocampal integrity. Our results add to increasing evidence that PTSD-related, morphological alterations in the hippocampus are a consequence of early adversity or may result from other factors, such as extensive use of alcohol.