Structural Neuroimaging of Hippocampus and Amygdala Subregions in Post-Traumatic Stress Disorder (PTSD): A Scoping Review

Numerous studies have explored the relationship between posttraumatic stress disorder (PTSD) and the hippocampus and amygdala, as both regions are implicated in the disorder’s pathogenesis and pathophysiology. Nevertheless, these key limbic regions consist of functionally and cytoarchitecturally distinct substructures that may play a different role in the etiology of PTSD. Spurred by the availability of automatic segmentation software, structural neuroimaging studies of human hippocampal and amygdala subregions have proliferated in recent years. Here, we present a pre-registered scoping review of the existing structural neuroimaging studies of the hippocampus and amygdala subregions in adults diagnosed with PTSD. A total of n=3513 studies assessing subregions volumes were identified, n=1689 of which were screened, and n=21 studies were eligible for this review (total n=2876 individuals). Most studies examined hippocampal subregions and reported decreased volumes of the CA1, CA3, dentate gyrus, and subiculum in PTSD. Fewer studies investigated amygdala subregions and reported altered volumes of the lateral, basal, and central amygdala. This review further highlights the conceptual and methodological limitations of the current literature and points out future research directions that may enhance our understanding of the distinct roles of hippocampal and amygdala subregions in post-traumatic psychopathology.