An investigation of resting state functional connectivity of the anterior and posterior Hippocampal subregions in posttraumatic stress disorder and its relationship with symptoms

Posttraumatic stress disorder (PTSD) is associated with abnormal hippocampal activity; however, the functional connectivity (FC) of the hippocampus with other brain regions and its relations with symptoms warrants further attention. I investigated FC of the hippocampus at a subregional level in PTSD during a resting state compared to trauma exposed controls (TECs). Based on imaging literature in PTSD, I targeted the FCs of the hippocampal head and tail subregions with the amygdala, medial prefrontal cortex (mPFC), and the posterior cingulate (PCC). The PTSD group had significantly greater FC compared to the TEC group between the left hippocampal head and the right amygdala, and for the left hippocampal tail with bilateral PCC. Resting state FC predicted symptom severity at time of scan and 4-months post-scan. These results highlight abnormal illness-related FC with both the hippocampal head and tail and provide support for future investigations of imaging biomarkers predictive of disease progression.