Abnormality and mediating effects of brain morphological similarity network in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a polygenic disorder with complex genetic mechanisms. This study leveraged the fusion of multiple morphology to construct the morphological similarity network (MSN), and combined polygenic risk score (PRS), aiming to systematically explore structural changes in the brain due to PTSD, and the regulatory effects of genetic risk factors on brain structure.

200 adults who had lost their sole child, including 52 PTSD and 148 nonPTSD, and 45 healthy controls received structural MR scans and psychological assessments, and had peripheral venous blood for genetic testing. The MSN of each subject was constructed based on T₁WI, while PRS was calculated based on genetic testing data. Analysis of covariance (ANCOVA) and linear regression analysis were performed to evaluate relationship between MSN and PRS, as well as psychological assessment. Mediation analysis was also used to construct the mediation effect model of PRS-MSN-clinical symptoms/cognition.

PTSD patients demonstrated significantly abnormal morphological similarity values in multiple cortical regions and showed higher MSN values in the left isthmus of cingulate, pars opercularis of the inferior frontal gyrus and the right supramarginal gyrus, along with lower MSN values in the left superior frontal gyrus and the right inferior parietal gyrus and inferior temporal gyrus. The morphologically similar strength in the right precuneus fully mediated the relationship between PRS and anxiety severity.

PTSD patients demonstrate structural irregularities in numerous brain regions, and the MSN value in the right precuneus serves as a major mediator between PRS and anxiety severity.