Published online by Cambridge University Press: 22 November 2017
Limbic white matter pathways link emotion, cognition, and behavior and are potentially malleable to the influences of traumatic events throughout development. However, the impact of interactions between childhood and later life trauma on limbic white matter pathways has yet to be examined. Here, we examined whether childhood maltreatment moderated the effect of combat exposure on diffusion tensor imaging measures within a sample of military veterans (N = 28). We examined five limbic tracts of interest: two components of the cingulum (cingulum, cingulate gyrus, and cingulum hippocampus [CGH]), the uncinate fasciculus, the fornix/stria terminalis, and the anterior limb of the internal capsule. Using effect sizes, clinically meaningful moderator effects were found only within the CGH. Greater combat exposure was associated with decreased CGH fractional anisotropy (overall structural integrity) and increased CGH radial diffusivity (perpendicular water diffusivity) among individuals with more severe childhood maltreatment. Our findings provide preliminary evidence of the moderating effect of childhood maltreatment on the relationship between combat exposure and CGH structural integrity. These differences in CGH structural integrity could have maladaptive implications for emotion and memory, as well as provide a potential mechanism by which childhood maltreatment induces vulnerability to later life trauma exposure.
The authors thank Benjamin Paul, Ashlee McKeon, Ryan Stocker, and Noelle Rode for their assistance with participant screening, MRI procedures, and data organization. This work was supported by the American Academy of Child & Adolescent Psychiatry (AACAP) Pilot Research Award (to R.J.H.); National Institute of Mental Health Grants MH102406-01 (to L.B.), MH096944 (to M.L.W.), MH080696 and MH083035 (to A.G.), and MH100267 (to R.J.H.); and Department of Defense Congressionally Directed Medical Research Program Grants PT073961 and PR054093 (to A.G.).