White matter correlates of dissociation in a diverse sample of trauma-exposed women

•Dissociation has been linked to functional alterations in emotion regulation-related brain pathways.•Little is known regarding the relationship between dissociation and alterations in brain structure, particularly white matter microstructure.•Lesser microstructural integrity of white matter tracts that subserve information relay and processing, sensory integration, and memory was associated with greater dissociation severity.•These stress-sensitive white matter pathways may be good targets for future psychotherapeutic and neuromodulatory interventions for dissociative individuals. Dissociation is a common response to trauma linked to functional brain disruptions in brain networks subserving emotion regulation and multisensory integration; however, structural neural correlates of dissociation are less known, particularly abnormalities in stress-sensitive white matter (WM) tracts. The present study examined associations between dissociation and WM microstructure, assessed via fractional anisotropy (FA), in a large, diverse sample of women recruited as part of a long-standing trauma study, the Grady Trauma Project (GTP). As part of GTP, 135 trauma-exposed women (18–62 years old, M=34.25, SD=12.96, 84% self-identifying as Black) were recruited, received diffusion tensor imaging, and completed the Multiscale Dissociation Inventory (MDI); FA values were extracted from ten major WM tracts of interest. Partial correlations were conducted to examine associations between dissociation facets (MDI total and subscales) and FA while covarying age and temporal signal-to-noise ratio; false discovery rate corrected p < 0.05 indicated statistical significance. FA in seven tracts showed significant negative associations with overall dissociation (MDI total score; rs