A new study shows that the experience of racial discrimination affects the microstructure of the brain, as well as increasing the risk for health disorders. The study, led by Negar Fani, PhD, Emory University Department of Psychiatry and Behavioral Sciences, Atlanta, GA, USA, appears in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier.
Racial discrimination is consistently associated with adverse health outcomes and has been linked to structural decrements in brain white matter. However, it is unclear whether discrimination-related neuroplastic changes could indirectly affect health outcomes. The goal of the research was to evaluate racial discrimination’s indirect associations on health outcomes through white matter microstructure in a sample of trauma-exposed black women.
Seventy-nine black women were recruited for a trauma study in an urban hospital setting and received a history and physical exam to assess medical disorders (compiled into a summed total of disorder types). Participants reported on experiences of racial discrimination and underwent diffusion tensor imaging; fractional anisotropy (FA) values were extracted from white matter pathways previously linked to racial discrimination (corpus callosum, CC, including the body and genu; anterior cingulum bundle, ACB; and superior longitudinal fasciculus, SLF) and entered into mediational models.
Indirect effects of racial discrimination on medical disorders through left ACB FA were significant β=.07, SE=.04, 95% CI [.003, .14] after accounting for trauma and economic disadvantage. Indirect effects of racial discrimination on medical disorders through CC genu FA were also significant β=.08, SE=.04, 95% CI [.01, .16].
Racial discrimination may increase risk for medical disorders via neuroplastic effects on microstructural integrity of stress-sensitive prefrontal white matter tracts. Racial discrimination-related changes in these tracts may affect health behaviors, which, in turn, influences vulnerability for medical disorders. These data highlight the connections between racial discrimination, prefrontal white matter connections and incidence of medical disorders in black Americans.
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