Recent trauma exposure is associated with greater thickness of area V1: a discovery and replication analysis.

BACKGROUND: Visual cortex morphology is associated with posttraumatic stress disorder (PTSD) symptoms. However, limited research has investigated whether trauma exposure itself relates to visual cortex structure. Distinguishing trauma-related variability from PTSD-specific variability has important implications for identifying potential neural signatures of the disorder. METHODS: We compared thickness of early visual areas (V1-V4v) in two independent samples (total n = 99) of recently trauma-exposed (RTE) individuals (Discovery n = 38, Replication n = 20) and individuals without recent (NRTE, Discovery n = 23) or no reported trauma exposure (NTE, Replication n = 18). We further investigated if visual cortex thickness was related to acute PTSD symptoms, and if trauma-related variability in thickness was specific to visual regions. RESULTS: We observed greater V1 thickness in the RTE compared to the NRTE/NTE group [Discovery: d = 0.84, p = 0.002; Replication: d = 0.67, p = 0.024]. V1 differences remained when including covariates such as sex, trauma load, current PTSD symptoms, and global cortical thickness. Ventral V4 thickness was positively associated with PTSD symptom severity in the discovery sample however this association was not observed in the replication dataset [Discovery: r = -0.49, p = 0.002; Replication: r = 0.08, p = 0.733]. CONCLUSIONS: The findings suggest trauma may acutely impact visual cortex morphology and may be partially independent of PTSD symptoms. Trauma-related variability in thickness was most observed in V1 which suggests this visual area may be key to understanding potential resilience or susceptibility to trauma-related psychopathology.