Recent Trauma Exposure Is Associated With Greater Thickness of the Primary Visual Cortex: 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 2 independent samples (N = 99) of recently trauma-exposed (RTE) individuals (discovery n = 38, replication n = 20) and nonrecently trauma-exposed (NRTE) (discovery n = 23) or nontrauma-exposed (NTE) (replication n = 18) individuals. Furthermore, we investigated whether visual cortex thickness was related to acute PTSD symptoms and whether trauma-related variability in thickness was specific to visual regions.

RESULTS

We observed greater primary visual cortex (V1) thickness in the RTE group compared with the NRTE/NTE group (discovery: d = 0.84, p = .002; replication: d = 0.67, p = .024). V1 differences remained when we included 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 = .002; replication: r = 0.08, p = .733).

CONCLUSIONS

The findings suggest that 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 that this visual area may be key to understanding potential resilience or susceptibility to trauma-related psychopathology.