FIG. 1.

Post-traumatic stress symptoms clusters showed specific relations with limbic microstructure. Higher fractional anisotropy (FA) in the left hippocampus to amygdala pathway was associated with lower re-experiencing in the exracranial injury (EI) group and with higher avoidance in the traumatic brain injury (TBI) group. For both TBI and EI groups combined, hyperarousal was linked to higher FA of bilateral pathways connecting the amygdalae with orbital pre-frontal cortical (PFC), left amygdala to rostral anterior cingulate bundle, as well as to mean diffusivity (MD) of bilateral hippocampi. Avoidance was also related to higher FA of the right hippocampus to amygdala tract. Numbing was predicted specifically by elevated left hippocampal MD. Amygdala-red, hippocampus-green, orbital PFC-orange, rostral anterior cingulate bundle-yellow. Pathways indicated in white.