Fig. 4.

Radial diffusivity (RD) was most sensitive at detecting changes in white matter properties following rmbTBI. (A) The most conspicuous difference in RD between injured and sham animals was at 7 days post-exposure in the ipsilateral motor (M1), sensory (S1), visual (V1/V2), and cingulate (Cg) cortex, as well as the hippocampus (Hc), lateral septal nucleus (LS), periaqueductal gray (PAG), and cerebellar gray matter. White matter tracts with increased RD included the corpus callosum (cc), cingulum (cg), anterior commissure (ac), internal capsule (ic), pyramids, and cerebellar white matter (cbw). Voxel-wise data are presented as t maps, cluster-corrected for multiple comparisons, and thresholded at the 0.05 significance level; R = right (ipsilateral hemisphere), L = left (contralateral hemisphere); scalebar = 2 mm. (B) Blast-induced increases in RD (mm²/s × 10⁻⁴) were significant in the corpus callosum at 7 days post-injury. ROI data are presented as box plots where red line = median, box = quartiles, whiskers = range, + = outliers; significant group differences (p < .05) are denoted as follows: * age-related changes in control rats; ** age-related changes in injured rats; ^# injury-related differences between age-matched groups. Key: cp, cerebral peduncle; cg, cingulum; icp, inferior cerebellar peduncle; SC, superior colliculus; sp5, spinal trigeminal tract; yc, young control; yb, young blast; oc, old control; ob, old blast.