FIG. 7.

The duration of heightened vulnerability to subsequent primary blast may be 72 to 144 h long. (A) The interval between exposures was extended from 24 h, shown in Figure 4 and here, to 72 h (A, middle) and 144 h (A, right; n ≥ 5; ± standard error of the mean [SEM]; *p < 0.05, compared with sham 24 h and sham 144 h intervals). Potentiation was still significantly depressed for the 72 h “Double Level 2” group but was not for the 144 h “Double Level 2” group. (B) Cell death for sham, single and repetitive Level 2 groups with the 24 h interval, shown in Figure 4 and here, were compared to that of the extended inter-injury interval groups. On average, cell death was below 5% in all regions of interest for all blast- and sham-injured groups (n ≥ 6; ± standard error of the mean; not significant).