Figure 1. Age-related differences in acute behavioral deficits following traumatic brain injury.

The percent change in body weight from baseline was recorded for young and aged mice for three days post-injury (A). Time spent on an accelerating rotarod was evaluated over the course of three days after TBI (B). Grip strength for young and old mice in sham and TBI groups is shown (C). Cylinder testing demonstrated significant asymmetric forelimb use in both age groups following TBI (D). Animals were then evaluated in an open field apparatus at three days after TBI to measure spontaneous locomotor activity. The total distance traveled in the open field apparatus for sham and TBI mice is shown (E). The ratio of the total time spent in the inner versus outer zones of the open field demonstrated significant effects of age and injury (F). The average speed (G) and time spent immobile (H) in the open field showed a robust interaction between age and injury. For all experiments, N=7 sham and N=12 TBI/group. Statistical comparisons between groups were determined by one- or two-way repeated measures ANOVA analysis with Tukey’s multiple comparisons test. For cylinder and open field analysis, analysis was performed using two-way ANOVA with Tukey’s test. Significant group effects of age, injury, and interaction between age and injury are shown in each box. Error bars show mean SEM. Abbreviation: TBI traumatic brain injury, g gram, BW body weight, L left, R right, n.s. not significant, m meters, s seconds, SEM standard error of mean. *p<0.05, **p<0.01, and ***p<0.001