Fig. 1: Repetitive concussion triggers perturbation in learning abilities in mice.

a Scheme of the controlled cortical impact device used to produce repetitive closed-skull concussions in mice. Note the location of the impact with the caudal landmark positioned on lambda. b Timeline of the experiment with the concussions delivered either single or repetitive at 48 h intervals. c Macroscopic view of the brains following sham injury, single concussion, or repetitive concussions. Red circles depict the impact size and location on the brain. d Schematic representation of the Y-maze test. e Quantification of the preference index in sham (light gray line), single concussion (dark gray line), and repetitive concussions (red line) at different time points following injury (48 h, 1 wk, 3 wks, 6 wks). p = 0.0480 (Two-way ANOVA followed by Tuckey’s multiple comparison test sham 1 wk vs 3 concussions 1 wk). n = 8–10 animals per group. f Quantification of time spent in the conditioning arm in sham (light gray line), single concussion (dark gray line), and repetitive concussions (red line) at different time points following injury (48 h, 1 wk, 3 wks, 6 wks). p = 0.0230 sham 1 wk vs 3 concussions 1 w and p = 0.0363 sham 6 wks vs 3 concussions 6 wks (Two-way ANOVA followed by Tuckey’s multiple comparison test). n = 8–10 animals per group. g Schematic representation of the tail suspension test. h Quantification of the percentage of total experimental time spent struggling in sham (white box), single concussion (gray box), and repetitive concussions (red box) at different time points following injury (48 h, 1 wk, 3 wks, 6 wks). p = 0.0074 sham baseline vs sham 3 wks; p = 0.0016 sham baseline vs sham 6 wks; p = 0.0054 1 concussion baseline vs 1 concussion 6 wks (Two-way ANOVA followed by Tukey’s multiple comparison test). n = 9–12 animals per group. i Quantification of the mean duration of struggles in sham (white box), single concussion (gray box), and repetitive concussions (red box) at different time points following injury (48 h, 1 wk, 3 wks, 6 wks). p = 0.0073 sham baseline vs sham 3 wks; p = 0.0015 sham baseline vs sham 6 wks; p = 0.0053 1 concussion baseline vs 1 concussion 6 wks (Two-way ANOVA followed by Tukey’s multiple comparison test). n = 9–12 animals per group. wk: week; h: hour. Data as mean ± SEM.