Fig. 4.

EEG slow wave counts in awake mice fluctuate over the 24-hour light:dark cycle, and increase during a period of enforced wakefulness. (A) Average number of EEG slow wave counts per hour during wake, superimposed upon percentage time spent awake per hour, over the 24-h sleep-wake cycle in sham control mice. (B) Average number of EEG slow wave counts per hour while awake, superimposed upon percentage time spent awake per hour, over the 24-h sleep-wake cycle in mice with TBI. (C) Comparison of the total slow wave counts over the 24-h light:dark cycle across during the awake state for sham and TBI mice shows significantly higher slow wave counts during the dark phase in mice with TBI. *p<0.05, Two-way ANOVA, Bonferroni post-hoc test for significant main effect of Phase. (D) Mice were kept awake for a short 3-hour period from ZT3-6 (10:00a.m. to 13:00p.m.), a period notable for heightened sleep pressure. EEG slow wave counts from Hour 0 included only the spontaneously-occurring wake epochs from 9:00 to 10:00 am, and were corrected for the percentage of wake during each 30-min interval. EEG slow waves significantly increased with by Hour 3 of enforced waking in mice with TBI compared to sham control mice. *p<0.05, Two-way ANOVA, Bonferroni post-hoc test for significant main effect of Hour, and significant interaction between Hour and Injury.