Mean bout length of sleep-wake states. Changes in bout lengths were assessed for wake, non-rapid eye movement (NREM), and REM during the light and dark phases at PID 6, 19, and 29. Significant decreases in wake and NREM bout length were found during the dark (active) phase. (A) There was no significant change in wake bout length during the light phase. (B) Bout length of wake during the dark phased decreased (F(1,28)=21.848; p<0.001) in injured animals. The length of wake bouts was significantly shorter at PID 6 (***p<0.001 vs. sham) and 29 (*p<0.05 vs. sham). (C) During the light phase, there was not a significant change in NREM bout length. (D) Similar to wake bouts, injured animals had NREM bout lengths significantly shorter (F(1,28)=12.183; p<0.01) than sham animals in the dark phase. Lateral fluid percussion resulted in shorter NREM bout lengths at PID 29 (*p<0.05 vs. sham). (E) and (F) There was no significant difference in REM bout lengths during the light and dark phase, respectively. Analysis by one-way (groups) repeated measures (trials/time) analysis of variance (A-F) followed by Student-Newman-Keuls post hoc test. Mean±standard error of the mean; n=11/injured group, n=8 (sham). Sham is open circle with dashed line. Moderate injury is solid circle and solid line.