Fig. 2.

Impaired locomotor activity and increased anxiety during the light cycle, but not dark cycle, following chronic caffeine treatment. (a) Representative activity traces in an open-field chamber during the light cycle with center zone shaded in grey. (b) In an open field test CAF treated mice had decreased total distance traveled in the light cycle, but no difference in the dark cycle. (c) Representative activity traces in an open-field chamber during the dark cycle with center zone shaded in grey. (d) The amount of time spent not moving (rest time) was not affected by CAF treatment. (e) Average velocity in the open-field test showed that CAF treated mice moved at a significantly lower average velocity during the light cycle with no difference during the dark cycle. (f) The number of vertical counts, which is a measure of exploratory behavior, showed a significant decrease with CAF treatment during the light, but not the dark cycle. (g) CAF treated mice spent significantly less time in the center zone of the open field chamber than control mice, an anxiety-like behavior, during the light cycle with no difference during the dark cycle. (Light cycle, control n=15, CAF n=14; for the dark cycle, control n=7, CAF n=8. ^#P<0.05 for main effect of treatment by two-way ANOVA; *P < 0.05 compared to control by Tukey’s post hoc test; all data are presented as mean ± standard error of the mean (SEM).