Figure 1

The locomotor rhythmic activities of ApoE^−/− mice.

(a–c) Representative actographs showing wheel-running activity of ApoE^−/− and C57BL/6J mice under bLD, dLD and DD conditions after 2 weeks of LD entrainment. (d) Scatter dot plot of phase angle of entrainment to ZT12 for three individual ApoE^−/− and C57BL/6J mice were shown, with mean ± SE indicated for each mouse. The phase angle of entrainment was calculated from 10 consecutive days for each mouse. Note the greater variability in ApoE^−/− mice. (e) Onset variability at ZT12 in ApoE^−/− and C57BL/6J mice with mean ± SD indicated. Note the greater variability in ApoE^−/− mice (n = 6 for both ApoE^−/− and C57BL/6J mice, **indicates P < 0.01). (f) Locomotor activity light/dark ratio in ApoE^−/− and C57BL/6J mice with percentage (%) indicated. The running activities were calculated in both the light and dark phases, and the ratio was determined. (g) Representative actograph showing wheel-running activity of ApoE^−/− and C57BL/6J mice as adapted to a “jet-lag” phase delay schedule. The grey areas indicate the darkness. (h) To determine the days of re-entrainment, the difference between offset (activity stop point) at each day after the abrupt phase delay schedule and ZT24 in the original LD schedule, was plotted against the number of days after phase delay for ApoE^−/− and C57BL/6J mice until a stable re-entrainment was established. The days of re-entrainment were also presented in bar graphs with mean ± SD indicated (n = 6 for both ApoE^−/− and C57BL/6J mice, **indicates P < 0.01). (i) Representative actographs showing a light-pulse induced phase shift of ApoE^−/− and C57BL/6J mice. A 15-min light pulse (200 lux) was given at ZT14 to animals kept in LD schedule, and phase shifts were calculated in reference to ZT12. (j) Light-pulse induced phase shifts were presented as bar graphs with mean ± SD indicated (n = 6 for both ApoE^−/− and C57BL/6J mice, **indicates P < 0.01).