Figure 4. Activity phase shift and cycle disruption following dark or light pulses.

(A). Locomotor activity oscillation phase is shifted following one hour of darkness (dark pulse) between ZT9 and ZT10 (of the second experiment day). (B). Locomotor activity oscillation is completely disrupted following 1 h of light pulse between ZT21 and ZT22 (of the first experiment day). White bars indicate light hours, black bars indicate dark hours, and gray bars indicate illumination conditions different from an LD cycle (dark instead of light; light instead of dark), stars indicate the locomotor activity peak, arrows indicate light/dark pulse.