Figure 1.

Light-dark cycle synchronization of circadian rhythms in blind primates. Shown are representative double-plotted motor activity records of a blind marmoset during photoentrainment, advance and delay of light phase, and free-run in constant light condition (LL). Time is indicated at the bottom, day at left side, and the light-dark cycle (LD) or LL on the right side. The boxes represent the light phase of the LD cycle.