Fig. 2
From: The suprachiasmatic nucleus: age-related decline in biological rhythms
Reduced behavioral circadian rhythms in middle-aged mice. Representative double-plotted actograms of wheel-running activity in C57BL/6J mice. These plots show the effects of aging on circadian rhythms influencing locomotor activity for both young (a) and middle-aged (b) mice. The mice were maintained in an LD cycle for 2Â weeks and then transferred into DD. Light conditions are indicated at the top of the figure; open bars are light phases, and closed bars are dark