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. Author manuscript; available in PMC: 2016 Feb 22.
Published in final edited form as: Front Neuroendocrinol. 2012 May 23;33(3):211–229. doi: 10.1016/j.yfrne.2012.04.003

Figure 4. Reproductive Cycles Affect Daily Rest/Activity Rhythms.

Figure 4

In many rodent species, females show large changes in their rest/activity rhythms over the course of their reproductive cycle. Following elevated estrogen, on the day of estrus females exhibit increased activity and begin their activity earlier in the day (phase-advance). Shown are two examples of estrus-typical wheel-running activity from a degu, with the putative day of estrus marked with an “E.” The activity is graphed as an actogram, with each horizontal line sequentially representing a day of activity (# wheel turns/10 min bin) and the environmental light-dark cycle indicated by the bar at the top of the figure. The red line in the middle of the actogram represents a one-week break in recording, and the estrous cycle length for the female is noted at the bottom [108].