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. Author manuscript; available in PMC: 2011 Mar 17.
Published in final edited form as: Annu Rev Physiol. 2010 Mar 17;72:605–624. doi: 10.1146/annurev-physiol-021909-135815

Figure 1.

Figure 1

Drosophila circadian locomotor behavior. (a) An averaged locomotor activity plot for wild-type flies. Light and dark bars indicate normalized activity levels during 12 h of light and 12 h of dark, respectively. Increases in activity are evident in advance of light-to-dark and dark-to-light transitions. (b) An activity plot, or actogram, for a single wild-type fly. The height of vertical bars indicates level of activity during a 30-min interval, or bin. Each horizontal line contains 48 h of activity data (double-plotted plot), with the second day of data on one line repeated on the first day of data on the following line to ease visualization of the circadian period. The transition from light-dark conditions (LD) to dark-dark conditions (DD) has been indicated by a dashed horizontal line. Under DD, activity bouts occur at the same time each day, indicating a free-running period of near 24 h.