A double-plotted median actogram illustrating the basic paradigm used in this manuscript (A), and a Phase Response Curve (B).

<p>A) A median actogram showing the results of a light pulse during late subjective night on circadian phase in constant darkness (DD). Flies were entrained to a 12 hr;12 hr light dark schedule with green light for 6 days, then given a 6 hr blue light pulse of intensity 33 nw/cm² at ZT18-24. The resulting phase advance (double arrow line) is shown by extrapolating from the computer called RMS line (blue) marking the activity off times (red dots) in DD. Phase shift data in this manuscript is computed from individual flies, relative to the phase shift of a control set of flies not receiving a light pulse. Data in this figure is double plotted for ease of viewing, but annotations are only shown for one of the two occurrences. B) A phase response curve, showing the averaged phase shifts resulting from a 1 hr light pulse at the indicated circadian times. Light pulses were of white light of intensity ∼150 µw/cm². Averaged data reprinted from <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003615#pgen.1003615-Kistenpfennig1" target="_blank">[24]</a>.