Fig. 2

The phase of PER2::LUC rhythms in non-SCN tissues is shifted under long photoperiods by the SCN shell. a Time of peak bioluminescence (± SEM) on the first cycle in vitro displayed by SCN regions and peripheral tissues collected from PER2::LUC mice housed under LD12:12 (blue symbols) or LD20:4 (red symbols). The white and black bars on the abscissa represent lighting conditions for each photoperiod, with internal symbols indicating the time of dissection. n = 5–14/tissue/photoperiod. b Difference in the peak time of PER2::LUC expression (± SEM) between cultures collected under LD12:12 and LD20:4. Tissues are ordered by the magnitude of the difference in peak time. Dashed vertical lines indicate the magnitude of the shift displayed by the SCN shell and SCN core. *Significant phase shift different from 0 h, one sample t-test, P <0.05