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. Author manuscript; available in PMC: 2014 Nov 20.
Published in final edited form as: Neuron. 2013 Nov 20;80(4):10.1016/j.neuron.2013.08.022. doi: 10.1016/j.neuron.2013.08.022

Figure 1. SCN reorganization under long day lengths.

Figure 1

A) Representative double-plotted actograms depicting wheel-running rhythms of individual PER2::LUC mice entrained to LD12:12 or LD20:4. Lighting conditions are represented by internal yellow shading and the light:dark bar above each actogram. Only the last two weeks of entrainment are illustrated for clarity. B) Still images of PER2::LUC expression from SCN slices collected from LD12:12 or LD20:4 mice (see also Supplementary Videos 1–2). Number in upper left corner indicates the number of hours in vitro, and the left lobe of each SCN is outlined in yellow to highlight the compartmental nature of PER2::LUC expression within the LD20:4 slice. C) Individual phase maps depicting peak time relative to the field rhythm of the whole slice on the first cycle in vitro. Cool and warm colors indicate early- and late-peaking regions, respectively. D) PER2::LUC time series from dorsal SCN (d, dSCN) and central SCN (c, cSCN) regions used to assess rhythms in the SCN shell and core, respectively. E) On the first cycle in vitro, LD20:4 altered the peak time of the cSCN region relative to that for the dSCN region (n=12/condition), such that the cSCN peaked earlier than the dSCN. * Student’s t-test, p < 0.0001. F) LD20:4 increased the level of PER2::LUC expression within the cSCN (n=12/condition). Still images of total PER2::LUC expression within representative SCN slices over the first 24h in vitro. PER2 expression level was quantified by summing brightness values for the cSCN region expressed relative to that for the dSCN region (n=12/condition). * Student’s t-test, p < 0.0001. See also Figure S1.