Figure 3. Examples of MASCO-driven activity rhythms in mice.

A: Period lengthening of the activity rhythm during short-term methamphetamine administration. The rhythm is controlled by coupled SCN and MASCO in wild-type mice in DD. B: Dissociation of SCN and MASCO-driven activity rhythms by methamphetamine administration in a wild-type mouse in an LD cycle. C: The MASCO-driven activity rhythm in an SCN-lesioned wild-type mouse revealed by methamphetamine administration (NOTE: birhythmicity). D: Birhythmicity of the MASCO-driven activity rhythm in Per1/2 double knockout mice in DD. MA: methamphetamine administration. The actograms were generated from original data published in Pendergast et al., 2013 ¹⁸ and 2014. ⁵⁵ The data are re-plotted with the same x-y scale, so the periods of the free-running rhythms can be compared by the angle of the slope. Figure modified from Yamazaki 2019 ⁵⁴ with permission.