Murine Clock∆19/∆19 and WT models. (a) Wheel running actigraphy characterizing Clock∆19/∆19 (left) and WT (middle) mice under normal diurnal conditions (12 hour light:12 hour dark) for 10 days, and circadian (constant darkness, DD) conditions for 10 days. Quantification of period under DD (right) showing that the CLOCK mutation extends the circadian period from 23.9 hours to ~27.6 hours, as anticipated (n = 4 mice/group, P < 0.05). (b) Actigraphy of HF mice, showing that Clock∆19/∆19 (left) and WT (middle) mice, and period under DD (right) maintain their respective phenotypes, and are significantly different from each other (n = 4 mice/group, P < 0.05). (c) Exemplar photomicrographs of one traced neuron are shown. A low-magnification view is shown in the left panel, with the neuron of interest indicated by the red arrow and a scale bar of 500 µm. A high-magnification view of the area enclosed by the red box is shown in the middle panel, with a scale bar of 100 µm, and a tracing of a layer 2/3 neuron on the right, with a scale bar of 100 µm. (d) Representative neuron tracings illustrating the smaller mPFC apical dendrite tree size in Clock∆19/∆19 versus WT mice. *Indicates P < 0.05 by Bonferroni post-hoc analysis.