Proportion of cells among identified retinal neurons that express the core circadian clock components at ZT02/06.

Retinal sections were reacted with antibodies against a clock protein and a specific neuronal marker (see Table 1 for details about the antibodies). Clock protein expression within an identified retinal neuron was determined by measuring the mean fluorescence intensity within the boundaries of the cell soma labeled for a specific marker for all the somas within a section. Mean fluorescence in rods was determined within a large area (∼50×20 µm) selected in the ONL that did not include the cone somas. Significant clock protein expression was defined as fluorescent level higher than 150% background. Results are scored as: - (not significant, labeling intensity