Quantification of the accumulated angle prior illumination (min. 9) compared to post-UV illumination (min. 20) for Pd CO-expressing (blue, n = 14) and EYFP-expressing control mice (gray, n = 13). The paired mean difference for both comparisons is shown in the Cumming estimation plot. Each paired mean difference is plotted as a bootstrap sampling distribution. Mean differences are depicted as dots; 95% confidence intervals are indicated by the ends of the vertical error bars. * P < 0.05; two-sided permutation t -test; 5.80 x 10 -3 .