Fig. 7.

The wavelength dependence of the reflectance response links it to phototransduction. (A) For each subject, the horizontal shifts of the sigmoid fits for each wavelength relative to the 550 nm fit were taken as the relative action. To assess the variability of the amplitude responses and the sigmoidal fits, we bootstrapped each reflectance response, extracted the reflectance response amplitudes and repeated the fitting process 1,000 times. Error bars delineate the 5^th through the 95^th percentile of the bootstrapped values. In cases where error bars are not visible, they are smaller than the plotted points. (B) The average (across subjects) action spectrum of the intrinsic reflectance response (gold) overlaid on the human luminosity function (black dashed line). Overall, the action spectrum of the intrinsic reflectance response is well-matched to the photopic luminosity function. Error bars are ± 2 standard deviations.