The top row identifies a measured or computed ERG parameter. a_max is the saturating amplitude of the a-wave component of the ERG (Fig. 6), and b_max the saturating amplitudes of the gaussian-filtered b-wave, obtained under cone-isolation conditions (Fig. 4A).S̄_M and S̄_UVare the relative sensitivities of the cone-driven b-wave in the midwave and UV spectral regions, derived as follows. The peak amplitudes of gaussian-filtered cone b-wave responses were obtained in the linear region of the amplitude versus intensity function and were normalized by the amplitude of the saturating response (Fig. 4B);S̄_M was calculated as the average of all data obtained with 492, 501, and 513 nm flashes, andS̄_UV is the mean of all data obtained with 346, 356, and 361 nm flashes.S̄_UV/S̄_M is the ratio, determined separately for each animal. The errors given are SDs. *The observations in parentheses are taken from Lyubarsky et al. (1999) and were obtained in the presence of a steady background estimated to produce 6000 photoisomerizations rod⁻¹sec⁻¹ and shown to suppress at least 95% of the rod circulating current. To obviate a possible residual contribution from the rod a-wave that may have contaminated this previous estimate of the cone a_max in some mice, the measurements of the cone a-waves of WT mice reported in this table (n = 4) were all obtained in a double-flash paradigm, which measures the cone response a few seconds after the rod a-wave is suppressed with a very intense flash (Lyubarsky et al., 1999) and which takes advantage of the very rapid recovery of the cone a-wave (Figs. 6,7).