FIGURE 9.

How to make a cone from a rod. The simulations show the mean PDE response for faster PDE and rhodopsin deactivation. The initial values for the rates are given in Fig. 2 for N_p = 6. In panel a, the PDE deactivation rate k₄ is increased from the initial value 1 s⁻¹ by factors of 5, 10, and 15. In panel b, only the phosphorylation rate λ₇ is increased from the starting value 3.2 s⁻¹ by factors of 5, 10, and 15. As a consequence, rhodopsin lifetime decreases from 3 s to 0.6 s, 0. 3 s, and 0.2 s. In panel c, k₄ and λ₇ are increased simultaneously.