Table 1.
Parameters of Van Hateren's model used to simulate the responses of goldfish, salamander and cat cones
| Parameter | Goldfish cones | Cat cones | Salamander cones |
|---|---|---|---|
| Lifetime of activated conopsin (ms) | 8–31 | 8 | 88 |
| Lifetime of activated transducin (ms) | 16–30 | 12 | 101 |
| Dark phosphodiesterase activity (ms−1) | 0.003 | 0.0028 | 0.003 |
| Constant of the dependence of phosphodiesterase activity on transducin activation | 0.00004–0.00023 | 0.00016 | 0.0002 |
| Apparent Hill coefficient of CNG channels | 1 | 1 | 1 |
| Hill coefficient of guanylyl cyclase activation | 4 | 4 | 4 |
| Time constant of calcium extrusion (ms) | 12–28 | 9 | 24 |
| Guanylyl cyclase activation constant | 0.1 | 0.09 | 0.1 |
| Capacitive membrane time constant (ms) | 15 | 6 | 15 |
| Parameter of membrane non‐linearity | 0.7–1.1 | 0.8 | 0.85 |
| Constant of membrane non‐linearity | 0.03–0.07 | 0.07 | 0.085 |
| Time constant of membrane non‐linearity (ms) | 300 | 120 | 300 |
For the goldfish, model parameters were obtained by fitting cone responses (n = 7) to skew stimulus set 2 while constraining the range of the parameters varied to within that determined by Endeman & Kamermans (2010). For the cat and salamander, parameters were adjusted such that the impulse response function time to peak of the simulated cone approximately matched that estimated, respectively, by Donner & Hemila (1996) and by Rieke (2001) and Baccus & Meister (2002).