Table 1.
Relative difference (maximum − minimum) in latency at threshold and for a fixed stimulus intensity under chromatic isolation of various cone mechanisms
| Mechanism(s) isolated | UV + S | UV + S | M | M | M + L | M + L | L | L |
|---|---|---|---|---|---|---|---|---|
| Response parameter | λ, nm | Latency, ms | λ, nm | Latency, ms | λ, nm | Latency, ms | λ, nm | Latency, ms |
| ON Threshold | ||||||||
| Maximum | 400 | 61 ± 3 | 500 | 57 ± 8 | 630 | 56 ± 4 | 630 | 65 ± 11 |
| Minimum | 540 | 34 ± 5 | 600 | 34 ± 3 | 360 | 47 ± 4 | 500 | 37 ± 9 |
| Difference | 27 | 23 | 9 | 28 |
| ON Fixed Intensity | ||||||||
|---|---|---|---|---|---|---|---|---|
| Maximum | 460 | 60 ± 3 | 400 | 50 ± 4 | 430 | 43 ± 1 | 370 | 52 ± 5 |
| Minimum | 520 | 47 ± 4 | 600 | 39 ± 4 | 600 | 38 ± 0 | 500 | 36 ± 4 |
| Difference | 13 | 11 | 5 | 16 |
| OFF Threshold | ||||||||
|---|---|---|---|---|---|---|---|---|
| Maximum | 360 | 63 ± 3 | 430 | 72 ± 7 | 500 | 79 ± 10 | 460 | 67 ± 7 |
| Minimum | 600 | 33 ± 4 | 600 | 48 ± 7 | 630 | 49 ± 14 | 500 | 43 ± 8 |
| Difference | 30 | 24 | 30 | 24 |
UV, ultraviolet cone mechanism; S, short wavelength (λ) cone mechanism; M, middle λ cone mechanism; L, long λ cone mechanism; ON, optic nerve response (ONR) to light onset; OFF, ONR to light termination. Adapted, with permission, from Beaudet (1997).