Figure 6. Dependence of the apparent delay on the stimulus intensity in cones. Trans-retinal recordings of the aspartate-isolated receptor
potential of frog red-sensitive cones. Each trace is the average of 100 to 500 responses. Green (525 nm) background illumination
was applied to saturate the rods’ responses, and an orange (longer than 600 nm) 1-ms flash was used as the stimulus for the
cones. The beginning of the flash is at 0.0 s. Experimental recordings are shifted by –1 ms to account for the analog filter
delay. The horizontal red dot-dash line marks the 0.0025 criterion level. The numbers near the traces show the relative flash
intensities. Intensity 1.0 corresponds to 1.4 × 10−4 fractional bleach per flash.