The unspecified role of cones and rods in grating detection: a theoretical note.

Detection and resolution thresholds for two 50 ms square-wave gratings (1.5 and 6.7 cps) were determined as a function of background luminance. Results indicated differential cone and rod involvement in resolution of the two targets at low background levels. Implications for other studies employing similar stimuli in terms of retinal inhomogeneity were suggested.