Drum B
Vision Res. 1982;22(7):823-6. doi: 10.1016/0042-6989(82)90014-1.
Visual thresholds were measured for rod stimuli, cone stimuli and mixtures of rod and cone stimuli. Comparisons of the rod and cone thresholds to the corresponding components of the mixed-stimulus thresholds revealed summation between subthreshold rod and cone responses. The amount of summation was less than linear addition but greater than either probability summation of orthogonal vector addition.
