Fig. 3.

A, Distributions of BPI_lum for luminance gratings and for the gratings isolating the receptive field center cone class (BPI_cc) for populations of midget ganglion cells and of parvocellular LGN cells show considerable similarity. For luminance there is much variability of BPI_lum, with some cells showing little low-spatial-frequency roll-off (BPI_lum = 1). B, Comparisons of BPI_lum and BPI_cc for the two cell samples on a cell-by-cell basis. The solid curves represent the relationship between the BPI for luminance and the center cone expected if the M:L ratio were 1:1. See the text for the derivation.