Topography of the long- to middle-wavelength sensitive cone ratio in the human retina assessed with a wide-field color multifocal electroretinogram

Abstract

The topographical distribution of relative sensitivity to red and green lights across the retina was assayed using a custom-made wide-field color multifocal electroretinogram apparatus. There were increases in the relative sensitivity to red compared to green light in the periphery that correlate with observed increases in the relative amount of long (L) compared to middle (M) wavelength sensitive opsin mRNA. These results provide electrophysiological evidence that there is a dramatic increase in the ratio of L to M cones in the far periphery of the human retina. The central to far peripheral homogeneity in cone proportions has implications for understanding the developmental mechanisms that determine the identity of a cone as L or M and for understanding the circuitry for color vision in the peripheral retina.

The genetics of normal and defective color vision

“…The relative ratio of L to M cones among individuals with normal color vision is highly variable. The first direct evidence for the relative distribution of L versus M cones came from adaptive optics and retinal densitometry (Hofer et al, 2005, Roorda & Williams, 1999), and the results confirm reports of variation in the L:M ratio among humans with normal color vision from studies that use indirect methods (Rushton & Baker, 1964, Carroll, Neitz, & Neitz, 2002, Kuchenbecker, Sahay, Tait, Neitz & Neitz, 2008, Mollon & Bowmaker, 1992, Neitz et al, 2006,). In summary, the development of S cones and their arrangement in the adult retina compared to L and M cones all point to the identity of S cones as being distinctly different from L and M cones, with S cones being non-randomly distributed.…”

Response Inhibition Is Facilitated by a Change to Red Over Green in the Stop Signal Paradigm

“…Faster search times, automatic target selection, greater pursuit gain, as well as stronger and faster propagation of ERPs for red stimuli relative to others can be explained by early biases in visual processing. The retina has a greater proportion of red cones than green or blue (e.g., Kuchenbecker et al, 2008). Thus there are more neural responses to red through the early visual system.…”

Curing Color Blindness--Mice and Nonhuman Primates

“…This produced two distinct cone types absorbing in the middle-tolong wavelengths: "MþL" and M. Thus, together with S cones, the treated animals had three cone types, as required for trichromacy. The spectral sensitivity shift was readily detected using a custom-built, wide-field, color multifocal electroretinogram (mf-ERG) system (Kuchenbecker et al 2008). In experiments performed on separate animals that were not involved in behavioral testing, the color mf-ERG was validated by treating an animal with a mixture of two viral vectors that were identical except that one carried the human L-opsin gene whereas the other carried the gene for humanized green fluorescent protein (GFP).…”