Differential distributions of red–green and blue–yellow cone opponency across the visual field

Abstract

The color vision of Old World primates and humans uses two cone-opponent systems; one differences the outputs of L and M cones forming a red-green (RG) system, and the other differences S cones with a combination of L and M cones forming a blue-yellow (BY) system. In this paper, we show that in human vision these two systems have a differential distribution across the visual field. Cone contrast sensitivities for sine-wave grating stimuli (smoothly enveloped in space and time) were measured for the two color systems (RG & BY) and the achromatic (Ach) system at a range of eccentricities in the nasal field (0-25 deg). We spatially scaled our stimuli independently for each system (RG, BY, & Ach) in order to activate that system optimally at each eccentricity. This controlled for any differential variations in spatial scale with eccentricity and provided a comparison between the three systems under equivalent conditions. We find that while red-green cone opponency has a steep decline away from the fovea, the loss in blue-yellow cone opponency is more gradual, showing a similar loss to that found for achromatic vision. Thus only red-green opponency, and not blue-yellow opponency, can be considered a foveal specialization of primate vision with an overrepresentation at the fovea. In addition, statistical calculations of the level of chance cone opponency in the two systems indicate that selective S cone connections to postreceptoral neurons are essential to maintain peripheral blue-yellow sensitivity in human vision. In the red-green system, an assumption of cone selectivity is not required to account for losses in peripheral sensitivity. Overall, these results provide behavioral evidence for functionally distinct neuro-architectural origins of the two color systems in human vision, supporting recent physiological results in primates.

L and M Cone Contributions to the Midget and Parasol Ganglion Cell Receptive Fields of Macaque Monkey Retina

“…The anatomical (Wässle et al, 1989;Boycott and Wässle, 1991;Goodchild et al, 1996;Calkins and Sterling, 1996), physiological (Dacheux and Raviola, 1990;Dacey et al, 1996Dacey et al, , 2000a, and psychophysical (Mullen and Kingdom, 2002) data from outer retina consistent with the random connection model (Lennie, 1980;Paulus and Kroger-Paulus, 1983;Shapley and Perry, 1986;Lennie et al, 1991;Mullen and Kingdom, 1996) might be reconciled with the selective connection model (Reid and Shapley, 1992;Dacey, 1993;Lee et al, 1998;Martin et al, 2001) by invoking inner retinal selectivity. However, selective connections are inconsistent with the covariance of horizontal and ganglion cell L/(L ϩ M) ratios at single retinal locations, as is the lack of peripheral midget opponency.…”

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

“…If sensitivity drops are examined in comparable conditions-meaning that for each direction in the colour space the optimal spatial frequency must be used-the sensitivity attenuation rates for the blue-yellow and for the achromatic mechanisms are comparable. 95 …”

Contrast sensitivity perimetry tests along the cardinal directions in color space: Correlation with the properties of the neural mechanisms mediating detection of spatio-temporal patterns

“…A nivel foveal, las propiedades de esta superficie pueden explicarse a partir de las propiedades de los mecanismos acromáticos de origen Magno (M) y Parvocelular (P) [35,[38][39][40][41][42][43][44]. Los experimentos de lesiones selectivas en monos demuestran que las CSFs acromáticas espacio-temporales mediadas separadamente por el Magno y por el Parvo tienen formas de pasa-banda y que la CSF es la envolvente de ambas [45][46][47][48].…”

“…Nuestros resultados muestran que la sensibilidad al contraste decrece con la excentricidad en cada uno de los puntos del domino espacio-temporal tanto para el mecanismo acromático como para cada uno de los mecanismos cromáticos, aunque lo hace de modo distinto en cada uno de ellos, lo cual es consistente con resultados previos de la literatura [35,39,[55][56][57][58][59]. Estas pérdidas de sensibilidad al contraste pueden ir ligadas tanto a una disminución de la densidad de células con la excentricidad como a una disminución de la sensibilidad de las células individuales.…”

“…Sin embargo, en la bibliografía existente es difícil encontrar mediciones de superficies espaciotemporales completas, sobre todo a nivel cromático [28][29][30][31][32][33], encontrándose por tanto un vacío en este campo importante. De hecho, la información que se puede encontrar respecto a los mecanismos cromáticos fuera de la zona foveal está básicamente restringida a estímulos estacionarios (sin información temporal) [34][35][36].…”