Contrast sensitivity of individual colour mechanisms of human vision.

Cavonius, C. R.; Estévez, O.

doi:10.1113/jphysiol.1975.sp010994

Cited by 60 publications

(24 citation statements)

References 13 publications

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“…This mapping agreed with the Nyquist limit predicted from S-cone spacing mapped by immunostaining (Curcio et al, 1991) and other psychophysical measurements (Stiles, 1949;Green, 1968;Cavonius and Estévez, 1975;Metha and Lennie, 2001). The present results, that every S cone has what amounts to a private ON pathway, certainly support this conclusion.…”

Section: Correspondence To Psychophysicssupporting

confidence: 75%

Evidence That Each S Cone in Macaque Fovea Drives One Narrow-Field and Several Wide-Field Blue-Yellow Ganglion Cells

Schein¹,

Sterling²,

Ngo³

et al. 2004

J. Neurosci.

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A rule of retinal wiring is that many receptors converge onto fewer bipolar cells and still fewer ganglion cells. However, for each S cone in macaque fovea, there are two S-cone ON bipolar cells and two blue-yellow (BY) ganglion cells. To understand this apparent rule reversal, we reconstructed synaptic patterns of divergence and convergence and determined the basic three-tiered unit of connectivity that repeats across the retina. Each foveal S cone diverges to four S-cone ON bipolar cells but contacts them unequally, providing 1-16 ribbon synapses per cell. Next, each bipolar cell diverges to two BY ganglion cells and also contacts them unequally, providing ϳ14 and ϳ28 ribbon synapses per cell. Overall, each S cone diverges to approximately six BY ganglion cells, dominating one and contributing more modestly to the others. Conversely, of each pair of BY ganglion cells, one is dominated by a single S cone and one is diffusely driven by several. This repeating circuit extracts blue/yellow information on two different spatiotemporal scales and thus parallels the circuits for achromatic, spatial vision, in which each cone dominates one narrow-field ganglion cell (midget) and contributes some input to several wider-field ganglion cells (parasol). Finally, because BY ganglion cells have coextensive ϩS and Ϫ(LϩM) receptive fields, and each S cone contributes different weights to different BY ganglion cells, the coextensive receptive fields must be already present in the synaptic terminal of the S cone. The S-cone terminal thus constitutes the first critical locus for BY color vision.

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Section: Correspondence To Psychophysicssupporting

confidence: 75%

Evidence That Each S Cone in Macaque Fovea Drives One Narrow-Field and Several Wide-Field Blue-Yellow Ganglion Cells

Schein¹,

Sterling²,

Ngo³

et al. 2004

J. Neurosci.

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“…There will also be retinal locations for which the resolution of the M-or L-cone submosaic ought to be as high as for the full mosaic. This is likely to be the reason why acuity measured with stimuli that are visible to only L or M cones is not worse than acuity based on the entire mosaic (Green, 1968;Cavonius and Estévez, 1975;Williams, 1990;Carroll et al, 2004). A patchy cone arrangement may have the additional advantage in helping to ameliorate the spectral blurring that occurs as a result of electrical coupling between neighboring cones (Hsu et al, 2000;DeVries et al, 2002;Hornstein et al, 2004).…”

Section: Implications Of L/m Cone Arrangement For Visionmentioning

confidence: 99%

Organization of the Human Trichromatic Cone Mosaic

Hofer¹,

Carroll²,

Neitz³

et al. 2005

J. Neurosci.

414

311

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Using high-resolution adaptive-optics imaging combined with retinal densitometry, we characterized the arrangement of short-(S), middle-(M), and long-(L) wavelength-sensitive cones in eight human foveal mosaics. As suggested by previous studies, we found males with normal color vision that varied in the ratio of L to M cones (from 1.1:1 to 16.5:1). We also found a protan carrier with an even more extreme L:M ratio (0.37:1). All subjects had nearly identical S-cone densities, indicating independence of the developmental mechanism that governs the relative numerosity of L/M and S cones. L:M cone ratio estimates were correlated highly with those obtained in the same eyes using the flicker photometric electroretinogram (ERG), although the comparison indicates that the signal from each M cone makes a larger contribution to the ERG than each L cone. Although all subjects had highly disordered arrangements of L and M cones, three subjects showed evidence for departures from a strictly random rule for assigning the L and M cone photopigments. In two retinas, these departures corresponded to local clumping of cones of like type. In a third retina, the L:M cone ratio differed significantly at two retinal locations on opposite sides of the fovea. These results suggest that the assignment of L and M pigment, although highly irregular, is not a completely random process. Surprisingly, in the protan carrier, in which X-chromosome inactivation would favor L-or M-cone clumping, there was no evidence of clumping, perhaps as a result of cone migration during foveal development.

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“…Their post-receptoral connections form the basis of at least two The post-receptoral properties of the short wavelength mchanism have been investigated in normal vision by various psychophysical isolated procedures along the lines proposed by either Stiles (1939,1959,1978) or Rushton, Powell & White (1973). The general picture which has emerged is one of a system with a high degree of spatial summation (Brindley, 1954), low spatial acuity (Brindley, 1954;Green, 1968;Kelly, 1973;Cavonius & Estevez, 1975;Williams & Collier, 1983), low temporal resolution (Green, 1969; Kelly, 1974;Wisowaty & Boynton, 1980) and low overall sensitivity (Green, 1968;Cavonius & Estevez, 1975). Results of a similar kind (Green, 1972;Daw & Enoch, 1973) have been obtained by studying the visual properties of a group of achromats (of the complete and atypical variety) in which it is thought that only short wavelength cones subserve photopic function (Blackwell & Blackwell, 1957;Daw & Enoch, 1973;Smith, Pokorny, Delleman, Cozijnsen, Houtman & Went, 1983).…”

Section: Introductionmentioning

confidence: 99%

Human photopic vision with only short wavelength cones: post‐receptoral properties.

Hess

Mullen

Zrenner

1989

The Journal of Physiology

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SUMMARY1. Spatial and temporal contrast sensitivities were investigated in two subjects whose photopic vision has been previously shown to be subserved by only short wavelength cones.2. Spatial contrast sensitivity was uniformly reduced compared with that of the normal trichromatic observer. Peak contrast sensitivity reached 40 which is a factor of 2-3 better than previous estimates and extrapolated acuity was around 15 cycles deg-'. Central, non-aliased grating acuity was between 6-9 cycles deg-'. This declined with eccentricity such that at 20 deg it was around 1 cycle deg-'.3. The variation in contrast sensitivity across the visual field was measured for a range of different spatial frequencies. It was found to be of the same form as that for the normal trichromat but reduced in overall sensitivity.4. Temporal contrast sensitivity was measured for two different spatial frequencies and found to exhibit the spatio-temporal covariation which is typical of normal trichromatic vision. Temporal acuity exhibited a strong dependence on illuminance and reached asymptotic values of around [40][41][42][43][44][45] While this is more than a factor of two above most previous estimates for the short wavelength receptors of normal vision it agrees with some more recent estimates obtained using a different technique. Temporal resolution was found to be evenly distributed across the visual field.5. Similarities were found between the post-receptoral properties of these achromats and the properties of the isolated blue mechanism of normal vision and also the properties of normal luminance contrast processing in general. The present results provide an upper bound on the contribution of the short wavelength mechanism to normal vision and also provide a suitable model of its possible contribution to the processing of luminance contrast in the normal visual system.

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Contrast sensitivity of individual colour mechanisms of human vision.

Cited by 60 publications

References 13 publications

Evidence That Each S Cone in Macaque Fovea Drives One Narrow-Field and Several Wide-Field Blue-Yellow Ganglion Cells

Evidence That Each S Cone in Macaque Fovea Drives One Narrow-Field and Several Wide-Field Blue-Yellow Ganglion Cells

Organization of the Human Trichromatic Cone Mosaic

Human photopic vision with only short wavelength cones: post‐receptoral properties.

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