More than noise: Context-dependant luminance contrast discrimination in a coral reef fish (Rhinecanthus aculeatus)

AbstractAchromatic (luminance) vision is used by animals to perceive motion, pattern, space and texture. Luminance contrast sensitivity thresholds are often poorly characterised for individual species and are applied across a diverse range of perceptual contexts using over-simplified assumptions of an animal’s visual system. Such thresholds are often estimated using the Receptor Noise Limited model (RNL) using quantum catch values and estimated noise levels of photoreceptors. However, the suitability of the RNL model to describe luminance contrast perception remains poorly tested.Here, we investigated context-dependent luminance discrimination using triggerfish (Rhinecanthus aculeatus) presented with large achromatic stimuli (spots) against uniform achromatic backgrounds of varying absolute and relative contrasts. ‘Dark’ and ‘bright’ spots were presented against relatively dark and bright backgrounds. We found significant differences in luminance discrimination thresholds across treatments. When measured using Michelson contrast, thresholds for bright spots on a bright background were significantly higher than for other scenarios, and the lowest threshold was found when dark spots were presented on dark backgrounds. Thresholds expressed in Weber contrast revealed increased contrast sensitivity for stimuli darker than their backgrounds, which is consistent with the literature. The RNL model was unable to estimate threshold scaling across scenarios as predicted by the Weber-Fechner law, highlighting limitations in the current use of the RNL model to quantify luminance contrast perception. Our study confirms that luminance contrast discrimination thresholds are context-dependent and should therefore be interpreted with caution.

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More than noise: context-dependent luminance contrast discrimination in a coral reef fish (Rhinecanthus aculeatus)

Journal of Experimental Biology ◽

10.1242/jeb.232090 ◽

2020 ◽

Vol 223 (21) ◽

pp. jeb232090

Author(s):

Cedric P. van den Berg ◽

Michelle Hollenkamp ◽

Laurie J. Mitchell ◽

Erin J. Watson ◽

Naomi F. Green ◽

...

Keyword(s):

Luminance Contrast ◽

Individual Species ◽

Motion Pattern ◽

Diverse Range ◽

Bright Spots ◽

Context Dependent ◽

Luminance Discrimination ◽

Contrast Perception ◽

Contrast Discrimination ◽

Contrast Thresholds

ABSTRACTAchromatic (luminance) vision is used by animals to perceive motion, pattern, space and texture. Luminance contrast sensitivity thresholds are often poorly characterised for individual species and are applied across a diverse range of perceptual contexts using over-simplified assumptions of an animal's visual system. Such thresholds are often estimated using the receptor noise limited model (RNL). However, the suitability of the RNL model to describe luminance contrast perception remains poorly tested. Here, we investigated context-dependent luminance discrimination using triggerfish (Rhinecanthus aculeatus) presented with large achromatic stimuli (spots) against uniform achromatic backgrounds of varying absolute and relative contrasts. ‘Dark’ and ‘bright’ spots were presented against relatively dark and bright backgrounds. We found significant differences in luminance discrimination thresholds across treatments. When measured using Michelson contrast, thresholds for bright spots on a bright background were significantly higher than for other scenarios, and the lowest threshold was found when dark spots were presented on dark backgrounds. Thresholds expressed in Weber contrast revealed lower thresholds for spots darker than their backgrounds, which is consistent with the literature. The RNL model was unable to estimate threshold scaling across scenarios as predicted by the Weber–Fechner law, highlighting limitations in the current use of the RNL model to quantify luminance contrast perception. Our study confirms that luminance contrast discrimination thresholds are context dependent and should therefore be interpreted with caution.

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The Binocular Summation of Chromatic Contrast

Perception ◽

10.1068/v96l0409 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 145-145 ◽

Cited By ~ 1

Author(s):

D R Simmons ◽

F A A Kingdom

Keyword(s):

Contrast Sensitivity ◽

Detection Threshold ◽

Luminance Contrast ◽

Binocular Summation ◽

Chromatic Contrast ◽

Probability Summation ◽

Investigative Ophthalmology ◽

Contrast Thresholds ◽

Detection Mechanisms ◽

Neural Summation

The level of binocularity possessed by mechanisms sensitive to chromatic contrast is still unclear. Recent studies of stereopsis and chromatic contrast have suggested that stereopsis is maintained at isoluminance, although the contrast sensitivity and disparity ranges of chromatic stereopsis mechanisms are reduced compared to luminance stereopsis mechanisms. Rose, Blake, and Halpern (1988 Investigative Ophthalmology and Visual Science29 283 – 290) hypothesised a link between binocular summation (ie the superiority of binocular detection over monocular detection) and stereopsis. Is this link maintained with heterochromatic isoluminant stimuli? To address this question, the binocular and monocular contrast thresholds for the detection of 0.5 cycle deg−1 Gabor patches were measured. The stimuli possessed different relative amounts of colour and luminance contrast ranging from isoluminance (red/green) to isochrominance (yellow/black) through intermediate values. It was found that, with these stimuli, binocular detection was well modelled by assuming independent mechanisms sensitive to chromatic contrast and luminance contrast. Furthermore, with isoluminant stimuli, levels of binocular summation were above those expected from probability summation between the eyes, thus providing evidence for binocular neural summation within chromatic detection mechanisms. Given that stereoscopic depth identification is impossible at contrast detection threshold with isoluminant heterochromatic stimuli, these results suggest that the link between stereopsis and levels of binocular neural summation may not be a particularly strong one. These results also provide clear evidence for the binocularity of chromatic detection mechanisms.

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Color and luminance increment thresholds in poor readers

Visual Neuroscience ◽

10.1017/s0952523808080565 ◽

2008 ◽

Vol 25 (3) ◽

pp. 481-486 ◽

Cited By ~ 5

Author(s):

STEPHEN J. DAIN ◽

RICHARD A. FLOYD ◽

ROBERT T. ELLIOT

Keyword(s):

Luminance Contrast ◽

Poor Readers ◽

Chromatic Contrast ◽

Colored Overlays ◽

Visual Processes ◽

Computer Based ◽

Luminance Increment ◽

Contrast Discrimination ◽

Contrast Thresholds ◽

Higher Sensitivity

The hypotheses of a visual basis to reading disabilities in some children have centered around deficits in the visual processes displaying more transient reponses to stimuli although hyperactivity in the visual processes displaying sustained reponses to stimuli has also been proposed as a mechanism. In addition, there is clear evidence that colored lenses and/or colored overlays and/or colored backgrounds can influence performance in reading and/or may assist in providing comfortable vision for reading and, as a consequence, the ability to maintain reading for longer. As a consequence, it is surprising that the color vision of poor readers is relatively little studied. We assessed luminance increment thresholds and equi-luminous red-green and blue-yellow increment thresholds using a computer based test in central vision and at 10° nasally employing the paradigm pioneered by King-Smith. We examined 35 poor readers (based on the Neale Analysis of Reading) and compared their performance with 35 normal readers matched for age and IQ. Poor readers produced similar luminance contrast thresholds for both foveal and peripheral presentation compared with normals. Similarly, chromatic contrast discrimination for the red/green stimuli was the same in normal and poor readers. However, poor readers had significantly lower thresholds/higher sensitivity for the blue/yellow stimuli, for both foveal and peripheral presentation, compared with normal readers. This hypersensitivity in blue-yellow discrimination may point to why colored lenses and overlays are often found to be effective in assisting many poor readers.

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Specificity of the chromatic noise influence on the luminance contrast discrimination to the color vision phenotype

Scientific Reports ◽

10.1038/s41598-020-74875-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Bruna Rafaela Silva Sousa ◽

Terezinha Medeiros Gonçalves Loureiro ◽

Paulo Roney Kilpp Goulart ◽

Maria Izabel Tentes Cortes ◽

Marcelo Fernandes Costa ◽

...

Keyword(s):

Color Vision ◽

Luminance Contrast ◽

Color Information ◽

Noise Masking ◽

Central Target ◽

Luminance Threshold ◽

Color Vision Deficiencies ◽

Luminance Discrimination ◽

Contrast Discrimination ◽

Color Vision Impairment

Abstract Many studies have examined how color and luminance information are processed in the visual system. It has been observed that chromatic noise masked luminance discrimination in trichromats and that luminance thresholds increased as a function of noise saturation. Here, we aimed to compare chromatic noise inhibition on the luminance thresholds of trichromats and subjects with severe deutan or protan losses. Twenty-two age-matched subjects were evaluated, 12 trichromats and 10 with congenital color vision impairment: 5 protanopes/protanomalous, and 5 deuteranopes/deuteranomalous. We used a mosaic of circles containing chromatic noise consisting of 8 chromaticities around protan, deutan, and tritan confusion lines. A subset of the circles differed in the remaining circles by the luminance arising from a C-shaped central target. All the participants were tested in 4 chromatic noise saturation conditions (0.04, 0.02, 0.01, 0.005 u′v′ units) and 1 condition without chromatic noise. We observed that trichromats had an increasing luminance threshold as a function of chromatic noise saturation under all chromatic noise conditions. The subjects with color vision deficiencies displayed no changes in the luminance threshold across the different chromatic noise saturations when the noise was composed of chromaticities close to their color confusion lines (protan and deutan chromatic noise). However, for tritan chromatic noise, they were found to have similar results to the trichromats. The use of chromatic noise masking on luminance threshold estimates could help to simultaneously examine the processing of luminance and color information. A comparison between luminance contrast discrimination obtained from no chromatic and high-saturated chromatic noise conditions could be initially undertaken in this double-duty test.

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Color and Luminance Contrast Sensitivity Changes in Early- and Late-Onset Strabismic Amblyopia

Journal of American Association for Pediatric Ophthalmology and Strabismus ◽

10.1016/j.jaapos.2006.01.125 ◽

2006 ◽

Vol 10 (1) ◽

pp. 81

Author(s):

John J. Sloper ◽

Alison R. Davis ◽

Majella M. Neveu ◽

Chris R. Hogg ◽

Michael J. Morgan ◽

...

Keyword(s):

Contrast Sensitivity ◽

Late Onset ◽

Luminance Contrast ◽

Strabismic Amblyopia ◽

Sensitivity Changes

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Psychophysical Measurements of Luminance Contrast Sensitivity and Color Discrimination with Transparent and Blue-Light Filter Intraocular Lenses

Ophthalmology and Therapy ◽

10.1007/s40123-017-0101-y ◽

2017 ◽

Vol 6 (2) ◽

pp. 301-312 ◽

Cited By ~ 4

Author(s):

Marcelo Fernandes da Costa ◽

Augusto Paranhos Júnior ◽

Claudio Luiz Lottenberg ◽

Leonardo Cunha Castro ◽

Dora Fix Ventura

Keyword(s):

Contrast Sensitivity ◽

Blue Light ◽

Color Discrimination ◽

Luminance Contrast ◽

Light Filter ◽

Intraocular Lenses ◽

Blue Light Filter

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Visual Contrast Sensitivity Functions Obtained with Colored and Achromatic Gratings

Human Factors The Journal of the Human Factors and Ergonomics Society ◽

10.1177/001872087902100210 ◽

1979 ◽

Vol 21 (2) ◽

pp. 225-228 ◽

Cited By ~ 9

Author(s):

Michael A. Nelson ◽

Ronald L. Halberg

Keyword(s):

Contrast Sensitivity ◽

Spatial Information ◽

Sensitivity Functions ◽

Visual Contrast ◽

Spatial Frequencies ◽

Sinusoidal Gratings ◽

Visual Contrast Sensitivity ◽

Contrast Thresholds

Threshold contrasts for red, green, and achromatic sinusoidal gratings were measured. Spatial frequencies ranged from 0.25 to 15 cycles/deg. No significant differences in contrast thresholds were found among the three grating types. From this finding it was concluded that, under conditions of normal viewing, no significant differences should be expected in the acquisition of spatial information from monochromatic or achromatic displays of equal resolution.

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Spatial vision in strabismic cats

Journal of Neurophysiology ◽

10.1152/jn.1983.50.1.287 ◽

1983 ◽

Vol 50 (1) ◽

pp. 287-296 ◽

Cited By ~ 20

Author(s):

K. Holopigian ◽

R. Blake

Keyword(s):

Contrast Sensitivity ◽

Preceding Paper ◽

Spatial Vision ◽

Performance Difference ◽

Single Class ◽

Convergent Strabismus ◽

Contrast Thresholds

Contrast thresholds for detection of stationary and flickering gratings were measured behaviorally for each eye of cats raised with induced convergent strabismus. The performance of the deviating eye was inferior to that of the nondeviating eye when test patterns were stationary. Flicker served to reduce the performance difference between the eyes in two cats but not in a third. These results suggest that strabismus amblyopia may not result from deficits within a single class of neurons. In all strabismic cats the contrast sensitivity of the nondeviating eye was significantly reduced relative to normal cats. These behavioral findings, including the deficits found bilaterally, correspond very well with results from cortical recordings from these and other strabismic cats presented in the preceding paper (7).

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