Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Color Vision”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed1994

Ultraviolet receptors and color vision: evolutionary implications and a dissonance of paradigms.

The discovery of visual sensitivity to UV dates from 1882 and was made in an insect, the ant, but in the last 15 years evidence for photoreceptors maximally sensitive in the UV has been found for many vertebrates. Studies of behavioral responses of insects that possess more than one spectral class of photoreceptor have generated the concept of wavelength-dependent behaviors. These phenomena are distinct from color vision, where chromatic information can be used in multiple associations. Recent work on vertebrates has shown a variety of behavioral responses that appear to be based on specific combinations of spectral classes of receptors. Among these are behavioral responses of birds that are maximally sensitive in the UV, surprising findings since the retinas of birds contain only relatively small numbers of cones with peak sensitivity in the UV. These and other examples, suggestive of both wavelength-dependent behaviors of arthropods and "releasers" of ethology, emphasize anew the need for explanatory concepts that reach beyond the paradigms of primate color vision and for greater attention to the ontogeny of visually-directed behavior in non-mammalian vertebrates. The rapidly accumulating data on the evolutionary relationships of opsins continue to suggest that within specific opsin lineages the absorption maxima of the retinal-based visual pigments lie within about 40 nm of each other. Some UV pigments may provide the first exception to this generalization.

Animals↗
PubMed1992

Color vision in the California sea lion (Zalophus californianus).

Three California sea lions were trained to discriminate between a colored stimulus and two shades of gray in a 3-fold simultaneous choice situation. The colors blue, green and red were tested against shades of gray varying from low to high relative brightness. All animals distinguished blue from gray; two animals also distinguished green from gray; but none discriminated between red and gray. Our data suggest that California sea lions have dichromatic color vision. Their ability to discriminate colors in the blue-green part of the spectrum could be a physiological adaptation to their aquatic coastal habitat.

Animals↗
PubMedDate not supplied

High color-vision sensitivity in macaque and humans.

Psychophysical (behavioral) detection thresholds and color-discrimination thresholds were determined in a macaque using a two-alternative forced-choice procedure. On a white background, detection thresholds were determined for a white increment and three spectral increments: 618, 516, and 456 nm. Intermixed with detection threshold determinations, color-discrimination thresholds were determined by presenting the white increment, and one of the spectral increments, at 1.0 log units above their respective detection thresholds and dimming both until discrimination performance fell to threshold. The monkey could discriminate the color of the increments at detection threshold because the average color-discrimination threshold was 0.98+/-0.14 log attenuation. Because the monkey was much more sensitive to the spectral increments than the white increment, we performed an unconventional experiment. We determined the monkey's detection threshold for the white increment alone, and with broadband color filters in the white light path without adjusting the light's intensity. Insertion of several color filters in the light path lowered detection thresholds of both the macaque and six human trichromats. We believe that this improvement in detection thresholds produced by simply inserting color filters in a white light path is a threshold manifestation of the Helmholtz-Kohlrausch effect and suggests that one of color vision's important evolutionary advantages may be improved detection sensitivity.

Adolescent↗
PubMed1993

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

A patient from a large kindred with adrenoleukodystrophy showed profound disturbance of color ordering, color matching, increment thresholds, and luminosity. Except for color matching, his performance was similar to blue-cone "monochromacy," an X chromosome-linked recessive retinal dystrophy in which color vision is dichromatic, mediated by the visual pigments of rods and short-wave-sensitive cones. Color matching, however, indicated that an abnormal rudimentary visual pigment was also present. This may reflect the presence of a recombinant visual pigment protein or altered regulation of residual pigment genes, due to DNA changes--deletion of the long-wave pigment gene and reorganized sequences 5' to the pigment gene cluster--that segregate with the metabolic defect in this kindred.

Adrenoleukodystrophy↗
PubMed1987

The effect of a moderate level of hypoxia on human color vision.

This study reports the effect of a moderate level of hypoxia on human color discimination. We found a generalized loss of color vision affecting both red-green and blue-yellow discrimination at an altitude of 12,000 feet. Although the residual color discrimination at this altitude was within age-matched, sea-level norms, a statistically significant increase over sea level error scores was measured on the Farnsworth-Munsell 100-Hue test and the Pickford-Nicolson anomaloscope. An analysis of psychophysical and electrophysiological studies indicates that hypoxia acts by depressing retinal ganglion cell activity and that it can affect photopic visual processes as well as scotopic vision. We conclude that studies evaluating man's visual performance at altitude must consider post-receptoral processes.

Adult↗