Results 261 to 270 of about 265,631 (295)
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Cone visual pigments of aquatic mammals
Visual Neuroscience, 2005It has long been hypothesized that the visual systems of animals are evolutionarily adapted to their visual environment. The entrance many millions of years ago of mammals into the sea gave these new aquatic mammals completely novel visual surroundings with respect to light availability and predominant wavelengths.
Lucy A, Newman, Phyllis R, Robinson
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Cone Inputs in Macaque Primary Visual Cortex
Journal of Neurophysiology, 2004To understand the role of primary visual cortex (V1) in color vision, we measured directly the input from the 3 cone types in macaque V1 neurons. Cells were classified as luminance-preferring, color-luminance, or color-preferring from the ratio of the peak amplitudes of spatial frequency responses to red/green equiluminant and to black/white ...
Elizabeth N, Johnson +2 more
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Visual Field Changes in Cone-Rod Degenerations
Archives of Ophthalmology, 1982The visual field test results from 20 patients with con-rod degeneration (CRD) from all inheritance patterns were reviewed. Typical fundus findings of CRD included optic disc pseudoedema, temporal disc atrophy, parapapillary and disc telangiectasis, and few to no retinal pigmentary deposits.
H R, Krauss, J R, Heckenlively
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Cone spacing and the visual resolution limit
Journal of the Optical Society of America A, 1987It is commonly assumed that the visual resolution limit must be equal to or less than the Nyquist frequency of the cone mosaic. However, under some conditions, observers can see fine patterns at the correct orientation when viewing interference fringes with spatial frequencies that are as much as about 1.5 times higher than the nominal Nyquist ...
D R, Williams, N J, Coletta
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A visual nonlinearity fed by single cones
Vision Research, 1992An intensive nonlinearity in the visual system can produce distortion products, or difference frequency gratings, when observers view two high contrast, high spatial frequency interference fringes of slightly different frequency or orientation added together at the retina.
D I, MacLeod, D R, Williams, W, Makous
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Distribution and specificity of S-cone (“blue cone”) signals in subcortical visual pathways
Visual Neuroscience, 2014AbstractWe review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset ...
Martin, P., Lee, B.
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Ultrastructural visualization of primate cone photoreceptor matrix sheaths
Journal of Comparative Neurology, 1988AbstractGlycoconjugates, including glycolipids, glycoproteins, and proteoglycans, are present in the plasma membrane of photoreceptor cells and in the interphotoreceptor matrix surrounding photoreceptor cell ellipsoids and outer segments. Although the precise function of these molecules is unknown, they may be important in mediating photoreceptor ...
J C, Blanks +3 more
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The cone photoreceptors and visual pigments of chameleons
Journal of Comparative Physiology A, 2005Visual pigments, oil droplets and photoreceptor types in the retinas of four species of true chameleons have been examined by microspectrophotometry. The species occupy different photic environments: two species of Chamaeleo are from Madagascar and two species of Furcifer are from Africa and the Arabian Peninsula.
James K, Bowmaker +2 more
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Purification of cone visual pigments from chicken retina
Biochemistry, 1989A novel method for purification of chicken cone visual pigments was established by use of a 3-[(3-cholamidopropyl)dimethylammonio]-1- propanesulfonate-phosphatidylcholine (CHAPS-PC) mixture. Outer segment membranes isolated from chicken retinas were extracted with 0.75% CHAPS supplemented with 1.0 mg/mL phosphatidylcholine (CHAPS-PC system).
T, Okano +3 more
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Spectral Tuning of Rhodopsin and Visual Cone Pigments
Journal of the American Chemical Society, 2014Retinal is the light-absorbing biochromophore responsible for the activation of vision pigments and light-driven ion pumps. Nature has evolved molecular tuning mechanisms that significantly shift the optical properties of the retinal pigments to enable their absorption of visible light.
Zhou, Xiuwen +3 more
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