scholarly journals Two spectral sensitivity curves ofXenopus laevisobtained by using the melanophore response to light on white and black backgrounds

1963 ◽  
Vol 169 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Priscilla H. Silver
Keyword(s):  
Spectral Sensitivity ◽  
Sensitivity Curves

scholarly journals Wild hummingbirds discriminate nonspectral colors

2020 ◽  
Vol 117 (26) ◽  
pp. 15112-15122 ◽  
Author(s):  
Mary Caswell Stoddard ◽  
Harold N. Eyster ◽  
Benedict G. Hogan ◽  
Dylan H. Morris ◽  
Edward R. Soucy ◽  
...  
Keyword(s):  
Spectral Sensitivity ◽  
Uv Light ◽  
Monochromatic Light ◽  
Color Space ◽  
Color Perception ◽  
Color Discrimination ◽  
Behavioral Experiments ◽  
Simultaneous Stimulation ◽  
Cone Type ◽  
Sensitivity Curves

Many animals have the potential to discriminate nonspectral colors. For humans, purple is the clearest example of a nonspectral color. It is perceived when two color cone types in the retina (blue and red) with nonadjacent spectral sensitivity curves are predominantly stimulated. Purple is considered nonspectral because no monochromatic light (such as from a rainbow) can evoke this simultaneous stimulation. Except in primates and bees, few behavioral experiments have directly examined nonspectral color discrimination, and little is known about nonspectral color perception in animals with more than three types of color photoreceptors. Birds have four color cone types (compared to three in humans) and might perceive additional nonspectral colors such as UV+red and UV+green. Can birds discriminate nonspectral colors, and are these colors behaviorally and ecologically relevant? Here, using comprehensive behavioral experiments, we show that wild hummingbirds can discriminate a variety of nonspectral colors. We also show that hummingbirds, relative to humans, likely perceive a greater proportion of natural colors as nonspectral. Our analysis of plumage and plant spectra reveals many colors that would be perceived as nonspectral by birds but not by humans: Birds’ extra cone type allows them not just to see UV light but also to discriminate additional nonspectral colors. Our results support the idea that birds can distinguish colors throughout tetrachromatic color space and indicate that nonspectral color perception is vital for signaling and foraging. Since tetrachromacy appears to have evolved early in vertebrates, this capacity for rich nonspectral color perception is likely widespread.

The Spectral Sensitivity of the Goldfish and the Clawed Toad Tadpole Under Photopic Conditions

1965 ◽  
Vol 42 (3) ◽  
pp. 481-493
Author(s):  
J. R. CRONLY-DILLON ◽  
W. R. A. MUNTZ
Keyword(s):  
Spectral Sensitivity ◽  
Physiological Data ◽  
Optomotor Response ◽  
Goldfish Carassius Auratus ◽  
Phototactic Response ◽  
Sensitivity Curves ◽  
Maximal Sensitivity ◽  
Toad Tadpole ◽  
Cone Sensitivity ◽  
Vitamin A2

1. Photopic spectral sensitivity curves have been obtained by means of the optomotor response for the tadpole of the clawed toad (Xenopus laevis), and for the goldfish (Carassius auratus). Both these animals have visual pigments based on vitamin A2, and would be expected therefore to have photopic sensitivity curves maximal at about 615 mµ and fitting, at any rate approximately, the absorption spectrum of cyanopsin. 2. The results with Xenopus show a broad curve extending far into the red, and having its maximal sensitivity at about 630 mµ It is probable that this curve reflects the summated activity of two receptors, maximally sensitive at 610 and 630 m/t. 3. The results are discussed in relation to other behavioural work with Xenopus, using the phototactic response, in which an entirely different form of spectral curve was obtained, and in relation to behavioural and physiological data which are available for Rana. 4. The photopic curve of the goldfish shows three humps, which can be separated out to a large extent by using different background illuminations. One hump is maximal at about 610 mµ, the classical position for cone sensitivity in freshwater fish. A second hump is maximal at about 530 mµ and is probably due to the rods, and the third hump is maximal at about 450 mµ in the blue. The relation of these three receptors to colour vision in this animal are discussed.

Regional specialization in the eye of the sphingid moth Manduca sexta: Blue sensitivity of the ventral retina

1997 ◽  
Vol 14 (3) ◽  
pp. 523-526 ◽  
Author(s):  
Ruth R. Bennett ◽  
Richard H. White ◽  
Jeffery Meadows
Keyword(s):  
Manduca Sexta ◽  
Spectral Sensitivity ◽  
Compound Eye ◽  
Regional Specialization ◽  
Relative Contribution ◽  
Flower Visitation ◽  
Nectar Feeding ◽  
Sensitivity Curves ◽  
Receptor Mosaic ◽  
Dorsal Retina

AbstractThe compound eye of the tobacco hornworm moth Manduca sexta contains green-, blue-, and ultraviolet-sensitive photoreceptors. Electroretinogram spectral-sensitivity measurements were recorded from different regions of the retina in order to broadly map the distribution of the three receptor types. The relative contribution of the three receptors to spectral-sensitivity curves was estimated by fitting theoretical curves based on the absorption spectra of the three rhodopsins. This analysis indicated that the dorsal retina is green and ultraviolet dichromatic, with green-sensitive cells greatly predominating. The ventral retina is trichromatic with a substantial population of blue- and ultraviolet-sensitive receptors. We previously showed that flower visitation for nectar feeding is mediated mainly by blue-sensitive cells. Their localization in the ventral retina seems an appropriate adaptation of the receptor mosaic, since the moths hover above flowers as they feed.

Designing spectral sensitivity curves for use with Artificial Color

2007 ◽  
Vol 40 (8) ◽  
pp. 2251-2260 ◽  
Author(s):  
Jian Fu ◽  
H. John Caulfield
Keyword(s):  
Spectral Sensitivity ◽  
Sensitivity Curves

Recovery and spectral sensitivity curves for color-anomalous observers

1968 ◽  
Vol 8 (7) ◽  
pp. 929-938 ◽  
Author(s):  
Whitman Richards ◽  
S.M. Luria
Keyword(s):  
Spectral Sensitivity ◽  
Sensitivity Curves

Fly photoreceptors I. Physical separation of two visual pigments in Calliphora retinula cells 1-6

1975 ◽  
Vol 190 (1099) ◽  
pp. 211-224 ◽  
Keyword(s):  
Spectral Sensitivity ◽  
Polarized Light ◽  
Visual Pigments ◽  
Polarization Sensitivity ◽  
Physical Separation ◽  
Adaptation Mechanisms ◽  
Sensitivity Curves ◽  
Peak Sensitivity ◽  
Two Peaks ◽  
Different Parts

The two peaks of the spectral sensitivity curves of Calliphora correspond to two visual pigments. The peak sensitivity to polarized light for the u. v. sensitive pigment is at an angle to that for the green-sensitive pigment. The change in angle of the maximum polarization sensitivity as a function of wavelength occurs near 400 nm; in this transition the curves do not follow a cos 2 function. The angle between the two maxima is different for each retinula cell. The only explanation of this phenomenon is that there are two visual pigments in different parts of the receptor, and one part is twisted relative to the other. There are therefore two metarhodopsins and the adaptation mechanisms are partially separate for the two peaks of the spectral sensitivity. The inference of two separated pigments modifies the interpretation of much previous work on fly photoreceptors.

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