The cone oil droplets of avian retinas

@article{Goldsmith1984TheCO,
  title={The cone oil droplets of avian retinas},
  author={Timothy H. Goldsmith and J. Spencer Collins and Sherry Licht},
  journal={Vision Research},
  year={1984},
  volume={24},
  pages={1661-1671}
}
Distribution of Retinal Cone Photoreceptor Oil Droplets, and Identification of Associated Carotenoids in Crow (Corvus macrorhynchos)
TLDR
Three types of carotenoid (astaxanthin, galloxanthin and lutein), together with one unknown carotanoid, were recovered from the crow retina; astaxanth in was the dominant carotnoid among them and the recovery ofcarotenoids was affected by saponification conditions.
The cone photoreceptors and visual pigments of chameleons
TLDR
Visual pigments, oil droplets and photoreceptor types in the retinas of four species of true chameleons have been examined by microspectrophotometry and appear to be mixtures of rhodopsins and porphyropsins.
Avian retinal oil droplets: dietary manipulation of colour vision?
TLDR
The study provides the first experimental evidence of dietary intake over a short time period affecting carotenoid concentration of retinal oil droplets, an area about which very little is known, with implications for the understanding of trade-offs in carOTenoid allocation in birds.
Oil droplets of bird eyes: microlenses acting as spectral filters
  • D. Stavenga, B. Wilts
  • Environmental Science, Physics
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2014
TLDR
Quantitative modelling of the filter characteristics using known carotenoid pigment spectra indicates that the pigments’ absorption spectra are modified by the high concentrations that are present in the yellow and red droplets, which causes narrow-band photoreceptor spectral sensitivities, which are well suited for spectral discrimination.
Cone photoreceptor oil droplet pigmentation is affected by ambient light intensity
TLDR
Calculations show that the reduced levels of oil droplet pigmentation in chickens reared in dim light would increase the sensitivity and spectral bandwidth of the outer segment significantly, which might explain why nocturnal animals have evolved oil droplets with low pigment densities or no pigmentation or have lost their oil Droplets altogether.
A complex carotenoid palette tunes avian colour vision
TLDR
This study integrated results from high-performance liquid chromatography, hyperspectral microscopy and microspectrophotometry to obtain a comprehensive understanding of oil droplet carotenoid pigmentation in the chicken.
Absorbance of retinal oil droplets of the budgerigar: sex, spatial and plumage morph-related variation
TLDR
This work found a spatial pattern of droplets absorbance across the retina that matched a pattern found in another parrot, and other avian species, and suggests a common mechanism and function for carotenoid deposition in the retina across bird species.
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References

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The visual pigments and oil droplets of the chicken retina
The visual pigments, oil droplets and spectral sensitivity of the pigeon
Super dense carotenoid spectra resolved in single cone oil droplets
TLDR
This work has shown that structureless cutoff absorbance curves reminiscent of commercial colour filters have been found to truncate at about one absorbance unit without any evidence of carotenoid spectral fine structure in individual oil droplets.
Photoreceptors and oil droplet colors in the red area of the pigeon retina
TLDR
Six types of photoreceptors in the red area (dorso‐temporal quadrant) of the pigeon retina are identified using Golgi impregnation, light microscopy and electron microscopy to categorize the receptors into morphological types.
Absorption spectra of retinal oil globules in turkey, turtle and pigeon.
Absorption spectra and function of the coloured oil drops in the pigeon retina.
GALLOXANTHIN, A CAROTENOID FROM THE CHICKEN RETINA
  • G. Wald
  • Chemistry
    The Journal of general physiology
  • 1948
TLDR
Galloxanthin appears to be one of the carotenoid filter pigments associated with cone vision in the chicken, and may act as an auxiliary to the other filter Pigments in differentiating colors; or its primary function may be to exclude violet and near ultraviolet radiations for which the eye has a large chromatic aberration.
The ultraviolet receptor of bird retinas.
TLDR
Measurements demonstrate the basis for the ultraviolet sensitivity of birds that has been seen in behavioral experiments, and they provide further evidence that many vertebrates share with insects vision in the near-ultraviolet.
Spectral transmittance of retinal colored oil globules re-examined with microspectrophotometer.
TLDR
It was quite impossible to determine the absorption maximum of oil globule pigments because of its extreme high concentration in situ, and the difference in oil globules tint seemed not due to the difference of chemical kind of carotenoid but to the different in concentration or in mixture ratio of the known carotanoids.
Carotenoids of the Chicken Retina
TLDR
The cones of many bird and reptile retinas contain brilliantly coloured oil globules, which may serve as a mechanism for colour vision in birds and reptiles.
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