Don’t be envy green, but fish may be able to distinguish colors more effectively than humans

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Researchers have shown that vertebrates other than mammals may have a much easier and more effective way to decipher color and grayscale information than humans.

Tom Baden, a professor of neuroscience in his laboratory at the University of Sussex, and others were investigating how zebrafish react and decode between different wavelengths or colors of light.

“Zebrafish, unlike humans, have four types of pyramidal photoreceptors, which are special neurons in the retina that respond to light. These four types are often red and green. , Blue, called UV. What is written on the can — red reacts to red light, green reacts to red light Green light, and so on. But it turns out that is not the case. “

For the first direct in-vivo measurement of “color tuning” from vertebrate photoreceptors, Professor Baden and his team collaborated with researchers at the University of Tubingen in Germany and the Baylor Medical College in Texas, USA. Zebrafish decipher colors in a much easier way for humans. Their research is Science AdvancesExplains how the “red cone” responded to brightness, that is, black or white information, and how the “green cone” responded to color information.

Professor Baden said, “In the basic principle, color vision requires a visual circuit to unravel brightness from color information. In nature, these are basically intertwined, so unraveling is not an easy task, if Some may require quite a few neurons.

“In humans, some of these are distributed throughout the eye and brain in ways that are not yet understood. In contrast, zebrafish are synapses of the photoreceptors themselves, and this basis as soon as possible. Problem is solved. “

from Evolutionary perspectiveProfessor Baden explains that this “fish strategy” is probably much closer to the “origin of vision” of vertebrates.

In contrast, during the dinosaur era, early human ancestors of mammals are believed to have fled to the forest and adopted a nocturnal lifestyle. In the process, all but two pyramidal photoreceptor types were lost, and most mammals became bicolor and could only be seen in two colors. Even dogs, cats, horses, hamsters, and mice can all distinguish between blue and green, but nothing can easily distinguish between green and red.Therefore, we imagine they see the world in colors that may resemble red-green color blindness. human You may experience it.

Unlike the evolutionary lines of other mammals, humans, gorillas and chimpanzees, it evolved much later into three colors, regaining some of its color-blind abilities. However, this happens in a much more complicated way and requires a lot of calculations. This is believed to be done by the brain, not the inside of the eye. This is a complex process, meaning that early infancy needs to learn to distinguish several colors through the developing cortex.

“Our study is that vertebrates like zebrafish, and perhaps most non-mammalian vertebrates like other fish, birds, reptiles, amphibians, are at the first synapse of vision,” said Baden. It essentially shows that you can actually solve a “color puzzle”. Humans are sticking to this overly complex “knock-off” strategy for their early mammalian ancestors. “

This study focuses on insects because flies also have four such “color-blind photoreceptors” that, despite their completely independent evolution, determine color in exactly the same way as zebrafish. I also refer to the link.

With follow-up paper, Current biology Soon, researchers will use the same technique to investigate the second layer of retinal processing, the so-called retina cells. Extending the above result, in this second layer processing, Zebrafish Represents three types of color contrast (rather than the previous two). This “third” is built by comparing UV- with all other wavelengths and is very similar to the so-called “blue-yellow” system, one of the two color channels used by humans.

Together, the treatise implies that the human bluish-yellow system is truly ancient and precedes the division of tetrapods from fish almost 400 million years ago. When it comes to seeing color, we seem to share at least some features with at least all vertebrates that see color.

Lamprey’s newly discovered two-cell color detection system is a clue to the evolution of color vision

For more information:
Takeshi Yoshimatsu et al., An ancestral circuit of vertebrate color blindness appears at the first retinal synapse, (2020). DOI: 10.1101 / 2020.10.26.356089

Philipp Bartel et al, Spectral Inference, Reveals Major Pyramid Integration Rules Inside the Retina of Zebrafish. (2021). DOI: 10.1101 / 2021.08.10.455697

Quote: Not the envy, but the fish are humans obtained on October 13, 2021 from https: // (October 13, 2021) It may be possible to distinguish colors more effectively than days). envy-fish-distinguish.html

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Don’t be envy green, but fish may be able to distinguish colors more effectively than humans

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