Overview: Researchers have questioned whether our brain can take three primary color inputs and convert them into the range of different colors we can see.
For birders struggling to tell the difference between male and female titmouses, the answer is here. Male crests actually show up as ultraviolet (UV) light on other breasts, which we humans can’t see.
Like other primates, our vision has only three colors: red, green and blue. Many other mammals usually see in two (blue and green), but birds he sees in a mixture of four (red, green, blue and UV).
If our brain could take three primary inputs and translate them into all the colors we perceive, could we unlock new hues with a little brain exercise?
look to evolution
The eyes we know and love today were some of the earliest life forms on Earth, and may have begun their evolutionary journey 800 million years ago.
“These ancestral creatures lived in water, so being able to perceive light sources, distinguish between day and night, and indicate depth helps them survive,” Baden says.
Consequently, evolution mutated melatonin receptors into opsin proteins, which underlie nearly all photoreceptors, leading to the vertebrate retina during the Cambrian explosion more than 500 million years ago.
Fascinated by the evolution of the classical vertebrate visual system, Baden used two-photon imaging and computational analysis, along with fieldwork with specialized cameras and photometers, to identify the zebrafish as a model for our ancestors. Researched.
“Zebrafish have four color receptors, known as cone cells, for red, green, blue and UV, each with a different role. We found that red cones sense light.” “The sensory colors of green and blue. UV helps identify foods. Importantly, all color perceptual processing occurs at the output synapses of photoreceptors, the retina itself,” explains Baden.
a product of our perception
Our visual arrangement contrasts markedly with zebrafish. Her four retinal cones in the zebrafish function as neurons, each with a different cell-surface protein that performs the task of distinguishing wavelength inputs directly and therefore easily.
The human retina has three color receptors, each sensitive to different parts of the light spectrum. One short wavelength cone responds to light perceived as blue. The other he two medium-wave cones “sense” green and the remaining long-wave cones “sense” red.
But unlike zebrafish, these are only the first stages of our color perception.
The ‘blue’ retinal cones are distinct, but the other two (nominally ‘green’ and ‘red’) are actually both ‘red’ cones. An original and a duplicate that sense green in response to slightly different wavelengths. Importantly, from an evolutionary and molecular perspective they are identical.
“As a result, the retinal circuitry cannot distinguish between them and outsources the problem to the brain. It could be involved,” Baden said.
A sensible reason not to extend the color space
But if our sense of color is generated by the brain decoding the signals of the photoreceptors, then perhaps we could teach neural processing or expand the color space, such as tweaking software to manipulate digital images. Why can’t I evolve it to become
“When the brain compares the signals of the cones to produce the sensation of color, it infers the original wavelength. We need to know,” says Baden.
“There are already very few signals to process, but our big brains have learned to process them. It’s wired like this.”
Ultimately, even sophisticated algorithms are limited by inputs. This suggests that the only way to extend the color space is to change the retinal input.
But if evolution brings us the lost ancestral vision, allowing us to see, say, ultraviolet light, we may have to make trade-offs, such as increased cancer risk.
Surprisingly, virtually all modern vertebrates (fish, amphibians, reptiles and birds) retain their ancestral color receptors intact.
“Mammals, including us, are far from the gold standard for color vision, and are really outliers, perhaps the result of evolutionary survival strategies that date back to the age of the dinosaurs. It’s not about whether we can see things, but with what little we have, how can we see as much as we do?” Baden concludes.
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