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If we developed new "eyes" that could see "non-visible spectrum colours" and connected them to our brains, would our brain be capable of identifying and interpreting those new colours? Is our brain hardwired to only de-encode information about RGB using our SML cones?

How is color information transmitted from the eye to the brain? Our brain receives the information as an FM signal, but does that mean a different "carrier frequency" is used in the FM will the brain detect and interpret this new colour?

Cerebral activity during exposure to non - visible light We lack the ability to see colours outside of the visible-spectrum due to a lack of photoreceptors.

https://www.quora.com/Why-cant-we-think-of-a-new-colour-Is-it-really-impossible-to-think-of-any-colour-that-doesnt-exist-right-now-Is-the-light-spectrum-the-only-possible-source-for-new-colours-or-might-there-be-something-else Note that this link states we can "imagine" new colours in a pseudo kinda way.

The two points I found online providing information about my question: Yes adding new photoreceptors/sensors to our eyes could be a way to see new colours and yes sending a different signal would seem to be the way to interpret a new "colour". But those answers only partly apply to whether it's actually possible and only narrowly approach this question.

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  • $\begingroup$ "new eyes" = synthetically designed or robotic. I'm aware that the modulation of another animal's eye's wouldn't fit the bill and therefore we can't reliably transplant eyes from other creators to boost our vision capabilities. (e.g. Mantis Shrimp eyes would certainly be incompatible and require special vision processing capabilities phenomena.nationalgeographic.com/2014/07/03/… ) $\endgroup$ – Tmanok Mar 9 '18 at 7:44
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Each human optic nerve contains between 770,000 and 1.7 million nerve fibers, So it will be beyond human grasp to swap eyes in the near future, genetic eye and optic fiber development has to happen in the womb. Eye grafts require some kind of neural nanotechnology which is probably multiple generations away.

If you replace a human photoreceptor with another color, the result is: un-demonstrated/unknown.

Genetically engineered photoreceptor color swap (swap UV and blue) which sends impulses to the same optic nerves as the previous color, may, and probably would work fine.

If you switch one eye to CMY and keep the other as RGB, it should have a usable result.

If you switch both eyes to CMY it's fine too, we would expect that there would be a fair vision perception, perhaps equivalent to RGB in clarity.

If you design a fetus with 4-5 photoreceptors and let it develop normally, It would have an unknown result. Perhaps the baby would have augmented vision, perhaps troubled. It's not know and many scientists would love to know the result.

I'd wager that a human with 4-5-6 colors of photoreceptors can be genetically engineered to see, within our lifetime.

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  • $\begingroup$ Awesome, I believe that there is a man or woman who's been given a robotic eye (about 3 years ago) and it was very blurry and low saturation but the same colours as our SML receive. I just did a quick google and found about 5 links to different events claiming to be the first transplant and one really neat one to combat ARMD. I think that with Crispr being our modern DNA modifier would could eventually learn enough about DNA to design improved sight. But back to the question, yes certainly would be fascinating to know the outcome of "extra" or "new" colours. $\endgroup$ – Tmanok Mar 9 '18 at 9:12
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    $\begingroup$ @Tmanok If I get the reference correctly that was a photoreceptor chip grafted to the retina. $\endgroup$ – ratchet freak Mar 9 '18 at 13:14
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    $\begingroup$ There be tetrachromatic humans already. web.archive.org/web/20120214002707/http://www.klab.caltech.edu/… $\endgroup$ – John Mar 9 '18 at 14:19
  • $\begingroup$ Awesome John thanks for sharing! @Ratchet Freak, yes there was a transplant of an entire bionic eye in colorado 2015, another in the UK but different operation and then a neat one for ARMD (AMD is the generally more accepted term) where they grafted an electrode array connected to a pair of glasses with a camera. I'm sure there have been more but when you read "first, first, first, first" all during different years it makes you think "first time using this method? Your title is misleading and earns a skepticism award". $\endgroup$ – Tmanok Mar 9 '18 at 18:27
  • $\begingroup$ Humans probably couldn't use UV photoreceptors, a study found that all animals that can see UV's, birds and some mammals, have eyes smaller than 5-7mm. io9.gizmodo.com/… $\endgroup$ – com.prehensible Mar 9 '18 at 22:33
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There are two issues associated with "seeing extra colors". One is seeing parts of the light spectrum we currently do not see; for example, seeing ultraviolet or infrared light. Another is discriminating between different combinations of wavelengths, and perceiving more colors than we actually do.

Our color vision is based on three different receptors who are sensitive to different wavelengths; the brain infers color from the differences between how those receptors are activated. This allows to tell some combinations of wavelengths from others, but not all: we can tell red light from blue light, because the first excites the red-detecting cells a lot more than the two others and the second excites the blue-detecting cells a lot more than the two others, but we cannot tell yellow light from a combination of red and green light, because in both of those cases we have the red and green cells excited the same and the blue cells not as much. This is why our color vision is "three-dimensional", i.e. all colors can be generated from three basic ones.

Somebody who instead of a blue receptor had an ultraviolet receptor, would be able to perceive more wavelengths than we do, but they would probably see more or less the same colors - "ultraviolet" would be "blue" to them. There may be differences because the kind of combinations they ran into would be different - for example because they'd have a wider range between the "green" and "ultraviolet" sensors than we have between "green" and "blue", maybe more of the world would look cyan than it does to us.

To see additional colors, the same way that ordinary trichromat humans see more colors than color-blind people, and be able to discriminate between more combinations of wavelengths than we do now, we would need extra receptors. And that's where the questions arise of whether the brain would be able to handle the extra colors, or whether the optic nerve would transmit it as its own channel.

As it happens there are cases in humans where they have four different color receptors. The main case happens because the genes for some color receptors (red/green) are on the X chromosome, and in women one of their two X chromosome is inactivated in each cell, but which it is is random - meaning that if they have two slightly different versions of that receptor on their two chromosomes, some cells in the retina will have one and others the other - making two different color receptors in their eyes where other people have one.

It appears that most women with this conditions do not see more colors than others, which could be because the two receptors don't vary enough. But it appears that some rare cases do have better abilities to discriminate colors and a richer color experience, which suggests that human tetrachromacy is possible and already exists in a few rare individuals.

See also:

https://en.wikipedia.org/wiki/Tetrachromacy#Humans

https://theneurosphere.com/2015/12/17/the-mystery-of-tetrachromacy-if-12-of-women-have-four-cone-types-in-their-eyes-why-do-so-few-of-them-actually-see-more-colours/

https://theness.com/neurologicablog/index.php/tetrachromacy-in-humans/

https://www.researchgate.net/profile/Zoltan_Jakab/publication/254932347_Looking_for_potential_indicators_of_human_tetrachromacy/links/546c88c80cf2c4819f216fa5/Looking-for-potential-indicators-of-human-tetrachromacy.pdf

https://arxiv.org/abs/1703.04392 Enhancing human color vision by breaking binocular redundancy (this isn't about the abovementioned cases of tetrachromacy, but of people trying to induce tetrachromacy by stimulating the two eyes differently)

This paper gives a good general overview of color vision in the animal kingdom, and debunks some misconceptions (such that animals with a zillion color receptors see a bazillion more colors than we do - they actually process color very differently and the number of color receptors they have is related to that).

https://www.sciencedirect.com/science/article/pii/S0960982214013013

Another overview of human color vision:
https://www.imbs.uci.edu/colorcoglab/4-9.pdf
Human Potential for Tetrachromacy

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  • $\begingroup$ Hi Rozenn, this makes perfect sense after having read about Mantis Shrimp perceiving very specific wavelengths of UV, although researchers have no idea why they have this innate need to see those wavelengths it can be assumed that they're related to something in their habitat and the fact that they filter out non-essential colours leads me to think that they are blocking out sun refraction underwater. Who knows, but do you'd think having photoreceptors that do not overlap with each other in the UV spectrum would be very odd- binary colour hue but with variable saturation in fact. $\endgroup$ – Tmanok Mar 9 '18 at 18:22

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