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> does not involve ... ‘opening another colour band’ That's not so obvious to me. If this chemical were uniformly spread across the retina, then I'd agree. But
by improbable22 8y ago
> does not involve ... ‘opening another colour band’
That's not so obvious to me. If this chemical were uniformly spread across the retina, then I'd agree. But if it's sufficiently clumpy, or ideally attached to every second green-sensitive cone, then it absolutely would give (N+1)-colour vision (N=3 in humans). On first glance I can't figure out what the paper has to say about this distribution... and even if it were uniform in their mice, perhaps the next step would be to make it non-uniform somehow.
The earlier way to do something similar was by genetically altering some cells, [1]. If you inject a virus (carrying the modification) at a low concentration, then you do get just half the cells. Then the brain learns (in a few weeks) which cells are now giving what information, and you get more colours. [1] did this in monkeys, IIRC they are N=2 and the virus added the gene for one of the human receptors. I don't think it was safe enough for humans.
[1] https://www.nih.gov/news-events/nih-research-matters/gene-therapy-corrects-monkey-color-blindness https://www.nih.gov/news-events/nih-research-matters/gene-th...
- golergka 8y agoI don't know enough about the subject matter to judge if this comment is correct or not, but it is polite, on-topic, and therefore shouldn't be downvoted.
- buboard 8y agostill it would not be possible to discriminate if the green that i see is normal green or IR green. it would be rather obvious in the night, when color cones are not used, but during the day it would be confusing. I 'm thinking "Aww that s a beautiful tree ... oh , it's a trash fire"
- improbable22 8y agoNo, that's exactly what the monkeys learned to discriminate. After a few weeks they pass monkey-specific colour-blindness tests, which wild-type monkeys cannot. I don't think you are born with different wiring to the three different kinds of cones, your brain just learns to lump all the red ones together, so that a red object stays the same colour in different parts of your visual field. The claim is that the monkeys learned which of the previously-identical cones now had a new colour.
- buboard 8y agoyes it is possible to create objects that can discriminate between colorblind and wild type. but from the point of view of the colorblind person (the augmented person) it will still be a source of confusion.
- improbable22 8y agoJust to be clear, the point isn't that we can distinguish which monkeys are treated, it's that the monkeys can distinguish many colours which they could not before. The treated ones behave like trichromats. Do they lose any sleep philosophising about how these new colours are possible, and what to call them? Who knows. But I believe they can still do all the usual monkey things.
- buboard 8y ago> it's that the monkeys can distinguish many colours which they could not before That's the point they can not distinguish more colors. Their retinal cones still have the same spectral response. They cannot distinguish between a normal 500nm green leaf and a 900nm infrared source.
- improbable22 8y agoAh, you mean the mice? In the near-IR study it's not clear (to me, yet) whether all the cones are altered, or just some of them. If all of them are altered, then for sure, same N=2 as normal mice. The monkeys are in a different study, the one I linked a few posts above.
- buboard 8y agosorry i was referring to the nanoparticles. Indeed rhodopsins are used so routinely in neuroscience that one wonders why it has not been used to treat colorblindness in humans yet.
- 8y ago