Natures wonders: Color vision (Introduction)

by David Turell , Friday, September 16, 2016, 00:19 (2989 days ago) @ Balance_Maintained

Further understanding of human color vision is described: - https://www.sciencenews.org/article/color-vision-strategy-defies-textbook-picture - "Color vision may actually work like a colorized version of a black-and-white movie, a new study suggests. - "Cone cells, which sense red, green or blue light, detect white more often than colors, researchers report September 14 in Science Advances. The textbook-rewriting discovery could change scientists' thinking about how color vision works. - "For decades, researchers have known that three types of cone cells in the retina are responsible for color vision. Those cone cells were thought to send “red,” “green” and “blue” signals to the brain. The brain supposedly combines the colors, much the way a color printer does, to create a rainbow-hued picture of the world (including black and white). But the new findings indicate that “the retina is doing more of the work, and it's doing it in a more simpleminded way. - *** - "Red and green cone cells each come in two types: One type signals “white”; another signals color, vision researcher Ramkumar Sabesan and colleagues at the University of California, Berkeley, discovered. The large number of cells that detect white (and black — the absence of white) create a high-resolution black-and-white picture of a person's surroundings, picking out edges and fine details. Red- and green-signaling cells fill in low-resolution color information. The process works much like filling in a coloring book or adding color to a black-and-white film, - *** - "Of the red cones the researchers stimulated, 119 made the men see white, while only 48 flashed red. Similarly, only 21 of the green cones tested actually signaled green, while 77 registered white. Each individual cone probably signals only white or color, the researchers say. “It's a rather inefficient arrangement,” says Donald MacLeod, a vision scientist at the University of California, San Diego. All the cone cells are capable of detecting color, but few actually seem to do so. - "Cells surrounded by cones that detect a different color were more likely to send white signals, the researchers found. That finding is unexpected and runs counter to a popular idea that cones ringed by cells detecting other colors would be better at color detection, MacLeod says. - "These findings could be good news for people with color blindness. The results suggest that gene therapy that adds red or green cones could work even in adults, Neitz says. Although his group gave a monkey full color vision (SN: 10/10/09, p.14), many researchers thought human brains would never be able to incorporate additional color information even though the eye could detect it. The new findings indicate the brain needs to learn only that there is one more color needed to fill in to a basically black-and-white picture, a task it should accomplish easily, Neitz says." - Comment: Our plastic brain should handle this easily. I wonder how color vision developed It is quite a trick.. It is certainly a very helpful attribute which most animals have to varying degrees, based on the fact they have the same or similar color cones in their retinas. Solipsism is an issue here. Do I see the same shade of green as you do, while at the same time agreeing the object in question is green?