After walking on earth for a few hundred thousand years, humans might think that they have seen everything. But not according to a team of scientists who claim to have experienced a color that no one has seen before.
The daring – and disputed affirmation – follows an experience in which researchers in the United States have had laser pulses drawn in their eyes. By stimulating the individual cells of the retina, the laser has pushed their perception beyond its natural limits, they say.
Their description of the color is not too striking – the five people who saw it call it blue -green – but that, they say, do not fully capture the richness of the experience.
“We have predicted from the start that it would look like an unprecedented color signal, but we did not know what the brain would do,” said Ren Ng, an electrician engineer at the University of California in Berkeley. “It was breathtaking. It’s incredibly saturated. “
The researchers shared an image of a turquoise square to give an idea of the color, which they named Olo, but stressed that the shade could only be felt by the laser manipulation of the retina.
“There is no way to transmit this color in an article or on an instructor,” said Austin Roorda, scientist of the vision in the team. “The fact is that this is not the color we see, it is simply not. The color we see is a version, but it pale absolutely compared to the Olo experience.”
Humans perceive the colors of the world when light falls on cells sensitive to color called cones in the retina. There are three types of cones that are sensitive to long wavelengths of light (L), medium (m) and short.
Natural light is a mixture of several wavelengths that stimulate the L, M and S cones with different expanses. Variations are perceived as different colors. Red light mainly stimulates the L cones, while blue light mainly acts the S. but the M cones are seated in the middle and there is no natural light which excites them alone.
The Berkeley team has decided to overcome the limitation. They started by mapping a small part of a person’s retina to identify the positions of their cones. A laser is then used to scan the retina. Regarding a M cone, after adjusting the movement of the eye, he draws a small light impulse to stimulate the cell, before going to the next cone.
The result, published in Scientific advancesis a color patch in the field of vision about twice the size of a full moon. The color is beyond the natural beach of the naked eye because the m cones are stimulated almost exclusively, a natural state light cannot achieve. The name olo comes from the binary 010, indicating that from the L, M and S cones, only the M cones are on.
The complaint left an expert perplexed. “This is not a new color,” said John Barbur, a vision scientist at City St George’s, University of London. “It is a more saturated green that can only be produced in a subject with a normal red chromatic green mechanism when the input comes from M cones.” The work, he said, had a “limited value”.
Researchers think that the tool, named Oz Vision after the city of Emerald in the books of Frank Baum, will help them to probe the basic questions of science on the way the brain creates visual perceptions of the world. But it can have other applications. Thanks to a tailor -made cells in the retina, researchers could learn more about blindness or diseases that affect vision such as pigmentary retinitis.
Will the rest of the world have the chance to live Olo by themselves? “It’s a fundamental science,” said NG. “We are not going to see Olo on smartphone screens or TVs immediately. And it’s very, very well beyond VR helmet technology. ”