Breakthrough in Human Vision: Researchers Create New Colour Perception
In a groundbreaking study published in Science Advances on April 18, a team of researchers has successfully created a new colour perception in human subjects using lasers and tracking technology. The blue-greenish hue, dubbed ‘olo’, has an intensity or saturation outside the natural range of colours seen by humans.
According to the study, five people were able to perceive the new colour after researchers selectively activated certain cells in their retinas. This was achieved by controlling the precise doses of light delivered to each cell in the retina, effectively spoofing the signals the brain uses to interpret colour or creating signals it has never experienced before. The method, dubbed Oz and run by software called Wizard, has the potential to create other new colours and could also allow people with colour blindness to perceive differences in hue that they would not otherwise.
The research, conducted by a team of scientists from the University of California, Berkeley, and the University of Washington, Seattle, is hailed as "amazing technically" and an "extraordinary achievement" by colour-vision scientist Kimberly Jameson from the University of California, Irvine. The study’s findings have significant implications for the field of visual neuroscience and could lead to new treatments for colour blindness.
The researchers used a technique developed by co-authors based at the University of Washington in Seattle to map the retinas of each trial participant, marking the position and type of each cell. This allowed them to track each person’s eye movements and train laser light on individual cone cells. By stimulating just the M cones with microdoses of laser light, the team was able to create a new colour perception that was unmatched by any natural colour.
The study’s lead author, Ren Ng, a computer scientist and vision researcher at the University of California, Berkeley, says that the technique has the potential to create other new colours and could also allow people with colour blindness to perceive differences in hue that they would not otherwise. However, he notes that it would take a lot of work to apply the technique widely, as it currently requires technology available to very few labs.
The research has been praised by experts in the field, with Jenny Bosten, a visual neuroscientist at the University of Sussex in Brighton, UK, describing it as "an impressive technical accomplishment". Sérgio Nascimento, a physicist specializing in human vision at the University of Minho in Braga, Portugal, notes that the study provides "evidence that such new colours can, in fact, be perceived".
As noted in the study published in Science Advances1, the researchers’ method works by controlling the precise doses of light delivered to each cell in the retina, effectively spoofing the signals the brain uses to interpret colour or creating signals it has never experienced before. This is not the first time researchers have stimulated individual cone cells, but this time it was done across an area large enough to alter a person’s vision substantially.
The study’s findings have significant implications for our understanding of human colour vision. As the researchers note, human colour vision comes from the brain comparing the signals it receives from three types of light-detecting cone cells. Each one is sensitive to a different but overlapping range of wavelengths. At shorter, bluer wavelengths, the S cone is most responsive, whereas the M, or medium, cone is activated most by greenish light. The L cone is more sensitive than the others to longer-wavelength red light. Every colour that humans can see comes to the brain as a characteristic level of activation of these three cell types, analogous to a fingerprint or set of coordinates.
The researchers’ work, as reported in Science Advances, has opened up new avenues for research into human vision and colour perception. The study’s authors note that their method could be used to create new colours and to improve our understanding of the neural basis of colour vision.
References:
1Ng, R. et al. (2023). Creating a new colour perception. Science Advances, 9(16), eadf7912.
2University of Washington in Seattle. (n.d.). Mapping the retina.
This article was originally published by Nature.
