How the brains of healthy older people perceive color

There is a difference between the way the brains of healthy older people perceive color and those of younger adults, a new study by UCL researchers reveals.

The research, published in Scientific reportscompared how younger and older students responded to different aspects of color in the environment.

The team recruited 17 healthy young adults, with an average age of 27.7 years, and 20 healthy older adults, with an average age of 64.4 years.

Participants were placed in a blacked-out room and viewed 26 different colors for five seconds each, while researchers measured the diameter of their pupils.

The pupils constrict in response to increased brightness and color saturation (color).

Colors featured included dark, muted, saturated and light shades of magenta, blue, green, yellow and red, as well as two shades of orange and four grayscale colors.

Using a highly sensitive eye-tracking camera, which recorded pupil diameter 1,000 times per second, the team found that healthy older people’s pupils constricted less in response to saturation of the eyes. colors than those of young adults. This was particularly marked for green and magenta shades.

However, both younger and older adults had similar reactions to the “lightness” of a color shade.

This study is the first to use pupillometry to show that as we age, our brains become less sensitive to the color intensity of the world around us.

The study results also complement previous behavioral research that has shown that older adults perceive surface colors as less colorful than younger adults.

Lead author Dr Janneke van Leeuwen (UCL Queen Square Institute of Neurology) explained: “This work challenges the long-held belief among scientists that color perception remains relatively constant throughout life. life, and instead suggests that the colors slowly fade over time. “We are getting older. Our findings could also help explain why our color preferences may change with age and why at least some older people may prefer to dress in bright colors.”

Researchers believe that as we age, the body’s sensitivity to color saturation levels in the primary visual cortex, the part of the brain that receives, integrates and processes visual information relayed from the retina, decreases.

Previous research has also shown that this is a feature of a rare form of dementia called posterior cortical atrophy (PCA), where notable difficulties and abnormalities in color perception could be due to a significant decline of the brain’s sensitivity to certain color tones (especially green and green). magenta) in the primary visual cortex and its connected networks.

Co-corresponding author, Professor Jason Warren (UCL Queen Square Institute of Neurology), noted: “Our findings could have broad implications for how we adapt fashion, decoration and other things.” “color spaces” for older adults, and potentially even on our understanding of diseases of the aging brain, such as dementia.

“People with dementia may exhibit changes in color preferences and other visual brain-related symptoms. To interpret these correctly, we must first assess the effects of healthy aging on perception colors. Further research is therefore needed to delineate the functional neuroanatomy of our findings, as higher cortical areas could also be involved.