Researchers said the wavelengths at sunrise and sunset have the biggest impact on brain centers that regulate our circadian clock and our mood and alertness.
Wavelengths at sunrise and sunset have the biggest impact on brain centers that regulate our circadian clock
Their study, “A color vision circuit for non-image-forming vision in the primate retina,” published in Current Biology Feb. 20, identifies a cell in the retina, which plays an important role in signaling our brain centers that regulate circadian rhythms, boost alertness, help memory and cognitive function, and elevate mood.
Effects have been attributed to a pigment in the eye called melanopsin
These effects have been attributed to a pigment in the eye called melanopsin, which is sensitive to blue light, but researchers say cone photoreceptors are a thousand times more sensitive to light than melanopsin. The cone photoreceptor inputs to the circadian circuity respond to short wavelength blue light, but they also respond strongly to long wavelength oranges and yellows and contrasting light — the colors at sunrise and sunset. What makes good lighting, researchers discovered, is lighting capable of stimulating the cone photoreceptor inputs to specific neurons in the eye that regulate circadian rhythms.
What makes good lighting?
Lead author Sara Patterson, a graduate student in neuroscience at the University of Washington School of Medicine, said how we set our internal clocks to the external light-dark cycle has been studied a lot. But how the changes in the color of light affect our brain has not.
“Color vision used for something other than color perception was the most exciting part for me,” she said.
In the study
In the study, Patterson and colleagues identified a cell known as an inhibitory interneuron or amacrine cell in the retina, which signals to photosensitive ganglion cells that affect our circadian brain centers. The researchers said these amacrine cells provide “the missing component of an evolutionary ancient color vision circuit capable of setting the circadian clock by encoding the spectral content of light.”
Patterson said so little is known about rare retinal circuitry that it was possible to find a new blue cone cell. She said there is a lot more to be discovered about how blue cone cells are projecting to other areas of the brain.
Sunrise lights, blue lights and seasonal affective disorder (SAD) lights
While sunrise lights, blue lights and seasonal affective disorder (SAD) lights have all tried to capture benefits of natural light, they haven’t been that effective because they are missing key science data, said corresponding author Jay Neitz, professor of ophthalmology at the UW School of Medicine, a scientist at the UW Medicine Eye Institute, and a well-known color vision researcher. He said the science behind SAD lights, for example, is to make lights hundreds of times brighter than normal lights to stimulate melanopsin.
Research began because of interest in health benefits of having natural light that occurs at the right time of day
“This research all started because of our interest in the health benefits of having natural light that occurs at the right time of day that helps regulate our circadian clock and our mood and alertness,” Neitz said.
The University of Washington has licensed technology based on this discovery to TUO (https://www.thetuolife.com/), a lighting technology company that will be selling white LED lightbulbs that will incorporate undetectable sunrise and sunset wavelengths for commercial use.
The work was supported by the National Eye Institute and Research to Prevent Blindness. Other collaborators include James A. Kuchenbecker, research scientist/biomedical engineer with the Department of Ophthalmology at the University of Washington School of Medicine; James R. Anderson, research scientist/software architect with the John A. Moran Eye Center at the University of Utah School of Medicine, and Maureen Neitz, professor of ophthalmology at the University of Washington School of Medicine.
- Sara S. Patterson, James A. Kuchenbecker, James R. Anderson, Maureen Neitz, Jay Neitz. A Color Vision Circuit for Non-Image-Forming Vision in the Primate Retina. Current Biology, 2020; DOI: 10.1016/j.cub.2020.01.040
Razi Berry is the founder and publisher of the journal Naturopathic Doctor News & Review, which has been in print since 2005, and the premier consumer-faced website of naturopathic medicine, NaturalPath. She is the host of The Love is Medicine Project docuseries, The Natural Cancer Prevention Summit, The Heart Revolution-Heal, Empower and Follow Your Heart, and the popular 10-week Sugar Free Summer program. From a near death experience as a young girl that healed her failing heart, to later overcoming infertility and chronic fatigue syndrome and fibromyalgia through naturopathic medicine, Razi has lived the mind/body healing paradigm. Her projects uniquely capture the tradition and philosophy of naturopathy: The healing power of nature, the vital life force in every living thing and the undeniable role that science and mind/body medicine have in creating health and overcoming dis-ease. You can follow Razi on social media: Facebook at Razi Berry, Instagram at Razi.Berry and join the Love is Medicine group to explore the convergence of love and health. Look for more, and listen to more Love is Medicine podcast episodes here.