Researchers said the wavelengths at sunrise and sunset have the biggest impact to brain centers that regulate our circadian clock and our mood and alertness.
Their study [cell.com], “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. (See interview [uw.edu] with lead researchers)
[...]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, 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.
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 (DOI: 10.1016/j.cub.2020.01.040 [doi.org])
The entire article is available on Science Direct [sciencedirect.com].