A team at Washington University Medical School has figured out what makes lighting stimulate photoreceptors and neurons that regulate circadian rhythms.
Their study published today in Current Biology identifies a cell in the retina, which plays an important role in signaling our brain centers that regulate circadian rhythms. It increases alertness, memory and cognitive function, and improves mood. We are moving towards the development of a "circadian" light that influences our rhythms "on demand".
A beautiful sunny day in the middle of the night.
Circadian light, the role of a pigment
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.
Cone photoreceptor impulses respond to short-wavelength blue light, but they also respond strongly to long-wavelength orange and yellow, coincidentally the colors that occur at dawn and dusk.
The leader of the study on "circadian" light is Sara Patterson, a neuroscience student at the University of Washington.
The mechanisms that regulate our internal clock have been studied for a long time. In the study, for example, Patterson and colleagues identified a special cell. It is known as inhibitory interneuron o amacrine cell in the retina, which can send signals to the photosensitive cells connected to our brain centers that regulate the circadian cycle.
The researchers claimed that these cells are “the missing component of an ancient evolutionary circuit of vision of colors. A circuit that is able to set the circadian clock by encoding the spectral content of light."
“This research began out of our interest in the benefits of getting natural light to help us regulate our lives. In particular our clock, our attention and our mood,” says Neitz.
The next goal is to make these lights hundreds of times brighter than normal lights, to stimulate melanopsin.
For this reason, the University of Washington has granted the license to use this technology to TUO, a lighting technology company. The company will develop LED light bulbs that incorporate “circadian” wavelengths.
