Past studies, as well as personal experiences from people, suggest that green light produced by LEDs can diminish pain levels in people suffering from migraines or conditions such as arthritis. However, the reasons behind this mysterious mechanism remained an enigma.
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In a new endeavor, a group of scientists from, among others, the Chinese Frontiers Center for Brain Science, started to search for an explanation. They published their findings in the peer-reviewed science journal Science Translational Medicine.
In a study with mice, the team looked at the retina of the eye containing so-called rod and cone photoreceptors. These photoreceptors are sensitive to light. By disabling each of these receptors at different times in, researchers tested how they led to changes in pain perception.
The team found that the neural pathway to pain alleviation started with the photoreceptors. Photoreceptors send signals to cells on the inside of the retina. Those cells are affected by the type of light that shines on the eyes. It turns out that if that light is green, more so-called GABA signaling occurs. GABA signaling leads to the additional release of PENK proteins, indirectly activating the opioid receptors in the brain, which ultimately leads to the reduction of pain.
In a nutshell, the study shows that when green light catches the eye, cones within said eye will send a signal to cells on the retina, activating a protein that ensures that analgesic substances can bind with opioid receptors. When that bonding takes place, we experience the lessening of pain.
It will be interesting to see if this research will ultimately lead to different and better treatments for migraines. If you are interested in a more detailed overview of the research, be sure to check out the paper listed below.
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