But I seem to have missed that there is something called biophotons, which have been known about for some time, even if their purpose (if any) was unknown. Here's some information from a recent article about them:
Here’s an interesting question: are there optical communication channels in the brain? This may be a radical suggestion but one for which there is more than a little evidence to think it is worth pursuing.
Many organisms produce light to communicate, to attract mates, and so on. Twenty years ago, biologists discovered that rat brains also produce photons in certain circumstances. The light is weak and hard to detect, but neuroscientists were surprised to find it at all.
Since then, the evidence has grown. So-called biophotons seem to be produced naturally in the brain and elsewhere by the decay of certain electronically excited molecular species. Mammalian brains produce biophotons with wavelength of between 200 and 1,300 nanometers—in other words, from near infrared to ultraviolet.
If cells in the brain naturally produce biophotons, it’s natural to ask whether nature may have taken advantage of this process to transmit information. For that to happen, the photons must be transmitted from one place to another, and that requires some kind of waveguide, like an optical fiber. So what biological structure could perform that function?
Today we get an answer of sort thanks to the work of Parisa Zarkeshian at the University of Calgary in Canada and a few pals. They've studied the optical characteristics of axons, the long thread-like parts of nerve cells, and conclude that photon transmission over centimeter distances seems entirely feasible inside the brain.