Scientists have been proposing that biophotons play a role in cellular communication for at least a century. In 1923 Alexander Gurwitsch conducted experiments where he showed that photon-blocking barriers placed between onion roots could prevent the plant from growing. In the past few decades, a handful of studies have added weight to the possible role biophotons play in cellular communication, which influences an organism’s growth and development.

But while biophotons coming from participants’ heads could be easily distinguished from background levels of photons in the room, increased EEG activity in a given brain region didn’t result in higher levels of biophotons being captured by the closest detector. Clearly, something changes when you move from a few cells on a petri dish to a living brain. “Maybe [UPEs] are not getting picked up by our detector because they could be getting used or absorbed or scattered within the brain,” Murugan suggests. The researchers did find, however, that changes in the UPE signals came only when participants changed cognitive tasks, such as opening or closing their eyes, suggesting some link between brain processing and the biophotons it emits.