Many creatures on Earth are known to emit visible light, but humans typically aren’t thought to be among them.
However, that assumption might not be entirely accurate. As far back as 1923, research has shown that humans give off faint light—luminescence at frequencies that, while technically visible, are far too dim for the human eye to detect. From conception to death, we quite literally emit a subtle glow.
Though still a topic of debate, detecting these so-called “biophotons” could offer valuable insights into the body’s inner workings.
Scientists Detect Subtle Brain Glow That Changes With Activity, Offering New Insight Into Neural Function
In a recent study, a research team led by biologist Hayley Casey of Algoma University in Canada focused on one specific area: the human brain. They managed to measure the brain’s extremely faint light emissions through the skull and discovered that the glow shifts depending on brain activity.
This finding opens the door to a potentially groundbreaking method for monitoring brain health—an approach the researchers are calling photoencephalography, though it’s still in its early stages of development.
First Proof-of-Concept Links Brain’s Ultraweak Light Emissions to Functional Activity in Real Time
“As the first proof-of-concept showing that ultraweak photon emissions (UPEs) from the human brain can reflect functional activity, we recorded and analyzed photon levels above participants’ heads while they were either resting or performing an auditory perception task,” the researchers explain in their paper.
“Our findings show that brain-generated UPEs can be reliably separated from background photon noise. Moreover, the data suggest that UPE levels tend to stabilize during a specific cognitive task.”
Everything in the universe above absolute zero—including humans—gives off infrared radiation, known as thermal radiation. However, UPEs are something different.
Unlike thermal radiation, UPEs occur in the near-visible to visible light range. They result from electrons releasing photons as they lose energy—a natural side effect of metabolic processes in the body.
Casey’s Team Aims to Isolate Brain-Generated Light and Uncover Activity-Linked Emission Patterns
Casey and her team set out to clearly separate brain-generated UPEs from background light and to determine whether these emissions show patterns linked to different levels of brain activity.
To do this, participants were placed in a completely dark room. Each wore an electroencephalography (EEG) cap to track brain activity, while highly sensitive photomultiplier tubes—devices capable of detecting even the faintest traces of light—were positioned around them to capture any photon emissions.
Participants were observed both at rest and while performing auditory tasks, which could be done in darkness. The findings confirmed that UPEs are not only detectable outside the skull, but also vary in a way that closely aligns with the brain activity measured by the EEG.
The researchers suggest that future studies could investigate how the brain’s physical structure influences UPE emissions, and how a wider range of mental tasks might produce distinct UPE patterns—beyond just comparing resting and active states.
They also note that it’s still unknown whether individuals have a unique UPE “fingerprint” that would need to be recorded as a personal baseline for detecting unusual brain activity.
The researchers consider these results a proof of concept, showing that patterns of UPE signals from the human brain can be distinguished from background light even in dark environments, despite the signals being extremely faint.
They suggest that future studies could improve detection by using specific filters and amplifiers to isolate and enhance UPE characteristics from both healthy and diseased brains.
Read the original article on: Science Alert
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