Scientists have found that the human brain gives off a very faint light, and this glow could help track how the brain is working. This light, called biophoton emission, is not visible to the naked eye but is a natural part of our body’s activity.

A new study by biologist Hayley Casey and her team at Algoma University in Canada has shown that the amount of light from the brain changes depending on brain activity. For example, when people were resting or doing a simple listening task, the glow changed. The researchers believe this light could be used to create a new way of checking brain function, which they’ve named photoencephalography.

This glow comes from ultra-weak photon emissions (UPEs). These are light particles released when the body’s cells use energy. While all objects above absolute zero give off some heat or light, UPEs are different because they come from specific biological processes inside the body, not just body heat.

In the study, scientists carefully measured this light around people’s heads and compared it to background light. They found that the brain’s light signals were real and changed with different mental tasks. Although still in the early stages, this research could lead to a new, non-invasive way to monitor brain health. Unlike CT scans or MRIs, this method wouldn’t need large machines. It could one day help doctors understand brain disorders or measure brain function using just light, offering a simpler and safer tool for studying the brain.