The human brain emits a strange light that puzzles scientists 💡

The human brain literally glows, but with a light so faint that it remains invisible to the naked eye. Canadian researchers recently measured this brain glow and discovered that it varies depending on neural activity, opening the door to new scientific perspectives.


This emission of ultra-weak photons, called bioluminescence, is believed to be linked to the brain's metabolic reactions. Although known for nearly a century, this biological property is now sparking renewed interest, particularly for its potential in studying brain functions.

A light revealing brain activity

Biophotons are emitted when excited molecules release energy in the form of light. Unlike body heat, these emissions fall within the visible or near-ultraviolet spectrum. Hayley Casey's team used photomultiplier tubes to detect them through the skull.

Participants, placed in darkness, performed auditory tasks while their brain activity was recorded by electroencephalography (EEG). The results show a correlation between neural activity and biophotons, although the precise mechanism remains to be elucidated.

This discovery could lead to the development of a new imaging technique, photoencephalography. This would complement EEG by providing additional data on brain metabolism without resorting to invasive methods.

An exploratory research field

While the existence of biophotons is confirmed, their exact role in cellular communication remains debated. Previous studies suggest they might participate in regulating biological processes, such as cell growth. However, their involvement in human cognition requires further investigation.

Researchers still don't know whether these emissions form an individual signature or vary according to psychological states. Future experiments will use more precise sensors to locate their origin in the brain and study their link with neurodegenerative pathologies.

In the meantime, this study lays the groundwork for an innovative approach to observing the brain. Though speculative, the idea that neurons communicate through light opens new avenues for neuroscience.