If we had the X-ray vision to see through each other’s skulls in total darkness, we might be able to make out a faint glow. That’s what Canadian researchers learned with a new technique called photoencephalography: Subjects wore an EEG cap that had electrodes attached, along with photomultiplier tubes, which are so hypersensitive that they can pick up even the faintest trace of light. The observation? The human brain actually lights up with signals known as ultra-weak photon emotions (UPEs), which are a byproduct of metabolic processes. And someday, the imaging technique behind this discovery could supplement PET scans and MRIs as a diagnostic tool.
