Bright light therapy has been used since the 1980’s, but it has been mostly administered through the eyes, which are known to be sensitive to light. This therapy requires people to sit in front of a bright light lamp, anywhere from 30 minutes to two hours each day.

Between 2008 and 2010, Researchers at the University of Oulu discovered the presence of photoreceptor-proteins on the surface of the brain, similar to those which exist in the eye. Following further research it was proven that light can also reach these areas of the brain through the ear canals, the tissue of the ear, and skull.

The skull of large mammals, including humans, lets light pass through naturally, and in ordinary daylight and daytime conditions the brain is always exposed to light.