The Nobel Prize in medicine was awarded Monday to three scientists who created a tool using light to help unravel how the brain works.

Karl Deisseroth, 54, Peter Hegemann, 71, and Georg Nagel, 73, have carried out research into light-gated ion channels and optogenetics.

The Nobel Assembly lauded their work and said the method is now being used in laboratories around the world to reveal the brain’s mysteries.

The assembly said Deisseroth is based at Stanford University in California, while Hegemann is at Humboldt University in Berlin and Nagel at the University of Würzburg, also in Germany.