India, Oct. 5 -- The Nobel Prize in Physiology or Medicine was awarded Monday to three scientists whose research has transformed understanding of how the brain controls the activity of individual nerve cells.

Karl Deisseroth, 54, Peter Hegemann, 71, and Georg Nagel, 73, were recognised for their discoveries involving light-gated ion channels and the development of optogenetics, a technique that allows researchers to control nerve-cell activity using light.

The Nobel Assembly said their work has provided scientists with a powerful tool for investigating the brain and is now used in laboratories around the world.

Deisseroth is based at Stanford University in California, while Hegemann works at Humboldt University in Berlin and Nagel is a...