Three scientists have won the 2026 Nobel Prize in Physiology or Medicine for discoveries that have transformed the study and control of nerve cells in the living brain.

Karl Deisseroth of Stanford University in the United States, Peter Hegemann of Humboldt University of Berlin and Georg Nagel of the University of Würzburg in Germany were jointly awarded the prize.

They were recognised for their discoveries involving light-gated ion channels and optogenetics, a technique that uses light to control nerve-cell activity.

The breakthrough began with research into how a single-celled alga responds to light, leading to the discovery of a protein called channelrhodopsin.

Deisseroth later applied the discovery to neuroscience, using blue light to activate nerve cells in living mice.

The Nobel Assembly said optogenetics has become an important tool for studying how the brain controls memories, emotions and behaviour.

Researchers are also exploring the technology for treating neurological and psychiatric conditions and potentially restoring sight in people with visual impairment.