The Nobel Prize in medicine has been awarded to three scientists working on the mechanisms the brain uses to switch on, or off, the activity of individual nerve cells.
Karl Deisseroth, 54, Peter Hegemann, 71, and Georg Nagel, 73, have carried out research into light-gated ion channels and optogenetics.
They are based at universities in Germany and the United States.
The Nobel Assembly lauded their work on Monday, writing on X that 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 Wurzburg, also in Germany.
Thomas Perlmann, the secretary of the medicine committee, said he was able to reach all three winners by phone on Monday.
Associated Press efforts to reach the winners were not immediately successful.
Optogenetics opened what the Nobel assembly called a new era in neuroscience, the discovery of a light-controlled switch to turn on and off nerve cells and circuits in the brain to better learn how it works - to start unravelling the pathways that lead to behaviour and disease.
It started when Hegemann explored how a single-celled type of green algae can swim towards light.
He and Nagel discovered a particular protein that, when illuminated by blue light, opens a channel to create an electrical impulse.
Putting that protein into other cells makes them light-sensitive.
Deisseroth then worked with the gene that controls that protein to create a light-controlled switch for nerve cells in the brains of living mice.
The prize was announced on Monday at the Karolinska Institute in Stockholm, kicking off Nobels week.
The prize money is 12 million Swedish kronor (about $A1.7 million), whether for an individual, small group of laureates or organisation.
In 2025, the prize went to three scientists researching the immune system.
Monday's medicine prize is followed by the physics prize on Tuesday, chemistry on Wednesday and literature on Thursday.
After Friday’s peace prize is awarded, the Nobel Memorial Prize in Economic Sciences will be announced on October 12.
