New Delhi: The Nobel Assembly at Karolinska Institutet in Stockholm has decided to award the 2026 Nobel Prize in Physiology or Medicine jointly to Karl Deisseroth, Peter Hegemann and Georg Nagel “for their discoveries concerning light-gated ion channels and optogenetics.”

Hegemann and Nagel discovered channelrhodopsin, a protein with unique properties. They found that regardless of which cell they put the protein in, those cells became light sensitive. Deisseroth introduced the gene for channelrhodopsin into nerve cells from rats. By illuminating the cells with blue light, he was able to trigger a nerve signal. Later, he made this light-controlled switch for nerve cells work in the brains of living mice.

This method for controlling nerve signals with light is now called optogenetics, and it has rapidly gained global impact.

"Optogenetics provides opportunities for mapping the brain in a way that we could once only dream of," said Per Svenningsson, Chair of the Nobel Committee for Physiology or Medicine.

According to an official statement, Hegemann and Nagel discovered "channelrhodopsin", a protein with unique properties.

They found that regardless of which cell they put the protein in, those cells became light-sensitive.

Hegemann's research helped reveal how certain microorganisms sense light through specialised proteins.

Nagel subsequently helped demonstrate that these proteins could function as light-controlled ion channels.

Using optogenetics, researchers have been able to reveal neural circuits governing specific memories, feelings, and behaviours relevant for neurological and psychiatric disorders.

In clinical medicine, researchers are using the method in attempts to restore sight in people with visual impairment.

Deisseroth is a professor of bioengineering, psychiatry, and behavioural sciences at Stanford University in the US. Hegemann, a German biophysicist, studied light-sensitive proteins in microorganisms. Nagel, a German neuroscientist, contributed to the discovery and characterisation of microbial opsins and demonstrated their potential as light-controlled ion channels.