The Nobel Assembly at Karolinska Institutet 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.