Optogenetics lets researchers switch individual nerve cells on and off with light

Researchers can now switch individual nerve cells on or off inside living brains, turning brain circuits into something scientists can test directly. That is why optogenetics has become such a powerful way to study memory, emotion and behavior, not just observe correlations.

The technique started with light-sensitive channelrhodopsin proteins found in algae. Peter Hegemann and Georg Nagel identified those proteins, while Karl Deisseroth helped adapt them to control neurons with light.

The Nobel committee awarded all three the 2026 Nobel Prize in Physiology or Medicine for discoveries involving light-gated ion channels and optogenetics. Georg Nagel discussed the work after learning the news while in Italy.