The same cause-and-effect approach is changing how researchers study brain disorders..

Last updated: October 23, 2026 | 09:16

The major advance is that scientists can investigate what particular nerve cells actually do, rather than simply observe when they become active

It started with a question about pond algae.

Peter Hegemann wanted to know how Chlamydomonas , a green alga made of a single cell, steers itself towards light. In the early 2000s, he and Georg Nagel found the answer: Channelrhodopsin, a protein that opens a small gate in the cell when light strikes it. Karl Deisseroth, a psychiatrist and bioengineer at Stanford University, then took the leap. He put the gene for that protein into nerve cells, so that a flash of light could make them fire. By 2006 the method had a name: Optogenetics.

On October 5, the three scientists were awarded the 2026 Nobel Prize in Physiology or Medicine for their discoveries concerning light-gated ion channels and optogenetics.…