Nobel Prize in Medicine Goes to the Scientists Who Taught Brain Cells to Respond to Light

Keypoints:

• Karl Deisseroth, Peter Hegemann and Georg Nagel share the 2026 Nobel Prize in Physiology or Medicine
• The prize honors discoveries on light-gated ion channels and optogenetics
• The prize sum is 12 million Swedish kronor, about $1.2 million, split equally
• The research began with Chlamydomonas, a tiny aquatic alga
• Optogenetics lets scientists switch individual nerve cells on or off in living brains

The Karolinska Institutet in Stockholm announced the 2026 Nobel Prize in Physiology or Medicine on Monday, 5 October. It went to American Karl Deisseroth and Germans Peter Hegemann and Georg Nagel. Deisseroth, 54, is a professor at Stanford University. Hegemann, 71, works at Humboldt University of Berlin, and Nagel, 73, teaches at the University of Würzburg. The committee reached all three winners, and all were surprised.

Optogenetics uses light to control individual nerve cells. Thomas Perlmann, secretary-general of the Nobel Assembly at Karolinska Institutet, said it makes it possible to switch the activity of single neurons on or off in a living brain. Laboratories worldwide now use it to test how specific cell types contribute to learning, fear, addiction and movement.

The story starts with a plant-like organism. Committee member Abdel El Manira explained that the underlying work began with Chlamydomonas, a tiny aquatic alga that senses light. Proteins in its cell membranes act as light-gated ion channels. These are gateways that open when light hits them and let charged particles flow in or out of the cell. The three laureates' discoveries built on one another over decades.

The impact reaches beyond basic research. El Manira said optogenetics helps explain disease as well as the healthy brain. Christian Lüscher, an optogenetics expert at the University of Geneva who has published with all three winners, said the field is at the verge of translation into human therapies. Researchers also hope the approach can improve cochlear implants, because light could stimulate the auditory nerve more precisely than current electrical devices.

The winners' reactions were modest. Nagel said he thought it was too early to give the prize for optogenetics, since other discoveries in medicine have helped far more people. Deisseroth told Scientific American he had begun to drift off to sleep when the call came late at night. Per Svenningsson, chair of the Nobel Committee, said optogenetics offers a way of mapping the brain that scientists once could only dream of.

The Nobel Prize in Physiology or Medicine was first awarded in 1901. It has been given 117 times to 235 winners. The trio will split the 12 million kronor prize equally and receive their medals at the ceremony on 10 December.

The physics, chemistry, literature, peace and economics announcements follow over the coming days. Which field will the committee spotlight next?