The Nobel Assembly at Sweden’s Karolinska Institute selected the three scientists for research that has transformed the study of the brain and nervous system.
Deisseroth, 54, is an American, while Hegemann, 71, and Nagel, 73, are German. They will share a prize of 12 million Swedish crowns, equivalent to about $1.2 million.
The Nobel committee said optogenetics makes it possible to switch the activity of individual nerve cells in a living brain on or off using light.
The technique has become an important tool for researchers studying how the brain works and is now used in laboratories around the world to investigate neural activity and the mechanisms underlying behaviour and disease.
The medicine prize traditionally opens the annual Nobel Prize announcements. Awards for physics, chemistry, literature, peace and economics are announced later in the week.
The original five Nobel Prizes were established under the will of Swedish inventor and industrialist Alfred Nobel and have been awarded since 1901, with interruptions mainly during the First and Second World Wars.
The economics prize was established separately in 1968 by Sweden’s central bank, the Riksbank.
The medicine prize has recognised several major scientific discoveries over the past century, including Alexander Fleming’s discovery of penicillin, which was honoured in 1945, and Karl Landsteiner’s discovery of human blood groups, recognised in 1930.
In 2025, American scientists Mary Brunkow and Fred Ramsdell and Japan’s Shimon Sakaguchi won the medicine prize for discoveries explaining how the immune system prevents it from attacking healthy cells, opening possibilities for new treatments for diseases including cancer.
Nobel laureates are selected by expert committees appointed by the institutions responsible for each prize. The awards are presented in Stockholm, except for the Nobel Peace Prize, which is presented in Oslo.
The Nobel celebrations culminate on December 10, the anniversary of Alfred Nobel’s death, when the laureates receive their awards at ceremonies attended by members of the Swedish and Norwegian royal families before taking part in gala banquets.
