Karl Deisseroth, Peter Hegemann and Georg Nagel were recognised for their discoveries concerning light-gated ion channels and optogenetics.

Three scientists are the joint winners of the 2026 Nobel prize in physiology or medicine for their foundational work enabling research on how the brain forms memories, feelings and behaviours.

Karl Deisseroth, Peter Hegemann and Georg Nagel were recognised “for their discoveries concerning light-gated ion channels and optogenetics”, according to the Nobel Assembly at Sweden’s Karolinska Institutet.

Optogenetics makes it possible to ‘switch on’ or ‘switch off’ the activity of individual nerve cells in a living brain, according to the assembly.

These methods can be used to “bring memories to life, create feelings, drive behaviours” and help study the types of neurons involved in various psychiatric and neurological disorders, the assembly said.

“Optogenetics provides opportunities for mapping the brain in a way that we could once only dream of,” said Per Svenningsson, chair of the Nobel Committee for Physiology or Medicine.

The field, according to the committee, is “fundamentally transforming our understanding of the brain” – while also providing insights into how the nervous system interacts with various cells in other areas of the body, such as the heart and gut – and has its foundations in the winning trio’s research.

In the early 2000s, Hegemann, a neuroscientist, and Nagel, a biophysicist, discovered a protein named ‘channelrhodopsin’ in a single-celled alga. The protein’s unique properties meant it could be used to make any cell light-sensitive.

Deisseroth, a psychiatrist, transformed the protein into a light-controlled switch for nerve cells through his research on rats and mice, finalised between 2005 and 2007.

This breakthrough, the assembly said, “empowered the field of neuroscience with unprecedented ability to move from passively recording brain activity to actively controlling it, finally illuminating the precise causal relationships that dictate how the brain encodes cognition, emotion and behaviour”.

The three recognised laureates will share a prize of 12m Swedish kronor (€1.07m). Deisseroth is now affiliated with the Howard Hughes Medical Institute and Stanford University in the US, while Hegemann works at Humboldt University of Berlin and Nagel at the University of Würzburg, both in Germany.

Optogenetics “has transformed neuroscience from observing and ‘reading’ brain activity to actively ‘writing’ into it, establishing a causal link between distributed, genetically specified circuit motifs and behaviour, emotion and cognition”, the assembly added.

This means that researchers can now discover exactly which of the nerve cells in a complicated bundle are responsible for different brain functions, such as governing pain, social behaviours, thirst, food consumption, reward, and attention, controlling the circadian rhythm, or causing a fever when the immune system is activated.

The method, according to the assembly, has provided greater understanding of the distinguishing features of psychiatric and neurological disorders such as depression, anxiety, schizophrenia, Alzheimer’s disease and Parkinson’s disease, while researchers have also taken the first steps towards using optogenetics as a medical treatment for restoring lost vision caused by certain types of blindness.

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