Nobel Prize in Medicine or Physiology Awarded to Deisseroth, Hegemann, and Nagel for Their Discoveries on Light-Activated Ion Channels and Optogenetics

The Nobel Prize in Medicine awarded to Karl Deisseroth, Peter Hegemann, and Georg Nagel recognizes an idea as simple as it is revolutionary: controlling neurons with light. Hegemann and Nagel discovered proteins in algae—called channelrhodopsins—that open ion channels when illuminated, and Deisseroth adapted them for use in the mammalian brain to turn specific circuits on or off with millisecond-level precision.  

Optogenetics has enabled a shift from simply observing the brain to understanding which circuits underlie memory, fear, or addiction, while also opening up the possibility of treating diseases such as blindness. This recognition also represents a triumph for basic science, which, starting with a single algae, has shed light on neuroscience.

Optogenetics made the revolution of “science with light” possible. Previously, it was extremely difficult to manipulate specific cell populations with temporal precision, so this represented a dramatic simplification of our ability to intervene in brain circuits with precision. But its impact goes far beyond that: it has changed the way we study causality in neuroscience. We can no longer just observe which cells or cell types are activated—as Cajal did more than 100 years ago—but can now intervene in them and directly ask what their function is. 

Congratulations to the laureates! This is great news for neuroscience!

Although optogenetics—which allows for the control of cellular activity using light—was initially developed for neuroscience, it is now used in numerous biomedical disciplines, such as cardiology, ophthalmology, and immunology. 

Personally, I consider it a great success for neuroscience that the 2026 Nobel Prize in Physiology or Medicine was awarded to Karl Deisseroth, Peter Hegemann, and Georg Nagel, since this technique has allowed us to take the study of the brain to levels that would have been considered science fiction before its discovery in 2005—such as, for example, turning specific memories on and off in laboratory animals in a matter of milliseconds.

Optogenetics has marked a turning point in how the brain is studied. This technique allows researchers to use light to activate or inhibit the activity of populations of neurons in specific areas of the brain with great temporal precision. The major contribution of optogenetics is that it allows us to determine how the activity of different neurons contributes, among other cognitive processes, to memory formation and decision-making. This has transformed neuroscience, helping us understand what goes wrong in diseases such as Alzheimer’s and epilepsy, thereby opening up avenues of research for the development of new therapeutic interventions. 

The Nobel Prize awarded to Karl Deisseroth, Peter Hegemann, and Georg Nagel is a well-deserved recognition of one of the discoveries that has changed brain research and, above all, has enormous potential to benefit society.

We have just learned that this year’s Nobel Prize in Medicine or Physiology has been awarded to researchers Karl Deisseroth, Peter Hegemann, and Georg Nagel “for their discoveries concerning light-activated ion channels and optogenetics.” 

This came as no surprise, given that their discoveries have revolutionized neuroscience research. The use of light-sensitive ion channels, expressed in specific populations of cells in the brain, allows us to control their activity with unprecedented spatial and temporal resolution. 

This sophisticated technology enables us to activate and deactivate specific neural circuits, thereby characterizing their functions in the brain. It has become an essential tool for studying the brain, as well as for identifying the origins of neurological and psychiatric disorders, opening up new therapeutic possibilities.

The 2026 Nobel Prize in Medicine recognizes a revolution in the field of experimental neuroscience: optogenetics. Karl Deisseroth, Peter Hegemann, and Georg Nagel have forever changed the way we study how the brain works. 

Thanks to optogenetics, it is now possible to activate or inhibit specific neuronal populations simply by illuminating them with light at the correct wavelength. Its great advantage lies in its genetic precision, which allows light-sensitive proteins to be expressed only in neurons that share a specific molecular identity. In this way, by illuminating them, we can control their activity while the other neurons continue to function normally. 

When applied to laboratory animals, such as mice, while they are performing a specific behavior, neuroscientists can determine what happens when those neurons are inhibited (does the animal stop performing that behavior?) or when they are activated (does the same behavior occur?). This provides valuable insights into how the brain works, as it allows researchers to determine which groups of neurons are necessary or sufficient to produce specific behaviors.

The Nobel Prize in Medicine, awarded to Karl Deisseroth, Peter Hegemann and Georg Nagel for their work on optogenetics, recognises one of the most transformative advances in modern neuroscience. The discovery of light-activated ion channels and their application to precisely control the activity of specific neurons has revolutionised our ability to study the brain and understand how its circuits function. Furthermore, Karl Deisseroth’s commitment to sharing and democratising this technology has enabled thousands of laboratories to adopt it, accelerating scientific progress worldwide.

Optogenetics has not only changed the way we study the brain, but has also opened up new avenues for the development of more precise therapies for neurological and psychiatric disorders. Its impact will continue to shape the future of neuroscience for decades to come. It is a truly well-deserved prize!

My congratulations to Karl Deisseroth, Peter Hegemann and Georg Nagel. We in the neuroscience community have received the news with great excitement.

It is, moreover, a fascinating Nobel Prize, one that celebrates the convergence of disciplines. The story begins with microbiology, with single-celled photosynthetic algae that use light-sensitive proteins to orient themselves and swim towards the light. Peter Hegemann and Georg Nagel identified and studied these proteins. Karl Deisseroth, a psychiatrist by training, applied this idea to the brain, with the ultimate aim of one day treating brain disorders with greater precision. Using genetic engineering techniques, his team succeeded in expressing these algal proteins in neurons, making it possible to control their activity using pulses of light. A few years later, they used this idea to control the brain circuits involved in fear and anxiety, whose neurons now responded to light thanks to a protein derived from an alga.

In less than two decades, optogenetics has become a ubiquitous technology in neurophysiology laboratories and has allowed us to push the boundaries between science and science fiction. In laboratory animals, we have managed to control emotions, create false memories or even recover lost memories in models of Alzheimer’s disease. So far, one of its few clinical applications has been the partial restoration of vision in a patient. Perhaps the great promise it has yet to fulfil is precisely one of its founding promises: its ability to treat diseases of the human brain.

The discovery and development of these light-activated channels – in short, the birth of optogenetics – has brought about a hugely significant paradigm shift in brain research.

With optogenetics, we can use light stimuli to very specifically activate or inhibit particular groups of neurons, thereby identifying their causal role in specific actions and behaviours in experimental animals. This has been, and remains, one of the key questions in neuroscience: determining which neurons and which neural circuits are responsible for our actions or moods.

Consequently, the major contribution of these scientists to neuroscience research is the fundamental tool for investigating both healthy and diseased brains, enabling us to move from identifying the neuronal alterations associated with a disease to determining which ones are causally responsible for its symptoms, thereby providing a basis for developing more selective and personalised treatments.