Stockholm — Nobel Prize Honors Scientists Behind Optogenetics

The Karolinska Institute awarded the 2026 Nobel Prize in Physiology or Medicine to Karl Deisseroth of Stanford University, Peter Hegemann of Humboldt University in Berlin, and Georg Nagel of the University of Würzburg, according to WIRED. Their combined work produced optogenetics, a method that turns individual nerve cells on or off using light.

What did the Nobel Committee recognize?

The committee cited the trio for discoveries that let scientists control neurons with precision. Per Svenningsson, chair of the Nobel Committee for Medicine, said optogenetics "provides opportunities for mapping the brain in a way that we could once only dream of," per WIRED. No other technique allows that level of control in a living brain, the outlet reports.

How did researchers discover the light-sensing protein?

The work began with an alga, not a brain. In the late 1990s, Hegemann studied Chlamydomonas, a single-celled organism with a light-sensing "eye spot" containing a molecule called retinal. Using electrodes, he measured the alga's electrical response to light: 0.5 milliseconds. That is roughly 20 times faster than the human eye, which takes at least 10 milliseconds to detect light, per WIRED.

Hegemann concluded the alga's light detection had to run through a simpler process than the human eye uses. In the early 1990s he proposed a single protein that both sensed light and opened as an ion channel. The idea drew skepticism. No known ion channel at the time responded to light on its own, and isolated proteins from the eye spot proved unstable outside the cell.

A Japanese team's full genome sequence of Chlamydomonas gave Hegemann's lab two candidate genes. Nagel tested them by inserting each gene into frog eggs. The eggs produced the proteins, which moved to the cell membranes — confirming the light-sensing channel Hegemann had predicted, according to WIRED.

Why does optogenetics matter for neuroscience?

Deisseroth's lab adapted that channel protein for use in neurons, letting researchers trigger or silence specific brain cells with pulses of light. The approach has become a standard tool for mapping neural circuits tied to movement, memory, and disease, WIRED reports.

What's next for the technology?

What to watch

• Expanded use of light-based circuit mapping in studies of neurological and psychiatric disorders.
• Continued refinement of light-sensitive proteins derived from algae and other microorganisms.
• Broader application of optogenetics techniques beyond neuroscience, given their roots in microbiology.

The prize underscores a cross-disciplinary path: a technique now central to brain research began with a biologist asking how a brainless alga reacts to light, per WIRED's account of the Nobel Committee's announcement.

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