Scientists who developed the ability to control brain cells using light have been awarded the 2026 Nobel Prize in physiology or medicine. The prize recognizes the work of Karl Deisseroth, Peter Hegemann, and Georg Nagel for their research into light-gated ion channels and the field now known as optogenetics.
From algae to nerve cells
The journey began with a basic biological question about a single-celled alga called Chlamydomonas. Peter Hegemann at Humboldt University of Berlin and Georg Nagel at the University of Wurzburg sought to understand how this organism senses light. They discovered that the alga uses a protein called channelrhodopsin embedded in its cell membrane to detect light and move toward it.
When light hits a molecule called retinaldehyde inside the channelrhodopsin protein, the protein changes shape. This change opens a tiny passage through the cell membrane, allowing positively charged particles to flow into the cell. This movement of ions sends a signal that helps the alga swim.
The researchers realized that nerve cells also rely on the movement of ions to control their activity. They hypothesized that if they could insert the gene for channelrhodopsin into nerve cells, they could switch those cells on by shining a light on them. Karl Deisseroth, a psychiatrist and bioengineer at Stanford University in California, joined Hegemann and Nagel to test this idea.
A new tool for neuroscience
The resulting technique, optogenetics, allows scientists to switch specific groups of nerve cells on and off with light. To use it, scientists deliver the gene for channelrhodopsin to target nerve cells using a harmless virus. The cells then produce the light-sensitive protein.
In animal studies, researchers can shine light into the brain through a thin optical fiber. When the light reaches the modified cells, the channels open and the cells become active. Nearby nerve cells without the protein remain unaffected. This precision makes optogenetics a powerful tool for investigating how the brain works.
For example, scientists can determine if a specific group of nerve cells is involved in memory or movement by switching them on with light and observing the results. In a 2012 study, researchers used optogenetics to reactivate memory cells in mice. The mice froze in fear when the cells were stimulated, even though they were in a different cage and had not received a shock in that location.
Future medical applications
Optogenetics has transformed the study of the nervous system and may soon lead to new treatments. Early-stage clinical trials are already underway for people with retinal degeneration. In these trials, researchers introduce light-sensitive proteins into surviving nerve cells in the retina. This allows the cells to respond to light and potentially restore some vision.
Researchers are also investigating whether optogenetics could treat neurological conditions such as Parkinson’s disease and epilepsy. The Nobel Prize celebrates work that started with a simple question about how algae swim, demonstrating how basic research can lead to profound scientific and medical advances.
Source: ScienceDaily
