Karl Deisseroth has won the 2026 Nobel Prize in Medicine along with German scientists Peter Hegemann and Georg Nagel for discoveries that led to optogenetics, a technique that lets researchers control the activity of specific nerve cells using light. But science was not always his only interest.
His father was a physician and professor, while his mother was a high school chemistry teacher. But science was not his only early interest. He was also known for having an extraordinary memory. Deisseroth had initially planned to become a neurosurgeon. But after encountering patients with severe psychiatric illnesses during his psychiatry rotation, he began questioning how much remained unknown about the brain and mental health. Peter Hegemann and Georg Nagel had studied light-sensitive proteins called opsins in algae and other microorganisms. Deisseroth and his colleagues saw that these proteins could be used to control the activity of nerve cells and began developing the technique for neuroscience. The approach became known as optogenetics, giving researchers a way to control specific groups of nerve cells with light and study how they affect the brain and behaviour. The importance of the technique lies in its precision. Instead of simply observing which parts of the brain become active, researchers can manipulate particular groups of nerve cells and examine what happens. Optogenetics has since been used to study neural circuits involved in memory, behaviour and emotions, as well as conditions such as depression, addiction and Parkinson’s disease. Deisseroth has continued to work at the intersection of neuroscience and psychiatry. He is a professor of bioengineering and psychiatry and behavioural sciences at Stanford and remains a practising psychiatrist.
Born in Boston in 1971, Deisseroth grew up in a family with strong scientific roots. In 2005, Deisseroth and his team showed that shining blue light on genetically modified nerve cells could make them fire.
He was an avid reader of prose, poetry and science and initially dreamed of becoming a writer, according to Stanford Medicine . The experience made him reconsider his plans and drew him towards psychiatry and neuroscience, according to Karolinska Institutet. The breakthrough that eventually earned Deisseroth the Nobel Prize began with an unlikely source: algae, according to Stanford Medicine . His research continues to explore how brain circuits are involved in behaviour and neuropsychiatric conditions, according to his Stanford profile.
