Karl Alexander Deisseroth is an American scientist and physician. He is the D.H. Chen Foundation Professor of Bioengineering and a professor of psychiatry and behavioral sciences at Stanford University. He was jointly awarded the Nobel Prize in Physiology or Medicine in 2026 for his work in optogenetics. The Nobel Prize in Physiology or Medicine 2026, announced October 5, 2026. Karl Deisseroth, Peter Hegemann, and Georg Nagel, “for their discoveries concerning light-gated ion channels and optogenetics”. Karl Deisseroth: born 1971, Boston, MA, USA. Peter Hegemann: born 1954, Münster, Germany. Georg Nagel: born 1953, Weingarten, Germany. Wiki link Wiki link Wiki link Data: the Nobel Foundation (CC0).