US psychiatrist and neurologist Karl Deisseroth and his German colleagues Peter Hegemann and Georg Nagel have been awarded this year's Nobel Prize in Physiology or Medicine for their work in the field of optogenetics.
Their research has helped scientists better understand how the human brain works.
The Nobel committee praised the trio for laying the foundation of a new era in neuroscience and revealing the neural circuits behind "specific memories, feelings, and behaviours relevant for neurological and psychiatric disorders".
In clinical medicine, researchers are using the method to try to restore sight in people with visual impairment.