2026 Nobel Prize in Physiology or Medicine

About 2026 Nobel Prize in Physiology or Medicine

• The 2026 Nobel Prize in Physiology/Medicine was awarded for discoveries concerning light-gated ion channels and optogenetics.
  • The work enabled researchers to use light to control specific nerve cells and study how particular neural circuits shape memories, feelings and behaviours.
  • It also helped establish causal links between neural activity and behaviour.
• Winners:
  • Peter Hegemann – from Germany.
  • Georg Nagel – from Germany.
  • Karl Deisseroth – from USA.

Key Discovery by winners

• Peter Hegemann:
  • Hegemann studied the single-celled alga Chlamydomonas and investigated how it could rapidly move towards a light source.
  • He and Nagel discovered channelrhodopsins, light-sensitive proteins that act as ion channels and open when exposed to light.
  • They showed that introducing the gene for channelrhodopsin-2 into other cells could make them light-sensitive and generate electrical signals.
• Georg Nagel:
  • Nagel tested the genes identified by Hegemann by introducing them into frog egg cells and found that the resulting proteins acted as light-sensitive ion channels.
  • He and Hegemann showed that channelrhodopsin-2 could open within 0.2 milliseconds of a light pulse and allow positively charged ions to flow.
  • In 2003, they proposed channelrhodopsin-2 as a tool for generating electrical impulses in cells using light.
• Karl Deisseroth:
  • In 2005, Deisseroth showed that channelrhodopsin-2 could trigger nerve signals in rat nerve cells when exposed to blue light.
  • In 2007, his group used the technique in living mice to control specific nerve cells and trigger whisker movement.
  • In 2012, Deisseroth and Susumu Tonegawa used the method to reactivate cells associated with a fear memory, demonstrating which nerve cells were necessary for a specific memory.
• Significance:
  • Optogenetics has helped researchers identify neural circuits that control pain, social behaviour, thirst, food consumption, reward, attention, circadian rhythm and fever.
  • The technique has deepened understanding of conditions such as depression, anxiety, schizophrenia, Alzheimer’s disease and Parkinson’s disease.
  • In ongoing clinical trials for retinitis pigmentosa, a channelrhodopsin-like protein placed in the retina has helped restore some vision in a blind person.