Understanding the brain is a daunting challenge. Each of the many billions of nerve cells in the human brain may make thousands of contacts with other neurons, resulting in an astronomical number of synaptic connections. The tools that allow us to trace and regulate neural networks in experimental animals have emerged in recent years thanks to the discoveries of our Shaw Life Science Awardees for 2020: Gero Miesenböck of Oxford University, Peter Hegemann of Humboldt University, Berlin, and Georg Nagel of the University of Würzburg.
Neuroscientists had long sought methods to control the activity of individual nerve cells in order to understand the networks in which they communicate and define the processes they control. Direct activation of nerve cells by physical or chemical means had been used for over two centuries, but the dream had been to modify nerve cells genetically so that electrical signals could be induced or suppressed remotely, allowing a less invasive and more precise means of controlling the function of neural networks in an intact organism. The first key breakthrough came in 2002 with the development of an optogenetic tool devised by Gero Miesenböck. Using a naturally light-responsive protein, rhodopsin, which serves as the pigment on which we rely for vision, his team inserted the Drosophila (fruitfly) genes necessary to express the light-responsive rhodopsin into a vertebrate nerve cell culture.