Gero Miesenboeck is one of the pioneers of the field of optogenetics – an incredible neurological tool that uses light to activate specific cells in the brain. He is using the technique in fruit flies, which can be put to sleep simply by flashing a red light in their direction. I went to Oxford University to meet Gero and find out why…

• Optogenetics works by genetically modifying cells in the brain to be activated by light, thus allowing them to be controlled.
• Gero and his team identified the area of a fly’s brain that causes it to go to sleep and then embedded a light-sensitive gene into DNA of these cells.
• By shining a red light onto the fly from above, the light penetrates the skull of the fly and acts as the ‘on switch’ to turn on the neurons that cause the fly to go to sleep.
• This is tested experimentally in Gero’s lab where flies that were previously buzzing around almost instantly stop moving when the red light is turned on and enter a state that demonstrates all of the classical hallmarks of sleep.
• When the light is turned off the fly begins to instantaneously move once again and returns to its normal behaviour.

You can listen to the full interview for the Naked Scientists here.