Putting flies to sleep with light

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.

Optogenetics: the algae that started it all

It may seem like science fiction, but with optogenetics scientists can control the behaviour of animals by simply shining a light into their brains. And believe it or not this technology began… in algae! These single-celled plants are powered by the sun and contain built-in light detectors to control their behaviour. This discovery, and the isolation of the light sensitive protein that is responsible, led to the birth of the science we now call optogenetics. I went to see Cambridge University’s Otti Croze and Kyriacos Leptos to try to catch some of these incredible life-forms…

  • The algae Chlamydomonas Reinhardtii are invisible to the naked eye at around one hundreth of a millimetre or one tenth of the width of a human hair
  • Chlamydomonas contain a light-sensitive protein called channelrhodopsin which triggers the algae to swim using tiny arms called flagella
  • They are phototactic which means that they move towards light which they need to photosynthesise and survive
  • By introducing the light-sensitive protein into nerve cells in the brain scientists can use it as an on/off switch to control the cells by shining light onto them

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



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