Optogenetics

News of this field, as yet in its early stages of development — the term optogenetics is first recorded in an article in Nature in April 2008 — has begun to emerge from research laboratories because of its astonishing results.

Neuroscientists have inserted genes that code for light-sensitive brain proteins into animal subjects. By firing laser light deep into the animals’ brains via fibre-optic cables, they have been able to to turn brain cells on and off at will, like clicking a light switch. It has proved possible to stop the electrical activity of various kinds of neurons, such as those that control movement or the establishment of memories. The technique can also be used as a research tool to monitor when neurons fire.

There is some hope that one day a method like this might be used, for example, to control epilepsy and other neurological conditions in humans. However, the need for genetic modification via gene therapy and insertion of fibre-optics in the brain make the idea very unattractive at the moment.

An even newer technique, magnetogenetics, uses a magnetic field rather than light to influence the modified neurons, so avoiding having to implant optical fibres.

The team were able to pinpoint the phenomenon by working with a technology called optogenetics, where nerve cells are rendered photo-sensitive so their action can be turned on or off by different wavelengths of light.

Daily Mail, 10 Mar. 2011.

For their study, Murthy and his colleagues at Harvard and Cold Spring Harbor Laboratory used light instead, applying the infant field of optogenetics to the question of how cells in the brain differentiate between odours.

The Times of India, 18 Oct. 2010.