Optogenetics

A technique called optogenetics is being used in the laboratory to observe and control what brain circuits are doing in real time.
Henning Dalhoff/Getty Images/Science Photo Library RM

It's a relatively new set of techniques called optogenetics that allows researchers to control the activity of brain cells using light.

"This is fantastic," says Elizabeth Hillman, a biomedical engineer at Columbia University. "We can turn things on, turn things off, read stuff out." In short, she says, it provides a way to observe and control what brain circuits are doing in real time in a living brain.

 

"You can select that very specific genetic cell type, and you can tell that specific cell type to react when you shine light on it," she says.

 

For one thing, Hillman says, when you use optogenetics, "You're actually altering the genes of the neurons." That's because most neurons don't normally respond to light. So you have to add genetic material to every brain cell you want to control. Scientists can do that in mice with genetic engineering, but that's not an option for people.

 

Another challenge for optogenetics, Hillman says, has to do with delivering light to cells deep in the brain. "It's really hard to get light to go deep," she says, "and we all know this just from trying to shine a flashlight through our hand."