The Beam of Light That Flips a Switch That Turns on the Brain

Which clusters of nerve cells trigger memory recall, or are associated with learning a new skill, or emotional states?

By INGFEI CHEN
Published: August 14, 2007

It sounds like a science-fiction version of stupid pet tricks: by toggling a light switch, neuroscientists can set fruit flies a-leaping and mice a-twirling and stop worms in their squiggling tracks.

Light stimulation every 200 milliseconds generates electrical activity, right, in an area of the brain associated with depression.

But such feats, unveiled in the past two years, are proof that a new generation of genetic and optical technology can give researchers unprecedented power to turn on and off targeted sets of cells in the brain, and to do so by remote control.

These novel techniques will bring an “exponential change” in the way scientists learn about neural systems, said Dr. Helen Mayberg, a clinical neuroscientist at Emory University, who is not involved in the research but has seen videos of the worm experiments.

“A picture is worth a thousand words,” Dr. Mayberg said.

Some day, the remote-control technology might even serve as a treatment for neurological and psychiatric disorders...