Magazine article Science News

Light Pulse Puts False Memories in Mouse Brains: Tweaking Just a Few Neurons Makes Imagined Connections

Magazine article Science News

Light Pulse Puts False Memories in Mouse Brains: Tweaking Just a Few Neurons Makes Imagined Connections

Article excerpt

Just a tiny fraction of the brain's neurons firing at the wrong time may be able to make a figment of the imagination seem real. Scientists have come to that conclusion after implanting false memories into the brains of mice.

"It's fairly astounding," says neurobiologist Mark Mayford of the Scripps Research Institute in La Jolla, Calif., who was not involved in the research. "Stimulating a small amount of cells can put a thought into an animal's head."

Neurobiologists have known for years that the hippocampus, a seahorse-shaped region deep in the brain, plays a role in learning and memory. And countless studies have shown that when it comes to recalling events, humans tend to make mistakes. (Of the first 250 U.S. prisoners exonerated based on DNA evidence, about three-quarters were originally convicted at least in part because of faulty eyewitness testimony.)

But exactly how neurons in the hippocampus harbor and retrieve memories --and where they go wrong--has been difficult to understand without observing an example in animals, says Susumu Tonegawa, a neuroscientist at MIT.

To understand how neurons create memories, Tonegawa and his colleagues used optogenetics. In the relatively new technique, researchers implant tiny optical fibers in the brains of living animals. The fibers deliver pulses of light directly to neurons that have been genetically engineered to react to the flashes.

In previous work, the researchers engineered mice with neurons that are sensitive to blue light--but only when a gene that turns on during new experiences is active. The team then showed that flashing the neurons with light alone forced a previously created memory of a new experience to pop into a mouse's head (SN: 4/21/12, p. 10). Neurons in a small region of the hippocampus called the dentate gyrus were particularly adept at triggering memories this way. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.