Scientists Rewrite Flies' Memories, Bring the Dollhouse Closer

We've already got memory-wiping drugs, and now researchers have taken the next baby step to a whole new you. They have used lasers to etch bad memories into the brains of flies, and changed their reactions to certain stimuli.

A team led by Gero Miesenbock of the University of Oxford has been working to identify and manipulate brain cells linked to associative learning, where an animal learns to associate a certain cue with a specific outcome. There are just 12 cells in the fly brain linked with associative learning.

To determine which cells are associated with bad memories, the researchers sought to trigger those cells and, at the same time release an odor. If the fly avoided the odor in the future, they new that they had successfully rewritten the fly's memory to associate that odor with a bad experience.

They modified neurons in the flies' brains by adding a receptor that is activated by ATP. They then injected the brains with ATP placed inside a light-activated cage. They then targeted a laser at the appropriate cells, causing the release of the ATP and activating the receptors. At the same time they flashed the laser, the researchers released the odor.

Sure enough, when presented with two odors placed at equal distances from the flies, the flies who had received the laser flash avoided the odor they had been programmed to associate with bad memories. The flies effective "remembered" that something bad was associated with the smell, even though they had never experienced it themselves.

And Miesenbock believes that this could have implications for human brains as well. Researchers may be just understanding how animals learn from and adapt to mistakes, but he has every expectation that the mechanism for humans will be, on a fundamental level, the same as the mechanism for flies.

Bad memories written with lasers [BBC]