False memories implanted in mouse brains

'Total Recall' for Mice | Science/AAAS | News

A very cool study out of MIT showing that it is possible to create false memories in a mouse brain. They first put the mice in a chamber and let them form a memory of that location. Then they put the mice in a different chamber and gave them painful electric shocks while simultaneously stimulating the same neurons in the brain that had been activated in the first chamber. Then, when the mice were put back into the first chamber, they froze as if they were recalling the memory of the electrical shock. They way they identified the neurons associated with the memory and reactivated them later is an impressive technological feat in and of itself. The mice were genetically modified to express a protein called channelrhodopsin-2 which was only expressed in active neurons. Essentially , this protein acted as a tag for activated neurons which means it labels the neurons that are involved in storing the initial memory. This protein is also light-sensitive and it causes the neuron it is expressed in to become active when exposed to certain colors of light. So, before being placed in the shock chamber, they put a fiber optic cable into the brains of the mice which would shine light onto the parts of the brain where the memory was stored and activated them. This is an example of a new field called optogenetics which is allowing lots of exciting new questions to be asked about brain activity. The Science article discusses the possibility of understanding how false memories are formed in the human brain, but the ability to create and manipulate memories in the brain may someday be a way to treat lots of psychological problems such as PTSD.