The New York Times reports: The vagaries of human memory are notorious. A friend insists you were at your 15th class reunion when you know it was your 10th. You distinctly remember that another friend was at your wedding, until she reminds you that you didn’t invite her. Or, more seriously, an eyewitness misidentifies the perpetrator of a terrible crime.

Not only are false, or mistaken, memories common in normal life, but researchers have found it relatively easy to generate false memories of words and images in human subjects. But exactly what goes on in the brain when mistaken memories are formed has remained mysterious.

Now scientists at the Riken-M.I.T. Center for Neural Circuit Genetics at the Massachusetts Institute of Technology say they have created a false memory in a mouse, providing detailed clues to how such memories may form in human brains.

Steve Ramirez, Xu Liu and other scientists, led by Susumu Tonegawa, reported Thursday in the journal Science that they caused mice to remember being shocked in one location, when in reality the electric shock was delivered in a completely different location.

The finding, said Dr. Tonegawa, a Nobel laureate for his work in immunology, and founder of the Picower Institute for Learning and Memory, of which the center is a part, is yet another cautionary reminder of how unreliable memory can be in mice and humans. It adds to evidence he and others first presented last year in the journal Nature that the physical trace of a specific memory can be identified in a group of brain cells as it forms, and activated later by stimulating those same cells.

Although mice are not people, the basic mechanisms of memory formation in mammals are evolutionarily ancient, said Edvard I. Moser, a neuroscientist at the Norwegian University of Science and Technology, who studies spatial memory and navigation and was not part of Dr. Tonegawa’s team.

At this level of brain activity, he said, “the difference between a mouse and a human is quite small.” [Continue reading…]