How to Erase Fear--in Humans

Daniel Lametti in Scientific American:

“Memory”, wrote Oscar Wilde, “is the diary that we all carry about with us”. Perhaps, but if memory is like a diary, it’s one filled with torn-out pages and fabricated passages.

In January, a group of New York University neuroscientists led by Daniela Schiller reported in the journal Nature that they had created fearful memories in people and then erased them. Besides being rather cool, the result provides new insight into how to treat traumatic memories in people.

The research was based on the work of neuroscientist Joseph LeDoux, a coauthor on the paper. Ten years ago, while experimenting with rats, Ledoux made a discovery that changed the way neuroscientists view memory from that of Wilde’s tidy diary to something more along the lines of a James Frey memoir.

In that experiment, Ledoux conditioned rats to fear a bell by ringing it in time with an electric shock until the rats froze in fear at the mere sound of the bell. Then, at the moment when the fear memory was being recalled, he injected the rats with anisomycin, a drug that stops the construction of new neural connections. Remarkably, the next time he rang the bell the rats no longer froze in fear. The memory, it seemed, had vanished. Poof!

Ledoux concluded that the neural connections in which memories are stored have to be rebuilt each time a memory is recalled. And during rebuilding—or reconsolidation, as he termed it—memories can be altered or even erased. Neuroscientists now believe that reconsolidation functions to update memories with new information—something of an unsettling idea, suggesting that our memories are only as accurate as the last time they were remembered.