Friday, June 14, 2013

Our memory can be selectively rewritten during its reconsolidation.

Chan and LaPaglia make an interesting observation in humans that had previously only been reported in animal studies. We can mess with an existing declarative memory of an event after that memory has been reactivated, if during its reconsolidation we are presented with changes that target and change some details of the original memory. Reactivated memories are vulnerable only to interference that specifically targets the existing memories. This work provides yet another example of how eye witness testimony of the sort used in legal proceedings can become unreliable.
During the past decade, a large body of research has shown that memory traces can become labile upon retrieval and must be restabilized. Critically, interrupting this reconsolidation process can abolish a previously stable memory. Although a large number of studies have demonstrated this reconsolidation associated amnesia in nonhuman animals, the evidence for its occurrence in humans is far less compelling, especially with regard to declarative memory. In fact, reactivating a declarative memory often makes it more robust and less susceptible to subsequent disruptions. Here we show that existing declarative memories can be selectively impaired by using a noninvasive retrieval–relearning technique. In six experiments, we show that this reconsolidation-associated amnesia can be achieved 48 h after formation of the original memory, but only if relearning occurred soon after retrieval. Furthermore, the amnesic effect persists for at least 24 h, cannot be attributed solely to source confusion and is attainable only when relearning targets specific existing memories for impairment. These results demonstrate that human declarative memory can be selectively rewritten during reconsolidation.

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