Scientists have found a way to erase long-term memory in rats, a discovery that could boost development of treatments for those suffering from memory loss or dementia.

The findings reveal that the memory-storage process is far more dynamic than once thought. Researchers involved in the study liken memory to a machine that must be constantly maintained in order to run smoothly. They found a way to briefly jam this machine using drugs and erase stored memories.

Prof. Yadin Dudai, head of the Weizmann Institute's Neurobiology Department, along with research student Reut Shema and Todd Sacktor of the State University of New York Downstate Medical Center, trained rats to avoid certain tastes. They then injected the rats with a drug to inhibit the enzyme PKMzeta, the so-called "memory molecule." The rats forgot their trained aversion to certain tastes after a single dose of the drug.

"This drug is a molecular version of jamming the operation of the machine," said Dudai. "When the machine stops, the memories stop as well."

The experiment worked as successfully a month after the memories were formed — in terms of relative lifespan, similar to several years in humans. This marks the first time that memories stored in the brain were proven capable of erasure so long after they were formed.

This research enhances existing knowledge about PKMzeta, the role of which was not yet fully understood. Scientists had already determined that the enzyme was vital to the hippocampus, the area of the brain involved in the initial storage of memory. But they knew little about its role in the neocortex, the area of the brain thought to be responsible for permanently storing long-term memories, including those necessary for advanced cognitive functions, such as language and complex thought.

With better knowledge of PKMzeta and the brain's memory-storage process, Dudai expressed optimism that the team's findings improve the possibility of developing drug-based approaches for boosting and stabilizing memory.

The study results were published in the August 17 edition of the journal Science.