San Diego neuroscientists have figured out how to instill a memory in a mouse, then erase that memory, and then reactivate it.
In order to mess with mouse minds, Roberto Malinow and his colleagues at UC San Diego first gave mice a little electric shock while at the same time triggering part of their brain. That created a memory. Every time the mouse had its brain triggered, it now expected to feel a shock.
Next, the researchers did a little surgery on that memory. They weakened the synapses that carry information through the brain, and the mouse eventually forgot to associate those triggers with a shock. The memory had been erased.
But other labs have already demonstrated ways to manipulate memories in mice. Malinow wanted to go one step further by putting the erased memories back in the mouse's brain. So he gave those same synapses a workout by sending rapid-fire signals to certain nerve cells.
These newly strengthened synapses were able to revive the forgotten memory. The mice again feared getting shocked whenever they felt that brain trigger. Malinow says this technique gave him great control over the mouse's memory.
"It's sort of like playing with a yo-yo," he said. "We could make it go away, make it come back."
The experiment would be too invasive for humans. But Malinow says the findings could help researchers better understand diseases involving memory loss, like Alzheimer's.
