Stimulating brain can create false memories
The idea that memories are fluid is taking on new meaning, as a recent study found that the memories of mice can be altered by turning on neurons in the brain associated with those memories and updating them with new information.
The findings, published in the journal Science, showed that a mouse can be made to fear a cage by giving it a foot shock while also reactivating a memory of the cage in order to associate the two.
For the study, scientists used a previously discovered technique to pinpoint the handful of neurons that are activated in the brains of mice in any given situation. The technique involves a method of controlling brain cells through bursts of light. Researchers engineered brain cells to produce light-sensitive proteins whenever the neurons were activated in a new setting or situation.
In this study, researchers first exposed mice to one of four unique cages with distinct flooring materials, artificial smells and lighting. As the mice discovered these surroundings, the activated neurons in their brain produced the special light-sensitive proteins. Then, the mice were moved to a second cage, where scientists turned on the neurons that had been activated in the first cage, while simultaneously shocking their feet. Then the mice were returned to the first cage, but they became clearly fearful of the setting even though they had never received a shock there.
In contrast, when the mice were put in a new third cage they showed no fear, and the control group that did receive shocks, but no neuron reactivation, were not afraid of the first cage.
Scientists hope to test their technique on memories of pleasure, memories of objects and memories of other mice.