"We Were Playing With Memory Like a Yo-Yo" - Scientists Create and Erase Memories

Researchers at University of California have demonstrated the ability to create memories, erase them and create them again. The researchers used light-sensitive proteins and optical fibers to enact long-term potentiation between neurons, creating new associations.

“We can make a memory of something that the animal never experienced before,” said University of California lead researcher Roberto Manilow.

In the study, researchers prepared the rats by injecting their brains with a virus that had been modified by a gene that produces a light-sensitive protein. The gene, once translated into protein, could be activated by a pulse of blue light delivered by an optical fiber the researchers had implanted in the rats’ brains.

Researchers fired a beam of light to the neurons that connect the sound processing region of the brain with a fear-related region, and then shocked the rats with electricity. The action created a memory of fear of sound.

The experiment was based on classic conditioning, wherein a tone is played to an animal followed by an electric shock. The animals develop a fear reaction to the tone.

The researchers then sought to erase the fear of sound they had created. They exposed the rats to a sequence of light pulses, which enacted long-term depression between the effected neurons. The rats no longer showed fear when a tone was simulated in the brain.

Fear could be created and erased over and over again, the researchers found. “We were playing with memory like a yo-yo,” said Malinow.

The method used in the study, long-term potentiation (LPT), was discovered during research experiments in the 1960s and 70s when repeated bursts of electricity to a neuron in the hippocampus seemed to increase the cell’s ability to communicate with a neighboring neuron. Scientists have long theorized that LPT is the basis of memory.

By James Haleavy

"We Were Playing With Memory Like a Yo-Yo" - Scientists Create and Erase Memories