False Memory Syndrome: Science Group Implant False Memories Into Mouse's Brain

A team of researchers implanted false memories in the brain of mice to shed light on the often disputed fact that people can remember experiences that never existed.

False memories are a major problem with eyewitness accounts in courtrooms. Many defendants have been convicted of offenses based on a witness testimony that was later proven to be faulty by DNA or other corroborating evidence.

To study how these false memories formulate in human brains, Susumu Tonagawa, a neuroscientist at the Massachusetts Institute of Technology, and his team encoded memories in the brains of mice by manipulating individual neurons. He described the results of the study in the newest edition of the journal Science.

"In humans, false memory phenomena are very well established, and in some cases it can have had serious legal consequences," said Tonegawa, according to CBS News.

The researchers used the otogenetics technique, which allowed them to control individual brain cells. The team engineered brain cells in the mouse hippocampus, a part of the brain known to be involved in forming memories, "to express the gene for a protein called channelrhopsin" reported The Guardian.

According to CBS News:

"The mice were put in a chamber where they experienced foot shocks, causing them to freeze in fear. The animals learned to associate the shocks with the chamber, forming a fear memory. Then the researchers put the mice in a different chamber, and shone a blue light on the cells that encoded the foot-shock memory. The animals reacted as fearfully as if they were in the first chamber.

In the present study, Tonegawa's group took the experiment a step further. First they allowed the mice to explore the first chamber without getting a foot shock. Then they put the mice in a second chamber where they gave them foot shocks while shining a blue light on the cells that encoded the memory of the first chamber. They wanted to see whether, when they put the mice back into the first chamber, they would react as if they had been shocked there.

The mice did exactly that, showing fear when they were placed in the first chamber, even though they had never experienced a shock there. The researchers had succeeded in implanting a false memory into the mice."

"Memory comes from experience," Tonegawa told LiveScience. But in this case, the animal never experienced any fear in the first chamber, and yet the animal was fearful of that chamber, he said.

Memories of experiences are made from a number of different elements like records of space, time, and objects, according to Tonagawa.

"Humans are very imaginative animals," said Tonagawa according to The Guardian. "Independent of what is happening around you in the outside world, humans constantly have internal activity in the brain. So, just like our mouse, it is quite possible we can associate what we happen to have in our mind with bad or good high-variance ongoing events. In other words, there could be a false association of what you have in your mind rather than what is happening to you."