Scientists Erased Specific Memories From Mice Using Light

As if out of a science-fiction novel, neuroscientists say they successfully erased specific memories in mice using light. Researchers at the UC Davis Center for Neuroscience and Department of Psychology say they also proved a basic theory of how different parts of the brain work together to access memories.

According to Science Daily, Optogenetics is a new technique that uses light to manipulate and study nerve cells. Stanford University’s Karl Diesseroth led the field of research, the magazine reports. Kazumasa Tanaka, Brian Wiltgen, and their fellow researchers at UC Davis applied the new technique so that they could test a theory about memory retrieval. The theory was that memories about specific places and events required the teamwork of both the cerebral cortex and the hippocampus.

“The theory is that learning involves processing in the cortex, and the hippocampus reproduces this pattern of activity during retrieval, allowing you to re-experience the event,” Wiltgen said.

“Wiltgen and Tanaka used mice genetically modified so that when nerve cells are activated, they both fluoresce green and express a protein that allows the cells to be switched off by light,” the Science Daily article stated. “They were therefore able both to follow exactly which nerve cells in the cortex and hippocampus were activated in learning and memory retrieval, and switch them off with light directed through a fiber-optic cable.”

The researchers trained mice with electric shock. The team noted that when a mouse is put into an area where they had previously experiences a shock, they will not explore the area, but will rather freeze with fear because they remember being shocked in the environment before. The researchers were able to use this behavior to tell if a mouse was able to remember a particular environment.

Tech Times compared the research of memories erased with light to a scene in the movie Men in Black. The article explained that losing some function in the hippocampus could cause a person to lose years worth of memories.

The team discovered more than just how to erase memories using light; they were also able to label the cells used in the process of learning, and saw that they were reactivated when the mice were recalling memories. They were also able to show the connections between the hippocampus and specific cells in the cortex. The team also saw how specific cells in the cortex connected to the amygdala.

“The cortex can’t do it alone, it needs input from the hippocampus,” Wiltgen said. “This has been a fundamental assumption in our field for a long time and Kazu’s data provides the first direct evidence that it is true.”

The groundbreaking research that proved memories could be erased using light was funded “by grants from the Whitehall Foundation, McKnight Foundation, Nakajima Foundation and the National Science Foundation.”

[Photo via Men In Black‘s Facebook page]