False memories

False memories implanted into mice

Scientists have activated memory forming cells in the brains of mice creating false memories and associations, reported the BBC.

The mice wrongly associated a benign environment with an unpleasant experience they had had in different surroundings. The researchers conditioned a network of neurons to respond to light, which made the mice recall the unpleasant environment.

The mice were genetically engineered and had optic fibres implanted in their brains to deliver pulses of light to specific groups of neurons. Known as optogenetics, this technique makes individual neurons responsive to light.

Our memories are stored in collections of cells, the same as they are in the brains of mice, and when we recall an event we reconstruct it from parts of these cells, almost like reassembling small pieces of a puzzle.

This can make our memories unreliable, something that has been well documented over the past few decades.

The researchers in this study found that when the mice recalled a false memory, it was indistinguishable from a real memory, in that it created a fear response in the memory forming cells of the mouse’s brain.

"If you want to grab a specific memory you have to get down into the cell level. Every time we think we remember something, we could also be making changes to that memory - sometimes we realise sometimes we don't," explained Dr Xu Liu from the RIKEN-MIT Center for Neural Circuit Gentics.

"Our memory changes every single time it's being 'recorded'. That's why we can incorporate new information into old memories and this is how a false memory can form without us realising it."

Neil Burgess from UCL, who was not involved in the study, told the BBC that the research was a good first step in understanding the fearful response to situations where nothing fearful has happened.

“One day this type of knowledge may help scientists to understand how to remove or reduce the fearful associations experienced by people with conditions like post-traumatic stress disorder," he said.

However, he also explained that this is still very early stages on this type of research and that any benefits for people with conditions like PTSD would still be many years away.

"But basic science always helps in the end, and it may be possible, one day, to use similar techniques to silence neurons causing the association to fear."

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