False memories implanted into mice

False memories have been implanted into mice, scientists say.

A team was able to make the mice wrongly associate a benign environment with a previous unpleasant experience from different surroundings.

The researchers conditioned a network of neurons to respond to light, making the mice recall the unpleasant environment.

Reporting in Science, they say it could one day shed light into how false memories occur in humans.

The brains of genetically engineered mice were implanted with optic fibres in order to deliver pulses of light to their brain. Known as optogenetics, this technique is able to make individual neurons respond to light.


How a memory was implanted in a mouse

• A mouse was put in one environment (blue box) and the brain cells encoding memory were labelled in this environment (white circles)
• These cells were then made responsive to light
• The animal was placed in a different environment (the red box) and light was delivered into the brain to activate these labelled cells
• This induced the recall of the first environment - the blue box. While the animal was recalling the first environment, they also received mild foot shocks
• Later when the mouse was put back into the first environment, it showed behavioural signs of fear, indicating it had formed a false fear memory for the first environment, where it was never shocked in reality

- BBC.co.uk