Can scientists really change your memories?

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stick_figure_thinking_cap_500_wht_10194Short of brain-washing people it sounds almost like a sci-fi fantasy. However scientists have succeeded in manipulating the brains of mice, turning fearful recollections into happy ones.

Whatever you think about the prospect of wiping out any memories – you could argue that we are shaped by our experiences and our memories of them, good or bad – it may be that for some people it’s the only way for them to live a normal life. But they said the same thing about ECT which seems barbaric now (although still used).

Steve Ramirez, a neuroscientist at MIT said “ We can now go in and study these memory centres and tinker with them to change the content. Our memories feel like a tape recorder of the past but in reality it’s a construction that is constantly being warped with some emotions fading and new ones coming in.

The authors of the recent study, published in Nature, believe that eventually it will be of clinical use in helping humans. But “tinkering” with our brains?

The leader of the study, Susumu Tonegawa, said “We have no intention of using this technology to alter normal healthy people’s minds or cognitions. If there is any application of this, it is for pathological conditions to reduce the suffering of people with psychiatric conditions”.

The study demonstrates that the factual content of our memories are stored in a different brain centre (the hippocampus) from the emotional content (in the amygdala) of those memories and can be altered using a technique called optogenetics.

This entails a light-sensitive protein being introduced into active brain cells so the neurons can be switched on and off by shining a laser at the head.

lab_rat_with_pen_clipboard_1600_wht_14929In the experiment scientists introduced the protein into the mice’s brains at the same time as they gave them an electric shock. They taught the mice to associate the shock with a small square in their cage and hit them with laser pulses every time they stepped on it until they began to avoid it.

Then they put them in a cage with female mice which the experimenters say evokes positive emotions! The memory of the electric shock was reactivated using the laser pulses (which they now associated with positive emotions) so that when they were returned to their original cages they actively sought out they small square they had previously associated with the electric shock.

If this technique works in humans it opens up a whole debate about the ethics of using it. Who decides what normal behaviour is? What’s to stop government agencies using the technique for their own ends.

Remember the film Total Recall based on the short story by Philip K Dick “We can remember it for you wholesale” about memories and reality (the 1990 version is the best one but here’s the trailer for the 2012 re-make)?