Researchers Change Bad Memories to Good Ones

Scientists have successfully developed a way to change fearful memories into good ones in mice.
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Scientists have successfully developed a way to change fearful memories into good ones in mice.

Photo Credit: Science Mag

A research team from the Massachusetts Institute of Technology have developed a way to neutralize bad memories in mice. Better yet, they were also be able to switch the memories for ones evoking more positive emotions. As Science Mag notes, the treatment is too invasive to be used on humans, but the team hopes the findings will lead to new treatments for post-traumatic stress and other anxiety disorders. 

Neuroscientist and lead researcher Susumu Tonegawa says that memories change as we learn from new experiences. Sometimes, this can help people recover from trauma. 

To manipulate memories Tonegawa and his colleagues used a tool called optogenetics to trigger neurons that were altered to fire up when a light shines on them. Additionally, they were able to trace certain memories as they formed. 

In the study, the mice's brains were genetically modified so that a light-sensitive protein was expressed when a specific antibiotic was removed from their diet. This allowed the researchers to watch as memories were being formed. They then rigged a blue light to the neuron to force the mice to recall the memories. 

One group of mice was given an electric shock to make a bad memories, while the other group of male mice hung out with a group of female mice to create good memories. The mice in the first group didn't spend much time thinking about the memories, but the group with good memories did. 

Then, the researchers took the mice from the shocked group and had them hang out with female mice, while the group with good memories were shocked. This time around, however, the blue light was activated, so the mice were experiencing the first memory again instead of making a new one. Afterwards, the emotional value of the original memory had switched.

"In the brain, there exists two competing neurocircuits — one involved in negative memories, and one involved in positive memories," Tonegawa told Vice. "We found that the competition of these circuits dictate the overall emotional value … and that we can switch a mouse's memory valence from negative to positive and from positive to negative."

Basically, this means that the researchers could potentially treat people with psychiatric disorders triggered by bad memories. For example, they could reprogram the way a person feels about an experience like witnessing a death or getting mugged.

Watch scientists read a mouse's mind in the video below.