As unbelievable as it sounds, scientists have discovered a way to erase past memories in mice. A new study shows that researchers were able to rid mice of bad past memories while leaving all of their other memories untouched. This kind of targeted eradication of bad past memories could open up new worlds of possibilities for people who have post-traumatic stress disorder or drug/alcohol addiction. The study can be found in the journal Biological Psychiatry.
Scientists originally got the idea for the experiment when they noted that people addicted to methamphetamine reported having drug cravings that were triggered by memories of certain objects or situations. Memories of a pack of cigarettes, the scent of a crisp dollar bill or even chewing gum could send the addicts into a state of extreme craving for drugs because those objects would remind them of times when they were high on methamphetamine.
Eradicating undesirable or unwanted memories is not a simple process.
Scientists discovered that when they blocked a protein called Actin, the mice forgot bad past cravings for methamphetamine and their memories were erased. This protein plays a key role in helping to signal neurons along what is called the dendritic spines. Actin was successfully blocked by interrupting myosin II, which is considered a sort of motor that makes molecules form into a chain. By blocking myosin II and ultimately inhibiting Actin, researchers were able to change the way nerve cells fired and eradicate the mice’s bad memories.
What is particularly significant about the experiment results is that the bad past memories which were erased were not erased shortly after forming, but rather during what is called the “maintenance phase” of memory. The Scripps Research Institute scientist Courtney Miller says this maintenance phase “refers to the long period that a memory sits in storage, after being formed, waiting to be retrieved,” and that this could indicate that the process they created in the lab “disrupts the memory long after it has formed.”
Potentially, this process of eradicating bad memories in the lab could one day eventually work in humans, though that is a long way off. Still, for people who have deep-seated and old unwanted memories, the finding could represent a tremendous breakthrough with a life changing treatment. For drug addicts especially, this finding could mean that their drug craving could one day be completely eradicated.
We maintain selectivity for the drug-associated memory without having to retrieve it. That’s valuable because substance abusers develop many, many associations with the drug, so it may not be practical to ask them to retrieve every single association in the clinic.
In our case, the manipulation can occur at any time and, apparently, only erase the drug-associated memories.
The ability to specifically target only the bad or unwanted memories regarding a certain thing, in this case, methamphetamine addiction, means that good memories and even other memories of unpleasant things could be left intact if desired.
Potentially, drug addicts could permanently lose their drug craving while still being able to remember everything else in their lives.
Miller went on to explain:
Not unlike in the movie Eternal Sunshine of the Spotless Mind, we’re looking for strategies to selectively eliminate evidence of past experiences related to drug abuse or a traumatic event.
Our study shows we can do just that in mice – wipe out engrained drug-related memories without harming other memories.
The experiments the researchers conducted also proved that the mice’s memory loss for methamphetamine addiction was permanent. Potentially, if the treatment were to be successfully recreated in humans in the future, the application could mean permanent loss of drug cravings and a complete recovery from drug and alcohol addiction.
Researchers found that methamphetamine addiction, in particular, was a rather “fragile” memory. They think that may be because of Dopamine playing a role in memory formation, but are unsure about the exact nature of the fragility of methamphetamine memory.
For now, this discovery by scientists may have an incredible impact on the future of humankind. Could erasing bad past memories in the lab pave the way to a science fiction future where our thoughts can be easily manipulated and we can be left with only pleasant memories? Certainly the drug and alcohol addiction application of this treatment would be very positive, but could there be any ethical considerations were people to seek out additional applications? What will the future hold for us and our memories?
By: Rebecca Savastio