The Spotless Mind: The Possibilities of Memory-Erasing

(Editor’s note: This article is from a past issue of Brain World magazine. If you enjoy this article, please consider a print or digital subscription!)

A traumatic memory has the means of replaying itself over and again with such tenacity that it’s almost as if it were on a constant loop. It has the alarming capability of magnifying the most horrific aspects and can run through the minds of its victims with such frequency that many report feeling as if they’re a prisoner of their own mind.

The act of remembering has left them looking for a key to a door that will not stay closed. More than 5 million people in the United States alone suffer from post-traumatic stress disorder (PTSD), and they live in constant fear of their own memories. But what if the emotional response to that memory could be erased?

Or, better yet, the memory itself?

Neuroscientists have revolutionized a concept that was once considered not only impossible but borderline science fiction (and featured famously as the theme of the film, “Eternal Sunshine of the Spotless Mind,” and in the book trilogy, “The Hunger Games”). Precision memory-erasing is something that we will possibly see in the next decade. Imagine the possibility of being able to administer a pill and live again.

Dr. Karem Nader, a professor of psychology and neuroscientist at McGill University in Montreal, has been testing and treating patients who suffer from PTSD. “For 100 years, people used to think that once a memory is consolidated it stayed that way, that when you were remembering something it was like you read it off of the hardware in the brain,” he says. “In functionally erasing memories, I rediscovered a property of memory. When you are remembering something, it goes from a stable state to an unstable state, and it has to be re-stabilized. If you block the process of re-stabilization, you seem to get rid of the memory. This is called reconsolidation.”

Using research dating back to the 1960s, in 2000, Nader figured out how to successfully erase an already formed memory. Although some of his studies are still in trial stages, he says it is possible to administer a beta blocker to a patient, and lessen — or even erase — the emotional impact of that person’s memory. “When you have them recall their trauma, the memory goes to an unstable state,” he says. “The beta blocker is something we use to block the consolidation of the emotional part of the memory being restored, while preserving the conscious part. We are erasing the emotional memory. Patients have improved tremendously in their condition but they can still tell you what happened.”

A 2006 study by Dr. Alain Brunet tested propranolol, a beta blocker which was originally used for treating heart conditions, for long-term sufferers of PTSD. The study had 19 patients recall their traumatic memory while receiving a dose of the propranolol. A week later, when they were asked to recall their fearful events, the patients who received the beta blocker reported having far less emotional response then a week prior.

Dr. Richard L. Huganir, a professor and director of the neuroscience department at Johns Hopkins University has been researching and testing fear and memory-erasing in mice. “We paired an innocuous noise with a mild shock and immediately the mice associate the tone with the shock,” Huganir says. “The next day if you just give them the tone, they will freeze as if expecting the shock, exhibiting that they are afraid.”

While the mice are experiencing fear, Huganir and his colleagues found that there was more stimulation in the amygdala. Researchers believe that the amygdala is the fear center of the brain, and that it assigns responses to traumatic experience, which affects memory consolidation. During this time of fear, Huganir found that it was possible to weaken memory-associated connections. “We dissected the pathway and found compounds that could potentially erase the traumatic memory,” he says. “We aren’t erasing the memory, just the emotional content. The treatment is a behavioral treatment. We did pharmacology on this phenomenon and found that certain drugs can block the erasure, so now we are testing related drugs that will enhance the erasure.” Though these works are not yet published, Huganir see this being a treatment in 10 or more years. It could possibly offer emotional relief and be used by people who suffer from PTSD.

When we think of our memory, many of us see our brains as a storage system; that we encounter or experience something in our life, and our brain takes that information and holds it for us. But what studies have found is that memories are not stored; in fact, there is no physical location in the brain were you can pick out a memory. Memory storage takes place on a neural level. Our encounters alter our central nervous system and modify our neurons, making some memories stronger and some weaker.

Any time we recall a memory, we are in the mode of reconstruction and editing. Researchers believe that the act of remembering is an act of re-creation; this is why memory can be reconsolidated or erased. When we are remembering an event that took place in our lives, we are running a new simulation of an old memory, fine-tuning certain aspects and possibly weakening others.

“When you form a memory, you are limited in what you are perceiving,” says Huganir. “Your sight, your taste, your smell, and hearing, they set up the memory, and those are all filters. As we go along, memories can get edited, you forget certain aspects, or they can become stronger, or weaker, or slightly modified. Memory is not written in stone and, in theory, can be erased.”

Disturbing memories can hinder an individual’s life and leave him or her in a constant state of debilitating fear. “Fear memory is such a robust and strong phenomenon. Everyone can relate to this. Something extremely scary does not have to be memorized; it’s called one-trial learning. If it happens once, you will remember it the rest of your life. Fear learning is much stronger than positive learning,” says Huganir.

Often, the pleasantness we feel from a wonderful memory can be completely overtaken by the stubbornness of a traumatic one. This is why people who suffer from PTSD report having such a difficult time forgetting their past experience. Every time they think of the memory it can become more vivid and more painful, therefore becoming stronger. “Certain things are extremely difficult to cope with,” says Nader.

Many ethical questions have arisen from the emotional erasing of memory. We are our memories — they define us. Our experiences are the building blocks that form us as individuals, and they allow us to learn from our mistakes and evolve as a species. But some encounters leave many stifled and unable to lead a fulfilling life. Minimizing the emotional response could allow many to move on.

“There is a huge ethical and philosophical issue, even if it is a traumatic memory, they are good, and we learn from them,” says Huganir. “You do not want to erase all traumatic memories. Emotional responses to experiences are very important. But you can debate that if a specific traumatic event from your life makes you nonfunctional and miserable, then you might be willing to give up that memory if it would bring you peace.”

(Editor’s note: This article is from a past issue of Brain World magazine. If you enjoy this article, please consider a print or digital subscription!)

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