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Can scientists delete memories? Science fiction comes to life!

Scientists have discovered how to “delete” unwanted memories.



This was the title of a new article I saw online recently. It caught my attention immediately. Surely this could only be science fiction!? Deleting or tampering with memories has been the subject of many science fiction films such as Eternal Sunshine of the Spotless Mind, Total Recall and Inception. It’s always been thought of as some distant and impossible procedure reserved only for our imaginations and Hollywood. Or is it...


I watched the PBS documentary “Memory Hackers” which explains this sensational claim and I found it absolutely fascinating.


In the documentary, we learn about a psychologist called Merel Kindt working in Amsterdam, who has developed a method for curing arachnophobia (fear of spiders) using a technique to erase the fear memory associated with the much feared 8 legged creature. And, surprisingly, her work has been successful. Many clients have been cured of their terrible fear, even those who had lived with the phobia for years. But how?! How did this idea come about? And how did she know where to start?


To answer these questions, first of all we need to know a little bit about how memories are formed in the first place. Memory is extremely complex and even today scientists still don’t understand it fully. However, there have been many recent discoveries that have led us to a better understanding of memory.


When something happens, let’s take hearing a joke that makes you laugh as an example, you experience that moment through all of your senses. You hear the joke, you notice smells in the room, you see the person telling the joke as well as your surroundings, you feel the temperature, and your emotions. Millions of sensory neurons (the cells that transmit sensory information to the brain) are firing. They are taking information about your surroundings and sending it to the brain for storage cell by cell.


Neurons are funny looking cells, I always thought of them as looking like a funny sort of sea squid! At the end of each cell is a synapse, the part that transmits information to the next cell. Where the cells meet each other there is a tiny gap called a synaptic gap through which the information passes from one to another.




So, all of this information is transmitted to the brain and stored. But rather than having a specific “Memory Cortex”, each component that makes up a memory is stored in a different place. Visual aspects are stored in the visual cortex, smells in the olfactory cortex, emotions in the amygdala and so on. When we remember something, the hypocampus part of the brain retrieves all of the memory componenets from their different locations and puts them together in one box to present in our mind as a full memory.


In the 1960s an American neuro-psychiatrist named Eric Kandel carried out research in single cells showing how messages where transmitted from one neuron to another. He discovered that each time a message is sent, new synaptic connections grow between neurons. This may sound simple, but it was the first time anyone had shown a new memory being formed and was the basis for much of what we now understand about memory.




It was long thought that once a memory was formed, it was neatly filed away in our brains and each time we wanted to recall the memory we would retrieve it, look at it and put it back away exactly as it was before.


However, wanting to test this theory, American scientist Karim Nader, decided to carry out research to put this to the test. Using a drug called anisomycin, which blocks the proteins needed to form new synaptic connections, Nader found that the memories could no longer be recalled. This showed that the actual act of remembering requires us to build new neural synaptic connections; that every time we remember something, new neural pathways are formed. The implication of this research was that memories are not these solid unchanging stories that are neatly filed away ready for whenever we want to retrieve them, but in fact are vulnerable to change each time we recall them. That we can add or remove things from the memory box before we put it away again.


So, back Merel’s spider study. How did this earlier research inspire Merel to cure arachnophobia? Using the findings of Eric Kandel and Karim Nader and the fact that memories are changeable, Merel designed her new therapy to cure fear.




First of all she exposed the clients to a spider to evoke their memory of fear... they have to stand a couple of feet away from a live tarantula and approach it. The experience is understandably terrifying for the clients. They feel shaky, sweaty, their hearts are pounding, breathing faster, adrenaline coursing around their body….ready for fight or flight.


The experience only lasts a few minutes, just enough time for the client to pull out their spider memory box and see what’s inside. Once the memory has been recalled, the clients get to breathe a sigh of relief and leave the spider alone. They then take a drug called propenalol which inhibits the body’s ability to produce adrenaline, the hormone which plays a large part in our anxiety response. By blocking this hormone, the body is no longer able to produce the physical effects associated with fear when the memory is recalled. This means that the next time the memory is recalled and the stored away in the brain again, the new neural pathways are formed without the fear association. The memory is reconsolidated differently.


The next day, the clients return and Merel again exposes them to a spider. This time, although they are cautious because they know that they are supposed to be afraid of siders, they are unable to feel the physical symptoms of anxiety and fear. The clients are encouraged to touch the creature this time. It sounds crazy but because they are not experiencing physical symptoms of fear, they are able to touch the spider. This time, when the memory is stored away in the brain, the new neural pathways are formed without any fear connected to the spider. The next time the client is exposed to a spider and pulls out their spider memory box, there’s no fear in there.


Amazingly, Merel tested this method on over 30 people and it was successful in every single client.




The implications are astounding, with so many people affected by phobias, anxiety problems and disorders such as PTSD, this type of therapy could offer real solutions.


So, no longer science fiction, memories can be altered. I’m not sure if delete is the correct word. Memory is far too complex and still too little understood for full memories to just be deleted but they certainly can be altered.


The Memory Hackers documentary goes on to show how using the same ideas and information regarding how memories are stored and recalled, false memories can be implanted. A disturbing thought. And then mind-blowingly, the documentary concludes showing how using genetic modification, scientists have been able to use a laser to switch on and off a particular memory in mice. It’s far too complex for me to explain how they did this but watch the documentary if you’re interested!


I found this research and the notion of genetically modifying animals, using them for research and tampering with memories all quite troubling and unsettling. I can see the potential benefits of memory research for things like treating phobias, PTSD and other anxiety related problems, as well as the potential for helping people with problems like Alzheimer’s. It would be wonderful to be able to help those whose memory significantly affects their quality of life.


And certainly there may be times when forgetting something troubling would be great. But I can’t help but wonder…don't we form memories for a reason, even bad ones?


We’ve all suffered a broken heart, or experienced grief, sadness or regret in our lives. These feelings are unpleasant but I think that it’s only through experiencing them that you can learn and grow as a person. If we were to start removing all of our unpleasant memories, how would we ever learn from them?


I actually suffered with a full blown phobia of spiders for many years. I would fly into a panic attack at the sight of a house spider and couldn't bring myself to even look at pictures of them. I would have given anything at the time for Merel's miracle cure. But in dealing with the phobia myself, I learned a great deal about myself, and the things in my life that were manifesting as that phobia. The phobia itself lead me to make much needed changes that I may never have tackled otherwise.




There’s a famous quote that says


“Sometimes, it takes sadness to know happiness, noise to appreciate silence and absence to value presence.”


I think there needs to be some careful thought and all new research into memory should be treated with caution and respect. Afterall, everything we know about our lives come from our memories. It's memory that enables us to know who we are.


What are your thoughts? Would you like to erase your memories? Have you experience of a phobia? What do you think the future implications of this research could be?



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