Everyone has a memory to a stupid thing they did when they were a lot younger. And thinking back to that makes you cringe. It’s awful. It’s almost like reliving the whole experience. If you could, would you want to get rid of that memory? When diving into the clinical side of memory, we are looking into PTSD, Post Traumatic Stress Disorder. Here, memories being relived are a lot worse than that one cringy thing you did as a child. Lots of soldiers or war survivors suffer from PTSD, reliving traumatic experiences and often also experiencing survivor’s guilt, because they were the one to make it through that living hell, whereas others weren’t. Wouldn’t it be great if those memories could be wiped?
Now I’m not saying that we’re there yet. In my previous article on hacking the brain I’ve clearly stated my skepticism towards the whole idea of being able to manipulate the brain and turn is into some super-human computer, also often referred to as cyborg. However, research by in neuroscience has given us some interesting insights with regards to memory. A team of neuroscientists conducted an experiment in which false memories were implanted in mice. Through the use of conditioning, certain smells were linked to having one of their paws electrocuted (life’s not nice being a lab rat). They only ever get shocked in one place (in their respective cage). As soon as mice smell the specific scent again, they stay away from that one specific place, as such avoiding the electrocution. This is learned behaviour through conditioning. The smell triggers the shock which only ever occurs in one place, and never without the smell being present. Smell + specific place = shock. This is something that could also be done with humans (ethics committee willing). The next part however, is definitely not for human experimenting. After the neuroscientists figured out which area within the brain was responsible for reacting to the smell and memorizing the “Smell + specific place = shock” equation, they messed about with that area. How? Optogenetics. Something that ethics will most definitely NOT allow on human beings. Optogenetics is breeding an animal, often mice, to be sensitive to certain lights, in certain parts of their body. Then, they put a light implant within the head of the mice, to trigger that light sensitivity and trigger the brain area. They activated this brain area, despite no smell being present. What happened? The mice still displayed the same behaviour: avoiding one specific place, out of fear of being shocked. Because the trigger, the optogenetically modified smell, had been presented to them. Well, at least on a neurological level. So far, most of this is “basic” conditioning with some neuroscience thrown into the mix. But the researchers took it further (surprise). They started targeting the brain area that gets active when actually experiencing a shock. Again, the mice never experienced the shock, this was yet another manipulation. They only experienced the shock on a neurological level. Result? Mice that never smelled an actual smell, or experienced an actual shock displayed the same behaviour: avoidance of a particular space within their cage. Interesting…
What we see here is not the wiping of memory, rather, a false memory is being implanted. This can of course, have massive repercussions for PTSD sufferers, but also for those suffering with dementia or other degenerative-memory disorders. Of course, the scientists are cautious. They argue that first, it working on mice might not replace to it working on humans, which is always a fair argument.
But second, and potentially more importantly: the mice and their brain tissue in the study were healthy. People suffering from PTSD, but most definitely those suffering from more degenerative diseases also affecting memory, often do not have healthy brain tissue. As such, this study shines a light (optogenetics joke, get it?) on some of the basic underlying systems within memory, whereas their application will get very complex very quickly. Moreover, although the research focused on implanting a memory, which is making me think more and more of Inception, the larger aim of the research was grounded in memory retrieval. Nothing had been discussed of destroying or “over-writing” memories, which is often the sci-fi and Hollywood interpretation. To hack a memory probably also raises more philosophical questions, not on an ethical level a la “eternal sunshine of the spotless mind”, but more like what exactly is a memory? What are we “hacking” or at least trying to retrieve and manipulate? And given that our memory is often very faulty or at least cloudy (look at severely different witness statements of the same event) and a lot of it happens subconsciously, can we ever get to the very bottom of them? And if so, what are the repercussions of messing about with something that is so formative to our personality? Disregarding all the complexities and many questions left, it is a really interesting study, and I’m eager to see more work within this domain!
References: Vetere, G., Tran, L. M., Moberg, S., Steadman, P. E., Restivo, L., Morrison, F. G., ... & Frankland, P. W. (2019). Memory formation in the absence of experience. Nature neuroscience, 22(6), 933-940. access: https://www.nature.com/articles/s41593-019-0389-0
Also discussed in Scientific American: https://www.scientificamerican.com/article/a-successful-artificial-memory-has-been-created/