Our sense of identity is largely shaped by the memories we accumulate over time, including the unpleasant ones. But what would happen if we could erase our negative memories or even fabricate positive ones?
Although this concept might seem like a scene from a science fiction movie or akin to the storyline of the 2004 film Eternal Sunshine of the Spotless Mind, starring Jim Carrey and Kate Winslet, advancements in neuroscience are turning it into a reality.
New experimental methods being tested on mice have enabled scientists to diminish the intensity of negative memories. These advancements could have significant therapeutic effects for various severe neurological conditions, such as PTSD and addiction, and might even aid in restoring memories for individuals with dementia.
Professor Steve Ramirez, a prominent figure in memory manipulation research, discusses this groundbreaking achievement in his book, How to Change a Memory. He elaborates on his experiments with mouse brains and how his team discovered ways to alter a fundamental aspect of human identity.
In an interview with the Daily Mail, Ramirez explained how this technique locates memories by targeting brain cells activated by light. His team can then manipulate these cells to recover lost memories or implant entirely new ones.
He described his findings as ‘pretty amazing’ and suggested that they could revolutionize medical treatment in the coming decades.
Ramirez stated: “Researchers have been able to successfully restore a memory that was thought to be forever lost, so that really begins shaking the foundations of what we think of when we think of memory.”
This method not only offers insights into memory manipulation but also enhances our understanding of how memory functions. According to Ramirez, each time we recall a memory, we’re not just retrieving a fixed snapshot from our past. Instead, we create a new version of that memory.
When you remember something, dormant cells in your brain’s emotional center become active and exchange chemicals. This process reconstructs your memory of that event, along with the emotions tied to it.
Thus, revisiting a memory can trigger an emotional response, such as happiness or fear, regardless of your surroundings. However, this process doesn’t store the memory in its original form; the act of remembering actually alters the memory.
Ramirez explained: “We know that when we recall the memory, it’s not a video of the past, but it’s a reconstructive process where we pull the book of memory out of the library, and when it’s at the forefront of our mind, we inadvertently start sketching details into that memory.”
This process activates specific areas of the brain, allowing scientists to track and influence these areas using techniques partially developed by Nobel Prize-winning immunologist and neuroscientist Susumu Tonegawa.
Tonegawa demonstrated his theory by implanting altered memory engram cells—essentially bits of information imprinted on brain tissue—into the hippocampus of mice to induce a predictable fear response.
The pioneering memory therapy described by Ramirez involves using drugs to compel the subject to recall particular moments. During this recall, scientists can modify or completely change the memory being retrieved, though this has only been achieved in mice so far.
Ramirez noted that while the capacity to reduce negative memories and enhance positive ones has therapeutic potential, the most significant benefit of this breakthrough could be in transforming the treatment of neurodegenerative diseases like dementia.
He said: “I think that’s a kind of mini Holy Grail of this all, to be able to really restore what we once thought was lost, especially something as near and dear as memory.
“There are tremendous amounts of more research we need to get there, but I think that would be what the path forward would look like.”