By Grace Li
We never see reality as it is—our memories overlay streets and sights, and everything we experience is influenced by what we have experienced before. Memory is a beautiful thing, but it can also be a dangerous thing. Traumatic events, for example, generate memories that are among the most enduring. For victims of PTSD, memories are at the root of their disorder. A recent study, “Epigenetic Priming of Memory Updating during Reconsolidation to Attenuate Remote Fear Memories,” attempts to help those who have memories of trauma.
For those who have experienced recent trauma, treatment can effectively use the brain’s own memory updating mechanisms simply by prompting the person to recall the traumatic memory. However, the same thing cannot be done with trauma that occurred further in the past. In order to enable memory updating, the researchers utilized epigenetics, or the chemical modifications that influence gene expression.
There is a gene in the brain that is important in memory updating but only works after it’s modified. Usually, there is something (more specifically, something called a histone deacetylase, HDAC2) that sits on that gene and prevents it from being modified. The brain activity that occurs when a person is recalling a recent memory results in HDAC2 falling off, freeing the gene to update memories. But when a person is recalling a more remote memory, there is less of the necessary brain activity, so the HDAC2 stays on and the gene can’t update memory. What the researchers did was use an inhibitor of HDAC2, so even though there wasn’t enough brain activity to cause HDAC2 to fall off, the gene could still be modified because the inhibitor prevented HDAC2 from working. Therefore, they were able to facilitate memory updating even in remote memories.
It’s a complicated bit of science, but what it boils down to is that memories that have been with us for years can be diminished and perhaps even erased, as the memory updating makes the brain “more capable of forming very strong new memories that will override the old fearful memories.” It holds promise for those that have experienced trauma and wish to be rid of it, but it also has some perils. We have memories for a reason, after all. Evolutionarily, they have helped us avoid danger, to remember what berries will kill and what paths to avoid. Even today, they protect us. A child who has a nut allergy and went to the emergency room after eating a spoonful of peanut butter has (hopefully) learned a valuable lesson.
There are times when memories can harm us, yes, but can the solution really be to override the memory completely? Given how little we know about the brain, the chances of using this research on humans in the near future is slight—the brain is a delicate thing, and one tweak could result in a malfunction of the entire, elaborate machinery. We do not yet have the knowledge to claim mastery over the mind—or even our own memory. This is one step in that direction, though, and like with all new advances, it holds great risk and great reward.