The Persistence of Memory is a famous surreal Salvador Dali painting where clocks melt in the landscape. It’s a statement on “the relativity and subjectivity of our perception of time” from 1931. Today, scientists from the University of Basel in Switzerland have found out more about how we maintain the persistence of memory in our brains.
As we experience new things in the present, we must adapt and learn to survive. Along the way, new contexts and insights inform our recollections of what already happened. In this way, we can anticipate what might come in the future.
As the study found, our brains help us navigate the material world by storing each memory in three or more parallel copies, each with slightly different roles.
“A new study now published in Science reveals that the memory for a specific experience is stored in multiple parallel ‘copies.’ These are preserved for varying durations, modified to certain degrees, and sometimes deleted over time, report researchers at the University of Basel,” shared the university.
The Persistence of Memory by The Canvas:
Three Parallel Copies of Every Memory
Three sets of neurons make a copy of a memory. The early-born neurons are first to develop in the womb, followed by the middle and last. It might remind you of the past, present, and future in a way.
- Early-born neurons
- Middle-born neurons
- Late-born neurons
With three copies of each memory, our recollections are subjective. As spiritual gurus say, it’s only what’s happening in the now that actually exists.
“We think that the world is limited and explained by its past. We tend to think that what happened in the past determines what is going to happen next, and we do not see that it is exactly the other way around! What is always the source of the world is the present; the past doesn’t explain a thing. The past trails behind the present like the wake of a ship and eventually disappears.” Alan Wilson Watts, What Is Zen?
The Master Copy
According to the study, the neurons that develop first appear to be like the master copy, “responsible for the long-term persistence of a memory,” as ScienceDaily put it. At first, we might not easily retrieve this memory. But long-term, this stored memory becomes the go-to when looking back on the “good old days.” Once locked in, we can’t easily change the recollection of events from long ago.
Built-In Redundancy Backups
As you reflect on memory shortly after it happens, a copy in the late-born neurons is readily accessible and more fluid. As you contemplate what happened, you could edit this copy with insights from the present. Thus, it’s possible to update the original memory.
Eventually, the late-born neuron copy can fade and become lost forever. Fortunately, another copy in the middle neurons is more stable, like a fall-back “built-in redundancy.”
“For example, if a memory is fresh, meaning that the late-born neurons are activated, it could still be changed before getting passed along to the middle and early-born neurons for storage. Once the late-born neurons are activated, though, and the memory is stored there, it becomes increasingly difficult to modify. Basically, the longer a memory has been stored in the brain the harder it is to change it,” shared New Atlas.
Although the study relates to our brains, the scientists were studying mouse models. Interestingly, mice have 75 different cell types in their cortex, the same as humans.
Related: Human Brain Atlas Reveals Cosmos of Neurons Working in Mysterious Ways
The Seat of Memory: The Hippocampus
The area of the brain where the three sets of neurons develop as a fetus is the hippocampus, which is considered the “seat of memory.” Previously, we explored how the hippocampus is also the part of the brain related to our sense of self or ego. Psilocybin studies revealed “an increase in connections to the anterior hippocampus, responsible for emotional memory, perception and imagination.”
Separate Pathways for Storage and Retrieval
A previous study found that the overall experience of memory is stored in the hippocampus. However, individual details of the memory can be “parsed and stored” in another part of the brain responsible for sensory experiences, the prefrontal cortex. As we sense things around us, it can trigger memories in a flash.
For example, you might suddenly have a memory from your childhood when you smell a familiar scent, like perfume.
“This separation ensures that, in the future, exposure to any individual cue is sufficient to activate the prefrontal cortex, which then accesses the hippocampus for recall of the whole memory,” the 2022 study found.
Image of Melted clock candlestick books, Wikimedia Commons with background via Pixabay