Unveiling the mystery of memory – breakthrough brain study uncovers why some memories seem like yesterday and others fade

Scientists have discovered a system that oversees how the brain manages and entrenches lasting memories. The team at Rockefeller University used virtual reality learning tasks to identify molecules that contribute to memories sticking around or sliding quickly out of our heads. Operating on different timescales, they found that differing molecules would be able to form a chain of extended memory maintenance, preserving memories that were thought of and by extension, deemed important. The new way of understanding memory maintenance has reshaped how researchers and scientists are looking at memory, and importantly, further studies to understand and treat brain diseases.

Many aged care personnel have mused that it would be useful if the brain would be able to retain information and memory at will, particularly with the significant overhaul of the new act’s rules and regulations. Sadly, memory has been an evasive area of research for decades, with the brain’s complexity impeding large breakthroughs. This is what makes the team at Rockefeller’s breakthrough so vital for the health and aged care sectors, understanding how memory is stored is a significant step in addressing the cruelty of many brain-related diseases being treated in aged care.

What to store

Researchers have known that a critical functional task of the brain has been to decide what experiences a human has makes the cut in being stored as a memory, and what to forget. The pervading scientific assessment has been that the process of memory storing has been determined by a basic on-off switch within the brain.

The new study out of Rockefeller university has upended this understanding, highlighting that instead, the viability of a memory to stick around is determined by a waterfalling cascade of molecular ‘timers’ that spread out over many regions of the brain.

Lead researcher, Priya Rajasethupathy, and her team have discovered that an unexpected node, what’s called the thalamus, is a key player in “shepherding” memories from the ‘short stay’ category to long term memory. This happens through “gene programs” that progressively stamp the memory with the importance category, which stabilises it in memory, meaning it will become harder and harder to forget.

Historically understood

Rajasethupathy shares that scientists thought of memories persisting as being, “something with an on-off switch where, if you flip that switch, the memory is tagged to be “on” and it stays that way forever. Such switches are attractive because they provide a mechanism for fleeting experiences to be coded into lasting changes in the brain.”

“The consistent idea in the field was the existence of some kind of enduring switch that tells the brain that we want to maintain this memory long-term.”

Newly discovered

The rigidity or finality of memory should be moved away from Rajasethupathy shares, “one of the key insights of our study is that we shouldn’t be thinking of the conversion of short- to long- term memory as one-and-done. Instead, it’s a progressive process.”

“The brain sets a timer for, let’s say, a few minutes. If the memory continues to be important, the brain then promotes that memory and turns on a second timer that can last, say, a few hours. If that memory is still important, the brain turns on yet another timer that can last days, then weeks, and so on.”

In a twist that elevates the importance of how we attribute importance to a memory, Rajasethupathy details, “in this view, everything we experience can be formed as a memory, but we have mechanisms in place to rapidly forget—unless a memory is promoted onto one of these timers.”

“In our present work, we identified three such timers that essentially allow memories to last longer and longer.”

Understanding the ability to forget

Rajasethupathy explains, “if memory involved turning on a persistent switch, it would be difficult to forget something in the future that had already been committed to long-term memory.”

However, “a cascade of timers offers an explanation for how the brain retains the flexibility to promote or demote memories over time.”

She outlines, “let’s say you experienced something emotionally rewarding, or traumatic, and you kept thinking about it. Over time, as you thought about it, that memory would get promoted through several of these timers.”

“But then say a month or a year goes by, and you haven’t thought about the event. Since each timer is set for a longer duration, eventually you might reach a checkpoint that the memory does not pass— thus, time and experience can be integrated to continuously sculpt the persistence of a memory.”

Improving cognitive resilience

The messaging from Rockefeller University and the researchers is one of opportunities for further breakthroughs. They assess that the study’s findings will not only be able to contribute to a novel framework for understanding how the brain manages and preserves memory but particularly elevates the possibilities of new approaches to treating memory disorders and diseases.

It seems that memory has the potential to be more malleable than previously understood and this window of insight has the potential to uplift research and answers for Alzheimer’s disease and other brain conditions.

“In many cases of memory loss, like Alzheimer’s, the hippocampus—where that initial timer first forms and stores a short-term memory—is getting damaged.”

She notes, “now that we know there is robustness and redundancy built into this system with multiple timers in multiple brain regions, we can begin to ask: what if we could bypass damaged areas by turning on molecules that can route memories to healthier circuits?”

“In other words, our brains are built to compensate—can we leverage brain redundancy to improve cognitive resilience?”

Next steps

Rajasethupathy and her team are set to further investigate the functioning of the brain to uncover more applicable discoveries to change lives.

“The role of the hippocampus in memory formation was so striking that it attracted a lot attention. But the flip side is that we know almost nothing about what happens to memory beyond the hippocampus. An area that my lab is just starting to make some exciting progress on.”

Through exploring the output channels of the hippocampus, Rajasethupathy’s team pin-pointed the thalamus as a key player that sorts, routes, and maintains memories in longer term storage, now there’s more to investigate in this life-changing area of science.

“How it does this is a major set of next steps for us.”