How Our Brains Create Timelines of the Past

Our brain's memory of events can sometimes be foggy or often non-existent – why is that?
Trevor English

While we know quite a bit about the biology of our bodies, our brains hold the vast majority of mysteries about humans. One aspect of the brain that is vital to our everyday life that we're still just learning about is how it stores and catalogs memories in the past. 

Brain storage is essentially a passive process that we undergo each and every day retaining information about our lives. Some of these memories are stored in the short-term, and others in the long-term. 


These two different types of human memory can be thought of as our brains filter system so that we don't get overwhelmed when we try to remember something. If our brain thinks that something is useful and will be needed frequently, it's stored in the more rigid long-term memory sections.

But thinking about that a little more, we're left with an inaccurate analogy. When we think of long-term and short term memory in the brain, it's natural to want to think of those different memories as different drawers in a filing cabinet. However, that's nothing near the truth.

In reality, neurologists working in the mid-1900s discovered that long-term memories are stored by being widely distributed throughout our entire cortex, or the outer portion of the brain. 

How Memories Get Stored

These memories get stored as groups of neurons that are arranged or primed to fire together in the same pattern every time. Each time they fire, they trigger the remembered memory. 

But our brains are neuroplastic, or rather they change over time, which begs the questions: what's to stop our brains from messing up the memory or just forgetting it altogether?

Redundancy. Our brains will store memories multiple times across different parts of the cortex in order to protect them from changes or losses the brain might undergo.

Now that said, our brains do actively rewrite past memories – one of the many reasons that evidence testimony in courts leads to so many wrongful convictions.

All of this interesting brain memory storage can be boiled down into an easy to understand metaphor.

Our brain's memories aren't stored like books on shelves or papers in drawers, rather they are stored like LEGOs scattered across the floor that have to consistently be put back together to create and encode the original message.

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The practice of remembering and storing past events is then an evolving process in our brain. As it amasses more legos scattered across the floor, it sometimes has to rearrange them in order to make room for the new patterns. In these instances, if our brains recognize weak patterns that haven't been assembled in a while, they may get written over.

The Process of Forgetting

While forgetting may seem a normal part of human life, neuroscientists are just discovering something mind-boggling. It appears that the human brain is theoretically capable of storing unlimited amounts of information indefinitely. What keeps most people from being able to do that is trauma or disorders. Trauma here being emotional or mental. 

This trauma affects not necessarily how the memories are stored, but rather how we catalog and retrieve them. Back to the LEGO analogy: the legos are still arranged across the room, the trauma or faulting retrieval just causes us to lose the instruction booklet of how they fit together.

The brain does other interesting things too that we might not expect when it comes to remembering that boost the idea that the memories are still there... somewhere. For example, trivial memories usually stored in the short term are instantly moved to the long-term if they occur right before a traumatic event. In fact, people's abilities to remember these trivial events are seen to be strengthened in the following days. 

In summary, it's best to think of the process of forgetting as the temporary and possibly permanent loss of ability to retrieve information. Forgetting is like losing the instruction booklet for how the LEGO model fits together. 

What Happens the Forgotten Blocks?

So, after you lose the instruction booklet for your memories, what happens to those blocks of memories? Scientists can't seem to agree.

Some theorize that those memories eventually decay and disappear, whereas others assert that the memory remains but the bonds become broken.

Aging and the Cataloging of the Past

As we age, it's natural for our brains to lose their ability to make new connections and even lose the connections it doesn't use. The brain shrinks as it starts to age and there just becomes not enough room for all of the "instruction books".

The hippocampus is crucial for memory and learning – it's also one of the first parts of the brain that starts to deteriorate with age. A recent study actually found that when elderly mice were injected with blood from younger mice, they saw a sudden growth in the hippocampus region. This study has actually led to the concept of "young blood" being able to restore people's mental faculties. 

How Our Brains Create Timelines of the Past
Source: coliN00B/Pixabay

One interesting thing that we are learning though as scientists study aging and the loss of memory: it appears impossible to be able to complete this process at will. In other words, you can't make yourself forget something. What the brain ends up doing is making these memories we're actively trying to forget some of the strongest in our entire brain timelines. 

Our brains are fascinating works of biological engineering that hold many more mysteries yet to be discovered. What we do know is that the brain is far more complex than once thought, and memories that you might not even know you had can affect how you respond in day to day life.

This is one reason why therapy can be so effective. The simple truth of the matter is if your brain isn't "broken"there's something wrong. The way our brains store our memories drastically affect our lives – and by working to understand that, you can change yours.

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