How exactly is memory stored in the brain? If the information is stored in your brain physically, is there a way to know how much space one memory takes up in your brain?

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How exactly is memory stored in the brain? If the information is stored in your brain physically, is there a way to know how much space one memory takes up in your brain?

In: Biology

We don’t exactly know all the details of memory, it’s complicated. But, ignoring that because this is ELI5:

Information is stored in connections between neurons. Memories are mostly references to other memories, that’s how your brain makes the sort of memory mistakes that are the most common. It’s hard to imagine a memory that is completely stand alone.

Memory isn’t permanent. It’s constantly changing, to optimize the use of the available neurons and accommodate new experiences.

Imagine you’ve got a dense forest. Rather than go around it, you decide to forge through it, struggling through the dense undergrowth and getting more than a few scratches for your trouble. You emerge on the other side.

Now imagine it’s not just you. It’s thousands of other people as well, each forging their own path through the forest.

As all those people try to pass through the forest, inevitably some will hit upon the path taken by another and – noticing it’s a bit more clear – will walk along the same path.

This reinforcement, over time, creates paths through the forest where it’s relatively easy to walk.

Those paths are the ‘memory’ of the forest about people passing through it.

Your brain is a complex network of neurons, connected to one another. As a connection is used more, it becomes an easier ‘path’ to take in the future. On the other hand, if a connection goes unused, it gets (from out analogy above) ‘overgrown’ and less likely to be used.

The overall impact of these varying paths through your network of neurons determines how you think and feel. The modifications made to that network in the process encodes your memory of the past.