[ELI5] What is the difference, in terms of inside the brain, between short term and long term memory?

Question

[ELI5] What is the difference, in terms of inside the brain, between short term and long term memory?

In: Biology

Answer 1

Hmm, that’s an interesting question.

Basically, your brain is like the most overworked, stressed out, high-functioning soccer mom you’ve ever met. She’s spinning so many plates that it’s insane it doesn’t all just fall to the ground.

Short term memory and long-term memory work in exactly the same way in terms of machinery. They’re just different “plates” that your brain is “spinning”. They live in different parts of your brain.

So here is the process.

Something happens. It either goes into your short-term memory or it doesn’t. Your brain actually trims a lot of fat right from the start, it ain’t got time for remembering everything, even briefly. You pick up your keys? Maybe you remember that, maybe you don’t.

But let’s say you do remember. Picking up your keys goes into your short term memory area of your brain. Neurones connect to one another like a bucket chain. When you access that memory (“Shit, did I remember my keys?”) the path to your short-term memory lights up like people passing that bucket along until you reach where that memory is stashed.

But you can’t record your whole day. So your brain will delete things that aren’t important. This happens on a case-by-case basis, as you fail to pass that bucket along. The less you use that neutron line, the less you will preserve that memory, and it will naturally fade away.

But let’s say that instead, it drops into your long-term memory. Say you drop your keys down the storm drain that day. That’s memorable! Suddenly, you’re re-visiting that morning in your mind. Recalling every moment that led up to you losing your key.

That is when your brain re-files that memory. It gets moved over to long-term: bad. (Different pathway to get there from long-term: good.) So, now the memory is living in your long-term part of your brain. You still need to reach it with that bucket chain of neurones. You must wear a path in your own mind by revisiting that memory again and again and again – or your mind will delete this memory. Your mind is always pruning memories, unless you make them very, very solidly engrained in your mind with repetition.