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How do memories work?


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I am interested in the possibility of uploading information to the brain like in The Matrix. To that end, I’ve been studying the brain and trying to understand how memories work. Unfortunately, I’ve hit a wall.

I have a basic understanding of the structure and function of neurons. I understand that memories are stored in the brain as cellular assemblies formed by the hippocampus. I also understand that memories are not stored in any particular region of the brain, but are stored across the entire cerebral cortex. I know that the temporal lobes become enlarged in people who memorize a lot of information due to the accumulation of cellular assemblies.

What I don’t understand is how cellular assemblies translate into memories. I can’t find any information on this, and the puzzle has been haunting me. Help would be much appreciated.

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Could you clarify what you mean by cellular assemblies? And could you explain the relevance of the hippocampus?
I could be wrong, but it seems you have just grasped the surface of brain signalling/memory formation and you may have some overly simplified ideas.

Synaptic plasticity seems to be, at least for a big part, responsible for adaption. Basically (this is highly oversimplified, see resources at the end), every thought or idea is (probably) represented by 1 or more (no reason there cannot be redundancy) networks of many neurons. Each neuron has many many connections (synapses) and these can all be adjusted (more or less likely to fire at a given signal, or a stronger/weaker signal when firing). When you memorise something, you consistently activate the group of neurons that represent that concept. More specifically, you activate THOSE synapses, not other synapses (as much). This leads to strengthening of those connections, making it easier to fire that specific pattern (concept) the next time.

The Principles of Neural Science by Kandel is an amazing text book to go through. If you want some more specific articles: 
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3514210/ 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367554/
https://onlinelibrary.wiley.com/doi/full/10.1111/j.1460-9568.2010.07344.x

If you can't access some, remember that sci-hub is a thing.

There is some evidence for signals to loop around inside the hippcomapus a few times, but I can't find the reference (nor can I find it in my notes).

Hope this helps.

Another paper discussing synaptic plasticity and counterarguments: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212519/ 
Another one by Kandel (just like the book and first article): https://www.cell.com/cell/fulltext/S0092-8674(14)00290-6 

Edited by Dagl1
Addition of papers:
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You can amplify the learning process and enhance long-term consolidation of newly formed memories through techniques like transcranial magnetic stimulation, but you cannot upload memories directly. 

No, you DON’T know Kung fu. There IS a spoon. :)

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2 hours ago, iNow said:

You can amplify the learning process and enhance long-term consolidation of newly formed memories through techniques like transcranial magnetic stimulation, but you cannot upload memories directly. 

No, you DON’T know Kung fu. There IS a spoon. :)

I wasn't very sure if what you said was true (cause it sounds very... broad;p) so I checked for a source, turns out that you are right and low frequency stimulation does seem to enhance episodic memory! https://www.frontiersin.org/articles/10.3389/fpsyg.2019.00993/full 

Quoted from the conclusion:

The findings of the meta-analysis on younger adults revealed that frequency interacts with MTI as well as with stimulation timing. Specifically, both online and offline 1 Hz rTMS led to enhancing effects, which was driven by below-MTI stimulation. In addition, offline 20 Hz rTMS had enhancing effects whereas, online 20 Hz rTMS and 20 Hz rTMS at below-MTI led to impairing effects on episodic memory. A systematic review of the older adults and those with clinical disorders revealed a similar pattern of enhancing and attenuating effects of rTMS on episodic memory performance. However, important differences did arise with older adults and clinical populations implementing both offline 5 and 10 Hz rTMS protocols that had enhancing effects on episodic memory.

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10 minutes ago, Dagl1 said:

turns out that you are right and low frequency stimulation does seem to enhance episodic memory

Many of the tests being done are by the military, but we don't generally have access to those results as members of the the public

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"Could you clarify what you mean by cellular assemblies? And could you explain the relevance of the hippocampus?"

Sure thing. There's actually a fascinating story behind this, which I'll sum up briefly. Once upon a time, a guy was having severe seizures. In order to stop the seizures, his surgeon removed his hippocampus. The procedure was a success, but had an unintended side effect. The man could no longer remember anything for more than a few hours. This led to the realization that any information committed to memory for more than a few hours had to be stored in the brain by the hippocampus. The hippocampus creates what are called "cellular assemblies". These cellular assemblies are assemblies of neurons that somehow hold the information we commit to long term memory.

That's where I'm stuck. I assume that the cellular assemblies create some kind of information code, similar to how DNA constitutes a code that can be used to create proteins. What I'm trying to figure out is how the code is read, and what exactly does the reading. How are the memories stored by the hippocampus as cellular assemblies recalled?

If you want to upload information into someone's brain, that would mean manipulating the hippocampus into creating specific cellular assemblies containing that information. We need to understand how the cellular assemblies created by the hippocampus translate into memories in order to do that.

Edited by semnae
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47 minutes ago, semnae said:

What I'm trying to figure out is how the code is read, and what exactly does the reading.

The brain is not a computer. Analogies are sometimes useful in aiding understanding, but they also often lead to seriously flawed assumptions.

https://aeon.co/essays/your-brain-does-not-process-information-and-it-is-not-a-computer

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3 hours ago, semnae said:

"Could you clarify what you mean by cellular assemblies? And could you explain the relevance of the hippocampus?"

Sure thing. There's actually a fascinating story behind this, which I'll sum up briefly. Once upon a time, a guy was having severe seizures. In order to stop the seizures, his surgeon removed his hippocampus. The procedure was a success, but had an unintended side effect. The man could no longer remember anything for more than a few hours. This led to the realization that any information committed to memory for more than a few hours had to be stored in the brain by the hippocampus. The hippocampus creates what are called "cellular assemblies". These cellular assemblies are assemblies of neurons that somehow hold the information we commit to long term memory.

That's where I'm stuck. I assume that the cellular assemblies create some kind of information code, similar to how DNA constitutes a code that can be used to create proteins. What I'm trying to figure out is how the code is read, and what exactly does the reading. How are the memories stored by the hippocampus as cellular assemblies recalled?

If you want to upload information into someone's brain, that would mean manipulating the hippocampus into creating specific cellular assemblies containing that information. We need to understand how the cellular assemblies created by the hippocampus translate into memories in order to do that.

I would highly recommend reading up a little further... It is very important that you at least understand the basic mechanisms of memory before going off and trying to figure out how to do something that no one (as far as I know) has been able to do.

3 hours ago, iNow said:

The brain is not a computer. Analogies are sometimes useful in aiding understanding, but they also often lead to seriously flawed assumptions.

https://aeon.co/essays/your-brain-does-not-process-information-and-it-is-not-a-computer

I don't really agree with this article, yes the brain isn't a computer, but information IS stored in the form of a complex network of neuronal connections. And when we adjust such information, those connections have to be changed or a new pattern is produced and the old one is (partially) discarded. I have no evidence for that last part (what happens when we adjust information, but I feel those are the two options we have).

The article describes that a newborn baby isn't born with data, but mentions reflexes and specific behavior. How is that not a form of data? 

I don't really understand the context of the article (in the end it seems a introduction to computing?), but on it's own I would say that while brains are certainly not computers, memory is stored in some form inside your brain. Additionally, things like the Default Mode Network (DMN) and other constant pathways do seem to at least on the face seem to imply  some type of processing (but what it seems to me, definitely isn't truth).

-Dagl

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  • 11 months later...

I think that it could be helpful for you, to consider a memory as a function over time... a memory is not a single photograph its a movie, even if the memory is of a photograph, its still a movie... memory is not stored, once you stop the process of recalling it, its gone forever even if one had photographic memory its still subjective and very prone to error... Carl Magnuson displayed faulty memory on 60 min he laughed and commented that his memory is not what it used to be. 

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6 hours ago, iridescentorangutan said:

a memory is not a single photograph its a movie, even if the memory is of a photograph, its still a movie... memory is not stored, once you stop the process of recalling it, its gone forever even if one had photographic memory its still subjective and very prone to error

The only thing accurate here is that last part regarding subjectivity and propensity for error in memories

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