Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Aging brains blend memories together instead of just forgetting them

studyfinds.com

Post reply on HN
Print view View original

61–70 of 142 posts

Re: Aging brains blend memories together instead of just forgetting them

#61

Post by chermi »

randomImmigrant wrote: post #31
HarHarVeryFunny wrote: post #23

I wonder how much of this is directly related to age (biological aging), and how much is just someone's brain becoming "full" due to more memories getting added every year? It seems that memories must be stored as embeddings with single multi-neuron assemblies (cortical columns?) storing multiple embeddings as a kind of contents-addressable memory that is able to keep memories distinct due to the very high dimensiona…

The brain does not have the Von Neumann bottleneck. Unlike most current digital systems, the brain doesn’t have a separate memory registry it needs to pull from. Engrams, that is, the physical trace of a memory, are not stable through life. They start out in the hippocampus, but as the stimulus recedes in time without reinforcement, it moves away. No evidence exists though that the memory is encoded in one set of cel…

None of that changes whether there is a physical capacity, which I think was the larger point? There is no reason to believe distributed memory doesn't suffer from the capacity component of the bottleneck. In fact iirc there was some late 80s/early 90s papers on the memory capacity of NN. Btw I would advise against the absolute statement that there's absolute segregation of memory and processing.

I guess my point is the brain not being "von Neumann" in architecture or digital is not proof that isn't a "computer" of some sort.

Re: Aging brains blend memories together instead of just forgetting them

#62

Post by rectang »

The concept of memories blending together resonates after watching a recent Kurzgezadt video entitled "How Are Memories Stored Inside Your Brain?". It makes the point that the very act of recalling a memory changes it:

https://www.youtube.com/watch?v=PqtggjVAi8M

> But memories are not static like photos. Like dioramas made from wax, each time they’re under the spotlight of your attention they can melt and change a tiny bit.

Re: Aging brains blend memories together instead of just forgetting them

#65

Post by LorenPechtel »

HarHarVeryFunny wrote: post #23

I wonder how much of this is directly related to age (biological aging), and how much is just someone's brain becoming "full" due to more memories getting added every year? It seems that memories must be stored as embeddings with single multi-neuron assemblies (cortical columns?) storing multiple embeddings as a kind of contents-addressable memory that is able to keep memories distinct due to the very high dimensiona…

I don't think there is a "full" state, but watching the changes as the years go by I have thought of collisions. Not really like a hash table, though--most collisions are with things that would be filed together. I think it's more like the brain returns a random item matching the category. Brains are expensive, memory that gets fuzzy with age is probably the better choice than trying to feed a brain that does better.

Re: Aging brains blend memories together instead of just forgetting them

#66

Post by p1esk »

thesz wrote: post #49
HarHarVeryFunny wrote: post #23

I wonder how much of this is directly related to age (biological aging), and how much is just someone's brain becoming "full" due to more memories getting added every year? It seems that memories must be stored as embeddings with single multi-neuron assemblies (cortical columns?) storing multiple embeddings as a kind of contents-addressable memory that is able to keep memories distinct due to the very high dimensiona…

A fascinating story of "Patient Sh." [1], the man who did not forget. [1] https://en.wikipedia.org/wiki/Solomon_Shereshevsky "His memory was so powerful that he could still recall decades-old events and experiences in the smallest details. After he discovered his own abilities, he performed as a mnemonist; but this created confusion in his mind. He went as far as writing things down on paper and burning it, so that h…

Our brain consists of approximately 86 billions quantum computers [2] controlling tens-of-thousands chemical neural networks with at least 10 coefficients

By that logic, a Blackwell GPU contains 208 billion quantum computers.

Each transistor is a quantum mechanical system and takes hundreds of model parameters to describe. So apparently a GPU is a 208-billion-node quantum supercomputer.

Re: Aging brains blend memories together instead of just forgetting them

#67

Post by darepublic »

rectang wrote: post #62

The concept of memories blending together resonates after watching a recent Kurzgezadt video entitled "How Are Memories Stored Inside Your Brain?". It makes the point that the very act of recalling a memory changes it: https://www.youtube.com/watch?v=PqtggjVAi8M > But memories are not static like photos. Like dioramas made from wax, each time they’re under the spotlight of your attention they can melt and change a ti…

Very poetic metaphor!

Re: Aging brains blend memories together instead of just forgetting them

#68

Post by BariumBlue »

rectang wrote: post #62

The concept of memories blending together resonates after watching a recent Kurzgezadt video entitled "How Are Memories Stored Inside Your Brain?". It makes the point that the very act of recalling a memory changes it: https://www.youtube.com/watch?v=PqtggjVAi8M > But memories are not static like photos. Like dioramas made from wax, each time they’re under the spotlight of your attention they can melt and change a ti…

I suspect my oldest memory, of me getting into a booster car seat as a child, is no longer the actual memory, but the accumulated imaginings of me trying to remember that specific memory, masquerading as a memory.

Re: Aging brains blend memories together instead of just forgetting them

#69

Post by sebastos »

randomImmigrant wrote: post #31
HarHarVeryFunny wrote: post #23

I wonder how much of this is directly related to age (biological aging), and how much is just someone's brain becoming "full" due to more memories getting added every year? It seems that memories must be stored as embeddings with single multi-neuron assemblies (cortical columns?) storing multiple embeddings as a kind of contents-addressable memory that is able to keep memories distinct due to the very high dimensiona…

The brain does not have the Von Neumann bottleneck. Unlike most current digital systems, the brain doesn’t have a separate memory registry it needs to pull from. Engrams, that is, the physical trace of a memory, are not stable through life. They start out in the hippocampus, but as the stimulus recedes in time without reinforcement, it moves away. No evidence exists though that the memory is encoded in one set of cel…

Hijacking your post with a dubious segue because I’m itching to bounce these thoughts off somebody:

I’ve been consuming a lot of talks / writing recently about “enactive” pictures of how our brains function. From what I gather, recent studies have called into question the entire idea of real world concepts being “represented” by an area of the brain at all. While it’s true that atandard fMRI-style snapshots of brain activity are semi-stable over the course of a short experiment, it’s not true over longer timeframes. The response to the same stimulus will change over time. They refer to this as “representational drift” in the literature, and some people are using this to bolster theories of mind that they consider non-representational. They instead emphasize the brain as a kind of dynamical system that learns to “resonate” with the world to pull itself back into homeostasis. The focus shifts away from facts and memories as data, and sees neuronal plasticity more as a mechanism for tuning the brain’s resonant frequencies. This obviously places high importance on the spiking, recurrent nature of actual neurons, as opposed to the neurons-as-functions / back-propagation / ML approach.

My mind’s not made up on how interesting and revolutionary this approach is / isn’t. The distinction seems to be about whether learning is more like “writing to disk” or “tuning a PID controller” - but in either case, the world is leaving a stateful imprint on your brain that will impact how it processes future data. Is that important to understanding how brains work, or is it just semantics?

Post reply on HN