So generalisation of concepts going to far?
Aging brains blend memories together instead of just forgetting them
121–130 of 143 posts
Re: Aging brains blend memories together instead of just forgetting them
#122I 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…
> You'd expect that with big brains being so costly, evolution has only equipped us with brains big enough to store a lifetime of memories
It hasn’t, and rightfully so. I don’t think there’s any evolutionary advantage in remembering the first steps you did or the first time you drank milk, for example, and indeed, nobody remembers those.
A brain that remembers where the berries grew last year, where that cosy cave is, or where that angry tribe lives has evolutionary advantages. Most of the rest such as remembering specifics about events we visited, I think, is collateral non-damage, plus, oftentimes, reinforcement learning (many childhood memories get reinforced by your (grand)parents telling you repeatedly what they remember happened)
Re: Aging brains blend memories together instead of just forgetting them
#123Earlier quoted context omitted.
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…
Some years ago, I heard a retired Lutheran priest ponder, in radio, about the concept of a prayer, and whether, as an edge case, an unborn child could be able to pray, with the child of that age having no understanding on the required concepts. This is apparently one of those questions that people ponder under the umbrella of philosophy of religion. His conclusion was that prayer was about harmonizing one's self with…
For a lot of people, I think religion provides this basis or promise of harmony with the world, in a simplified way that stipulates what you should or shouldn't do and how things work, and those people find comfort in having these clear "rules"; we want to be able to rely on our understanding of the world, so that we can act within it with confidence, or faith. Ultimately, the "god" that is present in many religions is synonymous with this absolute truth of how the universe works, it's an unattainable standard that we all try to aim for, intuitively and knowledge-wise, or seek wisdom from, and I believe the intention of prayer is to have a way to get closer to it, to tune the self to the god in order to sense and know this absolute truth more clearly. I reckon that conceptually, prayer and meditation are very similar in this sense, but with a focus on different areas of the self.
Re: Aging brains blend memories together instead of just forgetting them
#124I 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…
Am neurobiologist and I don't buy the "full" argument, its much more likely a brain aging thing.
The brain, before your born, in GW25 (gestational week 25) has finished growing all the neurons you're basically [we can talk about this later perhaps] going to have for the rest of your life. At GW25 current estimates say you have ~86 billion neurons. Now the timing for this next part is a bit unsure but your body doesn't need anywhere close to 86 billion neurons, so at some point as early as early adulthood you start to lose 85,000 neurons per day pretty steadily until you die. Now neurons are not the end all be all because connections are potentially what really matter but that is to say that the neurons that you have after GW25 are the neurons you basically have. Now going onto synaptic connections where things start to matter more. Now synapses form and then get pruned all the time its natural. But the rate of formation and the rate of pruning is not the same at all times of life. Now from a raw number of synapse scale we see a tipping point at around 16-26 years old (debated hence the big range) where the number of synapses start to go down, indicating that the rate of pruning is now outpacing the rate of formation. [It does seem however that the dysfunction of the rate of pruning i.e. not enough ends up with consequences like schizo or asd {autism}]. There is another factoid that the rate of decline seems to stay relatively stable until you hit ~60 and then synapse related decline becomes much more noticeable and we start to think of synapse loss as exponential.
Now about new neurons after GW25 is a whole topic in of itself... heavily debated but I won't get into that history, the most accepted viewpoint is that it does exist in the hippocampus [other regions as well] (really cool work with c14 carbon dating from atomic bomb {2010} and perhaps less cool new sequencing methods give evidence {2025/2026}). Note estimates of how many are born are comparatively low-ish, 500-1000 neurons per day.
That begs another question however which is why and what do they do? Final interesting part is that when you stop the mouse hippocampus neurons from dividing, [unethical to do in humans :( ] distinct representations of experiences start to look similar and overlap. I also know if you ablate neurogenesis in mouse nasal cortex I think mice lose the ability to form new sensory sensations all together.
Disclaimer, the evidence for function of new born neurons is actually pretty low only a few studies have tried this so its no where close to accepted and thus far far from textbook standard so take it as you will.
Re: Aging brains blend memories together instead of just forgetting them
#125Earlier quoted context omitted.
I went under for 2 different surgeries. One of them I had post surgery complications. Years later, we needed to know the year I had the complications. I remembered the surgery, simply look it up and ta-da I got the date. Except, my wife thought it was the other surgery. And insisted. I was incredulous and angry. I literally nearly died during the complications. I think I would remember the surgery it was from. And it…
At the risk of sounding rude, ignorant, and insensitive... did you all get married young? That all sounds a bit narcissistic. Life is too short to be miserable, and we don't celebrate divorce enough. I'm happy for you both, and hope you are too. It's just as much of a milestone as any other big life event. I've never been married, but I have noticed some couples get sort of locked into the level of emotional maturity…
It was not a healthy relationship. And things slowly got worse and worse over time. I was too inexperienced to see the red flags.
Eventually after 19 years I wised up.
Resentment started building up and up and up.
Re: Aging brains blend memories together instead of just forgetting them
#126Earlier quoted context omitted.
> The brain does not have the Von Neumann bottleneck Obviously not, which is why I didn't say it did! However, if you want to identify where long-term memories are stored, then that is in the cortex, but it should go without saying that this doesn't make the cortex the storage component of a von-Neumann architecture! > No evidence exists though that the memory is encoded in one set of cells I'm not sure what you are…
> Obviously not, which is why I didn't say it did! But you sneak it into your assumptions on what a memory must be. > However, if you want to identify where long-term memories are stored And why do you assume there is a specific “where” for the memory? > then that is in the cortex There’s good deal of evidence disproving this in the way you’re stating this. The cortex is involved in sensing, and yes, the sensory info…
My theory was that memory had some form of static store, something molecular like methylation. I hadn't considered something dynamic/temporal like you describe.
Would delay line memory be a fair analogy? Information stored in a delay line memory never stays in one place. I think you are saying biological information is "stored" in the amplitude and phase of oscillations of our cells. Is that correct?
I'm still inclined to believe there is some form of static store, which would be required for inherited memories. Things like our (and many other mammals) ability to recognize emotions in others. Somehow our gametes encode what a happy, sad, or scared face looks like. I instincts as inherited memories.
Re: Aging brains blend memories together instead of just forgetting them
#127Earlier quoted context omitted.
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…
> Live with that. ;) Well, sure, it's a computer of sorts, although in the abstract sense of being able to perform computations so is our liver, so perhaps not a very useful concept. What I meant (as I assume you realize) was "not a von Neumann architecture computer", but I'd also fairly confidently assert that it's not a quantum computer either. Our ANN model of a neuron is obviously too simple (especially being a s…
> Well, sure, it's a computer of sorts
Mostly analog, with some threshold-triggered functions and lots of weighted adders and maybe multipliers.
> but how much else will matter remains to be seen!
Indeed, and the similarities between the brains we were born with and the brains we build is tantalizing. I'm really curious about the next chapters of this all.
Re: Aging brains blend memories together instead of just forgetting them
#128My dreams imprint stronger than reality. This has the unfortunate effect of sometimes recalling memories as real, when in fact it was all a dream.
Unless the dreams are the reality and the reality is the fake!
A less traveled road to a cool story would be that, while dreaming, you are experiencing unfiltered realities from many nearby timelines simultaneously (hence the fluidity of the reality of dreams, where things change from a moment to the next).
I recently had a very curious experience - my in-dream me recalled a memory from a past dream. It was a really strange feeling that definitely added to the "realism" of the dream.
Re: Aging brains blend memories together instead of just forgetting them
#129Being an "aging brain" myself I can totally relate to this. I've been a relatively obsessive photographer (i.e. visual diary) since digital cameras were practical, i.e. over 25 years now. 238K photos in the collection so far, and I can actually find things in it. And I've more than once found that an anecdote I've been telling has been incorrect, precisely in a "melded memories" kind of way. It happened at this sort…
Wait, so you're taking ~26 pictures every single day for the last 25 years?
On average, obviously. Any given day ranges from zero, to a couple hundred for especially interesting days. Also a huge blip when the kids were young. Runs of "zero" days end up being dark ages in long term memory. Sure, went to work, ate, slept etc. but nothing interesting. That's where the "at least one interesting picture for Mom" thing provided a baseline.
Re: Aging brains blend memories together instead of just forgetting them
#130Earlier quoted context omitted.
Some years ago, I heard a retired Lutheran priest ponder, in radio, about the concept of a prayer, and whether, as an edge case, an unborn child could be able to pray, with the child of that age having no understanding on the required concepts. This is apparently one of those questions that people ponder under the umbrella of philosophy of religion. His conclusion was that prayer was about harmonizing one's self with…
For a lot of people, I think religion provides this basis or promise of harmony with the world, in a simplified way that stipulates what you should or shouldn't do and how things work, and those people find comfort in having these clear "rules"; we want to be able to rely on our understanding of the world, so that we can act within it with confidence, or faith. Ultimately, the "god" that is present in many religions…
If "god" is synonymous with the absolute truth of how the universe works then it can't address moral issues at all, since you can't prove an "ought" like "people shouldn't stab people" from an "is" like "stabbing hurts people and may kill them". You need to add extra axioms like "hurting people ought to be minimized".
The universe (and its intrinsic functions) holds no special value for people or trees or life in general. The best we can say is that it seems to have a slight preference for matter over antimatter for some reason.
All our moral codes and social norms we live by are purely human invention, derived from things that happen to work to produce a somewhat functioning society.