Along similar lines of interesting memory studies of simpler lifeforms, there is an article titled "These Decapitated Worms Regrow Old Memories Along with New Heads"[0] and study [1] which can alter your assumptions on how and where memories are stored and retrieved.
Also there were claims starting in the 50s where planarians were taught a maze or to respond to certain stimuli and then fed to other planarians and that the trait would sometimes transfer as well. I don't know if any of those studies were reproduced, thus the claims might be dubious, but it would be interesting if they were true.
> The acquisition of donor personality characteristics by recipients following heart transplantation is hypothesized to occur via the transfer of cellular memory
> There have been perplexing reports of organ transplant receivers claiming that they seem to have inherited the memory, experiences and emotions of their deceased donors, and which are causing quirky changes in their personality.
Yeah, find these highly dubious. A heart transplant is quite a traumatic event, both physically and emotionally, who knows what side effects the patients were experiencing after the procedure.
Over half of all neurotransmitters, including 80-95% of seratonin, originates in the gut. I wouldn't be surprised to hear a microbiome-based theory of personality but cellular memory is a new one to me
Possibly related: it turns out horizontal gene transfer is way more common in humans than we could expect and we really don't have a good explanation for how it's happening
Over half of all neurotransmitters originates in the gut, but the barrier preventing the entry of neurotransmitters into the brain is very effective in healthy individuals.
Signals from the gut to the brain arrive via the vagus nerve and probably also the other cranial nerves.
Interesting! The way I've often heard it is that "over half of neurotransmitters originate in the gut" — making it sound like it's talking about the neurotransmitters already at the brain. Do you have any citations that could clarify this?
Neurotransmitters are used all over the body. A lot is centralized in the brain, but the periphery also uses neurons and neurotransmitters.
Neurotransmitters in general don't particularly imply they're being used in the brain. Some neurotransmitters travel through the body, but a larger fraction are produced locally by a cell and intended only for close neighbors.
Same as "The Marked heart" / "Palpito" / "Herzschlag" on Netflix.
(For those about to watch it: the soul-vibing Neighbours-esque intro song is all part of the charm of this show. The shittier the intro, the more dramatic the needless melodrama is in contrast)
>Also there were claims starting in the 50s where planarians were taught a maze or to respond to certain stimuli and then fed to other planarians and that the trait would sometimes transfer as well
So superpowers were transferred when ate? Kirby devs were on to something.
Given this and the recent discovery that plants can pass down RNA through mycorrhizal networks and can recognize their own offspring, it seems plausible that memories can also be passed through mycorrhizal networks.
Not that crackpot imo. The essential difference between animals and fungi is that at some point one group decided to digest things internally with a stomach (animals) and another group decided to digest things externally with enzymes (fungi). This external relationship to nutrients might make fungi as an organism simply more modular and able to make more interesting symbiotic relationships. Acting not just as partners but organs of a larger body
Feynman quoted a Mr. Young for admirable rigorousness in maze-running experiments.
“Finding Mr Young”[1] identifies him as:
“Mr Young was probably Quin Fischer Curtis, in his theses published in 1931/1936, as part of John F. Shepard’s multi-decade research programme at the University of Michigan into ‘floor cues’, going well beyond just putting sand on the floor.”
That's typically through parasitic/grafting/symbiotic relationships, and even that takes a few half millienia of repeated symbiosis and selective pressures to take. What's being described here is much faster and much more immediate.
In micro-organisms, HGT happens in a very short timeframe. In fact, some soil fungi have been observed to somehow purposely increase their rates of HGT when put in a new and stressful environment. Borrowing genes from entire other domains of life like bacteria or archaea. Also study after study keeps showing that rates of HGT in complex multicellular species like fish[0][1] and even humans.[2] I'm not trying to be sensational (and generally agree it's likely not that relevant to the current discussion) but one thing that's clear from our consistent underestimation of the prevalence of HGT is that there's still a lot more to it than we currently understand
> alter your assumptions on how and where memories are stored and retrieved
I remember reading an anecdote about a baby who didn’t like being held by their father, who happened to beat the baby’s mother during pregnancy. No idea of the veracity of the story but something about it had me thinking similarly about “instincts” and where they come from. The meaning of the word does seem to be a lot like memories that are “passed on for generations”.
In late stage pregnancy babies in the womb can hear voices, and can often identify their father after birth by their voice immediately after birth. Violence often includes a lot of shouting, and physiological stress on the victim which would affect the baby. I’m guessing the baby learned to associate these.
n=1, but I sang to both my daughters in the womb (different songs) and after they were born singing "their" song would calm them down a lot faster. I don't think this is as much "instincts" as it is "very early experiences".
That’s one very specific type of risk, and a thankfully rare one. (That also appears to be a men’s rights activist site with an axe to grind on this subject).
… which suggests the opposite (but there’s not much in it).
In terms of broader risks, males commit a clear majority of violent offences and a vast majority of sexual offences.
This isn’t even just a human thing. Male primates (and mammals generally) exhibit more aggressive behavior than females. It’s probably a deep consequence of anisogamous sexual differentiation:
I don't know about people in biology in general, but it seems a whole new space of considerations.. topological communication, spread of information..
and if people are curious about other aspects of this, google peter reddien, he had a lab who focused on planaria regeneration too, and by playing with location and numbers of cuts they triggered some cascading patterns of regeneration (think https://www.explainxkcd.com/wiki/index.php/File:iso_paper_si... but with biological tissue and organs)
There’s another form of bacterial memory that is actually part of their immune system protecting against phages (viruses that attack bacteria).
The bacteria cut up the phage genome when they’re first attacked and (if they survive) store pieces in their own genome. Then when they detect the phage genes again they produce anti-phage defenses.
The system is called “clustered regularly interspaced short palindromic repeats”. It’s also known as CRISPR (better known for other work :)
I find it interesting how the literal antivirus mechanism used by those bacteria resemble antivirus software: have a repository of virus-code signatures that are checked against.
How else would you build such a system? It's probably easier than evolving a way to execute DNA/RNA in a sandbox or heuristically evaluating it. Life already had a reliable, extendable, self managing database system, so easier to repurpose that!
I wish there was more bio stuff on HN in general. Or that there was an HN for bio. (There is https://biostars.org , which is not at all really the same thing, more like a help forum).
Yep me too. There is also a discord server “biocord” which seems nice, but for some reason I am just unable to use discord. I don’t enjoy hanging there as much as on regular news aggregators as HN and Reddit.
I was also musing about making one myself using lobste.rs GitHub. But I never looked into it much.
Researchers discover a single dimension of measurement of iron--in low, "balanced," and high levels of concentration--persist behavior for several generations, disappearing by the seventh.
“These iron memories persist for at least four generations and disappear by the seventh generation.”
Make note that for example “when well fed, E. coli bacteria divide once every 20 minutes”[1], making that iron memory last for 80 to 140 minutes. Though that may still be longer than it takes them to discard a plasmid (genetic “loose change” on e.g. immunity resistance) when competing for reproductive speed.
1: Nick Lane, “Power, Sex, Suicide. Mitochondria and the meaning of life”, 2nd ed., 2018, p. 175
That type of plasticity is important for the survival of the species ( if the memories are important enough, then the later generations would have used it and it will probably remain)
Makes me wonder if there is a chemical mechanism by which humans pass information to each other as well, to combat an infection. If one human develops an ability to combat and infection to a novel virus, is there a mechanism by which antibody information is shared to other people. Infections eventually always fizzle out in the end.
In times of war and stress, how a society can come together and work in unison to defeat the threat. It seems like there's more to it than patriotism. Why should one individuals be willing to die for the benefit of others...Very often young man, who have not yet reproduced. Seems like an evolutionary dead end behaviour. Is there some Psycho/chemical mechanism by which its triggered.
The way so many people were scared of covid, that fear spread and like a virus infected the society.
Children of Time would be a closer match in terms of the ingestible knowledge transfer. Also, siderant: the rest of the series is not as great. I'd recommend new readers to try the first book (Time), and then maybe skim through the second (Ruin), and ignore the third (Memory).
Having just wrapped up Memory I found Time to be great. I thought Ruin was a slog, although I did love it at first. It was just a bad copy of the first. And while I thought the ending was telegraphed too much, I did enjoy how Memory was very different.
Came across a thread on Reddit recently about these three and many people made the point that Ruin & Memory are so different from each other in terms of sequels that which is the "good one" is a polarizing discussion.
My hope is that the brain is basically just a "consciousness" receiver and does not create it. Brain damage results in bad reception, people with schizophrenia receive signals not intended for them, people with alien hand syndrome have their brain split into several receivers and so on.
If that were the case, the body (including the brain) could die but the consciousness could continue to exist.
> That's what the religious and philosophical concept of a soul is.
Yes, I hope that it exists but it clashes with research that shows that brain damage can change a persons behavior and personality. So this take tries to combine both concepts.
I have no idea how the signals are transmitted but I believe there is some room for transmission mechanisms we have not discovered or understood yet.
And what if this system was used in the animal world for instant danger recognition etc. we as humans don't need that anymore, because we always grow up in a fast changing environment, where that kind of knowledge is almost obsolete.
I think we will find more examples countering our modern idea of discrete organisms separated across generations.
Consider again the glider translated across space time. Is it the same glider after 1,2,10 generations in time?
I always found it curious the ancient archons had rulerships which kept continuity in nominative identity across individuals for several generations. The social practice continues with the first, the second, III, IV etc.
Then you get examples like Marcus Aurelius -> Commodus, betraying all genetic and epigenetic reason alike. The apple doesn't fall far from the tree, except when it does.
but epigenetics usually stores information over much shorter timescales than generations. For example, cellular identity is stored epigenetically - whether a cell is a neuron or a white blood cell.
I often wonder if my Irish ancestors genes passed on trauma through my family to me. With 900 years of invasion, war, famine, and strife you'd think something like that would be passed on.
Huh? The article is able to summarize in one sentence what he thinks epigenetics is not, but is not able to summarize what it actually is. The post is clearly designed to make the reader feel like they are smarter than some other tribe, who don't believe that observations have molecular underpinnings. The Post-it notes analogy is also highly inaccurate and adds nothing.
Epigenetics is one way that cells have of turning on and off the genes that are expressed. The same way that you can 'comment' a piece of code out using some special flags.
What is special about it is that it turns out that your mom's experience during pregnancy (and your experience during development) can affect which genes are turned on and off in your cells.
The classic example of this is that children of starving mothers such as during the holocaust, or during other famines, often went on to be overweight, because they were conditioned to be in 'starvation mode' so the genes for uptake of nutrients were more turned on, or the genes for decreasing wastefulness were turned off.
It doesn't take much imagination to see how some of these things could reinforce each other, or alternate, over multiple generations.
There's a lot of sloppy usage of the term 'memory' to describe something that's more like a 'consequence'.
If you cut a tree, it will heal, and then decades later the effect of the cut will still be influencing the how the tree grows around the scar. But that's doesn't mean the tree 'remembers' the cut.
I don't think you should use the term for anything that doesn't have a consciousness, and only if the memory is something that is directly accessible to the conscious mind (via introspection, for instance), not indirectly via senses. Feeling a sore ankle is not a memory of an injury. Inheriting high lead levels in your blood from your mother is not a memory of lead exposure.
Also there were claims starting in the 50s where planarians were taught a maze or to respond to certain stimuli and then fed to other planarians and that the trait would sometimes transfer as well. I don't know if any of those studies were reproduced, thus the claims might be dubious, but it would be interesting if they were true.
[0] https://www.smithsonianmag.com/science-nature/these-decapita...
[1] https://pubmed.ncbi.nlm.nih.gov/13881412/