
Memory transfer between snails challenges view of how brain remembers - laurex
https://www.statnews.com/2018/05/14/memory-transfer-between-snails-challenges-standard-theory/
======
otp124
> Glanzman’s experiments — ... — involved giving mild electrical shocks to the
> marine snail Aplysia californica. Shocked snails learn to withdraw their
> delicate siphons and gills for nearly a minute as a defense when they
> subsequently receive a weak touch; snails that have not been shocked
> withdraw only briefly.

> Ryan knows Glanzman and trusts his work. He said he believes the data in the
> new paper. But he doesn’t think the behavior of the snails, or the cells,
> proves that RNA is transferring memories. He said he doesn’t understand how
> RNA, which works on a time scale of minutes to hours, could be causing
> memory recall that is almost instantaneous, or how RNA could connect
> numerous parts of the brain, like the auditory and visual systems, that are
> involved in more complex memories.

It sounds less like the standard definition of "memory", and more like RNA
stores/caches the response mechanism of a pain receptor. Thoughts on that
interpretation (I'm a layman on these subjects)?

~~~
obelix_
Its not just caching. This stuff seems to survive generations too by some as
yet unknown magic. Google "inherited PTSD".

~~~
ghostcluster
There is also a lot of activism masquerading as science in the field of
epigenetics, enough so that the journal Cell issued a warning about it:
[https://www.cell.com/cell/fulltext/S0092-8674(14)00286-4](https://www.cell.com/cell/fulltext/S0092-8674\(14\)00286-4)

~~~
tim333
There have been interesting animal experiments which perhaps avoid that eg

>Perhaps the most intriguing animal paper so far is a study published online
in the winter of 2013 that appeared to show that fear memories can be
inherited. Researchers from Emory University trained male mice to associate an
odor with an electrical shock, so that they would get startled simply by
smelling the odor by itself. Surprisingly, the scientists found that the smell
also startled the next two generations of mice.
[https://www.vox.com/2014/8/18/5927269/epigenetics-
definition...](https://www.vox.com/2014/8/18/5927269/epigenetics-definition-
cancer-diet-explained-inheritance-DNA-methylation)

~~~
phkahler
Did they rule out learning the behavior from the parent mice?

~~~
klmr
Yes, by raising pups with surrogate parents. However, the study was criticised
for other reasons (lack of statistical power, no explanatory mechanism) and,
in the intervening years, nobody has successfully replicated this experiment.

------
etatoby
The larger hyphothesis, if I understand correctly, is that RNA (and possibly
DNA?) is the seat of long-term memory and has some hereditary or otherwise
physically transferable component, while synapses would be our short-term
memory, as well as the expression or "cache" of the former.

This, as well as the worm-eating-worm-acquires-its-memory research, if true (a
big if) would vindicate so many theories, findings, and "magic" traditions
from around the world.

From Carl Jung's Collective Unconscious:
[https://en.wikipedia.org/wiki/Collective_unconscious](https://en.wikipedia.org/wiki/Collective_unconscious)
to many old cultural traditions of eating certain animal/human parts in order
to acquire their psychological properties such as courage.

I, for one, am looking forward to my injections of foreign languages and
musical instrument playing.

~~~
csomar
> This, as well as the worm-eating-worm-acquires-its-memory research, if true
> (a big if) would vindicate so many theories, findings, and "magic"
> traditions from around the world.

We don't have the same digestive metabolism as worms. I don't think the RNA is
going to make it from your stomach to your brain.

~~~
beobab
I don't think so either, but that's not science. I haven't checked, and
apparently neither has anyone else. _yet_

Further study is required. Facts must be established.

~~~
csomar
I mean if the RNA is going to dissolve in the stomach acid. Then there is no
way it is going to make it to the brain? And does the RNA transfer through
blood on its own? That's science.

The only possible explanation is that they picked up something else along RNA
that does affect memory and they are not aware of it.

~~~
manmal
I'm by no means educated about ways how RNA could get from food into your own
cells, but saying "RNA is dissolved by stomach acid" is a bit too easy. HCl
peaks only after a big meal with protein, and some people generally have low
stomach acid. Then there's the mucosa of the mouth and esophagus, through
which some food is absorbed before it even hits the digestive organs (even
bypassing the liver AFAIK). It might still get dissolved as soon as it hits
your bloodstream, or destroyed by antibodies, etc..

~~~
klmr
> some people generally have low stomach acid

Not to the extent that you (and many others) believe. The stomach is _always_
very acidic (pH 1–3), and this acidity is tightly regulated. Contrary to what
you’ve said, the pH is raised (and hence acidity lowered) when consuming food
(because HCl is used up in the digestive process). That said, much of the
digestion of RNAs happens through enzymes, not acid, so the point is moot.
It’s known that the human GI tract is highly efficient in digesting
oligonucleotides. Very little (and of that, only small fragments) has a chance
of being taken up.

------
blixt
Would this be similar to past studies[1][2] in how stimuli responses (e.g.,
fear to smell) can be inherited between generations?

The question is if we can ever transfer complex structured memories
(knowledge, past experiences) or if these transferable memories are limited to
basic emotional responses to specific signals?

I thought more complex memories were spread across many cells in the brain, in
a seemingly random structure when compared to another brain, making transfer
between brains incompatible.

[1] Worms:
[https://www.cell.com/cell/fulltext/S0092-8674(16)30207-0](https://www.cell.com/cell/fulltext/S0092-8674\(16\)30207-0)

[2] Mice:
[https://www.nature.com/articles/nn.3594.epdf?referrer_access...](https://www.nature.com/articles/nn.3594.epdf?referrer_access_token=13Y364MbUlYxwFlwbk8OuNRgN0jAjWel9jnR3ZoTv0MLhU4y4LZkONbbyIJwg8aPE0a1CCLmPmXJKFoyJaXxxaLY7RGhRQ9FdNDfwJ4apxIigJuQ54uRTkEl2Q2P0XKxvMb54h0QK8VvqSlDqBdgJPNXAyiH0jwIDJmBbsDXHWgHUVeWTevx9KEAco7GZSPrAdsfyhHXLGtF0JCacqmyIE8pcR9shg0hKG_RRrq6PMC9IY6yGVHeqMwq9_RvONKg&tracking_referrer=www.scientificamerican.com)

------
reilly3000
I wonder if environmentally ambient RNA could impact gene expression in
humans. RNA directly impacts gene expression:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612776/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612776/)

Say we swap some bacteria by using the same public restroom paper towel
dispenser. Your bacteria happens to carry some tragic memory of stress encoded
into some miRNA that formed when traveling to somewhere with very cold
temperatures. Certainly gene expression wouldn't be affected by a small
bacteria colony, but maybe if there was repeated exposure, every day in the
same place or with the same people, would I think twice about visiting Alaska?

I have observed how places like cities tend to affect people's 'look' in semi-
coordinated ways. How spending sustained time with a group of friends really
does change a person in subtle ways. Is there any way that ambient miRNA could
be a part of that process? Is there a way we can be sure that it isn't a
factor?

~~~
tim333
It's going to be hard for enough RNA to do anything to get in to your nervous
system from the towel dispenser. I'd put peoples looks changing that way down
to peer pressure and the like.

------
rejectedalot
It says that the snails retracted only briefly as a baseline, but learned to
retract for longer periods of time to avoid the jarring electrical stimuli.
I’m totally unfamiliar with this stuff, but it seems to me that injecting a
snail with RNA would also be a jarring stimulus. Therefore, wouldn’t it be
learning from the injection itself to remain in its shell for longer at a sign
of human touch?

~~~
eastophe
They injected the other snails with control RNA from snails which were not
subject to the shocks. In other words, they did control for this.

~~~
rejectedalot
I missed that - thank you for clearing this up!

~~~
mckenna
may be the control injection doesn't hurt as much as the rna injection?

~~~
ben_w
Control was also RNA, but _from_ unschocked snail.

------
ChuckMcM
I suppose we could call this effect "snail mail" :-)

More seriously though, while I understand the basic method they used for their
experiment, where is the theory about how the brain can catalyze the RNA into
understanding in millisecond times rather than days.

Or is it perhaps an epigenetic marker that signals "danger" ala the learned
muscle memory 'flex' from negative stimulus?

~~~
AgentME
>where is the theory about how the brain can catalyze the RNA into
understanding in millisecond times rather than days.

Maybe the brain often serializes memories from neurons into RNA and vice versa
often in order to replicate the memories throughout the brain. The RNA
injection caused some memories to be deserialized into the snail's neurons,
and the memory now in the neurons is what is affecting the snail's reaction.

------
barrkel
Let's not forget that it's also perfectly possible to have multiple mechanisms
for remembering things; there seems to be a false dichotomy being presented
here, either RNA or synaptic strength or synaptic topology. There are
different modes of memory too: the way you remember something as muscle
memory, vs short term memory, vs associative memory, etc.

~~~
slfnflctd
The possibility that different types of memories are stored in varying places
or ways based on unknown criteria is highly intriguing. If there is more than
one way to store/trigger a memory, that means a larger 'attack surface', and
therefore the process should be easier to hack.

------
omtinez
Maybe someone can take a second look at the paper. I couldn't find the
published version, just a manuscript[1] (kudos to the authors for making it
available under CC license). But... The only reference I could find about the
sample size says:

> "To prepare a single RNA injection, the pleural-pedal and abdominal ganglia
> were removed from 4-5 sensitization-trained animals—or from 4-5 untrained
> controls—immediately after the 48-h posttest"

4-5??? I really hope that I'm missing something here, otherwise I find truly
depressing how low the bar is for scientific journals.

[1]
[http://www.eneuro.org/content/eneuro/early/2018/05/14/ENEURO...](http://www.eneuro.org/content/eneuro/early/2018/05/14/ENEURO.0038-18.2018.full.pdf)

~~~
klmr
Figure legend 1D says: “Control RNA (5.4 ± 3.9 s, n = 7) and Trained RNA (38.0
± 4.6 s, n = 7)”

That’s a relatively low n but it might be sufficient. However, they don’t
explain how the number was reduced from ~30 donor animals to 7 test animals.
This might be entirely reasonable though (I know nothing about working with
Aplysia).

------
loa-in-backup
Transfer of fluid in fluid based capacitors at different level of charche
would basically also exchange circuit response times (in specific cases) so
I'm not too keen on making ut memory transfer. What if they transfered a snail
equivalent of cortisol ("stress hormone").

~~~
John_KZ
This was my first though too. Something happened, but it was not memory
transfer.

However RNA and biological indicators like hormones could (and probably do)
have a big effect on learning, in terms of how fast we learn, how aware to be,
feedback mechanisms, triggering long-term memory formation etc.

The idea of storing memories in genetic materia has been really popular for a
long time, but imo this is mostly due to either hope/belief for immortality
and romantic trans-generational memory transfer, or new age trends.

Of course it's not impossible, but it's very unlikely.

------
jonmc12
I was surprised to find so many studies regarding the relationship between
long-term memory, an enzyme (PARP-1, usually associated with DNA repair and
inflammation), and RNA. Seems relevant to Glanzman's research, but not cited.

In 2004 the enzyme PARP-1 was linked to long-term memory in Aplysia[1]. In
2009 another study claimed that PARP-1 was also required long-term memory in
Mammals[2]:

"Previous results linked the activation of PARP‐1 with long‐term memory
formation during learning in the marine mollusk Aplysia (Science 2004,
304:1820–1822).. Mice were tested in two learning paradigms, object
recognition and fear conditioning.. These findings implicate PARP‐1 activation
in molecular processes underlying long‐term memory formation during learning."

Another study of mice "demonstrated that augmentation of the stability of pro-
inflammatory mediator mRNAs presenting a regulatory mechanism of PARP1 in gene
expression at the post-transcriptional level".[3]

[1]
[http://science.sciencemag.org/content/304/5678/1820](http://science.sciencemag.org/content/304/5678/1820)
[2]
[https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1471-4159....](https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1471-4159.2009.06296.x)
[3]
[https://www.nature.com/articles/ncomms14632](https://www.nature.com/articles/ncomms14632)

------
daemonk
I think this was proposed back in the 60s with flatworms. There are some
recent experiments, again with flatworms, where they studied this.

Flatworms can regenerate heads. So they trained a flatworm to avoid a certain
type of light and cut the head off and allowed the tail to regenerate back a
new head. I think they claimed that the newly regenerated animal exhibit the
same behavior.

~~~
otoburb
>> _I think they claimed that the newly regenerated animal exhibit the same
behavior._

As directly referenced in the article, flatworm experimenters (James McConnell
in the 50's and 60's, and Michael Levin in 2015[1]) definitely claimed
regenerated flatworms exhibited the same behaviour.

[1] [https://www.theverge.com/2015/3/18/8225321/memory-
research-f...](https://www.theverge.com/2015/3/18/8225321/memory-research-
flatworm-cannibalism-james-mcconnell-michael-levin)

------
z3t4
It would be interesting to see a "diff" on the injection samples. With brute
forcing we could figure out how to program these sequences. Biological robot
snails!

~~~
klmr
That’s probably the next step (the authors raise the question of the identity
of the implicated RNA). Transcriptome profiling (which this is) has become
extremely routine recently. In fact, it’s highly unorthodox that this analysis
isn’t already part of the original paper (to clarify: it’s completely fine,
but quite unusual, to leave it as a follow-up study).

------
tneely
> It is generally accepted that long-term memory (LTM) is encoded as
> alterations in synaptic strength.

> RNA from a trained animal might be capable of producing learning-like
> behavioral change in an untrained animal.

Why did the author jump to the conclusion that RNA == LTM, when that RNA is
most likely just the driver for modulating synaptic strength? Whatever RNA
they extracted could easily just encode for various synaptic proteins.

~~~
vivekd
But wouldn't that still inevitability lead to the conclusion that rna is where
memories are stored and synaptic strength is just how memory gets expressed in
a way our brains can interact with.

------
fhayde
Maybe there's a transitive relationship between the environment before and
during transcription and the resulting RNA that in turn can affect its
environment. It would be difficult to identify in vivo because the environment
is already synchronized with the changes that may have been introduced from
the RNA, but in vitro maybe the effects of the altered RNA would become
apparent in an unmodified environment. Vice versa, if you could measure enough
samples of RNA from the same organism and source DNA I wonder if there'd be a
quantifiable difference when the environment was subject to the same sort of
changes that occur when memories are formed and an unmodified environment.

Really cool research!

------
williamxd3
So synapses are like a fast cache for memory stored in neurons nucleus?

~~~
mattnewton
Maybe. Maybe there was a problem or it will fail to replicate.

------
ThoAppelsin
Finally a childhood dream of the many can be established through this alleged
innovation: Learning math, physics, etc. through simple injection, information
pills, etc.

~~~
baalimago
Not sure how good this would be, deviations in learning creates further
developments in the fields. A child prodigy's idea of some odd physics
occurrence might one day grow into some completely new field of science.

I suppose I'm a memory conservative, I think I'll prefer the good old way, no
matter how cool that scene from the Matrix is

------
transfire
Interestingly, L. Ron Hubbard put forth the notion of cellular memory a long
time ago -- it is part of the premise of Dianetics. I think Gene Roddenberry
may have believed this too. I recall an early Star Trek NG episode where Data
told Geordi that's how human memory works, contrasting it to how his
positronic brain worked.

------
nickpsecurity
A lot of creatures reduce contact with something that just caused them a lot
of pain. I'd have asked if they ruled out whether the snails also withdraw a
bit after someone stabbed them with a needle. The subsequent test on Petri
dishes lends more credence to the theory, though, that the reaction is stored
and moving.

------
dschuetz
> “It’s as if we transferred a memory,” Glanzman said.

No, sorry. They did not transfer "memory", they transferred some specific RNA
which modulates some specific neuron activity. "Memory transfer" is a gross
misinterpretation of what they actually did there. Ugh.

------
helpfulanon
I know this will be an unpopular comment, but I've had a long-held theory that
past lives / reincarnation is a real phenomenon with a biological mechanism
that is as-yet unknown.

The theory being that trauma at time of death is somehow encrypted for the
next generation and passed on shortly after death, particularly if a corpse
enters the water or food supply.

The basis for this is a little embarrassing.. I had memories of being a bridge
engineer, frequent dreams of falling off a very specific truss bridge in my
head in childhood. To this day I'm terrified of certain types of truss
bridges, which are coincidentally quite common upriver of where my parents
lived when I was born, and where our water came from.

This theory would also explain why river burial is commonly associated with
reincarnation. Committing the tissue of a deceased person into a community
water supply would increase transfer of memory.

~~~
meowface
It doesn't seem physically impossible, but this would mean "past lives" can
only be from your direct ancestors.

But regardless, there's no evidence to support it and even this snail
experiment is a far cry from proving memories can even be transferred to
humans, let alone inherited.

------
csomar
I think, on the positive side, it'll make people reconsider that genetics and
race affect intelligence (and maybe gender?). We are too stubborn and
politically correct to discuss it. I kinda think it is true because my dog (a
german shepherd) is definitively a lot smarter and dexterous than the other
"normal" dogs. Hopefully, we'll be able to inject the intelligence DNA and
everyone can get a fair share of intelligence.

> He said he doesn’t understand how RNA, which works on a time scale of
> minutes to hours, could be causing memory recall that is almost
> instantaneous, or how RNA could connect numerous parts of the brain, like
> the auditory and visual systems, that are involved in more complex memories.

I was puzzled by that too. Also, it is not like they go pick a fork and select
the RNA. I wonder if they "picked up" something else along the way?

~~~
crummy
Isn't it likely that training has a significant effect on the apparent
"intelligence" of different dogs?

~~~
csomar
No. The german shepherd picks up very fast comparing to other dogs. It also
has dexterity. My dog figured out how to open various door by just watching us
come and go. The opening mechanism required some dexterity and manipulation.
No other dogs did that before.

------
magicalhippo
The RNA can turn off and on production of proteins no? If so, then surely the
ratio of proteins can affect the touch response sensitivity?

After all, it's not like he transferred memory of a complex maze.

------
baalimago
“It’s pretty shocking,” said Dr. Todd Sacktor, and giggled internally

------
intrasight
My guess is that their RNA solution also contained neurotransmitters

~~~
klmr
Even if: neurotransmitters are _extremely_ short-lived, and almost completely
unspecific: they’re either generally excitatory or inhibitory, they don’t
encode complex messages. They experimental setup sufficiently controls for
that due to the duration of the wait between the RNA injection and the
stimulus exposure.

~~~
intrasight
"neurotransmitters are extremely short-lived, and almost completely
unspecific"

That's the assumption that I think needs to be further validated.

------
jghjg
offtopic but, I find this "magazines" that use to appear on HN interesting

Which ones do you guys recommend and what's the best way to be subscribed to
them?

------
beached_whale
I wonder how this relates to Slime Molds. There was a Science Friday segment
on them and, if I remember correctly, they showed memory and memory transfer
too.

------
vivekd
layperson's question:

Since rna is gets information from the dna and is involved in the expression
and regulating of genes, does this mean that memory somehow becomes encoded in
our genes?

------
roywiggins
I for one welcome our new hive mind snail overlords.

~~~
dotancohen
So sad to know that this will be downvoted to oblivion. I would like to
subscribe...

~~~
pbhjpbhj
But /. still flourishes on hot-grits and such, so don't be sad, just go there.
Not all communities need [devolve] to be the same.

