[HN Gopher] Neuroscientists discover molecular mechanism that al...
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Neuroscientists discover molecular mechanism that allows memories
to form (2020)
Author : andyxor
Score : 154 points
Date : 2021-04-06 07:26 UTC (15 hours ago)
(HTM) web link (news.mit.edu)
(TXT) w3m dump (news.mit.edu)
| imvetri wrote:
| Structure is the memory. Neuron cells got nothing to do with it.
|
| Slime mold has memory, and it doesn't have a neural network.
| ChainOfFools wrote:
| this seems excessively reductive. by this reasoning we should
| expect to find that removing neurons from the "structure" has
| no effect on its capacity for encoding memory.
|
| if one reduces "memory" to anything that exhibits sustained
| interplay between hysteresis and goal optimization then yes,
| neurons may lie below the level of explanation you wish to use,
| and could thus be substituted with some other signaling medium,
| but this is not the same as claiming they are not involved at
| all.
| iandanforth wrote:
| Please please don't take away from this that there are "memory
| cells" that "encode memories." The article is so badly written it
| seems to imply that. Memory is a _whole brain_ phenomenon, and
| memory formation involves connections being formed and lost
| constantly between all types of neurons everywhere in the brain.
| One small aspect of memory (episodic memory) relies more heavily
| on hippocampal neurons during consolidation, and a small portion
| of that process is what is being discussed here.
| api wrote:
| Proper title: "Neuroscientists discover one potential mechanism
| of memory formation and make a preliminary attempt to identify
| the most active regions where it occurs."
|
| Less click baity.
| Robotbeat wrote:
| So, isn't the nature of memory in the brain still understood
| pretty vaguely? The "memory is connections and involves the
| whole brain" is still kind of a hypothesis and less of a hard,
| empirically-validated theory, no? May still be the best idea we
| have, but from what I understand (which isn't much), it's not
| nearly that cut and dry and we don't really know enough to
| exclude a lot of the other models of memory formation.
| deepsun wrote:
| There's no single concept of nature that's understood
| completely. For example, there are a lot of things still
| understood pretty vaguely about milk. Or apples. So you can
| say that about pretty much anything.
| Robotbeat wrote:
| >There's no single concept of nature that's understood
| completely. For example, there are a lot of things still
| understood pretty vaguely about milk. Or apples. So you can
| say that about pretty much anything.
|
| But that is practically untrue (I'm not just saying there
| are corner cases, but that the main topic is still very
| poorly understood) and a cop-out.
|
| And yet I can speak concretely about a hydrogen atom. Or
| even photosynthesis. Or DNA.
|
| In DNA, there are 4 base pairs. We can see how that maps to
| RNA and how that in turn codes to amino acids. (and
| exceptions exist to these things, but we have a pretty
| strong grasp on it.) We can even try to fold the resulting
| Amino Acids into shapes, although it's computationally very
| difficult to do so. So data storage within a cell has some
| concrete understanding. Empirically validated and useful
| (this is how we were able to engineer the mRNA vaccines).
|
| Our knowledge of memory, our knowledge of data storage in
| the brain is far less concrete. And not just because it's
| not thought to be precisely molecular like DNA or RNA
| (although perhaps it could be!) but we have a poor grasp of
| even where, precisely, information is stored in the
| connections. Like, sure, you can say it's not stored in a
| particular location in 3D space, but there must be some
| transformation, some (non-euclidian) representation of the
| connections where memories CAN be located. Because our
| brains are capable of recalling memories on demand. But we
| have only a vague understanding of how that all occurs.
| It's very unlike DNA or RNA or whathaveyou in that our
| understanding is still primitive and vague.
| T-A wrote:
| https://en.wikipedia.org/wiki/Grandmother_cell
| Kliment wrote:
| Original article here (fuck paywalls) https://sci-
| hub.se/10.1038/s41593-020-00717-0
| andyxor wrote:
| If you're interested in memory at somewhat higher level of
| abstraction check out the recent work on "cognitive maps".
|
| It started decades ago with seminal work on place & grid cells in
| spatial navigation
| (https://www.nobelprize.org/prizes/medicine/2014/may-britt-mo...)
| which was later shown to be generalizable to multidimensional
| "concept spaces".
|
| It's probably the most exciting field in neuroscience right now,
| it also maps very nicely into mathematics of high-dimensional
| spaces:
|
| "Navigating cognition: Spatial codes for human thinking"
| https://science.sciencemag.org/content/362/6415/eaat6766.abs...
|
| "Organizing conceptual knowledge in humans with a gridlike code"
| https://science.sciencemag.org/content/352/6292/1464
|
| "The Hippocampus Encodes Distances in Multidimensional Feature
| Space"
| https://www.sciencedirect.com/science/article/pii/S096098221...
|
| "A non-spatial account of place and grid cells based on
| clustering models of concept learning"
| https://www.nature.com/articles/s41467-019-13760-8
|
| "A learned map for places and concepts in the human MTL"
| https://www.biorxiv.org/content/10.1101/2020.06.15.152504v1....
|
| "What Is a Cognitive Map? Organizing Knowledge for Flexible
| Behavior"
| https://www.sciencedirect.com/science/article/pii/S089662731...
|
| "A map of abstract relational knowledge in the human hippocampal-
| entorhinal cortex" https://elifesciences.org/articles/17086
|
| "Map-Like Representations of an Abstract Conceptual Space in the
| Human Brain"
| https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884611/
|
| "Knowledge Across Reference Frames: Cognitive Maps and Image
| Spaces"
| https://www.sciencedirect.com/science/article/pii/S136466132...
|
| "Concept formation as a computational cognitive process"
| https://www.sciencedirect.com/science/article/pii/S235215462...
|
| "Efficient and flexible representation of higher-dimensional
| cognitive variables with grid cells"
| https://journals.plos.org/ploscompbiol/article?id=10.1371/jo...
|
| "The cognitive map in humans: spatial navigation and beyond"
| https://www.nature.com/articles/nn.4656
|
| "A general model of hippocampal and dorsal striatal learning and
| decision making" https://www.pnas.org/content/117/49/31427.short
|
| "On the Integration of Space, Time, and Memory"
| https://www.sciencedirect.com/science/article/pii/S089662731...
| FranOntanaya wrote:
| I guess one interesting question is whether other kinds of
| chromatin elsewhere encode any information by favoring expression
| of certain genes over other.
| iovrthoughtthis wrote:
| this seems incredibly related
| https://en.m.wikipedia.org/wiki/Histone_code
|
| i'm not surprised that a mechanism like this is involved in
| memory storage/retrieval.
|
| im left with questions about the heritability of these epigenetic
| parts of memory.
| andelu wrote:
| Heritability? How? Remember that gamets (egg/sperm) are not
| affected by this, so passing these memories onto the next
| generation is not plausible.
| beowulfey wrote:
| this particular kind of interaction would not be transmissible.
| Some other mechanisms, such as DNA methylation or miRNA may be
| though.
| henearkr wrote:
| What's interesting is that there is a category of specific
| neurons (called engram neurons) in which this process of
| chromatin-based memory formation occurs.
|
| It would be really cool to know how these neurons are different,
| and how and when they differentiate.
| DangTruckBuddiy wrote:
| With only 45 comments of seven hours we can presume that these
| premises are bullshit. Case closed!
| leemailll wrote:
| big deal, if this is the mechanism, the mechanism of memory was
| discovered dozens of times in the 90s
|
| I hate institution's PR release hyperbole everything to the max.
|
| And the senior author of the paper has a few listed on PubPeer
| https://pubpeer.com/search?q=li-huei+tsai
| andelu wrote:
| I wonder what the significance of this mechanism vs long term
| potentiation (LTP) is. Any insights?
| Zebrakopf wrote:
| From the article it sounds like it may describe another level
| of reduction to LTP. So, rather than 'this mechanism vs. LTP'
| it offers a potential genetic mechanism that may explain the
| changes to neuronal growth during memory formation.
| Roark66 wrote:
| It is really cool we're getting (slightly) closer to the
| understanding how memories work.
|
| It is still basic research, but if I understand the significance
| of this correctly having a confirmation there are specific
| physical changes neurons undergo when forming some kinds of
| memories allows at least theoretically extraction of those
| memories from pieces of inactive tissue. As a layman in the
| subject I've been always very much interested how much of our
| personality and consciousness is "encoded" in the electro-
| chemical activity (software) vs how things are connected and
| formed together(hardware). The more of "us" is in the hardware
| the more likely someone in future will come up with a way to
| "scan" features of dead tissue to recover (in a simulation
| perhaps) the person lost to death.
|
| We're currently probably as far from that as a medieval
| battlefield "surgeon" from modern heart transplant, but at least
| we're moving in the right direction.
| cblconfederate wrote:
| If our current connectionist understanding of the brain is
| correct, then we should be able to recover a personality from a
| very detailed CT scan, and maybe in the future to revive it.
| (Personally, i d prefer that in a solar-powered ball that is
| shot out of the solar system in high velocity)
| hans1729 wrote:
| I'd argue that the line between software and hardware isn't as
| clear in neuro as someone with an IT background would like to
| think, specifically _because_ the electro-chemical activities
| going on are both, hard and soft, at the same time. This isn 't
| some abstract process running on a biological computer, the
| biological computer is the sum of the processes that constitute
| itself. (That's the fascinating thing about bio)
|
| To form a memory is something completely different than to
| store data in a db, as it involves lots and lots of encoding
| factors. If anything is actually stored, it's not the memory
| itself, but the perception at time T in relation to the
| expectations for T, i.e. a delta (think of the times when you
| listen to a song from the old days and it hurts, because the
| emotional connotation from back then doesn't match the current
| situation). Retrieving this delta would be meaningless unless
| you have the matching interpreter, the entire status machine.
| erikerikson wrote:
| I have a background in both. Both are implemented in physical
| mediums. The gating and current flow are similarly physical
| as are magnetic field changes on disk mediums. There is a
| greater diversity in the brain which uses field effects ala
| hormones, ion movement, transmitter diffusion, and direct
| electrical connection. The physical/informational duality is
| present in both so I would suggest that the building out of
| the hardware using the ambient materials (i.e. trophic
| factor) is the more specific difference you're looking for
| rather than the duality.
|
| You transition to a difference in encoding which is a
| significant but separate consideration. I think the thrust of
| your statement agrees with the science but quickly nice into
| speculation and undue specificity that to me reads as though
| you are declaring fact. Language and good communication are
| hard.
| d110af5ccf wrote:
| > The physical/informational duality is present in both
|
| A very important distinction is that a computer has clean
| separation between physical data representation (magnetic
| bits) and physical device implementation (transistors &
| etc). As an analogy to a biological system I'd suggest an
| FPGA running a self modifying program that's _also_
| reconfiguring the FPGA on the fly. No sane engineer would
| design such a system (I hope).
| andelu wrote:
| "Notably, in line with previous publications12,13,23, our data
| suggest that memory formation is largely an enhancer-driven
| phenomenon."
|
| This is very interesting, and for me a new take on memory
| formation. It seems to have the advantage over LTP that it can
| work as a conincidene detector over longer time-spans.
| WaltPurvis wrote:
| I experienced an episode of transient global amnesia [1] a couple
| of years ago. It lasted for 6-7 hours, during which I was
| transported to the hospital, but every 2-3 minutes I would ask
| anew "Why am I in the hospital?" -- having no memory at all of
| being there. I still have no clue what might have caused it. I
| mean, _scientists_ don 't have a clue what causes it, only a wide
| range of speculated causes, none of which really applied to me.
|
| Since there's no known way to prevent TGA, no treatment, and
| apparently no lasting damage, it has never (AFAIK) been
| researched, certainly not researched much, but it strikes me as
| the kind of thing that _should_ be studied. If scientists could
| figure out how memory formation is completely blocked in episodes
| of TGA, it seems like that would provide useful data about how
| memory formation normally works.
|
| [1] https://en.wikipedia.org/wiki/Transient_global_amnesia
| d110af5ccf wrote:
| > Since there's no known way to prevent TGA, no treatment, and
| apparently no lasting damage, it has never (AFAIK) been
| researched, certainly not researched much
|
| I suspect the issue may be the lack of a good biological model.
| I'd guess it would be a very attractive and obvious research
| target for anyone aiming to investigate memory formation and
| recall. However, systematic studies generally require a model
| system that can be reliably reproduced.
| sprafa wrote:
| Indeed, studying TGA would mean finding these people who have
| 2-8 hour episodes.
| d110af5ccf wrote:
| > finding these people
|
| Possibly, but I strongly suspect humans wouldn't be very
| good models in this case given how much we don't know about
| memory in general. Rather you'd want a robust non-human
| animal model of some sort, with a straightforward way of
| inducing TGA (or something that appeared to be
| substantially similar) on demand. Think rodent with
| optogenetic modifications or similar.
| haolez wrote:
| I've suffered a serious head injury when I was a teenager and
| my brain lost the feeling of time for two days. I knew,
| logically, that lunch happened before dinner, but I couldn't
| _perceive_ it as such. It's hard to explain. The brain is a
| complex machine.
| BiteCode_dev wrote:
| Maybe one day we'll have pills to have total recall for a few
| hours, wouldn't that be cool for exams and learning languages ? I
| much prefer that than a chip in my head which the silicon valley
| seems super keen on selling me.
| k__ wrote:
| Reminds me of the book "There is no Antimemetics Division"
| where they take mnestics so they don't forget entities with
| antimemetic properties.
| jcims wrote:
| My memory is generally terrible. One discovery that was
| alarming, encouraging and disturbing at the same time is that I
| do appear to have some form of nearly total recall buried in
| there somewhere.
|
| Unfortunately it only surfaces in one way. If I listen to a
| podcast while I'm doing something, then listen to that same
| podcast again within a week or so, I will have regular,
| intrusive visual recall of exactly what I was doing the last
| time I heard whatever passage the podcast I was listening to.
| The recall is synchronized down to the word with the podcast,
| and is vividly detailed and colorful and includes some
| sensation of feeling as well.
|
| It's weird and cool at the same time. One of these days I'd
| like to do an experiment where I videotape myself listening to
| the podcast, wait a week, then listen to it again and record
| myself describing what I see in my mind to test how accurate it
| is.
| hatch_q wrote:
| Reverse it? Watch video and check if you can remember the
| podcast?
| jcims wrote:
| That will be interesting! Will definitely try if i actually
| pull this together.
| temp0826 wrote:
| That's sort of fascinating- it reminds me of how the ancient
| romans used to memorize long epic poems etc (walking around
| and making visual/spatial associations, then recalling their
| travel to recite it later. I might be butchering that a bit
| but that's how I understood the method)
| ThalesX wrote:
| I think you might be referring to the Method of loci [0].
|
| [0] https://en.wikipedia.org/wiki/Method_of_loci
| victor106 wrote:
| This is cool. Will try it.
| jcims wrote:
| I never noticed or attempted to prime it. Just go listen to
| some episodes that you've listened to recently and see what
| happens. It's not like rolling a projector when you hit
| play, it'll fade in and out most likely.
| mrtksn wrote:
| Oh definitely, making one part of the brain work together
| with the other part will help me remember either of those
| when I do one ore the other at later time.
|
| For example, I occasionally play Pubg Mobile and while I do
| it I ikte listening to some podcasts on a topic I do work.
| When it comes to apply something that I learned from the
| podcast I will can have a recall on where exactly I was in
| the game when this particular topic was discussed.
| doitLP wrote:
| I have the same, but notice it more with audiobooks. An
| entire year can go by and I will get a flash of where I was
| at a precise moment in the book exactly as you describe.
|
| Something similar was as a teenager: I could remember
| when/where I learned or first heard a new word. Sadly that
| ability has been waning.
| 20after4 wrote:
| I've noticed a sort of similar thing, though not nearly as
| vivid as what you describe. What I find is that listening to
| a song will trigger very specific memories of the place, time
| and feelings that I was experiencing when I first listened to
| that song. Or if not the first time I heard a song it will be
| from when I was listening to it regularly because it was new
| to me at that time. When this happens it's always especially
| vivid and compelling memory recall that is unlike any other
| I've experienced.
| amelius wrote:
| Or a pill to erase specific parts of memory. You could see the
| same movie over and over again. In fact, you could cancel your
| Netflix subscription.
| zo1 wrote:
| You could A/B test with a single person!
| HPsquared wrote:
| Total recall would be quite bad, every little irrelevant detail
| would be stored.
| PicassoCTs wrote:
| Imagine having product related flash-backs, this is the
| advertisement of the future. Hackernews coloured menue bars,
| trigger a urge to buy Fanta.
|
| The power of the market compels your good idea to turn evil.
| quonn wrote:
| Wouldn't that just make these exams (more) pointless? Non
| scholae, sed vitae discimus ...
| rini17 wrote:
| Making the absurd "drill, exam, forget" process flawless? That
| would be so sad to see.
|
| Instead, the material+process should be adapted to support long
| term memory. We know how to do it, already have spaced
| repetition and mnemonics, sadly teachers mostly ignore them.
| cblconfederate wrote:
| I often wonder why universities post these press releases for the
| general public. Epigenetic modifications and memory is still
| basic research in early investigation, known to play a role in
| memory extinction and reconsolidation for example, but this is
| still too early research to make any concrete announcements that
| would have actionable information, esp. for the general public.
| j7ake wrote:
| Universities do research, and publications in major journals
| are the units of outcome. It is not surprising to put this on
| the university website because it is good exposure. The people
| who browse university websites are often other academics, so
| this is indeed an announcement to the broad scientific
| community and brings prestige to the university.
|
| This would be comparable to winning some scientific prizes,
| since they are accomplishments that are hard and competitive to
| achieve. Of course the general public does not care about which
| scientists win which prizes.
|
| This is all part of marketing to get broad exposure to the
| scientific community first, general public second.
| he0001 wrote:
| I believe it's for the same purpose why we are seeing this. To
| reach a larger public audience than just the people at the
| faculty. I mean there might be others that work with this that
| may never hear about it and miss out on something. If they know
| the same things, well then it was just x minutes of wasted
| time.
| cblconfederate wrote:
| you dont need a layman's explanation for that. This is
| addressed to the general audience, not to colleagues.
| ChainOfFools wrote:
| A classic illustration of the science news cycle:
|
| http://phdcomics.com/comics/archive/phd051809s.gif
|
| (sorry for plaintext URl, poating from phone and can't recall
| what the HN markup is for a link.)
| culopatin wrote:
| Because people need something to talk about and universities
| benefit from the publicity perhaps?
| cblconfederate wrote:
| well people don't know what they re talking about when it's
| about so specialized basic research. Universities do benefit
| from the publicity , but it feels like selling snake oil to
| naive people.
| bsenftner wrote:
| This announcement is for student candidates in the field,
| fellow professionals in the field, and the larger layman
| field of financing sources for the University.
| mattkrause wrote:
| It's not really meant for "naive people": nobody expects
| you to change your behavior as a result of this press
| release.
|
| The target audience is really science journalists on
| EurekaWire. They're hoping this press release will get
| picked up by a science writer for the New York Times or
| Scientific American, etc.
|
| A parallel goal is to demonstrate that the university is
| doing cutting edge work, which helps with student
| enrollment, fundraising, and recruitment. This also applies
| to the funders: they want to demonstrate that donations (or
| tax dollars) are being put to good use.
|
| If it directly catches the attention of science
| aficionados, that's mostly a bonus.
| foldr wrote:
| Neuroscience is way out of my wheelhouse, but my layman's
| understanding of this led me to believe that it could be some
| indication that Randy Gallistel has been on the right track:
| https://ruccs.rutgers.edu/images/LangilleGallistel.pdf
| stinky wrote:
| Does this mean that memories are discrete? As in stored as
| integers corresponding to the DNA code?
| andelu wrote:
| Original article here (paywalled):
| https://www.nature.com/articles/s41593-020-00717-0
| Kliment wrote:
| de-paywalled here: https://sci-
| hub.se/10.1038/s41593-020-00717-0
| supernova87a wrote:
| Just reading the abstract, is it me, or did the authors revel
| in spewing a ridiculous amount of jargon instead of using the
| opportunity to give a simple and clear statement of the
| fundamental finding of the work to a general scientific
| audience?
|
| _" The epigenome and three-dimensional (3D) genomic
| architecture are emerging as key factors in the dynamic
| regulation of different transcriptional programs required for
| neuronal functions. In this study, we used an activity-
| dependent tagging system in mice to determine the epigenetic
| state, 3D genome architecture and transcriptional landscape of
| engram cells over the lifespan of memory formation and recall.
| Our findings reveal that memory encoding leads to an epigenetic
| priming event, marked by increased accessibility of enhancers
| without the corresponding transcriptional changes. Memory
| consolidation subsequently results in spatial reorganization of
| large chromatin segments and promoter-enhancer interactions.
| Finally, with reactivation, engram neurons use a subset of de
| novo long-range interactions, where primed enhancers are
| brought in contact with their respective promoters to
| upregulate genes involved in local protein translation in
| synaptic compartments. Collectively, our work elucidates the
| comprehensive transcriptional and epigenomic landscape across
| the lifespan of memory formation and recall in the hippocampal
| engram ensemble."_
|
| I think back to a historical abstract:
|
| _" We wish to suggest a structure for the salt of deoxyribose
| nucleic acid (D.N.A.). This structure has novel features which
| are of considerable biological interest."_
| [deleted]
| throwanem wrote:
| It's you.
|
| This paper describes a process significantly more complex
| than the static molecular structure of DNA, and its abstract
| is written for the audience of researchers sharing the
| authors' own specialism. That's actually more useful than the
| converse, because it enables members of that audience quickly
| to evaluate the contents for relevance to their own work, in
| a way that would be much more difficult, perhaps impossible,
| were it written more concisely.
| d110af5ccf wrote:
| Seconding this. The abstract reads as incredibly well
| written and clear to me. The technical terms are relevant
| and appropriately used. I don't see anything I would
| describe as reveling in jargon, though I have definitely
| come across such papers before.
|
| I really don't understand why a non-expert would expect
| experts who are writing for _other experts_ to dumb things
| down for them. You might as well complain that a graduate
| level physics textbook isn 't readily understandable to
| someone with no mathematical background!
| beowulfey wrote:
| Nature journals have strict structural requirements for
| submitted abstracts.
|
| And unfortunately, because this was Nature Neuroscience, the
| intended audience is more specific, which is why you see more
| jargon there.
|
| Here is an extracted example from the latest issue of
| Science, for which the intended audience is more general:
|
| _Psychotic disorders such as schizophrenia impose enormous
| human, social, and economic burdens. The prognosis of
| psychotic disorders has not substantially improved over the
| past decades because our understanding of the underlying
| neurobiology has remained stagnant. Indeed, the subjective
| nature of hallucinations, a defining symptom of psychosis,
| presents an enduring challenge for their rigorous study in
| humans and translation to preclinical animal models. Here, we
| developed a cross-species computational psychiatry approach
| to directly relate human and rodent behavior and used this
| approach to study the neural basis of hallucination-like
| perception in mice._
|
| https://science.sciencemag.org/content/372/6537/eabf4740
|
| It's not a perfect comparison because Science abstracts are
| apparently much larger (this is just the Intro!) but it does
| convey my point about language.
| RhodoGSA wrote:
| Article does a pretty terrible job at explaining how memory's are
| formed, some bits even misleading.
|
| If you're interested in the biological basis of memory, I suggest
| reading 'In search of memory' by Eric Kandel. It's a biographic
| tale of Eric Kandel winning his nobel and along the way you learn
| a ton about how the brain works.
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