Plasticity and language in the anaesthetized human hippocampus
96 points
by hhs
8 hours ago
| 8 comments
| bcm.edu
| HN
https://www.nature.com/articles/s41586-026-10448-0
tgv
58 minutes ago
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This sounds odd to me:

> ... neural signals could predict upcoming words in a sentence. ... This kind of predictive coding is something we associate with being awake and attentive, yet it’s happening here in an unconscious state

In psycholinguistics, the assumption is, and always has been, that language processing is unconscious, a background process like visual object recognition. For starters, conscious attention is too slow by two orders of magnitude, and infants can process language, while presumably not yet (fully) conscious.

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slicktux
6 hours ago
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I sometimes ge the most complex logical dreams whilst going to sleep on a programming problem. The dreams are normal dreams but structured like a programming problem or logic…it’s like my brain is trying to dream normally but it’s also Fixated on programming logic so it subliminally incorporates it into dreams. Then I wake up and I feel like I’ve compiled the whole code in my head and did not rest.
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anyfoo
6 hours ago
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I haven't had this in a long time, except for on the (fortunately rare) occasion that I have a fever. Fever dreams are already hell, but if they're non-sensical programming/computer science fever dreams, they were extra hell.

I remember one particular one a few decades ago, where I was feverishly (pun intended) trying to achieve something with XML, only it being a fever dream, nothing of it made sense, so I was wracking my brain for nonsense those entire hours.

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chrisweekly
5 hours ago
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I've had similar experiences, and (having studied neuroscience as an undergrad and in casual / amateur research in the many years since) feel there's a lot of untapped potential to leverage in our hypnopompic and hypnogogic states (at the fuzzy boundaries of sleeping / wakefulness). Fascinating stuff.

(tangent) Also, please forgive my question which may seem impolite but I really want to know: why did you type "whilst" instead of "when" or "while"? Have you ever said the word "whilst" out loud, in a normal conversation? More letters, an extra (half)syllable, zero meaning or nuance added, I just don't get it. I wonder this every time I see it, mean no disrespect and would be grateful for a straightforward reply. (/tangent)

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spaghettifythis
5 hours ago
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Not op, but I often do say 'whilst' out loud. It feels more structured and certain than 'while', which feels floppier as a word.
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skinfaxi
4 hours ago
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It's to be used when the word that follows begins with a vowel sound.
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moi2388
1 hour ago
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Is it? Do you have a source for this? Afaik ‘while’ is often used in US English and ‘whilst’ in British English.
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finghin
44 minutes ago
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both are definitely used in modern British English, but whilst is strange to my ears as I grew up in Ireland
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slicktux
3 hours ago
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No offense taken; I do say it out loud during conversations ; at times. I find myself ‘saying’ it more in my head whilst having a stream of consciousness moment.

I find that I have two personalities and my writing/text personality is much more sagacious and better spoken (if that makes sense??)

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satvikpendem
3 hours ago
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Now try lucid dreaming those, it's amazing and brings me closer to Nolan's Inception than ever before. I even think I've had lucid dreams since before that movie came out as apparently he was directly influenced by lucid dreamers.
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QuaternionsBhop
6 hours ago
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This happens to me too. Often my dream plows forwards with unsound assumptions and I wake up believing something confusing.
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lukan
5 hours ago
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Well, maybe you did work on your problems in your sleep and did get less rest because of it, so the new insights you got the next day(s), the groundwork for it might have happened in your sleepwork.
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healthworker
6 hours ago
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This is strong evidence against LLMs experiencing qualia. (I know that that topic often gets people laughed out of the room but please don't jump on me for engaging in that debate. When we can collect evidence and be able to show it to people.)
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ordu
4 hours ago
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How did you jumped to qualia from consciousness? I can see how this is a strong evidence against LLM being conscious, but to my mind it doesn't imply in any way or form that they do not experience qualia.

Or... well, ok, maybe they can't experience if they are not conscious? I see how this can be argued, but I still do not agree. I'm sure qualia is created not by consciousness (I would notice if it was), and I'm sure it is created not for consciousness specifically, it must have some other uses too.

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satvikpendem
3 hours ago
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How can qualia be experienced if not from a conscious observer? It's the same question as asking if a tree falls in the woods with no one to hear or know about it.
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stevenhuang
4 hours ago
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No disagreements with what you said in your first paragraph.

> I'm sure qualia is created not by consciousness

Whether or not qualia is created by consciousness, I don't see how we necessarily can tell one way or the other. We don't exactly have great introspective tools to do such self analysis, not to mention what we think we feel is often illusory/not reflective of reality.

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ordu
3 hours ago
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Yeah, I think you are right. "The content of consciousness" and "consciousness" are different things, and I mixed them up, when writing that sentence. I can watch the content, but not other parts that may be producing it.

Moreover, thinking about it, I come to a conclusion, that if I cannot reflect on qualia creation, then it is a (weak) evidence for qualia created by consciousness. I suppose the consciousness is harder to reflect on than other things, hard to map it into states of the content of consciousness. Like, I can reflect on my vision and see some hints on how I get these wonderful pictures, despite it being definitely not consciousness, I can reflect on how I produce or decode language. And to my mind it is because consciousness was devised to reflect on these things, so I could report on my observations to others. But to reflect on itself is a wholly different matter.

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LoganDark
3 hours ago
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We can't even meaningfully prove that human beings have qualia
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finghin
42 minutes ago
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We can’t meaningfully deny humans have qualia, there would be too much baby and not enough bathwater.
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Geste
4 hours ago
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Go on, where is the evidence ? I am actually curious and open-minded about it.
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slopinthebag
1 hour ago
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The Chinese room argument suggests that it's impossible anyways.
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finghin
40 minutes ago
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I don’t disagree with the general point here but the attraction of that argument has surely drifted much in ~5y.

I’d be REALLY curious to see a survey of philosophy 2015 vs 2025 UG entrants on mind-brain connection intuitions

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naasking
4 hours ago
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I don't see how that follows. The brain could be experiencing all sorts of things while processing, but simply not record it, and so of course the person will have no recollection of experiencing anything.
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ordu
3 hours ago
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An anecdote to demonstrate the point.

I broke my leg recently. Shortly after that I've lost my consciousness. It was very painful, the body reacted with a lot of adrenaline, and after a several minutes when adrenaline was drained away my consciousness was drained too.

I experienced something like this several times, though not to the point of fainting. But this time was special in other way too: I had friends near me, they observed me through all the process and we could compare our observations later. It seems, that my memory stopped recording before I fainted. I was still operating to some extent, but I couldn't remember a thing. When asked something I grunted in answer. When one of my friends insisted that I stand up and come to a better place to sit down, I actually stand up and did several steps before stopping and slowly (and carefully) sank to the ground. (An interesting observation, my controls over my body were weakening, but I was still using them for what they worth. It fits with all other similar experiences: the limbs and all the muscles seem to be losing their strength, and it takes a lot of will to make them work.)

On the light of this, I'm very interested what proponents of the idea, that feelings need consciousness to work, would say about my half-unconscious state. Did I feel myself extremely bad at the time? Or maybe I didn't feel anything? My friends are sure that the former statement is true, but they may be mistaken by my outside looks. I personally don't remember. Up to some point I remember that I felt really bad, but the next thing I remember I look at the sky and I'm surprised by what I see (I was not in a place I expected to be). And at that moment I was pretty ok already, no more adrenaline issues, just my leg was aching.

Was I experiencing qualia is another interesting question. I'm pretty sure I was, but I'd like to hear an argument for the opposite.

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satvikpendem
3 hours ago
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Maybe it was a different part of your nervous system experiencing them, akin to a BIOS versus the operating system. The brain is a very complex and fractal thing, it is entirely possible that a more basal part of "you" took over for a very traumatic part of your life, very similar, but not exactly, to those with multiple personality disorder act.
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stupidgeek314
6 hours ago
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holy no sequitur batman!
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johnbarron
6 hours ago
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This is not new. Read Phantoms in the Brain

https://en.wikipedia.org/wiki/Phantoms_in_the_Brain

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mrsvanwinkle
5 hours ago
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awesome to see a VS Ramachandran rec on HN. normally it's the rare secondary rec after someone mentions Man Who Mistook His Wife For a Hat by Oliver Sacks.
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satvikpendem
3 hours ago
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Maybe I just know how it's like to be a bat.
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jdw64
5 hours ago
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If that mechanism can be activated, it may significantly compress the time required for education and learning.
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pstuart
6 hours ago
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I guess this makes sense -- a brain is gonna do brain stuff. The only difference is that we're not present to witness it.
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doginasuit
5 hours ago
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It's been understood for quite some time that we only experience a small part of brain activity. Unfortunately that small part is where everything useful happens.
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satvikpendem
3 hours ago
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No, definitely not. Our consciousness is honestly an afterthought, as the brain processes mountains of information that does not even get to out conscious level yet is arguably more useful than anything we primitive primates can think of.
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Kim_Bruning
4 hours ago
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Or is the small part the bit where the least useful stuff happens? ;-)

A bit more seriously, the brain actually uses a significant chunk of the body's energy budget (no matter how efficient it is relative to human made equipment). So evolutionarily, it doesn't make sense unless it's doing something exceptionally useful.

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avadodin
4 hours ago
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It's the part that makes everything useful happen but most of everything useful happens in unconscious parts of the brain and even outside of the brain.
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westurner
5 hours ago
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ScholarlyArticle: "Plasticity and language in the anaesthetized human hippocampus" (2026) https://www.nature.com/articles/s41586-026-10448-0

Sleep-learning https://en.wikipedia.org/wiki/Sleep-learning

Also, Sleep and learning https://en.wikipedia.org/wiki/Sleep_and_learning

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alexfromapex
6 hours ago
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I would think anesthesia, in specific doses, would only attenuate consciousness...if it stopped other processes your organs and nervous system would stop. I guess this confirms that.
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EA-3167
4 hours ago
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General anesthesia disrupts the ability of regions of the brain to network coherently. Individual regions might still be ticking along, but your experience of consciousness is a result of the network.
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