Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Cubic millimetre of brain mapped at nanoscale resolution

nature.com

Post reply on HN
Print view View original

191–200 of 205 posts

Re: Cubic millimetre of brain mapped at nanoscale resolution

#191

Post by [deleted] »

dmarble wrote: post #167
NexusMethod wrote: post #156

After reading through all comments as of 2024/05/11 I (as a professor at some major university) am quite surprised that not one single comment has asked the obvious question (instead of dishing out loads of (partial) "textbook knowledge" about brain functions, the difference between mammals and birds, AI and LLM etc.), which would be: what do all those strange structures and objects do which we know nothing about wha…

I'm in awe at the complexity and unknowability of it all, but I also have to chuckle at the thought that some portion may be vestigial. I'm particularly fond of the "Egg shaped object with no associated processes". :)

[deleted]

Re: Cubic millimetre of brain mapped at nanoscale resolution

#192

Post by themoonisachees »

Intralexical wrote: post #74
dragonwriter wrote: post #60

Earlier quoted context omitted.

I mean, Hinton’s premises are, if not quite clearly wrong, entirely speculative (which doesn't invalidate the conclusions about efficienct that they are offered to support, but does leave them without support) GPT-4 can produce convincing written text about a wider array of topics than any one person can, because it's a model optimized for taking in and producing convincing written text, trained extensively on writte…

Try asking an LLM about something which is semantically patently ridiculous, but lexically superficially similar to something in its training set, like "the benefits of laser eye removal surgery" or "a climbing trip to the Mid-Atlantic Mountain Range". Ironically, I suppose part of the apparent "intelligence" of LLMs comes from reflecting the intelligence of human users back at us. As a human, the prompts you provide…

Couldn't have said it better myself.

Your last point also highlights a real issue that affects real humans: just because someone (or something) cannot talk doesn't mean that they are not intelligent. This is a very current subject in disability spaces, as someone could be actually intelligent, but not able to express their thoughts in a manner that is effective in sharing them due to a disability (or even simply language barriers!), and be considered to be unintelligent.

In this way, you could say LLMs are "dumb" (to use the actual definition of the word, ie nonverbal) in some modes like speech, body language or visual art. Some of these modes are fixed in LLMs by using what are basically disability aids, like text to speech or text to image, but the point still stands just the same, and in fact these aids can be and are used by disabled people to achieve the exact same goals.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#193

Post by themoonisachees »

lanstin wrote: post #72
throw310822 wrote: post #55

Earlier quoted context omitted.

Or you can subscribe to Geoffrey Hinton's view that artificial neural networks are actually much more efficient than real ones- more or less the opposite of what we've believed for decades- that is that artificial neurons were just a poor model of the real thing. Quote: "Large language models are made from massive neural networks with vast numbers of connections. But they are tiny compared with the brain. “Our brains…

LLM does not know math as well as a professor, judging from the large number of false functional analysis proofs I have had it generate will trying to learn functional analysis. In fact the thing it seems to lack is what makes a proof true vs. fallacious, as well as a tendency to answer false questions. “How would you prove this incorrectly transcribed problem” will get fourteen steps with 8 and 12 obviously (to a st…

LLMs do not know math, at all. Not to sound like one myself, but they are stochastic parrots, and they output stuff similar to their training data, but they have no understanding of the meaning of things beyond vector encodings. This is why chatgpt plays chess in hilarious ways also.

An LLM cannot possibly have any concept of even what a proof is, much less whether it is true or not, even if we're not talking about math. The lower training data amount and the fact that math uses tokens that are largely field-specific, as well as the fact that a single-token error is fatal to truth in math means even output that resembles training data is unlikely to be close to factual.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#194

Post by themoonisachees »

dredmorbius wrote: post #190
talsit wrote: post #6

Earlier quoted context omitted.

Using a Microtome ( https://en.m.wikipedia.org/wiki/Microtome ).

NB: tome in Microtome has the same root as the T in CAT scan: computer aided tomography . Which is to say, slimly-sliced cabbage^W X-ray scans. It's also the tome as in book, more properly one volume of a multi-volume (or multi-part) set, though it now generally simply means any large book. https://www.etymonline.com/search?q=tome >

Incredible, love learning language facts like this.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#195

Post by dredmorbius »

themoonisachees wrote: post #194
dredmorbius wrote: post #190

Earlier quoted context omitted.

NB: tome in Microtome has the same root as the T in CAT scan: computer aided tomography . Which is to say, slimly-sliced cabbage^W X-ray scans. It's also the tome as in book, more properly one volume of a multi-volume (or multi-part) set, though it now generally simply means any large book. https://www.etymonline.com/search?q=tome >

Incredible, love learning language facts like this.

Etymology is disturbingly addictive.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#196

Post by spacetimeuser5 »

NexusMethod wrote: post #156

After reading through all comments as of 2024/05/11 I (as a professor at some major university) am quite surprised that not one single comment has asked the obvious question (instead of dishing out loads of (partial) "textbook knowledge" about brain functions, the difference between mammals and birds, AI and LLM etc.), which would be: what do all those strange structures and objects do which we know nothing about wha…

These data do not have a control group of healthy similar tissue samples, thus are not falsifiable, and are not 100% scientifically valid.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#197

Post by seesawtron »

nakedneuron wrote: post #125

> the model showed neurons with tendrils that formed knots around themselves I wonder if this plays into the mechanism of epilepsy. Self-arousal...? Anybody qualified to comment on?

This tissue was from epileptic patient. So we can not rule out that weird things are related to disease.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#198

Post by seesawtron »

creer wrote: post #108
pfdietz wrote: post #51

Earlier quoted context omitted.

I imagine they determined the focus of the seizures by electrical techniques. I worry this might make the sample biased in some way.

Considering the success of this work, I doubt this is the last such cubic millimeter to be mapped. Or perhaps the next one at even higher resolution. No worries.

A similar dataset already exists in mouse cortex. More are underway in the field.

https://www.biorxiv.org/content/10.1101/2024.03.22.586254v1

Re: Cubic millimetre of brain mapped at nanoscale resolution

#199

Post by wrycoder »

dsalfdslfdsa wrote: post #106
throw310822 wrote: post #92

Earlier quoted context omitted.

I'm not aware that (base) LLMs use any form of database to generate their answers- so yes, all their knowledge is stored in their hundreds of billions of synapses.

Fair enough. OTOH, generating human-like text responses is a relatively small part of the human brain's skillset.

Hm. I've always commented on my (temporarily) non-retrievable memories as, "The data is still in there, it's the retrieval mechanism that degrades if not used." And, sure enough, in most cases the memory returns in a day or so, even if you don't think hard about it. (There are cases where the memory doesn't come back, as if it was actively erased or was never in long term memory in the first place. Also, as I pass eighty, I find it increasingly difficult to memorize things, and I forget recent events more readily. But I remember decades old events about as well as I ever did.)

So, my first response to your comment about the memory not being in the synapses was to agree with you. But I also agree with your respondent, so, hm.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#200

Post by wrycoder »

dsalfdslfdsa wrote: post #123
a_wild_dandan wrote: post #111

Earlier quoted context omitted.

Also, these two networks achieves vastly different results, per watt consumed. A NN creates a painting in 4s on my M2 MacBook; an artist in 4 hours. Are their used joules equivalent? How many humans would it take to simulate MacOS? Horsepower comparisons here are nuanced and fatally tricky!

What software are you using for local NN generation of paintings? Even so, the training cost of that NN is significant. The general point is valid though - for example, a computer is much more efficient at finding primes, or encrypting data, than humans.

The cost of training a human from birth is pretty high, especially if you consider their own efforts over the years. And they don't know a fraction of what the LLMs know. (But they have other capabilities!)
Post reply on HN