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this is a terrible list of 'brain facts'. they're not interesting or constructive to a larger understanding, and analogizing the cerebellum to a GPU is naive an

this is a terrible list of 'brain facts'. they're not interesting or constructive to a larger understanding, and analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. working neuroscientist don't think about consciousness, we look at neurobiology, develop experimental techniques to allow imaging of ever larger numbers of neurons, try to understand how the brain computes. I don't see how one could boil down the staggering complexity of the field in the one-bite popsci factoids that leave a layperson with any useful model of the brain. People certainly try though (ahem, Andrew Huberman...). Here are some facts though: you have some neurons, they do things sometimes. we have some vague ideas about what different bits of brain do in very specific context. we have absolutely no idea how it all fits together, and are decades away from such an understanding. the fruit fly visual cortex, which is several orders of magnitude smaller than mammalian cortex, has been exhaustively studied for 40+ years, and we are only recently starting to build a circuit level model of the computation in the first layers. Here is your fact: brains are the most complex objects in the known universe

SemanticStrengh 4y ago
What an absurd dismissal. > they're not interesting You have a failure of appreciation, yet those facts are potent and surprising. >constructive to a larger understanding Yes they are not, who cares? Teaching neuroscience is of course a non-goal of my comment, what an irrelevant thing to say.. >analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. Exactly, but if you had allocated a few neurons while reading my comment you would have seen I said "a poor simplist-ification" akin to only transmitting the idea that it is the place in the brain with the most compute power/parallelism. >working neuroscientist don't think about consciousness, we look at neurobiology, Such a useless thing to say. It is a truism that scientists mostly focus on what can be studied by the means of metrology/empiricism and indeed for now, qualias are low-studiable. Saying this has no more value than saying water is wet. Your shallow dismissal is just a pretext to your layman explanation of what is the brain. Explanation with btw zero level of detail. I have read over 1000 papers in neuropharmacology and there are in facts a lot of things we understand about brains. But, the C.elegans ~150-300 neurons, which is much simpler than the fruit flies, is as of now unexplained in terms of neural code, despite having an almost complete connectome of its neuroreceptors. But no the C.elgans is not one of the most complex thing in the universe. This is a fallacy that make seems progress seems impossible. The truth is, C.elgans has a relatively reasonable complexity, however we lack real-time datasets and we lack accurate instruments to observe and retroengineer the while system.
- deleted 4y ago
  [deleted]
- andbberger 4y ago
  > we lack real-time datasets and we lack accurate instruments to observe and retroengineer the while system. wrong again. whole brain 2p imaging is routinely performed in c elegans ( and drosophila for that matter) for a number of years now. in fact whole brain ephys in c elegans is feasible, although it would be an experimental tour de force. c elegans does not have '~150-300 neurons', it has precisely 302, and the complexity therein cannot be underestimated. it wasn't a layman explanation for I am not a layman, and you are missing my point, which is that reductive facts about such staggeringly complex things are neither interesting or useful. it's the feynman magnet explanation, but grumpier
  - SemanticStrengh 4y ago
    Come on, who do you think you are talking with? I have read many papers about C.elegans and my claims are backed up: "the inability to reliably identify all neurons within whole-brain recordings has precluded a full picture with circuit-level details." "we expect our work to aid in these endeavors (Bargmann and Marder, 2013; Brennan and Proekt, 2019; Kaplan et al., 2020; Kato et al., 2015). A richer set of network responses, even for simple chemosensory inputs, has broad relevance in understanding sensorimotor processing" "The application of NeuroPAL to whole-nervous-system activity recording is mainly limited by nuclear localization of the GCaMP activity sensor, as this may fail to capture highly localized events in axodendritic compartments. This limitation, combined with potentially incomplete or variable anatomical synaptic annotations, may have contributed to the lack of correlation we observed between functional activity and synaptic connectivity." Neuropal is an extremely recent advance (2021) https://www.cell.com/cell/fulltext/S0092-8674(20)31682-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867420316822%3Fshowall%3Dtrue https://www.cell.com/cell/fulltext/S0092-8674(20)31682-2?_re... it is the first to allow a complete mapping of GABA receptors (except mitochondria GABA translocator) however complete maps for other receptors, such as mGLURs, NMDA, kainate, ampa, etc are LACKING, as I said. Let alone realtime data that take into account the individual variances over multiple worms. (they should study genetic clones btw) real time data are rare, nowhere near big-data https://www.youtube.com/watch?app=desktop&v=B4gNamS8Ars https://www.youtube.com/watch?app=desktop&v=B4gNamS8Ars and when they exist, they lack the complete information (receptor locations, precise neurostransmitter density per axon, etc) C.elegans might be trivial to understand, without a complete map of axons and recpetors, it would still appear generally un-studiable. As for the 150-300 neurons it is a matter of debate. IIRC the paper I linked refer to ~150 neurons in the head, the rest would be the PNS, not the CNS. But I'm not sure of the exact CNS/PNS ratio besides this paper.
exikyut 4y ago
*Puts mr bucket of water back where they came from* FWIW that's not how you argue, that's just letting all the air out of the balloon. As for your arguments, IMHO humans are fundamentally wanderers, and we stumble on discoveries and accidental solutions to problems as much (if not more often) than we intentionally set out to understand or achieve something. Given the expanse of the brain, the theoretical paradox of a scanner trying to scan itself, and the post-discovery nature of how we structure and organize things, I think we'll only make progress once we fully let go a bit. Not to a stupid extreme, of course - unhinged conspiracy theories are as useless as trying to build load-bearing insights from drug experiences, IMHO - but just scientifically accepting that we'll never truly understand how we tick until we accept the wild nature behind it. We are not nearly there yet. I liked the GP comment.
subroutine 4y ago
Here's an interesting fact about the cerebellum: it has more neurons than the rest of the brain combined, and as far as we know, all it does is help with balance a bit. There have been cases studies of people with a fully ablated cerebellum, and they can still walk, just a bit unsteadily.
- SemanticStrengh 4y ago
  > There have been cases studies of people with a fully ablated cerebellum, and they can still walk, just a bit unsteadily. ? I had heard the cerebellum is responsible for predicting the next token in a sentence (reminiscent of language models) but you're saying language is not impaired without a cerebellum?
  - kaba0 4y ago
    The axons are just as important as the neurons. While neural networks are not good analogues of the real thing, one can imagine that no matter the neurons, without weights between them it would be utterly useless. The cerebrum is chock full of axons.
    - SemanticStrengh 4y ago
      > The axons are just as important as the neurons We don't know about that. > without weights between them it We don't know where are located the weights but yes probably. We know for sure that individual neurons and axons do not reduce to a single floating point though. They have action potential memory and many dynamic modulators. Basically I believe the idea that neurons are mostly doing linear regression (which is what neural networks are) is very broken. I have read papers about neural coding and neurons are able to encode information in the spike timing frequency and in the strength (weight) but non of those two mechanisms even begin to explain how the system works. Anyway to answer your comment you have a tentative point but mostly unknown. It is unknown how much percent of human axons are in the cerebrum vs the cerebellum. I would be surprised if the cerebellum would have less since I expect some kind of neuron/axon proportionality. Especially since the main neuron type in the cerebellum are highly branchial.
rawoke083600 4y ago
It would be kinda funny if it turns out our brains are all running LISP underneath. duck
- SemanticStrengh 4y ago
  Always has been. BTW homoiconicity matters in artificial intelligence research https://en.wikipedia.org/wiki/Homoiconicity https://en.wikipedia.org/wiki/Homoiconicity

SemanticStrengh 4y ago

What an absurd dismissal. > they're not interesting You have a failure of appreciation, yet those facts are potent and surprising. >constructive to a larger understanding Yes they are not, who cares? Teaching neuroscience is of course a non-goal of my comment, what an irrelevant thing to say.. >analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. Exactly, but if you had allocated a few neurons while reading my comment you would have seen I said "a poor simplist-ification" akin to only transmitting the idea that it is the place in the brain with the most compute power/parallelism. >working neuroscientist don't think about consciousness, we look at neurobiology, Such a useless thing to say. It is a truism that scientists mostly focus on what can be studied by the means of metrology/empiricism and indeed for now, qualias are low-studiable. Saying this has no more value than saying water is wet. Your shallow dismissal is just a pretext to your layman explanation of what is the brain. Explanation with btw zero level of detail. I have read over 1000 papers in neuropharmacology and there are in facts a lot of things we understand about brains. But, the C.elegans ~150-300 neurons, which is much simpler than the fruit flies, is as of now unexplained in terms of neural code, despite having an almost complete connectome of its neuroreceptors. But no the C.elgans is not one of the most complex thing in the universe. This is a fallacy that make seems progress seems impossible. The truth is, C.elgans has a relatively reasonable complexity, however we lack real-time datasets and we lack accurate instruments to observe and retroengineer the while system.

deleted 4y ago
[deleted]
andbberger 4y ago
> we lack real-time datasets and we lack accurate instruments to observe and retroengineer the while system. wrong again. whole brain 2p imaging is routinely performed in c elegans ( and drosophila for that matter) for a number of years now. in fact whole brain ephys in c elegans is feasible, although it would be an experimental tour de force. c elegans does not have '~150-300 neurons', it has precisely 302, and the complexity therein cannot be underestimated. it wasn't a layman explanation for I am not a layman, and you are missing my point, which is that reductive facts about such staggeringly complex things are neither interesting or useful. it's the feynman magnet explanation, but grumpier
- SemanticStrengh 4y ago
  Come on, who do you think you are talking with? I have read many papers about C.elegans and my claims are backed up: "the inability to reliably identify all neurons within whole-brain recordings has precluded a full picture with circuit-level details." "we expect our work to aid in these endeavors (Bargmann and Marder, 2013; Brennan and Proekt, 2019; Kaplan et al., 2020; Kato et al., 2015). A richer set of network responses, even for simple chemosensory inputs, has broad relevance in understanding sensorimotor processing" "The application of NeuroPAL to whole-nervous-system activity recording is mainly limited by nuclear localization of the GCaMP activity sensor, as this may fail to capture highly localized events in axodendritic compartments. This limitation, combined with potentially incomplete or variable anatomical synaptic annotations, may have contributed to the lack of correlation we observed between functional activity and synaptic connectivity." Neuropal is an extremely recent advance (2021) https://www.cell.com/cell/fulltext/S0092-8674(20)31682-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867420316822%3Fshowall%3Dtrue https://www.cell.com/cell/fulltext/S0092-8674(20)31682-2?_re... it is the first to allow a complete mapping of GABA receptors (except mitochondria GABA translocator) however complete maps for other receptors, such as mGLURs, NMDA, kainate, ampa, etc are LACKING, as I said. Let alone realtime data that take into account the individual variances over multiple worms. (they should study genetic clones btw) real time data are rare, nowhere near big-data https://www.youtube.com/watch?app=desktop&v=B4gNamS8Ars https://www.youtube.com/watch?app=desktop&v=B4gNamS8Ars and when they exist, they lack the complete information (receptor locations, precise neurostransmitter density per axon, etc) C.elegans might be trivial to understand, without a complete map of axons and recpetors, it would still appear generally un-studiable. As for the 150-300 neurons it is a matter of debate. IIRC the paper I linked refer to ~150 neurons in the head, the rest would be the PNS, not the CNS. But I'm not sure of the exact CNS/PNS ratio besides this paper.

exikyut 4y ago

*Puts mr bucket of water back where they came from* FWIW that's not how you argue, that's just letting all the air out of the balloon. As for your arguments, IMHO humans are fundamentally wanderers, and we stumble on discoveries and accidental solutions to problems as much (if not more often) than we intentionally set out to understand or achieve something. Given the expanse of the brain, the theoretical paradox of a scanner trying to scan itself, and the post-discovery nature of how we structure and organize things, I think we'll only make progress once we fully let go a bit. Not to a stupid extreme, of course - unhinged conspiracy theories are as useless as trying to build load-bearing insights from drug experiences, IMHO - but just scientifically accepting that we'll never truly understand how we tick until we accept the wild nature behind it. We are not nearly there yet. I liked the GP comment.

subroutine 4y ago

Here's an interesting fact about the cerebellum: it has more neurons than the rest of the brain combined, and as far as we know, all it does is help with balance a bit. There have been cases studies of people with a fully ablated cerebellum, and they can still walk, just a bit unsteadily.

SemanticStrengh 4y ago
> There have been cases studies of people with a fully ablated cerebellum, and they can still walk, just a bit unsteadily. ? I had heard the cerebellum is responsible for predicting the next token in a sentence (reminiscent of language models) but you're saying language is not impaired without a cerebellum?
- kaba0 4y ago
  The axons are just as important as the neurons. While neural networks are not good analogues of the real thing, one can imagine that no matter the neurons, without weights between them it would be utterly useless. The cerebrum is chock full of axons.
  - SemanticStrengh 4y ago
    > The axons are just as important as the neurons We don't know about that. > without weights between them it We don't know where are located the weights but yes probably. We know for sure that individual neurons and axons do not reduce to a single floating point though. They have action potential memory and many dynamic modulators. Basically I believe the idea that neurons are mostly doing linear regression (which is what neural networks are) is very broken. I have read papers about neural coding and neurons are able to encode information in the spike timing frequency and in the strength (weight) but non of those two mechanisms even begin to explain how the system works. Anyway to answer your comment you have a tentative point but mostly unknown. It is unknown how much percent of human axons are in the cerebrum vs the cerebellum. I would be surprised if the cerebellum would have less since I expect some kind of neuron/axon proportionality. Especially since the main neuron type in the cerebellum are highly branchial.

rawoke083600 4y ago

It would be kinda funny if it turns out our brains are all running LISP underneath. duck

SemanticStrengh 4y ago
Always has been. BTW homoiconicity matters in artificial intelligence research https://en.wikipedia.org/wiki/Homoiconicity https://en.wikipedia.org/wiki/Homoiconicity