8 ms·

I find a lot of the common explanations of how the brain works in neuroscience to be unsatisfying… compared to molecular biology, it just feels like often we do

I find a lot of the common explanations of how the brain works in neuroscience to be unsatisfying… compared to molecular biology, it just feels like often we don’t have a solid (falsifiable, etc) grasp of what’s actually happening, yet… too much handwaving (for instance, the lack of any specifics on where precisely some data is located… even “it’s stored in the connections” seems not quite true or falsifiable… although perhaps not exactly false, either). So I find discoveries like this exciting as it’s starting to peel back the curtain on a true understanding of the brain and neurons.

radicaldreamer 5y ago
There’s a strong bias toward things that are model-able in neuroscience. The role of microtubules, for example, are mostly ignored even though they may explain the complexity of cognition displayed by relatively “simple” brains.
- mikewarot 5y ago
  Fringe Tangent: It's possible those microtubules in our brains are 1 dimensional superconductors, and thus might be capable of holding Qubits. We might have quantum memory. https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf
  - airstrike 5y ago
    This is why I come to HN daily. Thanks for the very interesting read.
  - tsimionescu 5y ago
    That's still extremely unlikely given all we know about quantum computers so far, and about biology. It's also important to note that quantum computers are just faster classical computers, they are still Turing machines. Many people who are looking for some non-computable element of consciousness in quantum effects in microtubules seem to forget that.
    - mikewarot 5y ago
      Quantum computers are not Turing machines as far a I know. They can encode exponentially many states simultaneously, and are non-deterministic.
      - tsimionescu 5y ago
        You can simulate any quantum computer on a Turing machine, though it generally takes exponentially more time than with a real QC. Whether this means they are the same thing or not is a matter of semantics. But what is clear is that there is no computation that can be done on a QC that can't be done on a TM. The role of non-determinism in computation is more debatable. There is even a notable MIT professor (who coined the term Actor model) who claims that real computers, like the Android phone I'm writing this on, are in fact not Turing machines, because of non-determinism / parallelism. He also claims that Godel's incompleteness theorem doesn't apply to actual mathematics, so I would take his words with a huge spoonful of salt.
      - smegger001 5y ago
        they are they just dont work in binary bits they work with qbits which simply have behavior rules diffrent from digital but can be simulated by one just inefficiently. much like a binary computer can be approximated by a balanced trianay computer or analog computer or by pumps valves and flowing water like in MONIAC. they are all turring complete and can simulate each other just not efficiently. they dont have any magical logic gates they are just able to do a task that would need require lot of time or many parrelel computaions or both in less time because a single qbit is in super position of 1 and 0 simaltaniously and we can do mathmatical operations on it without collapsing the superposition until we have observed it. to simulate this on a traditional computer you would need to run it for each 2 time per bit. so for a 8 bit key for example you would need to run the same operation 256 times 65536 for a 16 bit key and 4,294,967,296 for a 32 bit. so in essence quantum computation just lets you cheat on massively parallel processes but is not a hyper-turring machine or a turring oracle. in fact there are many algorithms that you get no gain from using qubit other than i higher energy bill
        5y ago
  - mikewarot 5y ago
    If (a huge if) our memories are stored in qubits, a sufficiently strong magnetic pulse (one much larger than found in an MRI) might be able to erase our brains. This also has interesting (morbid?) implications for how long our memories last after death.
- seg_lol 5y ago
  Reverse lamp post? We don't routinely take MRIs because of false positives, meaning we might have more questions than answers so we won't ask. Seems like neuroscience is still in the phase of reducing misunderstanding.
- mr_toad 5y ago
  Microtubules are found in all eukaryotic cells. Even single celled organisms. If microtubules are responsible for cognition, what are brains for, and why aren’t amoeba intelligent?
  - kortex 5y ago
    Have you ever watched an amoeba do its thing? I wouldn't call it cognition, but its behavior is remarkable for something with no neurons. In fact microtubules are the exact structure posited to be responsible for where and how amoebas move their pseudopods. https://pubmed.ncbi.nlm.nih.gov/7983169/ https://pubmed.ncbi.nlm.nih.gov/7983169/
  - procgen 5y ago
    Amoebas are intelligent. All living things are intelligent.
stinos 5y ago
it just feels like often we don’t have a solid (falsifiable, etc) grasp of what’s actually happening, yet… It feels like that, because it is like that: there's probably way more which isn't known about the brain yet, than things known with a decent amount of certainty. Just skimming over recent papers in the fundamental area, a lot of that summarizes as 'So here we found that area A is connected to area B and modulated when things happen in C, so attributes to function D. But way more research needed, and unsure what this means in relation to E and F'.
- londons_explore 5y ago
  My benchmark of "this thing is well understood" is that it's possible to build that thing, or a replacement for it, again. Kidneys probably meet that criteria - we have dialysis machines which allow someone to survive without kidneys almost perfectly. Yet the idea of replacing someones brain with something artificial and having them function as normal is still a LOOOOOOONG way off.
  - munificent 5y ago
    > My benchmark of "this thing is well understood" is that it's possible to build that thing, or a replacement for it, again. Something I've been thinking a lot about lately: Implicit in statements like this is the idea of a system. That some complex-seeming artifact is actually composed of a relatively smaller number of essential things and all of the observed complexity is just emergent properties of the simpler underlying system. Find the handful of hidden rules and you can build back up to the whole thing from first principles. For example, if you were to learn chess purely by watching people play, it would be a huge struggle at first. Does how they hold the pieces matter? What role does timing play? Why does one player rest their head on their cheek while staring at the board? Eventually you start to figure out which actions are essential and which aren't. It doesn't matter where inside a square a piece is placed. All pawns are behaviorally equivalent, etc. We really really like systems. So much so that we tend to assume everything is one. But I see no evidence to assume that biology and evolution work that. Evolution is a semi-random walk over the phenotype space and fitter organisms are discovered (mutated) entirely randomly. It may be that a kidney mostly filters blood, but also does a little of this other thing, and the fact that it pushes your small intestine out of the way is important, and also and also and also... We can increase our understanding by learning more, but there may simply be no "first principles" for what makes an organism tick and almost all of its complexity may be irreducible. There may be absolutely no separation between "fundamental property" and "implementation detail". It may be that no terms in the grand equation of life cancel out.
BitwiseFool 5y ago
I had a crazy idea about neurons that I'll share here, because why not? What if each time a neuron sends a signal to another neuron the potential required for that connection decreases slightly? So the next time there's an action potential between neurons it's more likely to go where it has already gone. In other words, frequent connections make that same pathway more readily traversed. Could it be that a memory is simply a new signal traveling down a 'worn path'? I realize that there needs to be some way for this resistance change to be reset over time, so is it possible that dreams serve the purpose of writing somewhat random data, like wear leveling or trimming on an SSD? This is just pure speculation and I have "Hello World" levels of knowledge about neuroscience. But hey, it's fun to speculate, right?
- kwertyops 5y ago
  It sounds like you are essentially describing long-term potentiation (LTP). See here: https://en.wikipedia.org/wiki/Long-term_potentiation https://en.wikipedia.org/wiki/Long-term_potentiation
- jph 5y ago
  The catchphrase is "neurons that fire together wire together".
- mstipetic 5y ago
  I have a completely layman theory that that’s what dreams are. Worn out pathways that our ego or consciousness is not letting through to us, but are being used in our subconscious, being able to manifest themselves finally. That’s why we can see things that are bothering us or on our mind in the background there
  - meowkit 5y ago
    https://www.biorxiv.org/content/10.1101/2020.07.24.219089v1 https://www.biorxiv.org/content/10.1101/2020.07.24.219089v1 It’s recently suggested there is nothing special about dreaming - its just a confluence of himan interpretation with a mechanism to stop you from going blind.
vmception 5y ago
From my understanding, the current approach is basically the idea that if you put a bunch of neurons in a room, it eventually starts questioning the universe It really lacks nuance
- morpheos137 5y ago
  What if the universe and the room is neurons all the way down?
bena 5y ago
I mean, we can't really completely inspect a working brain to see what's happening. To get that level of inspection, we'd need to dig into the brain while it is functioning. Unfortunately, this kills the patient. And then the brain stops working. It's a black box essentially. We have tools that allow us some degree of insight, but honestly, it is incredibly difficult and progress is slow and staggered.
- nosianu 5y ago
  You might want to ask Google about two-photon microscopy links. Example papers: https://pubmed.ncbi.nlm.nih.gov/25391792/ https://pubmed.ncbi.nlm.nih.gov/25391792/ -- "Two-photon excitation microscopy and its applications in neuroscience" https://www.nature.com/articles/s41598-018-26326-3 https://www.nature.com/articles/s41598-018-26326-3 -- "Three dimensional two-photon brain imaging in freely moving mice using a miniature fiber coupled microscope with active axial-scanning" Sure, it's localized and you cannot go deep, but there is so much to learn that that is plenty at this point.
  - bena 5y ago
    So my point remains. I'm not saying there's nothing to learn. I'm saying that we cannot go deep. That we currently cannot understand the brain to the degree we understand other systems. And that there are fundamental difficulties because we're dealing with living beings.
- stinos 5y ago
  I mean, we can't really completely inspect a working brain to see what's happening. To get that level of inspection, we'd need to dig into the brain while it is functioning. Unfortunately, this kills the patient Leave out the completely and it's a different story though: it's perfectly possible to 'dig in while functioning' i.e. inspect small parts using electrode arrays and that will not kill the patient and only do minimal damage (the couple of cells killed by that are nothing in comparison with the entirety). Non-invasive fMRI techniques also have come a long way but temporal resolution is low. But as you say: difficult, slow, and by no means a 'complete' view. On the other hand: no idea how one would even begin to handle the insane amount of data which would come from inspecting a complete brain. So what goes on now, tackling smaller areas/connections thereof one by one, is not even that bad of an approach.
mensetmanusman 5y ago
I wish we had a large research effort on just trying to understand a cpu running windows 98. E.g. put all of our best analysis tools to task against an operating pentium chip and see if we can determine from first principals that it is running a W98 screen saver. That would give us a small sense of the challenge we are facing.
- hcineb 5y ago
  Well, you are not the first one https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005268 https://journals.plos.org/ploscompbiol/article?id=10.1371/jo...

radicaldreamer 5y ago

There’s a strong bias toward things that are model-able in neuroscience. The role of microtubules, for example, are mostly ignored even though they may explain the complexity of cognition displayed by relatively “simple” brains.

mikewarot 5y ago
Fringe Tangent: It's possible those microtubules in our brains are 1 dimensional superconductors, and thus might be capable of holding Qubits. We might have quantum memory. https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf
- airstrike 5y ago
  This is why I come to HN daily. Thanks for the very interesting read.
- tsimionescu 5y ago
  That's still extremely unlikely given all we know about quantum computers so far, and about biology. It's also important to note that quantum computers are just faster classical computers, they are still Turing machines. Many people who are looking for some non-computable element of consciousness in quantum effects in microtubules seem to forget that.
  - mikewarot 5y ago
    Quantum computers are not Turing machines as far a I know. They can encode exponentially many states simultaneously, and are non-deterministic.
    - tsimionescu 5y ago
      You can simulate any quantum computer on a Turing machine, though it generally takes exponentially more time than with a real QC. Whether this means they are the same thing or not is a matter of semantics. But what is clear is that there is no computation that can be done on a QC that can't be done on a TM. The role of non-determinism in computation is more debatable. There is even a notable MIT professor (who coined the term Actor model) who claims that real computers, like the Android phone I'm writing this on, are in fact not Turing machines, because of non-determinism / parallelism. He also claims that Godel's incompleteness theorem doesn't apply to actual mathematics, so I would take his words with a huge spoonful of salt.
    - smegger001 5y ago
      they are they just dont work in binary bits they work with qbits which simply have behavior rules diffrent from digital but can be simulated by one just inefficiently. much like a binary computer can be approximated by a balanced trianay computer or analog computer or by pumps valves and flowing water like in MONIAC. they are all turring complete and can simulate each other just not efficiently. they dont have any magical logic gates they are just able to do a task that would need require lot of time or many parrelel computaions or both in less time because a single qbit is in super position of 1 and 0 simaltaniously and we can do mathmatical operations on it without collapsing the superposition until we have observed it. to simulate this on a traditional computer you would need to run it for each 2 time per bit. so for a 8 bit key for example you would need to run the same operation 256 times 65536 for a 16 bit key and 4,294,967,296 for a 32 bit. so in essence quantum computation just lets you cheat on massively parallel processes but is not a hyper-turring machine or a turring oracle. in fact there are many algorithms that you get no gain from using qubit other than i higher energy bill
      - 5y ago
- mikewarot 5y ago
  If (a huge if) our memories are stored in qubits, a sufficiently strong magnetic pulse (one much larger than found in an MRI) might be able to erase our brains. This also has interesting (morbid?) implications for how long our memories last after death.
seg_lol 5y ago
Reverse lamp post? We don't routinely take MRIs because of false positives, meaning we might have more questions than answers so we won't ask. Seems like neuroscience is still in the phase of reducing misunderstanding.
mr_toad 5y ago
Microtubules are found in all eukaryotic cells. Even single celled organisms. If microtubules are responsible for cognition, what are brains for, and why aren’t amoeba intelligent?
- kortex 5y ago
  Have you ever watched an amoeba do its thing? I wouldn't call it cognition, but its behavior is remarkable for something with no neurons. In fact microtubules are the exact structure posited to be responsible for where and how amoebas move their pseudopods. https://pubmed.ncbi.nlm.nih.gov/7983169/ https://pubmed.ncbi.nlm.nih.gov/7983169/
- procgen 5y ago
  Amoebas are intelligent. All living things are intelligent.

stinos 5y ago

it just feels like often we don’t have a solid (falsifiable, etc) grasp of what’s actually happening, yet… It feels like that, because it is like that: there's probably way more which isn't known about the brain yet, than things known with a decent amount of certainty. Just skimming over recent papers in the fundamental area, a lot of that summarizes as 'So here we found that area A is connected to area B and modulated when things happen in C, so attributes to function D. But way more research needed, and unsure what this means in relation to E and F'.

londons_explore 5y ago
My benchmark of "this thing is well understood" is that it's possible to build that thing, or a replacement for it, again. Kidneys probably meet that criteria - we have dialysis machines which allow someone to survive without kidneys almost perfectly. Yet the idea of replacing someones brain with something artificial and having them function as normal is still a LOOOOOOONG way off.
- munificent 5y ago
  > My benchmark of "this thing is well understood" is that it's possible to build that thing, or a replacement for it, again. Something I've been thinking a lot about lately: Implicit in statements like this is the idea of a system. That some complex-seeming artifact is actually composed of a relatively smaller number of essential things and all of the observed complexity is just emergent properties of the simpler underlying system. Find the handful of hidden rules and you can build back up to the whole thing from first principles. For example, if you were to learn chess purely by watching people play, it would be a huge struggle at first. Does how they hold the pieces matter? What role does timing play? Why does one player rest their head on their cheek while staring at the board? Eventually you start to figure out which actions are essential and which aren't. It doesn't matter where inside a square a piece is placed. All pawns are behaviorally equivalent, etc. We really really like systems. So much so that we tend to assume everything is one. But I see no evidence to assume that biology and evolution work that. Evolution is a semi-random walk over the phenotype space and fitter organisms are discovered (mutated) entirely randomly. It may be that a kidney mostly filters blood, but also does a little of this other thing, and the fact that it pushes your small intestine out of the way is important, and also and also and also... We can increase our understanding by learning more, but there may simply be no "first principles" for what makes an organism tick and almost all of its complexity may be irreducible. There may be absolutely no separation between "fundamental property" and "implementation detail". It may be that no terms in the grand equation of life cancel out.

BitwiseFool 5y ago

I had a crazy idea about neurons that I'll share here, because why not? What if each time a neuron sends a signal to another neuron the potential required for that connection decreases slightly? So the next time there's an action potential between neurons it's more likely to go where it has already gone. In other words, frequent connections make that same pathway more readily traversed. Could it be that a memory is simply a new signal traveling down a 'worn path'? I realize that there needs to be some way for this resistance change to be reset over time, so is it possible that dreams serve the purpose of writing somewhat random data, like wear leveling or trimming on an SSD? This is just pure speculation and I have "Hello World" levels of knowledge about neuroscience. But hey, it's fun to speculate, right?

kwertyops 5y ago
It sounds like you are essentially describing long-term potentiation (LTP). See here: https://en.wikipedia.org/wiki/Long-term_potentiation https://en.wikipedia.org/wiki/Long-term_potentiation
jph 5y ago
The catchphrase is "neurons that fire together wire together".
mstipetic 5y ago
I have a completely layman theory that that’s what dreams are. Worn out pathways that our ego or consciousness is not letting through to us, but are being used in our subconscious, being able to manifest themselves finally. That’s why we can see things that are bothering us or on our mind in the background there
- meowkit 5y ago
  https://www.biorxiv.org/content/10.1101/2020.07.24.219089v1 https://www.biorxiv.org/content/10.1101/2020.07.24.219089v1 It’s recently suggested there is nothing special about dreaming - its just a confluence of himan interpretation with a mechanism to stop you from going blind.

vmception 5y ago

From my understanding, the current approach is basically the idea that if you put a bunch of neurons in a room, it eventually starts questioning the universe It really lacks nuance

morpheos137 5y ago
What if the universe and the room is neurons all the way down?

bena 5y ago

I mean, we can't really completely inspect a working brain to see what's happening. To get that level of inspection, we'd need to dig into the brain while it is functioning. Unfortunately, this kills the patient. And then the brain stops working. It's a black box essentially. We have tools that allow us some degree of insight, but honestly, it is incredibly difficult and progress is slow and staggered.

nosianu 5y ago
You might want to ask Google about two-photon microscopy links. Example papers: https://pubmed.ncbi.nlm.nih.gov/25391792/ https://pubmed.ncbi.nlm.nih.gov/25391792/ -- "Two-photon excitation microscopy and its applications in neuroscience" https://www.nature.com/articles/s41598-018-26326-3 https://www.nature.com/articles/s41598-018-26326-3 -- "Three dimensional two-photon brain imaging in freely moving mice using a miniature fiber coupled microscope with active axial-scanning" Sure, it's localized and you cannot go deep, but there is so much to learn that that is plenty at this point.
- bena 5y ago
  So my point remains. I'm not saying there's nothing to learn. I'm saying that we cannot go deep. That we currently cannot understand the brain to the degree we understand other systems. And that there are fundamental difficulties because we're dealing with living beings.
stinos 5y ago
I mean, we can't really completely inspect a working brain to see what's happening. To get that level of inspection, we'd need to dig into the brain while it is functioning. Unfortunately, this kills the patient Leave out the completely and it's a different story though: it's perfectly possible to 'dig in while functioning' i.e. inspect small parts using electrode arrays and that will not kill the patient and only do minimal damage (the couple of cells killed by that are nothing in comparison with the entirety). Non-invasive fMRI techniques also have come a long way but temporal resolution is low. But as you say: difficult, slow, and by no means a 'complete' view. On the other hand: no idea how one would even begin to handle the insane amount of data which would come from inspecting a complete brain. So what goes on now, tackling smaller areas/connections thereof one by one, is not even that bad of an approach.

mensetmanusman 5y ago

I wish we had a large research effort on just trying to understand a cpu running windows 98. E.g. put all of our best analysis tools to task against an operating pentium chip and see if we can determine from first principals that it is running a W98 screen saver. That would give us a small sense of the challenge we are facing.

hcineb 5y ago
Well, you are not the first one https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005268 https://journals.plos.org/ploscompbiol/article?id=10.1371/jo...