8 ms·

This is a good article for deepening the complexity model of the brain, but mere physical structure and behavior of subcomponents of neurons is only a tiny piec

This is a good article for deepening the complexity model of the brain, but mere physical structure and behavior of subcomponents of neurons is only a tiny piece of the puzzle. To understand the workings of the brain you will also need to add in the complex interactions of hormones and other chemical agents in the brain and throughout the nervous system and the feedback loops they establish with the other systems of the body and through them, with the external world. Neural networks of neural networks doesn’t begin to describe it. We haven’t even scratched the tip of the tip of the iceberg in understanding this stuff.

ltbarcly3 8y ago
I appreciate what you are saying, but it may be that it's premature to try to list things necessary to understand something when it's not understood by anyone. In fact, I think you're probably dead wrong. Certainly hormone interactions and feedback loops in the body have some consequence on an organism, but these things take time. Lets say that some feedback loop is extremely fast, say 10 seconds. It seems reasonable to assume that you can't have a complex feedback loop with the body much faster than that, just because it takes time for chemicals to physically move. Cognition is much, much faster than that. There are many situations where you can learn, and then apply that learning in less than a second. Now if we were instead talking about what it takes to build a complex organism that can satisfy it's own needs, then certainly these complex hormonal feedback loops are essential. You can't have an organism survive when it doesn't look for food when it's body is out of fuel or keeps eating poisonous berries because it's body can't send the reasonable feedback to it's brain, and you can forget about dropping everything and competing for mates at the correct time without some kind of behavior modifying hormonal signals! I would say that your assertion is not significantly different from saying "you can't understand the workings of the brain without considering the complex interactions of the brain with the lungs, since without oxygen the brain can't work". So while I agree that the brain exists as part of the body, I don't see why you would automatically assume that the hormonal feedback loops with the body are at all necessary for cognition rather than a way to tell the brain when it's necessary to find food, when it's adaptive to conserve energy and be lethargic, or what have you. My point is that we may or may not find that there is some critical ingredient of cognition hiding in this place or that, and you can't very well tell us where that will be if nobody knows if it's there.
- deleted 8y ago
  [deleted]
- feanaro 8y ago
  Well neurotransmitters are a kind of hormone and they certainly play a direct role in the computational processes of neurons.
  - seandhi 8y ago
    Neurotransmitters are not hormones. Some neurotransmitters are also hormones.
    - feanaro 8y ago
      Yes, you're right. That was phrased a bit haphazardly. My point was that we can't just determine the typical time constant for a hormone's effect and run home with it since there are chemicals which have significantly lower time constants and some of them act as endocrine hormones as well. Furthermore, an immediate feedback loop isn't the only possible way the body could play a role in cognition, though I suppose the OP is aware of this and was talking about moment-by-moment interaction with the body on purpose.
- skywhopper 8y ago
  Well sure. My point was that there’s countless additional factors to consider, beyond just physical structure. Those feedback loops may be slow, but there’s plenty of evidence that they influence aspects of cognition quite strongly. On the flip side, a lot of current research about brain function is built on fMRI scans which monitor blood flow changes to exact locations in the brain, but necessarily at a long temporal distance from the actual “decisions” being made. So yes I think we agree that it’s all more complicated than anyone can even comprehend just yet.
- Balgair 8y ago
  > My point is that we may or may not find that there is some critical ingredient of cognition hiding in this place or that, and you can't very well tell us where that will be if nobody knows if it's there. It's like the parable of the Drunken man looking for his lost keys under the street-lamp. He only looks under the lamp for his keys because that's the only place the light is. Similarly, in neuroscience, we only have a few tools to look at the brain. By some miracle, the brain happens to be electrically active to a degree that we can shove wires into it and pick up signals. So, dutifully, grad students across the world have been shoving needles into brains and trying to pick up signals and then tell advisers what that means. Another miracle is that blood has a ferromagnet in it and the brain has a fair bit of blood in it. So, after a lot of trial and error, we've been able to build very complicated fMRI machines that can give grad students an idea of the usage of blood in the brain. This is then correlated with other measurements to find out what is happening in the brain. Recently, we've been able to combine two different little miracles together. One is opto-genetics, a little serendipity we pulled out of the chromatic hot-pools in Yellowstone. Essentially, when you shine light on a little bacteria, it's cell wall opens up and you can squeak certain ions through the hole. The other little miracle is CRISPR-CAS9. Here, you can again use some tricks bacteria have made up to more easily copy-paste in the genetic code. Using these tricks and a lot of help from post-docs, yet more grad students have been able to report results in lab meetings to their advisers. More techniques exist, of course, but my point is that the vast majority of neuroscience is still in the dark, away from the drunken man searching for his keys in the light. Look at astrocytes. These guys make up ~50% of the brain. Very recent research says that they play something of a role in the synapse, moving NMDA receptors around the cleft, recycling, phospho-tagging recpetor, etc. It's super recent work. But also super important. Before, we thought that only the neurons were involved in the synapse, but now we have good evidence that other, action-potential lacking, cells are also deeply involved. That vein of research is also really hard to do and preform experiments in. As such, most grad students are wise not to do their work in that kinda lab. It's hard and has a high potential of failure, and therefore no degree. So, wait and see. Our understanding of the brain is still very much in it's infancy. We've not really even got a good accounting of all the cell types and connections in the brain yet.
nabla9 8y ago
Gene Regulatory Network (GRN) within cells is similar to recurrent neural network (RNN). RNN is at least useful partial model for GRN. If you think gene expression within neurons as small RNN, it's neural networks all the way down. RNN within neuron reacts to hormones and chemical signals altering the functioning of individual neurons. There is also feedback loop to other direction.
- j7ake 8y ago
  Could you please elaborate how GRNs are analogous to RNNs? I fail to see the link.
  - nabla9 8y ago
    The regulation of the expression of a group of genes, can be expressed using Recurrent Neural Network formalism. Genes regulate the expression of each other with positive and negative feedback loops that are often additive or non-linear and similar to higher order RNN. RNN nodes represent genes and connections between them are regulatory feedback loops in gene expression.
psandersen 8y ago
As a gross approximation, the hormones and other chemicals might act like hyperparameters in the neural networks. Increase learning rates, adjust regularisation penalties, few-shot learning vs generalisation etc.
neuronic 8y ago
I enjoy that we are seemingly aware about our lack of understanding of the workings of the brain but are happy and eager to proclaim the advent of intelligent machines who will replace humans in all aspects imaginable. What we are really building are pretty good pattern recognition machines, often with surprising capabilities. But we overreach when we equate that with intelligence. At least it's useful to discuss the ethics due to buzzwords, media hype and industry demands before we are actually able to produce something truly artificially intelligent. Until then, we continue to add DL algorithms to our Madam Tousseau-esque collection of artificial intelligence.
- michaelmcmillan 8y ago
  Intelligent machines are not predicated on understanding the brain, necessarily.
  - JackFr 8y ago
    This. We didn't reach the moon by studying birds.
    - neuronic 8y ago
      But we did reach it by understanding physics...
  - lurquer 8y ago
    Your statement presupposes that there is an abstract notion of 'intelligence' that can manifest itself in qualitatively different types of systems. That might be true. But, so far, the only kind of 'intelligence' that seems recognizeable to us as such is the product of squishy bunches of biological neurons... maybe squisky bunches of biological neurons are essential to 'intelligence.'
    - michaelmcmillan 8y ago
      It is unlikely that our future scientific endeavours respect "What we know so far".
amelius 8y ago
Or to say it differently: the tip of an iceberg is also an iceberg.
DigiMortal 8y ago
This saddens me as I wonder how much time it will take? As my name states I'd like to establish a connection to the human brain and digitalize it, though the mystery of consciousness is something I cannot grasp right now
- echelon 8y ago
  I can't imagine we'll get anywhere close to creating fidelity backups of human memories or consciousness within our lifetimes, let alone any sort of realtime brain-computer interface like what you see in the Matrix. The problem is that the biology of the brain is incredibly complicated. Dynamic instability of microtubules, contribution of extracellular factors, neuron biochemistry, etc etc... Sure, we've extracted signal to reconstruct primitive visual features from the basal ganglia of mammals, but that's a long way off from what we'd need for humans. (I can't easily cite atm, but I'll be happy to come back and put in references if desired.) The other big issue is that it's quite invasive to get data out of this system. I imagine we'll be making progress on human cloning and artificial organs long before we crack this nut simply because of how disruptive and insufficient current techniques are. All that said, I'm pretty sure we're all going to die without any archival backup of our brain-encoded memories. Progress will be made, but not in time for us.
themeiguoren 8y ago
I would argue that we have definitely scratched the tip, though there’s a lot more iceberg to go. To anyone interested in this, I would highly recommend picking up a copy of “Principles of Neural Design”. It’s a look at how and why brains operate the way they do, from thermodynamic and information theory axioms up. A lot of the biology went a good bit over my head, but the authors do a great job of developing a set of hardware-agnostic principles that all brains follow.

ltbarcly3 8y ago

I appreciate what you are saying, but it may be that it's premature to try to list things necessary to understand something when it's not understood by anyone. In fact, I think you're probably dead wrong. Certainly hormone interactions and feedback loops in the body have some consequence on an organism, but these things take time. Lets say that some feedback loop is extremely fast, say 10 seconds. It seems reasonable to assume that you can't have a complex feedback loop with the body much faster than that, just because it takes time for chemicals to physically move. Cognition is much, much faster than that. There are many situations where you can learn, and then apply that learning in less than a second. Now if we were instead talking about what it takes to build a complex organism that can satisfy it's own needs, then certainly these complex hormonal feedback loops are essential. You can't have an organism survive when it doesn't look for food when it's body is out of fuel or keeps eating poisonous berries because it's body can't send the reasonable feedback to it's brain, and you can forget about dropping everything and competing for mates at the correct time without some kind of behavior modifying hormonal signals! I would say that your assertion is not significantly different from saying "you can't understand the workings of the brain without considering the complex interactions of the brain with the lungs, since without oxygen the brain can't work". So while I agree that the brain exists as part of the body, I don't see why you would automatically assume that the hormonal feedback loops with the body are at all necessary for cognition rather than a way to tell the brain when it's necessary to find food, when it's adaptive to conserve energy and be lethargic, or what have you. My point is that we may or may not find that there is some critical ingredient of cognition hiding in this place or that, and you can't very well tell us where that will be if nobody knows if it's there.

deleted 8y ago
[deleted]
feanaro 8y ago
Well neurotransmitters are a kind of hormone and they certainly play a direct role in the computational processes of neurons.
- seandhi 8y ago
  Neurotransmitters are not hormones. Some neurotransmitters are also hormones.
  - feanaro 8y ago
    Yes, you're right. That was phrased a bit haphazardly. My point was that we can't just determine the typical time constant for a hormone's effect and run home with it since there are chemicals which have significantly lower time constants and some of them act as endocrine hormones as well. Furthermore, an immediate feedback loop isn't the only possible way the body could play a role in cognition, though I suppose the OP is aware of this and was talking about moment-by-moment interaction with the body on purpose.
skywhopper 8y ago
Well sure. My point was that there’s countless additional factors to consider, beyond just physical structure. Those feedback loops may be slow, but there’s plenty of evidence that they influence aspects of cognition quite strongly. On the flip side, a lot of current research about brain function is built on fMRI scans which monitor blood flow changes to exact locations in the brain, but necessarily at a long temporal distance from the actual “decisions” being made. So yes I think we agree that it’s all more complicated than anyone can even comprehend just yet.
Balgair 8y ago
> My point is that we may or may not find that there is some critical ingredient of cognition hiding in this place or that, and you can't very well tell us where that will be if nobody knows if it's there. It's like the parable of the Drunken man looking for his lost keys under the street-lamp. He only looks under the lamp for his keys because that's the only place the light is. Similarly, in neuroscience, we only have a few tools to look at the brain. By some miracle, the brain happens to be electrically active to a degree that we can shove wires into it and pick up signals. So, dutifully, grad students across the world have been shoving needles into brains and trying to pick up signals and then tell advisers what that means. Another miracle is that blood has a ferromagnet in it and the brain has a fair bit of blood in it. So, after a lot of trial and error, we've been able to build very complicated fMRI machines that can give grad students an idea of the usage of blood in the brain. This is then correlated with other measurements to find out what is happening in the brain. Recently, we've been able to combine two different little miracles together. One is opto-genetics, a little serendipity we pulled out of the chromatic hot-pools in Yellowstone. Essentially, when you shine light on a little bacteria, it's cell wall opens up and you can squeak certain ions through the hole. The other little miracle is CRISPR-CAS9. Here, you can again use some tricks bacteria have made up to more easily copy-paste in the genetic code. Using these tricks and a lot of help from post-docs, yet more grad students have been able to report results in lab meetings to their advisers. More techniques exist, of course, but my point is that the vast majority of neuroscience is still in the dark, away from the drunken man searching for his keys in the light. Look at astrocytes. These guys make up ~50% of the brain. Very recent research says that they play something of a role in the synapse, moving NMDA receptors around the cleft, recycling, phospho-tagging recpetor, etc. It's super recent work. But also super important. Before, we thought that only the neurons were involved in the synapse, but now we have good evidence that other, action-potential lacking, cells are also deeply involved. That vein of research is also really hard to do and preform experiments in. As such, most grad students are wise not to do their work in that kinda lab. It's hard and has a high potential of failure, and therefore no degree. So, wait and see. Our understanding of the brain is still very much in it's infancy. We've not really even got a good accounting of all the cell types and connections in the brain yet.

nabla9 8y ago

Gene Regulatory Network (GRN) within cells is similar to recurrent neural network (RNN). RNN is at least useful partial model for GRN. If you think gene expression within neurons as small RNN, it's neural networks all the way down. RNN within neuron reacts to hormones and chemical signals altering the functioning of individual neurons. There is also feedback loop to other direction.

j7ake 8y ago
Could you please elaborate how GRNs are analogous to RNNs? I fail to see the link.
- nabla9 8y ago
  The regulation of the expression of a group of genes, can be expressed using Recurrent Neural Network formalism. Genes regulate the expression of each other with positive and negative feedback loops that are often additive or non-linear and similar to higher order RNN. RNN nodes represent genes and connections between them are regulatory feedback loops in gene expression.

psandersen 8y ago

As a gross approximation, the hormones and other chemicals might act like hyperparameters in the neural networks. Increase learning rates, adjust regularisation penalties, few-shot learning vs generalisation etc.

neuronic 8y ago

I enjoy that we are seemingly aware about our lack of understanding of the workings of the brain but are happy and eager to proclaim the advent of intelligent machines who will replace humans in all aspects imaginable. What we are really building are pretty good pattern recognition machines, often with surprising capabilities. But we overreach when we equate that with intelligence. At least it's useful to discuss the ethics due to buzzwords, media hype and industry demands before we are actually able to produce something truly artificially intelligent. Until then, we continue to add DL algorithms to our Madam Tousseau-esque collection of artificial intelligence.

michaelmcmillan 8y ago
Intelligent machines are not predicated on understanding the brain, necessarily.
- JackFr 8y ago
  This. We didn't reach the moon by studying birds.
  - neuronic 8y ago
    But we did reach it by understanding physics...
- lurquer 8y ago
  Your statement presupposes that there is an abstract notion of 'intelligence' that can manifest itself in qualitatively different types of systems. That might be true. But, so far, the only kind of 'intelligence' that seems recognizeable to us as such is the product of squishy bunches of biological neurons... maybe squisky bunches of biological neurons are essential to 'intelligence.'
  - michaelmcmillan 8y ago
    It is unlikely that our future scientific endeavours respect "What we know so far".

amelius 8y ago

Or to say it differently: the tip of an iceberg is also an iceberg.

DigiMortal 8y ago

This saddens me as I wonder how much time it will take? As my name states I'd like to establish a connection to the human brain and digitalize it, though the mystery of consciousness is something I cannot grasp right now

echelon 8y ago
I can't imagine we'll get anywhere close to creating fidelity backups of human memories or consciousness within our lifetimes, let alone any sort of realtime brain-computer interface like what you see in the Matrix. The problem is that the biology of the brain is incredibly complicated. Dynamic instability of microtubules, contribution of extracellular factors, neuron biochemistry, etc etc... Sure, we've extracted signal to reconstruct primitive visual features from the basal ganglia of mammals, but that's a long way off from what we'd need for humans. (I can't easily cite atm, but I'll be happy to come back and put in references if desired.) The other big issue is that it's quite invasive to get data out of this system. I imagine we'll be making progress on human cloning and artificial organs long before we crack this nut simply because of how disruptive and insufficient current techniques are. All that said, I'm pretty sure we're all going to die without any archival backup of our brain-encoded memories. Progress will be made, but not in time for us.

themeiguoren 8y ago

I would argue that we have definitely scratched the tip, though there’s a lot more iceberg to go. To anyone interested in this, I would highly recommend picking up a copy of “Principles of Neural Design”. It’s a look at how and why brains operate the way they do, from thermodynamic and information theory axioms up. A lot of the biology went a good bit over my head, but the authors do a great job of developing a set of hardware-agnostic principles that all brains follow.