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This strikes me as totally unsurprising. How could it be otherwise? It's basically saying that a brain normally operates in an interesting dynamical mode: not

This strikes me as totally unsurprising. How could it be otherwise? It's basically saying that a brain normally operates in an interesting dynamical mode: not chaotic, and not very regular. Wow? If it were chaotic, we wouldn't have coherent or consistent behavior at any scale. If overly regular, we'd be incredibly dull and unable to respond to the environment. You could do this with a computer. If your signals coming from the computer are either too regular or too unexpected, then it's probably broken. This sort of thing might be useful diagnostically, but doesn't really provide us with greater understanding...

tomrod 5y ago
A captured signal may represent a pathway for intervention, a cause, or a margin to address. Imagine if we found that schizophrenia or other potentially debilitating mental health condition were 99.9999% correlated with this signal being weak or strong. That would be telling. If only for diagnosis, and possibly as a cause. EDIT: a word - "would be telling"
civilized 5y ago
Welcome to the world of Complex Systems research. Complex Systems guy: we just showed a system operates in a critical state scale-free phase transition and its key statistics have a power law distribution! Everyone: okay, so? CS guy: I dunno? That's what our discipline does. It tells you things are in critical states with power laws. So now you know that...
- jquery 5y ago
  I think this research is super interesting, and it's disappointing such a blaze, dismissive comment is at the top. Cosmologists: we literally took a picture of a black hole! Someone: So? I already knew they existed. Besides, it's not a picture of a black hole, it's just the ring around the black hole. yawn Cosmologists: oh... sorry for wasting your time.
  - cjbgkagh 5y ago
    I was far more interested in the algorithms they used than the actual picture of the black hole.
    - iratewizard 5y ago
      The social politics that came out were most interesting to me. The person with a smaller contribution to the project taking a lion's share of credit. The lead, a soft coward who has been conditioned to let her take credit. The history of that tribe of people doing this sort of self promotion.
    - hoseja 5y ago
      And the imaging instrument.
  - hungryforcodes 5y ago
    It was pretty funny though -- and quite true, if you know CS people:)
jawarner 5y ago
It's interesting that we can measure, quantiatively, what the dynamical operating mode of a system is. It's interesting, to me anyway, because it's a high-level characteristic that describes most (all?) information processing systems.
Gravityloss 5y ago
Yes, and what you said is not novel. It was widely known at least 20 years ago when I was working in the business. From quick skimming, maybe it's some more subtle point in the publication.
croddin 5y ago
A computer sending compressed or encrypted network traffic would look as if it were sending unexpected noise if you don't know how to read it.
abeppu 5y ago
I didn't read the whole thing, but I did find parts of it surprising. Some things that jumped out at me: > during conscious states, the electrodynamics of the cortex are poised near a critical point or phase transition and that this near-critical behavior supports the vast flow of information through cortical networks during conscious states But we've had a lot of success building artificial systems that support a "vast flow of information" which I would expect are mostly nowhere near such a boundary. Stuff moves around within a periodic structure, and moving more info has corresponded to moving more information per period. Why would we not expect a pile of neurons with a ginormous number of connections to be able to move a lot of information even through largely periodic behavior? > we found that the Lempel–Ziv complexity of the model’s simulated electrodynamics (with noise inputs) was maximal when the deterministic component of its dynamics were poised near this critical onset of chaos I guess if the measure of "information richness" is based in compressibility of electrical activity ... is it surprising that it isn't higher in the chaotic phase? Why wouldn't one expect the chaotic system to produce as much or more random output?
- derefr 5y ago
  > Why wouldn't one expect the chaotic system to produce as much or more random output? Because neurons as systems don't like random input. Noisy random input doesn't make (most) neurons fire. Rather the opposite, actually. Neurons aren't (usually) simple threshold comparators of a single input; they're arbitrarily-complex gate-like recognizers, that fire in response to detecting signals in their combined inputs, or even upon matching temporal firing patterns within the signals of their combined inputs. In that sense, if you tune every component in the system to produce more noise (chaos), you decrease the signal-to-noise ratio, and so the components that react to "important recognizable changes in the signal" within that noise have a harder time recognizing the thing they're looking for, and so they recognize it less, and so switch less. --- By trite analogy: suppose you're a security guard. Your job is to recognize+report "real crimes in progress", while not reporting "false alarms." (Pretend that the police charge for false dispatches in your town, so your boss wants to optimize shrinkage vs. call budget.) Also, your boss has decided to "keep you on your toes" by introducing "noise" into your computerized security system. Sometimes it'll show a burglary in progress when there isn't one. Sometimes it'll show that everything's fine, when actually the boss has secretly sent in a white-hat burglar of his own. How willing to believe the security cameras should you be, to optimize your output signal to downstream demand? As it turns out, you should probably try to figure out the false-positive vs. false-negative rate you're seeing reported by the downstream, and then calibrate your confidence up/down until you're making a balanced number of Type 1 vs. Type 2 errors. That level of confidence is the "critical point" — where the noise in the system is equally likely to help your detection (by "correcting" a false negative/positive, turning it into a true positive/negative) as it is to harm. Moving away from that critical point, in either direction, makes your output less useful as a downstream signal.
bjornsing 5y ago
I had the same reaction. I wouldn’t be surprised if you could even formalize it and say that all information processing takes place on this edge between stability and chaos. That’s where all interesting/useful Turing machines live, for example.
- bloqs 5y ago
  Im fairly uneducated in CS, but this fascinates me, could you expand more? I can see why the brain's randomly firing neurons leads to novel thought and exploratory behavior but other than generating random numbers for various purposes, what good is chaos? What turing machines for example? Thanks
  - GolDDranks 5y ago
    It's not that the interesting Turing machines are chaotic, but they are close to the boundary, in the sense that they have interesting dynamical behaviour. The reason why it's so hard to do static analysis of computer programs (for example, an automated detection of memory vulnerabilities in C programs) is pretty much this near-chaotic dynamic behaviour that doesn't easily yield to static analysis.
  - bjornsing 5y ago
    One example that doesn’t require any CS to appreciate is Rule 110[1], arguably the simplest Turing complete system. It clearly shows this pattern graphically. Wikipedia describes it this way: “Rule 110, like the Game of Life, exhibits what Wolfram calls "Class 4 behavior", which is neither completely stable nor completely chaotic. Localized structures appear and interact in complex ways.” 1. https://en.m.wikipedia.org/wiki/Rule_110 https://en.m.wikipedia.org/wiki/Rule_110
steve76 5y ago
idiocrat 5y ago
Interestingly, this is how (surgical) sedatives usually work. They increase the average activity of all neurons, so the brain is losing consciousness, because no coherent thoughts can circulate anymore.
- hulahoof 5y ago
  That sounds really interesting and I have not heard of this before, where would you suggest to start reading into surgical sedatives?
- oarabbus_ 5y ago
  This is not supported by the literature as far as I'm aware, do you have a source? Propofol, the most common adult surgical anesthetic, decreases neuronal activity via the mechanism of making it harder for action potentials to fire [0], and has a litany of effects few of which are excitatory , and generally correlated to decreasing cortical activity [1]. And ketamine, the most common pediatric and veterinary anesthetic, has a complex mechanism of action acting on GABA, NMDA, and other receptor systems, often with generally inhibitory characteristics [2] and with definite decrease in brain activity in animal models [3]. [0] https://www.ncbi.nlm.nih.gov/books/NBK430884/ https://www.ncbi.nlm.nih.gov/books/NBK430884/ [1] https://elifesciences.org/articles/60824#:~:text=The%20broad%20range%20of%20dynamics,with%20the%20slow%2Ddelta%20oscillation https://elifesciences.org/articles/60824#:~:text=The%20broad.... [2] https://journals.lww.com/anesthesia-analgesia/Fulltext/1998/11000/KetamineTeaching_an_Old_Drug_New_Tricks.39.aspx https://journals.lww.com/anesthesia-analgesia/Fulltext/1998/... [3] https://www.sciencedirect.com/science/article/abs/pii/0028390868900671 https://www.sciencedirect.com/science/article/abs/pii/002839...
- hoseja 5y ago
  That sounds like it would scramble your brain long-term.
jquery 5y ago
>If overly regular, we'd be incredibly dull and unable to respond to the environment. What do you mean by this? Are computers regular? What about a computer programmed to respond to its environment? What do you even mean "respond to environment"? Why does it operate in this mode when awake but not when asleep? Please, since this research is so obvious to you, I would love to hear your insights on consciousness. They are far beyond mine.
p_noumenon 5y ago
If overly regular, you're probably having a seizure.
periheli0n 5y ago
Indeed it has long been known that the awake human brain operates near a critical point. Unfortunately, their significance statement is very generic and doesn't really summarise their main contributions. The abstract has more information, describing how this paper adds to the picture a mathematical determination of that critical point, and the insight that low-frequency oscillations play a key role when switching consciousness states. The level of the experiments is quite high, also they use primates (humans and macaques), some of them epileptic, and they administer psychedelics. All this sets the paper apart from lower-tier work. It doesn't strike me as a real ground-breaking paper, but still an important contribution to the field. And the methods are impressive.

tomrod 5y ago

A captured signal may represent a pathway for intervention, a cause, or a margin to address. Imagine if we found that schizophrenia or other potentially debilitating mental health condition were 99.9999% correlated with this signal being weak or strong. That would be telling. If only for diagnosis, and possibly as a cause. EDIT: a word - "would be telling"

civilized 5y ago

Welcome to the world of Complex Systems research. Complex Systems guy: we just showed a system operates in a critical state scale-free phase transition and its key statistics have a power law distribution! Everyone: okay, so? CS guy: I dunno? That's what our discipline does. It tells you things are in critical states with power laws. So now you know that...

jquery 5y ago
I think this research is super interesting, and it's disappointing such a blaze, dismissive comment is at the top. Cosmologists: we literally took a picture of a black hole! Someone: So? I already knew they existed. Besides, it's not a picture of a black hole, it's just the ring around the black hole. yawn Cosmologists: oh... sorry for wasting your time.
- cjbgkagh 5y ago
  I was far more interested in the algorithms they used than the actual picture of the black hole.
  - iratewizard 5y ago
    The social politics that came out were most interesting to me. The person with a smaller contribution to the project taking a lion's share of credit. The lead, a soft coward who has been conditioned to let her take credit. The history of that tribe of people doing this sort of self promotion.
  - hoseja 5y ago
    And the imaging instrument.
- hungryforcodes 5y ago
  It was pretty funny though -- and quite true, if you know CS people:)

jawarner 5y ago

It's interesting that we can measure, quantiatively, what the dynamical operating mode of a system is. It's interesting, to me anyway, because it's a high-level characteristic that describes most (all?) information processing systems.

Gravityloss 5y ago

Yes, and what you said is not novel. It was widely known at least 20 years ago when I was working in the business. From quick skimming, maybe it's some more subtle point in the publication.

croddin 5y ago

A computer sending compressed or encrypted network traffic would look as if it were sending unexpected noise if you don't know how to read it.

abeppu 5y ago

I didn't read the whole thing, but I did find parts of it surprising. Some things that jumped out at me: > during conscious states, the electrodynamics of the cortex are poised near a critical point or phase transition and that this near-critical behavior supports the vast flow of information through cortical networks during conscious states But we've had a lot of success building artificial systems that support a "vast flow of information" which I would expect are mostly nowhere near such a boundary. Stuff moves around within a periodic structure, and moving more info has corresponded to moving more information per period. Why would we not expect a pile of neurons with a ginormous number of connections to be able to move a lot of information even through largely periodic behavior? > we found that the Lempel–Ziv complexity of the model’s simulated electrodynamics (with noise inputs) was maximal when the deterministic component of its dynamics were poised near this critical onset of chaos I guess if the measure of "information richness" is based in compressibility of electrical activity ... is it surprising that it isn't higher in the chaotic phase? Why wouldn't one expect the chaotic system to produce as much or more random output?

derefr 5y ago
> Why wouldn't one expect the chaotic system to produce as much or more random output? Because neurons as systems don't like random input. Noisy random input doesn't make (most) neurons fire. Rather the opposite, actually. Neurons aren't (usually) simple threshold comparators of a single input; they're arbitrarily-complex gate-like recognizers, that fire in response to detecting signals in their combined inputs, or even upon matching temporal firing patterns within the signals of their combined inputs. In that sense, if you tune every component in the system to produce more noise (chaos), you decrease the signal-to-noise ratio, and so the components that react to "important recognizable changes in the signal" within that noise have a harder time recognizing the thing they're looking for, and so they recognize it less, and so switch less. --- By trite analogy: suppose you're a security guard. Your job is to recognize+report "real crimes in progress", while not reporting "false alarms." (Pretend that the police charge for false dispatches in your town, so your boss wants to optimize shrinkage vs. call budget.) Also, your boss has decided to "keep you on your toes" by introducing "noise" into your computerized security system. Sometimes it'll show a burglary in progress when there isn't one. Sometimes it'll show that everything's fine, when actually the boss has secretly sent in a white-hat burglar of his own. How willing to believe the security cameras should you be, to optimize your output signal to downstream demand? As it turns out, you should probably try to figure out the false-positive vs. false-negative rate you're seeing reported by the downstream, and then calibrate your confidence up/down until you're making a balanced number of Type 1 vs. Type 2 errors. That level of confidence is the "critical point" — where the noise in the system is equally likely to help your detection (by "correcting" a false negative/positive, turning it into a true positive/negative) as it is to harm. Moving away from that critical point, in either direction, makes your output less useful as a downstream signal.

bjornsing 5y ago

I had the same reaction. I wouldn’t be surprised if you could even formalize it and say that all information processing takes place on this edge between stability and chaos. That’s where all interesting/useful Turing machines live, for example.

bloqs 5y ago
Im fairly uneducated in CS, but this fascinates me, could you expand more? I can see why the brain's randomly firing neurons leads to novel thought and exploratory behavior but other than generating random numbers for various purposes, what good is chaos? What turing machines for example? Thanks
- GolDDranks 5y ago
  It's not that the interesting Turing machines are chaotic, but they are close to the boundary, in the sense that they have interesting dynamical behaviour. The reason why it's so hard to do static analysis of computer programs (for example, an automated detection of memory vulnerabilities in C programs) is pretty much this near-chaotic dynamic behaviour that doesn't easily yield to static analysis.
- bjornsing 5y ago
  One example that doesn’t require any CS to appreciate is Rule 110[1], arguably the simplest Turing complete system. It clearly shows this pattern graphically. Wikipedia describes it this way: “Rule 110, like the Game of Life, exhibits what Wolfram calls "Class 4 behavior", which is neither completely stable nor completely chaotic. Localized structures appear and interact in complex ways.” 1. https://en.m.wikipedia.org/wiki/Rule_110 https://en.m.wikipedia.org/wiki/Rule_110

steve76 5y ago

idiocrat 5y ago

Interestingly, this is how (surgical) sedatives usually work. They increase the average activity of all neurons, so the brain is losing consciousness, because no coherent thoughts can circulate anymore.

hulahoof 5y ago
That sounds really interesting and I have not heard of this before, where would you suggest to start reading into surgical sedatives?
oarabbus_ 5y ago
This is not supported by the literature as far as I'm aware, do you have a source? Propofol, the most common adult surgical anesthetic, decreases neuronal activity via the mechanism of making it harder for action potentials to fire [0], and has a litany of effects few of which are excitatory , and generally correlated to decreasing cortical activity [1]. And ketamine, the most common pediatric and veterinary anesthetic, has a complex mechanism of action acting on GABA, NMDA, and other receptor systems, often with generally inhibitory characteristics [2] and with definite decrease in brain activity in animal models [3]. [0] https://www.ncbi.nlm.nih.gov/books/NBK430884/ https://www.ncbi.nlm.nih.gov/books/NBK430884/ [1] https://elifesciences.org/articles/60824#:~:text=The%20broad%20range%20of%20dynamics,with%20the%20slow%2Ddelta%20oscillation https://elifesciences.org/articles/60824#:~:text=The%20broad.... [2] https://journals.lww.com/anesthesia-analgesia/Fulltext/1998/11000/KetamineTeaching_an_Old_Drug_New_Tricks.39.aspx https://journals.lww.com/anesthesia-analgesia/Fulltext/1998/... [3] https://www.sciencedirect.com/science/article/abs/pii/0028390868900671 https://www.sciencedirect.com/science/article/abs/pii/002839...
hoseja 5y ago
That sounds like it would scramble your brain long-term.

jquery 5y ago

>If overly regular, we'd be incredibly dull and unable to respond to the environment. What do you mean by this? Are computers regular? What about a computer programmed to respond to its environment? What do you even mean "respond to environment"? Why does it operate in this mode when awake but not when asleep? Please, since this research is so obvious to you, I would love to hear your insights on consciousness. They are far beyond mine.

p_noumenon 5y ago

If overly regular, you're probably having a seizure.

periheli0n 5y ago

Indeed it has long been known that the awake human brain operates near a critical point. Unfortunately, their significance statement is very generic and doesn't really summarise their main contributions. The abstract has more information, describing how this paper adds to the picture a mathematical determination of that critical point, and the insight that low-frequency oscillations play a key role when switching consciousness states. The level of the experiments is quite high, also they use primates (humans and macaques), some of them epileptic, and they administer psychedelics. All this sets the paper apart from lower-tier work. It doesn't strike me as a real ground-breaking paper, but still an important contribution to the field. And the methods are impressive.