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Neurons unexpectedly encode information in the timing of their firing

quantamagazine.org

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Re: Neurons unexpectedly encode information in the timing of their firing

#61

Post by sdenton4 »

nocturnial wrote: post #36
alexmorley wrote: post #14

> For decades, neuroscientists have treated the brain somewhat like a Geiger counter: The rate at which neurons fire is taken as a measure of activity, just as a Geiger counter’s click rate indicates the strength of radiation. This hasn't been true for at least 20 years. There's a classic paper showing evidence of this in 1993 (O'Keefe and Reece) in rats. And has been an active area of discussion both before and sinc…

They mentioned this in the 3rd paragraph: "This temporal firing phenomenon is well documented in certain brain areas of rats, but the new study and others suggest it might be far more widespread in mammalian brains."

Hilarious. We shouldn't trust rat/mouse studies, but it's typically because the mice are way LESS complicated than humans. I would expect complicated behavior in mice to be treated as a lower bound for the complexity in humans. (but what do i know, i'm just a monkey.)

Re: Neurons unexpectedly encode information in the timing of their firing

#62

Post by tsimionescu »

skohan wrote: post #54
tgbugs wrote: post #49

Rate coding vs temporal coding is literally a meme in neuroscience because the two camps seem to refuse to compromise. Everyone else has realized that both happen depending on how that particular part of the nervous system works, or even what particular kind of information is flowing through it. This title reads like it was written by a rate coder who woke up one day and was like "Woah, you mean ... there might be mo…

I feel like the more you learn about neuroscience, the more you learn how precise and complex neural information processing is. For instance, there's evidence that at least some neurons "record" information about their activity in the form of RNA. Also the placement of synapses in the dendritic arbour matters, and some synapses can act like logic gates with respect to the synapses farther down the same branches. I th…

I think it's also fascinating to learn about computation, sensing, reaction etc. in other cells, both within multicell organisms and when looking at single cell organisms.

There was an article on this that I don't know how to find again - the point being that neurons are not unique in their capacity for computation, they are only the most evolved formed of it.

Re: Neurons unexpectedly encode information in the timing of their firing

#63

Post by tsimionescu »

mikewarot wrote: post #16
radicaldreamer wrote: post #6

Earlier quoted context omitted.

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.

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

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.

Re: Neurons unexpectedly encode information in the timing of their firing

#64

Post by mikewarot »

tsimionescu wrote: post #63
mikewarot wrote: post #16

Earlier quoted context omitted.

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

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.

Quantum computers are not Turing machines as far a I know.

They can encode exponentially many states simultaneously, and are non-deterministic.

Re: Neurons unexpectedly encode information in the timing of their firing

#65

Post by tsimionescu »

mikewarot wrote: post #64
tsimionescu wrote: post #63

Earlier quoted context omitted.

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.

Quantum computers are not Turing machines as far a I know. They can encode exponentially many states simultaneously, and are non-deterministic.

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.

Re: Neurons unexpectedly encode information in the timing of their firing

#67

Post by LeifCarrotson »

In my very different field (robotics and industrial automation), temporal coding is one of the most powerful ways to expand your IO. Nearly all PLCs, sensors, and robots make heavy use of digital IO. But this parallel interface is limited, especially with hard-wired signals, and even if you're using serial network protocols the typical fieldbus abstraction represents the network as fixed-size buffers of digital IO that update every few milliseconds. Analog signals are usually an expensive optional extra!

However, the controllers all include high-resolution timers. If you need to transmit an analog value, rather than bit-coding it over 12 discrete digital IO, a clever programmer might turn on a digital output for the desired number of milliseconds, or select between 10 or 16 or however many states you want to represent with your one wire using a predefined list of durations. You can convey far richer information this way!

Always interesting to see what researchers are discovering in the automated control system that is biology... sometimes we can discover techniques for use in industry with biomimicry, sometimes biology we didn't know about seems to imitate technology we developed independently.

Re: Neurons unexpectedly encode information in the timing of their firing

#68

Post by pengstrom »

munificent wrote: post #32
londons_explore wrote: post #26

Earlier quoted context omitted.

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.

> 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 un…

Readers might be interested in the following philosophy subjects https://en.m.wikipedia.org/wiki/Property_dualism https://en.m.wikipedia.org/wiki/Computational_theory_of_mind https://en.m.wikipedia.org/wiki/Supervenience

Re: Neurons unexpectedly encode information in the timing of their firing

#69

Post by nielsole »

LeifCarrotson wrote: post #67

In my very different field (robotics and industrial automation), temporal coding is one of the most powerful ways to expand your IO. Nearly all PLCs, sensors, and robots make heavy use of digital IO. But this parallel interface is limited, especially with hard-wired signals, and even if you're using serial network protocols the typical fieldbus abstraction represents the network as fixed-size buffers of digital IO th…

Not sure I understood you.

Did you describe PWM?

Re: Neurons unexpectedly encode information in the timing of their firing

#70

Post by eloff »

sdenton4 wrote: post #61
nocturnial wrote: post #36

Earlier quoted context omitted.

They mentioned this in the 3rd paragraph: "This temporal firing phenomenon is well documented in certain brain areas of rats, but the new study and others suggest it might be far more widespread in mammalian brains."

Hilarious. We shouldn't trust rat/mouse studies, but it's typically because the mice are way LESS complicated than humans. I would expect complicated behavior in mice to be treated as a lower bound for the complexity in humans. (but what do i know, i'm just a monkey.)

There are lots of animals that can beat us at specific neural tasks. So I don't think it's helpful to think in those terms. For example, our visual short term memory is bested by chimpanzees, at least on certain tasks used to measure it across both chimps and humans.

Lowly mice likely have better olfactory capabilities than us. It wouldn't surprise me if their brains can handle some very specific things better than we do.

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