3 ms·

Do you need to not think of anything else to move your arms?

SavantIdiot 5y ago
Not until you said that. Thanks.
AussieWog93 5y ago
Ex-BCI research student here. The nerves that control your arm are wired directly into your central nervous system and can active your muscles in direct response to action potentials fanned out from a single neuron. These noninvasive technologies pick up aggregate signals from hundreds of thousands of neurons all firing pseudo-randomly, filtered spatially by the dura (thick layer of membrane that protects the brain), skull, flesh, skin and hair. A more "HN" analogy would be like comparing a directly wired Ethernet connection (nerves connected to the CNS) to a side channel attack on an air-gapped system (noninvasive EEG). While randomly running background processes (normally) won't affect the data transmitted to the network, they will absolutely foil most side channel attacks.
- zaptrem 5y ago
  This is a great analogy.
- westurner 5y ago
  What about with realtime NIRS with an (inverse?) scattering matrix? From https://www.openwater.cc/technology https://www.openwater.cc/technology : > Below are examples of the image quality we have achieved with our breakthrough scanning systems that use just red and near-infrared light and ultrasound pings. https://en.wikipedia.org/wiki/Near-infrared_spectroscopy https://en.wikipedia.org/wiki/Near-infrared_spectroscopy Another question: is it possible to do ah molecular identification similar to idk quantum crystallography with photons of any wavelength, such as NIRS? Could that count things in samples? https://twitter.com/westurner/status/1239012387367387138 https://twitter.com/westurner/status/1239012387367387138 : > ... quantum crystallography: https://en.wikipedia.org/wiki/Quantum_crystallography https://en.wikipedia.org/wiki/Quantum_crystallography There's probably some limit to infrared crystallography that anyone who knows anything about particles and lattices would know about ?
  - omgitsabird 5y ago
    A couple of studies linked in Wikipedia for this use (one retracted): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049706/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049706/ Retracted: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002593 https://journals.plos.org/plosbiology/article?id=10.1371/jou... Table with resolution differences between different techniques: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116487/table/T1/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116487/table/T...
    - westurner 5y ago
      > Table with resolution differences between different techniques: Looks like MEG has the best temporal and spatial resolutions.
  - AussieWog93 5y ago
    > What about with realtime NIRS with an (inverse?) scattering matrix? I've purged a lot of the knowledge from that time from my brain, but from what I recall fNIRS takes a long time (on the order of multiple seconds) to take a single reading. It also only really shows which regions of the brain are receiving more blood supply. While a huge improvement in spacial precision over EEG, it's still not anywhere near the same level of precision that a directly-wired nerve has. That doesn't mean it's useless technology, just probably not viable for the low-latency, high-accuracy control you'd want for a military drone. >Another question: is it possible to do ah molecular identification similar to idk quantum crystallography with photons of any wavelength, such as NIRS? Could that count things in samples? I have absolutely no idea about molecular identification or quantum crystallography, so probably can't give you a good answer on that one.
    - mattkrause 5y ago
      The newer systems can sample much faster (10-100 Hz), but they're still limited by the fact that they're measuring a hemodynamic signal that lags behind neural activity.
- deleted 5y ago
  [deleted]

Not until you said that. Thanks.

Ex-BCI research student here. The nerves that control your arm are wired directly into your central nervous system and can active your muscles in direct response to action potentials fanned out from a single neuron. These noninvasive technologies pick up aggregate signals from hundreds of thousands of neurons all firing pseudo-randomly, filtered spatially by the dura (thick layer of membrane that protects the brain), skull, flesh, skin and hair. A more "HN" analogy would be like comparing a directly wired Ethernet connection (nerves connected to the CNS) to a side channel attack on an air-gapped system (noninvasive EEG). While randomly running background processes (normally) won't affect the data transmitted to the network, they will absolutely foil most side channel attacks.

zaptrem 5y ago
This is a great analogy.
westurner 5y ago
What about with realtime NIRS with an (inverse?) scattering matrix? From https://www.openwater.cc/technology https://www.openwater.cc/technology : > Below are examples of the image quality we have achieved with our breakthrough scanning systems that use just red and near-infrared light and ultrasound pings. https://en.wikipedia.org/wiki/Near-infrared_spectroscopy https://en.wikipedia.org/wiki/Near-infrared_spectroscopy Another question: is it possible to do ah molecular identification similar to idk quantum crystallography with photons of any wavelength, such as NIRS? Could that count things in samples? https://twitter.com/westurner/status/1239012387367387138 https://twitter.com/westurner/status/1239012387367387138 : > ... quantum crystallography: https://en.wikipedia.org/wiki/Quantum_crystallography https://en.wikipedia.org/wiki/Quantum_crystallography There's probably some limit to infrared crystallography that anyone who knows anything about particles and lattices would know about ?
- omgitsabird 5y ago
  A couple of studies linked in Wikipedia for this use (one retracted): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049706/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049706/ Retracted: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002593 https://journals.plos.org/plosbiology/article?id=10.1371/jou... Table with resolution differences between different techniques: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116487/table/T1/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116487/table/T...
  - westurner 5y ago
    > Table with resolution differences between different techniques: Looks like MEG has the best temporal and spatial resolutions.
- AussieWog93 5y ago
  > What about with realtime NIRS with an (inverse?) scattering matrix? I've purged a lot of the knowledge from that time from my brain, but from what I recall fNIRS takes a long time (on the order of multiple seconds) to take a single reading. It also only really shows which regions of the brain are receiving more blood supply. While a huge improvement in spacial precision over EEG, it's still not anywhere near the same level of precision that a directly-wired nerve has. That doesn't mean it's useless technology, just probably not viable for the low-latency, high-accuracy control you'd want for a military drone. >Another question: is it possible to do ah molecular identification similar to idk quantum crystallography with photons of any wavelength, such as NIRS? Could that count things in samples? I have absolutely no idea about molecular identification or quantum crystallography, so probably can't give you a good answer on that one.
  - mattkrause 5y ago
    The newer systems can sample much faster (10-100 Hz), but they're still limited by the fact that they're measuring a hemodynamic signal that lags behind neural activity.
deleted 5y ago
[deleted]