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ref: -2020 tags: Neuralink commentary BMI pigs date: 08-31-2020 18:01 gmt revision:1 [0] [head]

Neuralink progress update August 28 2020

Some commentary.

The good:

  • Ian hit the nail on the head @ 1:05:47. That is not a side-benefit -- that was the original and true purpose. Thank you.
  • The electronics, amplify / record / sort / stim ASIC, as well as interconnect all advance the state of the art in density, power efficiency, and capability. (I always liked higher sampling rates, but w/e)
  • Puck is an ideal form factor, again SOTA. 25mm diameter craniotomy should give plenty of space for 32 x 32-channel depth electrodes (say).
  • I would estimate that the high-density per electrode feed-through is also SOTA, but it might also be a non-hermetic pass-through via the thin-film (e.g. some water vapor diffusion along the length of the polyimide (if that polymer is being used)).
  • Robot looks nice dressed in those fancy robes. Also looks like there is a revolute joint along the coronal axis.
  • Stim on every channel is cool.
  • Pigs seem like an ethical substitute for monkeys.

The mixed:

  • Neurons are not wires.
  • $2000 outpatient neurosurgery?! Will need to address the ~3% complication rate for most neurosurgery.
  • Where is the monkey data? Does it not work in monkeys? Insufficient longevity or yield? Was it strategic to not mention any monkeys, to avoid bad PR or the wrath of PETA?
    • I can't imagine getting into humans without demonstrating both safety and effectiveness on monkeys. Pigs are fine for the safety part, but monkeys are the present standard for efficacy.
  • How long do the electrodes last in pigs? What is the recording quality? How stable are the traces?
    • Judging from the commentary, assume this is a electrode material problem? What does Neuralink do if they are not significantly different in yield and longevity than the Utah array? (The other problems might well be easier than this one.)
      • That said, a thousand channels of EMG should be sufficient for some of the intended applications (below).
    • It really remains to be seen how well the brain tolerates these somewhat-large somewhat-thin electrodes, what percentage of the brain is disrupted in the process of insertion, and how much of the disruption is transient / how much is irrecoverable.
    • Pig-snout somatosensory cortex is an unusual recording location, making comparison difficult, but what was shown seemed rather correlated (?) We'd have to read an actual scientific publication to evaluate.
  • This slide is deceptive, as not all the applications are equally .. applicable. You don't need an extracellular ephys device to solve these problems that "almost everyone" will encounter over the course of their lives.
    • Memory loss -- Probably better dealt with via cellular / biological therapies, or treating the causes (stroke, infection, inflammation, neuroendocrine or neuromodulatory disregulation)
    • Hearing loss -- Reasonable. Nice complement to improved cochlear implants too. (Maybe the Neuralink ASIC could be used for that, too).
      • With this and the other reasonable applications, best to keep in context that stereo EEG, which is fairly disruptive w/ large probes, is well tolerated in epilepsy patients. (It has unclear effect on IQ or memory, but still, the sewing machine should be less invasive.)
    • Blindness -- Reasonable. Mating the puck to a Second Sight style thin film would improve channel count dramatically, and be less invasive. Otherwise you have to sew into the calcarine fissure, destroying a fair bit of cortex in the process & possibly hitting an artery or sulcal vein.
    • Paralysis -- Absolutely. This application is well demonstrated, and the Neuralink device should be able to help SCI patients. Presumably this will occupy them for the next five years; other applications would be a distraction.
      • Being able to sew flexible electrodes into the spinal cord is a great application.
    • Depression -- Need deeper targets for this. Research to treat depression via basal ganglia stim is ongoing; no reason it could not be mated to the Neuralink puck + long electrodes.
    • Insomina -- I guess?
    • Extreme pain -- Simpler approaches are likely better, but sure?
    • Seizures -- Yes, but note that Neuropace burned through $250M and wasn't significantly better than sham surgery. Again, likely better dealt with biologically: recombinant ion channels, glial or interneuron stem cell therapy.
    • Anxiety -- maybe? Designer drugs seem safer. Or drugs + CBT. Elon likes root causes: spotlight on the structural ills of our society.
    • Addiction -- Yes. It seems possible to rewire the brain with the right record / stim strategy, via for example a combination of DBS and cortical recording. Social restructuring is again a better root-cause fix.
    • Strokes -- No, despite best efforts, the robot causes (small) strokes.
    • Brain Damage -- Insertion of electrodes causes brain damage. Again, better dealt with via cellular (e.g. stem cells) or biological approaches.
      • This, of course, will take time as our understanding of brain development is limited; the good thing is that sufficient guidance signals remain in the adult brain, so AFAIK it's possible. From his comments, seems Alan's attitude is more aligned with this.
    • Not really bad per-se, but right panel could be better. I assume this was a design decision trade-off between working distance, NA, illumination, and mechanical constraints.
    • Despite Elon's claims, there is always bleeding when you poke electrodes that large into the cortex; the capillary bed is too dense. Let's assume Elon meant 'macro' bleeding, which is true. At least the robot avoids visible vessels.
    • Predicting joint angles for cyclical behavior is not challenging; can be done with EMG or microphonic noise correlated to some part of the gait. Hence the request for monkey BMI data.
  • Given the risk, pretty much any of the "sci-fi" applications mentioned in response to dorky twitter comments can be better provided to neurologically normal people through electronics, without the risk of brain surgery.
  • Regarding sci-fi application linguistic telepathy:
    • First, agreed, clarifying thoughts into language takes effort. This is a mostly unavoidable and largely good task. Interfacing with the external world is a vital part of cognition; shortcutting it, in my estimation, will just lead to sloppy & half-formed ideas not worth communicating. The compression of thoughts into words (as lossy as it may be) is the primary way to make them discrete enough to be meaningful to both other people and yourself.
    • Secondly: speech (or again any of the many other forms of communication) is not that much slower than cognition. If it was, we'd have much larger vocabularies, much more complicated and meaning-conveying grammar, etc (Like Latin?). The limit is the average persons cognition and memory. I disagree with Elon's conceit.
  • Regarding visual telepathy, with sufficient recording capabilities, I see no reason why you couldn't have a video-out port on the brain. Difficult given the currently mostly unknown representation of higher-level visual cortices, but as Ian says, once you have a good oscilloscope, this can be deduced.
  • Regarding AI symbiosis @1:09:19; this logic is not entirely clear to me. AI is a tool that will automate & facilitate the production and translation of knowledge much the same way electricity etc automated & facilitated the production and transportation of physical goods. We will necessarily need to interface with it, but to the point that we are thoroughly modifying our own development & biology, those interfaces will likely be based on presently extant computer interfaces.
    • If we do start modifying the biological wiring structure of our brains, I can't imagine that there will many limits! (Outside hard metabolic limits that brain vasculature takes pains to allocate and optimize.)
    • So, I guess the central tenet might be vaguely ok if you allow that humans are presently symbiotic with cell phones. (A more realistic interpretation is that cell phones are tools, and maybe Google etc are the symbionts / parasites). This is arguably contributing to current political existential crises -- no need to look further. If you do look further, it's not clear that stabbing the brains of healthy individuals will help.
    • I find the MC to be slightly unctuous and ingratiating in a way appropriate for a video game company, but not for a medical device company. That, of course, is a judgement call & matter of taste. Yet, as this was partly a recruiting event ... you will find who you set the table for.