Comment by ericjang | Hacker News Reader

Comment by ericjang | Hacker News Reader

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There are some very difficult challenges in brain-computer interfaces (BCI), some of which involve huge barriers presented by human biology. It's rather depressing.

Presently, there is no good way to read data from the brain to a device. You can drill a hole in your head and patch-clamp some electrodes to your brain tissue, but this procedure is only recommended for treating debilitating diseases like Parkinson's. Furthermore, there is the issue of scar tissue developing over time as a small region of your brain is being bombarded with electricity / contact with foreign metals that trigger immune response.

I do think a spinal tap of some sort might make more sense (rather than patching directly into brain tissue like in the Matrix), but you still get scar tissue.

Non-invasive methods don't have scar tissue, but it's unclear whether measuring the surface activity of the brain yields sufficient information. Furthermore, they are highly noisy due to ambient static and muscle activity. You shouldn't move much if you want o.k. readings.

The BCI dream is to have a lightweight headset that you put behind your ears like in Iron Man 3 or Big Hero 6 (and then you control robots with your mere thoughts). However, I think that kind of technology is really far away, short of some huge breakthroughs in compressed sensing and possibly superconductor physics.

Even more difficult than reading data is writing it back in. There have been very early results with getting monkeys to telepathically control each other's muscle movements, but my understanding is that it's not very reliable.

A reasonable survey can be found here: http://www.sciencedirect.com/science/article/pii/S1110866515...

On the other hand, going in the other direction (from machine to brain) is actually surprisingly easy. It turns out that, when you take what is possibly the best general-purpose signal and pattern interpretation and recognition engine in the entirety of our observable[1] universe (aka the human brain), and combine it with any kind of consistent, interpretable feedback from the outside world, after a little while it just kinda figures it out and goes along with it [2]. From stimulation under the tongue producing sight in the blind to a vibrating belt compass giving people a subcognitive sense of north vs south, the brain is really damn good at doing this. So in that sense, it's looking incredibly promising.

The success of innervated prosthetics[3] suggests that the peripheral nervous system is a viable point of access as well. And, what's more, these interfaces are already bidirectional.

This is absolutely wild conjecture, but I've had the thought for a while that you could conceivably induce (or externally grow and then graft) a new peripheral nervous "port" somewhere. It'd be a bit like teeing off of a plumbing line (understatement of difficulty level: over 9000), and then you'd have a dedicated cluster of new nerves you could start to "play" with, sending and receiving arbitrary signals. But there are some very difficult ethical questions involved for anyone who were hypothetically interested in pursuing this approach.

Ultimately, that's what I think (rightly) holds us back for BCI: invasive procedures are just too ethically questionable for anything other than self-modification, which is okay in the body-hacking community, but still decidedly un-mainstream.

[1] At this point in time, since we've yet to find extraterrestrial life, caveat emptor, etc etc etc

[2] Points-of-entry for googling and wiki'ing: "neural plasticity" and "sensory substitution"

[3] Terms to search for: "innervated prosthetics" and "targeted reinnervation"

My personal scifi idea: induce the growth of such a cluster of nerves in the neck, manipulate some of them to better respond to specific stimuli as an input, and try to force the brain to rewire itself to use the other nerves in the cluster as an output (not sure how to do this, but see reinforcement [1] for my current idea).

[1] http://qz.com/757516/paraplegics-are-learning-to-walk-again-...

Then you make a necklace as an interface with the noninvasive BCI hardware, communicating through your skin. (considering all the other noninvasive options, a necklace seems to be the most appropriate IMHO)

I've got no idea on how to make the nerves susceptible enough for it to provide useful bandwidth, but maybe a properly primed stemcell injection could provide the growth of usable nerves for it.

From there you can give the brain new senses via various sensors, give us high speed mental computer interfaces (awesome for quick calculations) and ditch the need for physical remote controls.

> and try to force the brain to rewire itself to use the other nerves in the cluster as an output

I think that's very likely to be innately possible, given both research like you linked, as well as existing animal experiments with BCI. The brain is just an incredibly impressive thing.

> There are some very difficult challenges in brain-computer interfaces (BCI), some of which involve huge barriers presented by human biology. It's rather depressing.

Completely agree. I don't think BCI is likely to take off seriously until we assert more confident control over our own biology. In particular, techniques like CRISPR may eventually open the door to temporary, local and reversible genetic manipulation of body tissues that would allow human body to grow and shed tiny BCI connectors with desired specs.

This is probably a few hundreds of years of development (and political and moral arguments) away though.

Depressing indeed.

> This is probably a few hundreds of years of development (and political and moral arguments) away though.

This. I might start getting excited about brain-computer interfaces once we have a proof-of-concept non-chemical local anaesthetic. Like, wire something into your finger neurons that erases pain signals sent from finger. That's several orders of magnitude simpler than a full-blown brain-computer interface, yet we're nowhere even close to it.

Even if you solve the scarring issue, the invasive option seems impractical. They might use it on patients that are locked out or missing senses. But what doctor would let a healthy person get brain surgery so they can use a computer slightly faster? Would the FDA ever approve something like that?

However there are other options. People have figured out how to hijack existing senses. There was a plate you could put on your tongue that would let you see images through the nerves on your tongue. There was a project that converted video to sound waves, so you could learn to see through your ears. And there was a guy who made a vibrating suit which could let deaf people hear again by converting sound to more noticeable vibration frequencies.

It's unclear what these extra inputs actually add over just presenting information on a computer monitor or HUD and using vision. I think brain interfaces are massively overhyped. Our brain is already super flexible and can learn to process info from existing interfaces just as well.

I recall in a sci-fi Asimov book, it was related to the 2001 series, there was a skull cap that everyone wore in the 3000's that once placed on your head was permanent as its tendrils weaved its way into your scalp. They were like nano-scale. That idea, although completely sci-fi, seems pretty awesome as there would be more direct input if the entire surface area of your brain was a read-write interface. Also that is scary in terms of abuse.

That was Arthur C. Clarke. 3001: The Final Odyssey.

yes, you got it. the sci-fi stack exchange chops are strong in you.

Optogenetics possibly provides a solution to the interface problem. When you can use light to read from and send signals to neurons, you don't have to worry about scar tissue at all, as far as I know.

But it is not applicable to humans because in order to use it with human brain one has to modify genes and breed humans from embrions with modified genes.

CRISPR techniques allow for editing genes of adult organisms.

Here's a good video about it: https://www.youtube.com/watch?v=jAhjPd4uNFY

I don't think optogenetics is feasible for human BCI. Optogenetics requires one to express channelrhodopsin proteins in the neurons of interest - which means you need to genetically modify the human at birth. We know how to do this in mice, but not humans since the gene expression pathway for neural proteins in humans is poorly understood (unlike mice and zebrafish). Even with optimal designer baby scenarios, there's no hope for us adults; gene-editing therapies for adults is way harder and we'll likely be long dead before we see anything close.

CRISPR techniques allow us to modify gene expression in organisms long after birth; it has been heavily used in adult animals, but I don't think it's been used in humans just yet.

CRISPR is cool, but isn't the challenge of adult genome editing bottlenecked by the delivery vehicle? Last time I checked it's still hard to deliver viral vectors past the blood-brain barrier. Does CRISPR have a unique solution to that? I also would imagine that a "BCI" optogenetic adapter would be so massive that payload size alone (never mind electric properties) would never make it past the BBB.

You don't need to genetically modify an organism at birth to use optogenetics.

What about circuits / probes made from biological materials rather than metal/silicon?

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