Double neural bypass restores movement, sense of touch after paralysis | Hacker News Reader

Double neural bypass restores movement, sense of touch after paralysis

feinstein.northwell.edu

181 pointskvee28 comments

The main problem they don't talk much about, and why this isn't ready to go mainstream, is that those brain implants will decay over time.

The brain will build up scar tissue around the electrodes and render them useless. These are basically little needles put into a jell-o which then wiggles around all the time. This constantly irritates and damages the tissue. Your immune system hates this.

Even within months there's a significant decay. But, within 5-10 years most of the array becomes pretty useless. Of course, you can't replace it easily. And the damage to that area, while local, isn't reversible.

There's a lot of research on trying to make a brain implant that can last longer so that all of these treatments become viable. But we still have basically nothing.

Couldn‘t one simple cut the decayed ends and graft new electrodes to fresher nerves behind?

Yes, yes, slowly cutting away at the non reneweable nerves, widening the gap to keep the connection working, becoming more cyborg as the time passes.

Sounds crazy, but for the reward it brings, is there a price too high?

Figuring out the required stem cell treatment to properly regenerate damaged nerves or creating some kind of non-degrading synthetic nerve that can be placed in the spine (or wherever) seems like a much better long term goal.

That sounds like a great idea for the long term, but what about the people that need a solution today? We have to make do with what we got until science advances.

I don‘t think there is any realistic path to those things though.

Makes you wish for a room temperature super conductor magnet that could deduce nerves from magnetic fields sensored and induce electric pulses via induction and wave intersection.

DBS hardware seems to work - does it also have these issues or are you excluding it for some reason?

https://en.m.wikipedia.org/wiki/Deep_brain_stimulation

Deep brain stimulation is a whole other ballgame.

Most DBS setups right now don't do any sensing. They just send a regular pulse that is manually adjusted. It doesn't really matter that much that there is a small amount of scar tissue around the electrode, the scar tissue is also a conductor. And, that area of the brain is likely pretty damaged anyway.

Sensing DBS with closed-loop feedback is very new. But there you're looking to sense at a totally different resolution. With something like a Utah array, they're looking to record extremely accurately from a very small number of neurons, like individual neurons. With DBS sensing they're looking to get the average response from somewhere between 1k-100k neurons. The scar tissue in the first case can overwhelm your signal, in the second case, it's a small fraction of the area you're recording from.

https://en.wikipedia.org/wiki/Neurotrophic_electrode

I mean 10 years with your life back is pretty significant. People spend 100k to get an extra year from cancer.

Is there an actual paper?

I am struggling to find concrete info, I only see media packages for press releases?

This is truly amazing. We are living in the future.

I wonder though, if the brain already has specific regions for control of specific parts of our body, will it be impossible to add new limbs in the future? An extra arm would be helpful.

I'm kind of surprised that in 2023, some signal replicator bridge from one side of the spinal cord to the other side isn't a lot more straightforward. I mean we're doing neural implants and the like already.

But for the use case you say, I think it's more likely a robotic arm with AI / voice instruction would do that. Or a neural helmet.

I think people drastically overestimate modern medical technology. We are not advanced by any means. We are still just barely learning small pieces...

Tell that to people who died from aids 40 years ago who could live a full life now.

Heck, tell that to my mother who had four knee replacements, one even with horrible infection, all in her lifetime (in her 60’s), before one last year finally got her back on her feet.

it took them like 30 years to completely dissect a single amino acid which would hold huge medical breakthroughs. AI found it's own way to do the same but to every amino acid saving decades of tedious work. in two years we've gone from barely knowing the full innards of amino acids and how they work etc, and now we know all of them.

Earlier this year, an AI research lab basically cured a rare cancer in a week time.

Imagine having 200 MDs and biologists in a virtual world working 24/7 with real world Drs and biologists. Nobody will know who is who they just work together on aspects then use the virtual lab to analyze potential results before trying in a real lab.

The regular researchers of course won't be able to go 24/7 but while they sleep the AI researchers could solve 2 years worth of problems.

We are way more advanced than we know because we have knew, never before realized potential to quadruple research in scientific endeavors.

That AI hype is a powerful drug.

At least AI is legitimately solving real world problems. I'll take that over crypto-hype any day.

That contrarianism is a powerful drug.

That's crazy. We had to learn the structure of all the amino acids in my biochem class a decade ago. I'm glad science has finally caught up. Maybe the advances could have happened faster if the scientists studied the structures of the amino acids that undergrads were drawing from memory.

I really like this approach even though it's antithetical to the way medical technology is structured right now. Basically medical device companies and drug companies just want to manufacture something and hold a patent for 20 years and whatever they can get for extended.

The described approach is a lot more like programming where you have a whole bunch of skilled professionals working together to solve specific bespoke problems because cancer is actually thousands of diseases depending on the gene expression and underlying genetics.

So I really like this approach. I hope it gets formalized and scaled to some degree outside of the auspices of the drug companies who just want to patent squat

I also don't know if the FDA is equipped for it because it sounds like cuz we're going to get specifically tailored drugs or other vectors individualized but how do you test that in a way that the FDA typically does?

We're making good strides in some areas and others are more resistant to breakthroughs.

This even works in different aspects of the same thing: We have the ability to genetically modify T-cells to kill some kinds of cancers, but it's more difficult to use that against solid tumors, which create their own microenvironments inside of them, than blood cancers.

https://stemcellres.biomedcentral.com/articles/10.1186/s1328...

But, of course, we keep making progress, and there's been some promising results in making CAR T-cell therapies that work against solid tumors:

https://www.cancernetwork.com/view/cldn6-car-t-cell-therapy-...

We advance piecemeal and some things are more difficult than others, but we definitely advance.

> I'm kind of surprised that in 2023, some signal replicator bridge from one side of the spinal cord to the other side isn't a lot more straightforward.

The issue is that the spinal cord is a bundle of cables essentially, a lot of axons from individual neurons. If you sever it, finding the right connection is impossible, so you have to use more blunt tools like electrical stimulation of the whole bundle.

We are getting better and better at labeling individual cells, even at a molecular level. When we understand how to do that, we might be able to do as you propose. I think we will see some forms of paralysis reverted in the coming decades with technologies such as those.

Interesting. So like how many axons? If you connect to all the axons on both ends and make the stimulation programmable then you could adjust simulation of the axons across the bridge. But I'm guessing we're talking a lot of axons.

Anyway, what do I know? I'm an idiot on the internet

In humans, around a million axons [1]. But not every lesion severs all axons. It's very challenging to stimulate individual axons as well, especially at scale.

https://www.frontiersin.org/articles/10.3389/fnana.2017.0012...

Brain plasticity to the rescue. There are examples of people being able to integrate completely new senses (vibrating compass belt) and controlling prosthesis with completely unrelated nerves.

But if you want to graft additional limbs to people, I highly recommend starting with baby aged humans already, their brain plasticity is unmatched. Imagine how much more fulfilment an amazon fulfilment center worker could bring with four arms! I should get Bezos on the phone.

https://www.carlosterminel.com/wearable-compass

https://www.dailymail.co.uk/health/article-4196408/World-s-p...

Equisapiens to the rescue!

Something similar to this was the core of the Neal Stephenson/George Jewsbury novel Interface (highly recommended read); it's absolutely wild that it's already a real thing.

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