[epups]

> 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.

[AtlasBarfed]

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

[epups]

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...