Epistemic status: I probably don’t know what I am talking about 50% of the time. Specifically, I expect that I am missing some bottlenecks that would be obvious to a neuroscientist.
Neuralink has a surgical robot to insert electrodes in your brain. They seem to try to target single neurons already.
Their interface unit has 1024 electrodes.
How about we just insert 100,000,000,000 electrodes instead? One for each neuron.
We want to evaluate: “Could you upload yourself by recording the activations of all your neurons for a year, and then train a giant Neural Network to predict the neuronal spikes, therefore simulating you?”
There are probably issues about “the brain just dies because it has 100,000,000,000 wires inside”. Also, the problem of precisely hitting a single neuron without hitting a blood vessel doesn’t become easier when there are literally billions of wires that you could entangle yourself with. And as I am not a brain surgeon I probably can’t even see the real bottlenecks.
But let’s ignore all that for now.
Today let’s just focus on one problem: SPEED. Specifically how long it takes to wire you up. The current surgical robot is terribly slow. In this video you can follow using these timestamps:
01:45.272 (start to move to insertion point)
01:45.306 (insertion point reached)
01:45.339 (starting insertion)
01:45.439 (insertion complete)
01:59.252 (starting the next insertion)
The important thing here is that it takes 33ms to insert an electrode once we are already in place. Obviously doing this with a 30fps video is very inaccurate. So as a lower bound let’s say it takes 5ms.
So that’s 15 years to wire you up! At 200 incisions per second.
And this is with best-case estimates. The actual time of the robot from incision to incision is over 13 seconds. So instead of 200 incisions per second, we have 0.075 incisions per second (the video is from 01.12.2022). However, I’d guess that most of the auxiliary robot activity, like fetching an electrode, can be sped up significantly. The incision itself seems harder to speed up.
Let’s continue with the best guess estimate. How many needles can be inserted at the same time without blowing the brain up? Well, that’s actually not the issue. Deformation is. As you can see from the video the insertion is quite forceful. So by default, we can’t make a second incision, at the same time, in the same area, because tissue in that area will be heavily deformed from the first incision.
But if we stab the brain far enough away, then the deformation would be manageable. I am close to just making numbers up now, as I used the following whiteboard drawing to compute that we can make 122 incisions at the same time, without having to worry about deformation.
That’s 47 days to wire you up. At 24400 incisions per second.
We could push further. We could try to make multiple incisions close to one another. We could model all the deformational forces, and then use that model to calculate how to make the incision. I’d guess that his problem is easy conceptually, but hard to get right in practice.
I suspect that Neurallink has already solved a simple version of this problem. A single incision already causes deformation. So maybe you already need a deformational model for a single incision.
Though once you worry about deformation you probably just want to build a new robot. One that is optimized to cause minimal deformation. I don’t expect that they optimized for minimizing deformation so far. Well, they haven’t optimized for inserting 100,000,000,000 electrodes in general.
So I’d tentatively guess that there is some big room for improvement there.
47 days is still pretty terrible, especially considering that these are best-case estimates. But it’s not something like 100,000 years for the best case, which wasn’t apriori clear to me.
So while there are gaping technical challenges, it seems not-defnetly-impossible that you could hook yourself up before you die of old age.
Let’s imagine a fictional world where somebody really competent, tries to develop a fast enough robot surgeon. Even if they had “infinite money”, I’d guess that it would take multiple years at a minimum.
But still, let’s imagine that you managed to hook yourself up. Can you now upload yourself?
Scanning your Brain with 100,000,000,000 wires?
Epistemic status: I probably don’t know what I am talking about 50% of the time. Specifically, I expect that I am missing some bottlenecks that would be obvious to a neuroscientist.
Song Version
Neuralink has a surgical robot to insert electrodes in your brain. They seem to try to target single neurons already.
Their interface unit has 1024 electrodes.
How about we just insert 100,000,000,000 electrodes instead? One for each neuron.
We want to evaluate: “Could you upload yourself by recording the activations of all your neurons for a year, and then train a giant Neural Network to predict the neuronal spikes, therefore simulating you?”
There are probably issues about “the brain just dies because it has 100,000,000,000 wires inside”. Also, the problem of precisely hitting a single neuron without hitting a blood vessel doesn’t become easier when there are literally billions of wires that you could entangle yourself with. And as I am not a brain surgeon I probably can’t even see the real bottlenecks.
But let’s ignore all that for now.
Today let’s just focus on one problem: SPEED. Specifically how long it takes to wire you up. The current surgical robot is terribly slow. In this video you can follow using these timestamps:
01:45.272 (start to move to insertion point)
01:45.306 (insertion point reached)
01:45.339 (starting insertion)
01:45.439 (insertion complete)
01:59.252 (starting the next insertion)
The important thing here is that it takes 33ms to insert an electrode once we are already in place. Obviously doing this with a 30fps video is very inaccurate. So as a lower bound let’s say it takes 5ms.
So that’s 15 years to wire you up! At 200 incisions per second.
5ms * 100,000,000,000 = 500,000,000,000ms
500_000_000_000 / 1000 / 60 / 60 / 24 / 365 = 15.85
And this is with best-case estimates. The actual time of the robot from incision to incision is over 13 seconds. So instead of 200 incisions per second, we have 0.075 incisions per second (the video is from 01.12.2022). However, I’d guess that most of the auxiliary robot activity, like fetching an electrode, can be sped up significantly. The incision itself seems harder to speed up.
Let’s continue with the best guess estimate. How many needles can be inserted at the same time without blowing the brain up? Well, that’s actually not the issue. Deformation is. As you can see from the video the insertion is quite forceful. So by default, we can’t make a second incision, at the same time, in the same area, because tissue in that area will be heavily deformed from the first incision.
But if we stab the brain far enough away, then the deformation would be manageable. I am close to just making numbers up now, as I used the following whiteboard drawing to compute that we can make 122 incisions at the same time, without having to worry about deformation.
That’s 47 days to wire you up. At 24400 incisions per second.
We could push further. We could try to make multiple incisions close to one another. We could model all the deformational forces, and then use that model to calculate how to make the incision. I’d guess that his problem is easy conceptually, but hard to get right in practice.
I suspect that Neurallink has already solved a simple version of this problem. A single incision already causes deformation. So maybe you already need a deformational model for a single incision.
Though once you worry about deformation you probably just want to build a new robot. One that is optimized to cause minimal deformation. I don’t expect that they optimized for minimizing deformation so far. Well, they haven’t optimized for inserting 100,000,000,000 electrodes in general.
So I’d tentatively guess that there is some big room for improvement there.
47 days is still pretty terrible, especially considering that these are best-case estimates. But it’s not something like 100,000 years for the best case, which wasn’t apriori clear to me.
So while there are gaping technical challenges, it seems not-defnetly-impossible that you could hook yourself up before you die of old age.
Let’s imagine a fictional world where somebody really competent, tries to develop a fast enough robot surgeon. Even if they had “infinite money”, I’d guess that it would take multiple years at a minimum.
But still, let’s imagine that you managed to hook yourself up. Can you now upload yourself?