4 ms·

What hard steps exist between mapping the physical structure of the brain and simulating a running one via software?

aithrowawaycomm 2y ago
Knowing what the individual neurons actually do. The connectome is like an electrical schematic but you don't even know which components are resistors, inductors, etc (let alone the resistances and inductances). The connectome for the C. elegans nematode was mapped in the 1980s and the OpenWorm project has successfully simulated all non-neuronal cells. But they are very far from simulating the brain abd it will take decades of experimental work to understand C. elegans's brain - it's very difficult to observe a living brain in the required molecular detail.
- s1artibartfast 2y ago
  I think it's even more complex. The neurons are like individual raspberry pi. They have both complex logic and physical memory.
  - notahacker 2y ago
    Yeah, I think it's close to "what steps exist between observing the network topology of the internet and being able to emulate a Google search query?" There's plenty of value to knowing where the datacentres are and which regions are active under which circumstances, but none of that is telling you what the internet is thinking...
- nonameiguess 2y ago
  I'm frankly not sure it will ever be possible. Forget about observing the inside of a running neuron. In spite of how confidently people on the Internet will tell you their body fat percentage, in reality we can't even accurately measure that without killing you first.
  - aithrowawaycomm 2y ago
    I wouldn't say never, at least for C. elegans: there's been quite a bit of progress on imaging its brain, and it's plausible we'll have a fairly complete picture in a few decades: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801769/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801769/ But the challenges are substantial, and these imaging techniques (mostly optical, not MRI/etc) depend on the simplicity of C. elegans: its brain is essentially a thin disk, with only 300 neurons in its entire nervous system, and it is surrounded by a transparent membrane. I am not sure how these techniques could possibly extend to something with a thick exoskeleton like Drosophila. And there are great difficulties keeping track of just the 300 neurons in a moving nematode with its own unique brain; it seems completely intractable with current tools to extend the complexity 50x, especially since fruit flies move far more rapidly and have far more individual variation.
flashman 2y ago
go look at a photo of a CPU and imagine what else you'd need to run Windows on it, and then imagine it's probably extremely exponentially more difficult

Knowing what the individual neurons actually do. The connectome is like an electrical schematic but you don't even know which components are resistors, inductors, etc (let alone the resistances and inductances). The connectome for the C. elegans nematode was mapped in the 1980s and the OpenWorm project has successfully simulated all non-neuronal cells. But they are very far from simulating the brain abd it will take decades of experimental work to understand C. elegans's brain - it's very difficult to observe a living brain in the required molecular detail.

s1artibartfast 2y ago
I think it's even more complex. The neurons are like individual raspberry pi. They have both complex logic and physical memory.
- notahacker 2y ago
  Yeah, I think it's close to "what steps exist between observing the network topology of the internet and being able to emulate a Google search query?" There's plenty of value to knowing where the datacentres are and which regions are active under which circumstances, but none of that is telling you what the internet is thinking...
nonameiguess 2y ago
I'm frankly not sure it will ever be possible. Forget about observing the inside of a running neuron. In spite of how confidently people on the Internet will tell you their body fat percentage, in reality we can't even accurately measure that without killing you first.
- aithrowawaycomm 2y ago
  I wouldn't say never, at least for C. elegans: there's been quite a bit of progress on imaging its brain, and it's plausible we'll have a fairly complete picture in a few decades: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801769/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801769/ But the challenges are substantial, and these imaging techniques (mostly optical, not MRI/etc) depend on the simplicity of C. elegans: its brain is essentially a thin disk, with only 300 neurons in its entire nervous system, and it is surrounded by a transparent membrane. I am not sure how these techniques could possibly extend to something with a thick exoskeleton like Drosophila. And there are great difficulties keeping track of just the 300 neurons in a moving nematode with its own unique brain; it seems completely intractable with current tools to extend the complexity 50x, especially since fruit flies move far more rapidly and have far more individual variation.

flashman 2y ago

go look at a photo of a CPU and imagine what else you'd need to run Windows on it, and then imagine it's probably extremely exponentially more difficult