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I worked on the Human Connectome Project. If they freeze the vesicles that deliver transmitters and make them analyzable, you've got all the information you ne

I worked on the Human Connectome Project. If they freeze the vesicles that deliver transmitters and make them analyzable, you've got all the information you need. In terms of a modern ANN, it's the connections (axons) and the weights (transmitters/receptors in tandem). That said, this article doesn't get to the point in the free section. How are they collecting the information? Slicing is inherently destructive. Someone's got to manufacture an entirely novel imaging modality. Perhaps they could scan millimeters ahead of the slice at a resolution high enough to image receptors. Not possible currently.

cjbgkagh 6mo ago
> If they freeze the vesicles that deliver transmitters and make them analyzable, you've got all the information you need. In terms of a modern ANN, it's the connections (axons) and the weights (transmitters/receptors in tandem). This is exactly what I’m doubting, how can you be so sure?
- vercaemert 6mo ago
  Same question answered under other comment.
  - cjbgkagh 6mo ago
    Yeah but it wasn’t though. I found your answer unconvincing. I suppose “we don’t know” is an answer but that is nothing like “we have all the information we need”
roarcher 6mo ago
> If they freeze the vesicles that deliver transmitters and make them analyzable, you've got all the information you need. How can we possibly know that the non-connectome details of the brain don't influence computation or conscious experience? It seems we ignore these only because they don't fit neatly into our piles of linear algebra that we call ANNs.
- vercaemert 6mo ago
  Take a gander at the OpenWorm project. It's a great example of how simple neuronal activity is (given details like the connections, number of receptors, and transmitter infrastructure). SOTA models of neuronal activity are simple enough for problem sets in undergraduate biomedical engineering programs. Sure, to your point, we don't know. But the worm above (nematode) swims and seeks food when dropped into a physics engine. My main point is that the scale of the human brain is well beyond the capabilities of modern imaging modalities, and it will likely remain so indefinitely. Fascicles we can image, individual axons we cannot. I guess, theoretically, we'll eventually be able to (but it's not relevant to us or any of our remote descendants).
  - bitwize 6mo ago
    I saw a putative 3D animation of a fly whose brain had been digitized and then run in a simulation. It buzzed around, sipped food it had found on the ground, even rubbed its forelegs together as flies do. A true Dixie Flyline. We live in strange times...
  - roarcher 6mo ago
    > But the worm above (nematode) swims and seeks food when dropped into a physics engine. Nematode worms have an oxytocin analogue called nematocin that is known to influence learning and social behaviors like mating. As far as I can find, the project doesn't account for this, or only minimally, but aims to in the future. It's not surprising that immediate short-term behaviors like movement depend mostly on the faster signaling of the connectome. But since we know of other mechanisms that most definitely influence the connectome's behavior, and we know we don't account for those at the moment, it is not accurate to say that the connectome is "all the information you need". I agree that mapping the connectome of the human brain is impractical to the point of impossibility. But even if we could, the resulting "circuit diagram" would not capture all the details needed to fully replicate human cognition. Aspects of it, sure. Maybe even enough to make it do useful tasks for EvilCorp LLC while being prodded with virtual sticks and carrots. But it would be incomplete.
  - DoctorOetker 6mo ago
smj-edison 6mo ago
What is the state of the art in regards to how neurons learn over time? Do existing neuron models account for that? Being trapped, unable to learn anything, sounds terrible.
kingkawn 6mo ago
All the information to replicate the structure we have delineated. But what else?
caditinpiscinam 6mo ago
Am I right in thinking that even if you had all of the connections and weights mapped out for a brain, the specifics of synaptic plasticity are still pretty poorly understood?

cjbgkagh 6mo ago

> If they freeze the vesicles that deliver transmitters and make them analyzable, you've got all the information you need. In terms of a modern ANN, it's the connections (axons) and the weights (transmitters/receptors in tandem). This is exactly what I’m doubting, how can you be so sure?

vercaemert 6mo ago
Same question answered under other comment.
- cjbgkagh 6mo ago
  Yeah but it wasn’t though. I found your answer unconvincing. I suppose “we don’t know” is an answer but that is nothing like “we have all the information we need”

roarcher 6mo ago

> If they freeze the vesicles that deliver transmitters and make them analyzable, you've got all the information you need. How can we possibly know that the non-connectome details of the brain don't influence computation or conscious experience? It seems we ignore these only because they don't fit neatly into our piles of linear algebra that we call ANNs.

vercaemert 6mo ago
Take a gander at the OpenWorm project. It's a great example of how simple neuronal activity is (given details like the connections, number of receptors, and transmitter infrastructure). SOTA models of neuronal activity are simple enough for problem sets in undergraduate biomedical engineering programs. Sure, to your point, we don't know. But the worm above (nematode) swims and seeks food when dropped into a physics engine. My main point is that the scale of the human brain is well beyond the capabilities of modern imaging modalities, and it will likely remain so indefinitely. Fascicles we can image, individual axons we cannot. I guess, theoretically, we'll eventually be able to (but it's not relevant to us or any of our remote descendants).
- bitwize 6mo ago
  I saw a putative 3D animation of a fly whose brain had been digitized and then run in a simulation. It buzzed around, sipped food it had found on the ground, even rubbed its forelegs together as flies do. A true Dixie Flyline. We live in strange times...
- roarcher 6mo ago
  > But the worm above (nematode) swims and seeks food when dropped into a physics engine. Nematode worms have an oxytocin analogue called nematocin that is known to influence learning and social behaviors like mating. As far as I can find, the project doesn't account for this, or only minimally, but aims to in the future. It's not surprising that immediate short-term behaviors like movement depend mostly on the faster signaling of the connectome. But since we know of other mechanisms that most definitely influence the connectome's behavior, and we know we don't account for those at the moment, it is not accurate to say that the connectome is "all the information you need". I agree that mapping the connectome of the human brain is impractical to the point of impossibility. But even if we could, the resulting "circuit diagram" would not capture all the details needed to fully replicate human cognition. Aspects of it, sure. Maybe even enough to make it do useful tasks for EvilCorp LLC while being prodded with virtual sticks and carrots. But it would be incomplete.
- DoctorOetker 6mo ago

smj-edison 6mo ago

What is the state of the art in regards to how neurons learn over time? Do existing neuron models account for that? Being trapped, unable to learn anything, sounds terrible.

kingkawn 6mo ago

All the information to replicate the structure we have delineated. But what else?

caditinpiscinam 6mo ago

Am I right in thinking that even if you had all of the connections and weights mapped out for a brain, the specifics of synaptic plasticity are still pretty poorly understood?