The images above are taken from the BPF’s Accreditation page. On the left, you can see the pig brain which I preserved, winning the Large Mammal prize. The cellular structure is intact and it’s easy to trace the connections between the neurons. The right-hand image shows the damage caused by traditional cryopreservation, even under ideal circumstances. Real preservation cases are far worse due to pre- and post-mortem brain damage. Maybe a superintelligence could reconstruct the structure – but it’s unclear whether the information to do so remains.
There’s got to be some way to see how much info we can reconstruct from brains which were cryopreserved a few hours after death. Perhaps if we could grow brains in a vat, we could make two copies of the same brain, and cryopreserve one brain properly and let another degrade before cryopreserving it. Then the former copy serves as a ground truth for reconstruction attempts. Of course, that’s replacing one hard problem with another hard problem. But it seems worth spending more than literally 5 minutes on this problem.
One experiment I’d LOVE to see (which I haven’t done yet because I’ve been working on the fixation stuff but might in the future) is to take YPF mice (sparse fluorescent labeling of entire neurons) and freeze / cryoprotect them in various combinations with various post-mortem delays, then do expansion microscopy and 3D imaging to see what happens to the YFP pattern. The idea is that you’d have the ground truth of what the intact neuron was and could see if it’s still traceable after the preservation attempt. I would be very impressed and ultimately convinced that a protocol maintains traceability if you could trace images with the YFP signal stripped and then have that tracing result match the YFP ground truth.
Certainly there’s some issues actually doing the experiments technically (which is one of the reasons I haven’t done them yet). It’s harder to do well than it might seem. But I do think it can be done, and I also think it’s never been easier because of expansion microscopy making it much easier and cheaper than it used to be by a factor of 100-1,000x.
growing brains in a vat would not produce identical brains, not even vaguely close. It would produce more similarity than between most brains, certainly. also, like, being a brain in a vat probably sucks big time
Sure, but I was assuming some sort of magical growth process which could make identical brains, perhaps some form of nanotech. I realize that’s a ridiculous ask and doesn’t reduce the difficulty of the problem in any way. Heck, it increases it. But that’s the only thing I could think of that would definitely produce identical (upto connectome) copies of brains with less than 5 minutes of thought.
There’s got to be some way to see how much info we can reconstruct from brains which were cryopreserved a few hours after death. Perhaps if we could grow brains in a vat, we could make two copies of the same brain, and cryopreserve one brain properly and let another degrade before cryopreserving it. Then the former copy serves as a ground truth for reconstruction attempts. Of course, that’s replacing one hard problem with another hard problem. But it seems worth spending more than literally 5 minutes on this problem.
One experiment I’d LOVE to see (which I haven’t done yet because I’ve been working on the fixation stuff but might in the future) is to take YPF mice (sparse fluorescent labeling of entire neurons) and freeze / cryoprotect them in various combinations with various post-mortem delays, then do expansion microscopy and 3D imaging to see what happens to the YFP pattern. The idea is that you’d have the ground truth of what the intact neuron was and could see if it’s still traceable after the preservation attempt. I would be very impressed and ultimately convinced that a protocol maintains traceability if you could trace images with the YFP signal stripped and then have that tracing result match the YFP ground truth.
Certainly there’s some issues actually doing the experiments technically (which is one of the reasons I haven’t done them yet). It’s harder to do well than it might seem. But I do think it can be done, and I also think it’s never been easier because of expansion microscopy making it much easier and cheaper than it used to be by a factor of 100-1,000x.
growing brains in a vat would not produce identical brains, not even vaguely close. It would produce more similarity than between most brains, certainly. also, like, being a brain in a vat probably sucks big time
Sure, but I was assuming some sort of magical growth process which could make identical brains, perhaps some form of nanotech. I realize that’s a ridiculous ask and doesn’t reduce the difficulty of the problem in any way. Heck, it increases it. But that’s the only thing I could think of that would definitely produce identical (upto connectome) copies of brains with less than 5 minutes of thought.