Wins for what? I don’t think plastination is an option for human preservation today. When it becomes an option, it probably wins.
The problem with plastination is scaling up the volume that can be done at once. This is a matter of pumping fluids around. Tiny chunks of mouse brain that were plastinated 50 years ago have readable synapses today. The experiment is whether new methods of applying chemicals to whole mouse brains work as well as first cutting up the brain; and whether cutting after plastination preserves enough information.
After scaling up plastination, it has the remaining downside that it displaces lots of chemicals. RH asks to preserve “two dozen chemical densities,” which it probably fails at. Also, lots of sub-synapse detail (eg, type and placement of ion channels) is probably lost.
Also, lots of sub-synapse detail (eg, type and placement of ion channels) is probably lost.
Are you sure? If I recall correctly (it’s been a long time), a typical ion channel consists of 10^4-10^6 atoms and is something like 1-10nm in size, which is about the same as the current 3D scan resolution, and it is reasonably easy to infer the type and abundance of channels from their location. In any case, even the current resolution is almost enough to identify channel location, and only a small increase in resolution would be enough to identify channel types.
No, I’m not sure. But I’m not talking about the limits of current read-out techniques, which will of course improve. I’m talking about the destruction of information by the process of plastination: chemical change of the membrane and replacement of almost everything else. Currently what is read is the shape of the membrane. The location, if not type, of an ion channel is probably readable from distortions of the membrame. They might be left intact, trapped by the membrane, readable by future techniques. But I wouldn’t be terribly surprised if they are completely wiped out.
Most likely, we don’t need to know, but can guess based on other details of the synapse.
(This comment is largely repeating something from my blog)
I would suggest storing, along with the brain, a representative “snapshot” of the working brain, possibly an EEG under standardized conditions.
In the cryonics model, storing your EEG’s didn’t make much sense. When (if) resuscitation “restarted your motor”, your brainwaves would come back on their own. Why keep a reference for them?
But plastination assumes from the start that revival consists of scanning your brain in and emulating it. Reconstructing you would surely be done computationally, so any source of information could be fed into the reconstruction logic.
Ideally the plastinated brain would preserve all the information that is you, and preserve it undistorted. But what if it preserved enough information but garbled it? The information got thru but it was ambiguous. There would be no way to tell the difference between the one right answer that reconstructs your mind correctly and many other answers that construct someone or something else.
Having a reference point in a different modality could help a lot. I won’t presume to guess how it would best be used in the future, but from an info-theory stance, there’s a real chance that it might provide crucial information to reconstruct your mind correctly.
And having an external reference point could provide something less crucial but very nice: verification that the process worked.
The ratio of the information it adds relative to the total available information is not the point. It’s a separate modality. It’s subject to a different set of noises and systematic distortions.
Wins for what? I don’t think plastination is an option for human preservation today. When it becomes an option, it probably wins.
The problem with plastination is scaling up the volume that can be done at once. This is a matter of pumping fluids around. Tiny chunks of mouse brain that were plastinated 50 years ago have readable synapses today. The experiment is whether new methods of applying chemicals to whole mouse brains work as well as first cutting up the brain; and whether cutting after plastination preserves enough information.
After scaling up plastination, it has the remaining downside that it displaces lots of chemicals. RH asks to preserve “two dozen chemical densities,” which it probably fails at. Also, lots of sub-synapse detail (eg, type and placement of ion channels) is probably lost.
Are you sure? If I recall correctly (it’s been a long time), a typical ion channel consists of 10^4-10^6 atoms and is something like 1-10nm in size, which is about the same as the current 3D scan resolution, and it is reasonably easy to infer the type and abundance of channels from their location. In any case, even the current resolution is almost enough to identify channel location, and only a small increase in resolution would be enough to identify channel types.
No, I’m not sure. But I’m not talking about the limits of current read-out techniques, which will of course improve. I’m talking about the destruction of information by the process of plastination: chemical change of the membrane and replacement of almost everything else. Currently what is read is the shape of the membrane. The location, if not type, of an ion channel is probably readable from distortions of the membrame. They might be left intact, trapped by the membrane, readable by future techniques. But I wouldn’t be terribly surprised if they are completely wiped out.
Most likely, we don’t need to know, but can guess based on other details of the synapse.
(This comment is largely repeating something from my blog)
I would suggest storing, along with the brain, a representative “snapshot” of the working brain, possibly an EEG under standardized conditions.
In the cryonics model, storing your EEG’s didn’t make much sense. When (if) resuscitation “restarted your motor”, your brainwaves would come back on their own. Why keep a reference for them?
But plastination assumes from the start that revival consists of scanning your brain in and emulating it. Reconstructing you would surely be done computationally, so any source of information could be fed into the reconstruction logic.
Ideally the plastinated brain would preserve all the information that is you, and preserve it undistorted. But what if it preserved enough information but garbled it? The information got thru but it was ambiguous. There would be no way to tell the difference between the one right answer that reconstructs your mind correctly and many other answers that construct someone or something else.
Having a reference point in a different modality could help a lot. I won’t presume to guess how it would best be used in the future, but from an info-theory stance, there’s a real chance that it might provide crucial information to reconstruct your mind correctly.
And having an external reference point could provide something less crucial but very nice: verification that the process worked.
EEG contains a trivial amount of information, probably not worth storing.
The ratio of the information it adds relative to the total available information is not the point. It’s a separate modality. It’s subject to a different set of noises and systematic distortions.