--- On Sat, 4/6/13, Luke Parrish wrote:
From: Luke Parrish
Subject: Re: Breaking News in Science
To: "Rick Potvin"
Date: Saturday, April 6, 2013, 6:17 PM
On the proposal page Hayworth does not much talk directly about patternism (apart from describing the technology "to inexpensively and nondestructively scan plastinated brains to upload the molecular features of memory and identity"), but look at this essay from him, I think it will surprise you:http://www.brainpreservation.org/content/killed-bad-philosophy
Note the subtitle: "Why brain preservation followed by mind uploading is a cure for death"
It's hard to get much more explicit than that. Hayworth is a very strong proponent of patternism who will argue in favor of it at great length.
So your decision to declare Hayworth the leader of cryonics but then say that patternists are traitors against cryonics is inconsistent. You should have researched the topic more before making that declaration.
"I declare the new de facto leader of the entire real applied cryonics movement, Kenneth Hayworth"
However, aside from that I think you make a valid point that testing for the absence of connectomes should falsify cryonics:http://www.network54.com/Forum/54032/message/1365258993/Luke+wrote+%26quot%3BWowk+and+Fahy+because+they+work+on+preventing+damage+such+that+neurons+can+com
"I'm supporting the case for going ahead with a connectomic modern microscope view with modern electron microscopes and other scopes and methods of vitrified brain slice and see where it leads. If connectomes are dead, then so is cryonics. The sooner we get there, the sooner we can move on to something else to get immortality."
This quote helps me see where you are coming from. However, Aschwin de Wolf highlights some reasons for legitimate concern about this method of falsification in this article:http://www.alcor.org/magazine/2013/01/16/chemical-brain-preservation-and-human-suspended-animation/
"A specific concern for Brain Preservation Technology Prize competitors using cryopreservation is that cryopreserved brains are currently very dehydrated. Due to this dehydration, which typically persists even after cryoprotectant removal, it is not yet clear that cryopreserved brains can be effectively evaluated by the Prize organizers. To be specific, the criterion for success is preservation of the connectome, which requires two things: preservation of synapses and preservation of enough information to infer the pattern of connections between them. Neural cryobiology researchers believe that they can achieve good ultrastructural preservation of the brain but dehydration compactifies the neuropil, reduces space between structures, and makes the tissue so dark in the electron microscope that it is hard to actually observe the synapses. So if a quick scanning method doesnt discern all synapses that are actually there, it will fail. There are techniques for doing electron microscopy at cryogenic temperatures in the vitrified state, but these depend on the tissue being sliced before vitrification. Making slices out of a whole vitrified brain while vitrified is a tough problem. It is easier to make thin slices out of a whole brain thats been turned into solid plastic because the resin used is designed for being cut into thin slices for microscopy. So plastination has a natural advantage in this competition in terms of processing for the tests rather than in actual results."
In other words, the test could be unable to discern the results properly even though the tissue is actually in good condition. That would be a falsification failure, and would leave wriggle room for people to justify cryonics without having to resort to inference or pattern based arguments. Dehydration is the big culprit here. A major advance for cryonics would be to find ways to reduce the amount of dehydration that happens in the brain. The brain is unlike other tissue in two major ways: the blood-brain barrier, and the myelin barrier. I am still uncertain which of these causes the most dehydration, because I have much to learn, but based on Aschwin's comments above this is something that would be immensely productive to focus research on.
Solving dehydration would make testing for the absence of a connectome a more realistic project. (Also testing for viability in brain cells and tissues, which is a different but equally empirical and valid approach.)
How do cells get dehydrated during cryonics? Because to vitrify you must perfuse with highly concentrated cryoprotectants. As you add more cryoprotectant to the solution that replaces the blood supply, it creates an osmotic difference between inside the cell and outside. With less of a barrier, cryoprotectants get inside the cell easier. However if the cryoprotectant can't get in, the difference gets evened out by water coming out of the cell, leaving its contents more concentrated and compacted. So with a cell that has a stronger barrier against cryoprotectant penetration you will get more dehydration as you ramp up the concentration.