<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">In the current issue of Cryonics Alexandre Erler comments on the following research article by McIntyre and Fahy about preserving the information in brains using a new process called aldehyde-stabilized cryopreservation (ASC), and Erler doesn't much like what he sees. You can download a PDF of the McIntyre and Fahy article here:</font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><a href="https://www.sciencedirect.com/science/article/pii/S001122401500245X">https://www.sciencedirect.com/science/article/pii/S001122401500245X</a></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><font size="4">This method is quite different from the way Alcor preserves brains and in my opinion superior, but Erier doesn't like it for philosophical reasons that I have to say seem downright silly to me. Basically what they did is fix the molecules in place with glutaraldehyde (the stuff in the wart removing lotion you can get at the drugstore ) then they infused ethylene glycol as a cryoprotectant and then cooled the brains down to -135 C where they became vitrified. After rewarming the brains were examined and "<i>show exquisite preservation of anatomical detail after vitrification and rewarming, with virtually no identifiable artifacts relative to controls</i>."</font><div><div class="gmail_default"><br></div><div class="gmail_default"><font size="4">So can Alcor's method match that? Erler says he doesn't know because with Alcor's method "the brain shrinks to almost 50% of its natural size due to osmotic dehydration hindering our ability to establish the quality of ultrastructure preservation". Well yes, I imagine such shrinkage would distort things and make it harder to see fine details, <span style="font-family:arial,helvetica,sans-serif">McIntyre and Fahy think so too:</span></font></div><div class="gmail_default"><span style="font-family:arial,helvetica,sans-serif"><br></span></div><div class="gmail_default"><font size="4">"<i>For the purposes of connectomics, this dehydration is undesirable because it distorts the brain's ultrastructure and causes difficulties in tracing fine<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>neural processes</i>. "</font></div><div class="gmail_default"><br></div><div class="gmail_default"><font size="4">But there is no shrinkage with the new method. After keeping the brains at -135 C for several days they then rewarmed them and examined them with a electron microscope. This is what they found: </font><br></div><div class="gmail_default"><br></div><div class="gmail_default"><font size="4"><i>"Rabbit brains upon
dissection revealed no cracks resulting from the vitrification or
rewarming processes. Brain weights were commensurate with
control brains, and we found no retraction of the brains from their
skulls. Control rabbit brains displayed excellent ultrastructural
preservation. [...] All 8 rabbit
brains preserved using ASC consistently displayed ultrastructural
preservation indistinguishable from that of controls [...] Intracellular organelles are also
well preserved: rough endoplasmic reticulum is clear and
compact, and the mitochondria appear normal [...] There are several synapses present, with clear pre-synaptic
vesicles and well defined, darkly stained post-synaptic densities [...] All capillaries are open
and clear of debris, there are no ‘‘dark’’ cells, and there is no obvious
mechanical or osmotic disruption or distortion of any cells. [...] We also observed no signs of ice crystal artifacts in
any of our ASC-processed brains. [...] .
Vitrified storage at -135 C should enable essentially indefinite
storage of brain tissue with no degradation due to suppressed
molecular motion in the vitrified state. [...]<span style="font-family:arial,helvetica,sans-serif">The aldehydes immediately stabilize the fine structure of the brain to an extent sufficient for connectomics research, meeting our goal of high-quality preservation. [...] </span><span style="font-family:arial,helvetica,sans-serif">ASC is scalable to
because the</span> chemicals are delivered via perfusion, which enables easy scaling to brains of any size; vitrification ensures that the ultrastructure of the brain will not degrade even over very long storage times, processes were easily traceable and synapses were crisp"</i></font></div><div class="gmail_default"><font size="4"><i><br></i></font></div><div class="gmail_default"><font size="4">So much for that old canard about a frozen brain resulting in mush. </font><span style="font-size:large">It seems pretty clear to me that the ASC method is better at preserving brain information and Alcor should switch over to it unless financial reasons make it impractical, and I don't think wart lotion is all that expensive. But the thing that bothers Alexandre Erler is not the expense but the fact that although the information about the brain is preserved the fixative would render the brain itself unviable, it would be easier to use the information to make another brain (or upload the brain software) than it would be to remove all the molecules of </span><font face="arial, helvetica, sans-serif" style="font-size:large">glutaraldehyde from the original brain so it can be restarted. Erler fears that the duplicate brain might not *really* be you even if all the information in both was identical, he wants to keep the "original" brain.</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><font size="4">But what exactly is so original about the "original"? Atoms are generic, our names are not scratched on <div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif">the atoms in our bodies</font></div>, not even <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">on </div>the atoms in our brain. And besides<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">,</div> atoms are constantly shifting in and out of our bodies anyway, today your brain is literally made of last years mashed potatoes. It seems to me if we are going to have any chance of escaping oblivion we need to totally embrace rationality<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">,</div> and that means we should go for whatever method that best preserve brain information regardless of what happens to "the original". Cryonicists often criticize others for failing to be rational about life and death, but with talk about "the original" and a immaterial "something" that a copied brain would lack we are doing the same thing; if we're going to go down that road we might as well abandon science altogether and stick with traditional religion and hope that mumbo jumbo will bring us immortality.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> I agree 100% with </div><span style="font-family:arial,helvetica,sans-serif">McIntyre and Fahy<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> that we don't "</div></span><i>need to preserve the biological viability of brain tissue; the
primary criterion for success is instead to maintain the delicate<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>ultrastructural appearance of the brain</i><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><i></i>"</div>.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div></font><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><br></div></font></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">John K Clark</font></div><br><div><font size="4"><br></font></div></div></div></div>