X-Message-Number: 726 Date: 12 Apr 92 03:13:39 EDT From: Thomas Donaldson <> Subject: Re: cryonics: #722 - #724 Dear Richard: I am Thomas Donaldson, whom you may have heard of from other contexts. I have a bit more to say on both of your questions. Not incidentally, I publish a newsletter, PERIASTRON, which deals solely with scientific questions relating to cryonics (PO Box 2365, Sunnyvale, CA 94087, $2.50 per issue). 1. Use of embalming technology for cryonics This question has often come up. Unfortunately there has been very little serious EMPIRICAL study of essential questions which come up when we consider such a use. First, all embalming chemicals alter the pliability of blood vessels, including the capillaries. It is not clear that present techniques are even good enough to embalm ALL parts of our brains (right now of course embalming is done more for cosmetic reasons than to preserve anyone or anything). Second, embalming fluids already react chemically with the cell material --- that's what cross-linking is, for a start. We do not know, and would want to verify, that they preserve (rather than destroy!) all the structures we need to infer memory and personality. Third, no embalming fluid preserves the embalmed cells indefinitely against chemical attack, particularly by living things but by general chemical deterioration too. This means that for long term preservation we will have to resort to cryogenic methods, and therefore that embalming methods will not cost less, and may cost more, than current methods. I do believe that someday, whether with present chemicals or with others, we will devise a method of long term preservation which makes the patient much less vulnerable than now. But I would not accept embalming for myself NOW, nor would I recommend it to others. 2. Very High Resolution Brain Scans. The resolution of a current CT scanner is limited by the number of sensor elements in the ring circling the brain (or object to be scanned). The first issue which needs solution, then, would be to make these far smaller without decreasing their sensitivity. It seems reasonable that this is within the bounds of physics, at least to take them down to mole- cular scales. Second, for scanning a living tissue such a scanner would create an energy density far higher than that of present CT scanners, and therefore will (purely by performing the scan) cause a great deal more disruption. I believe there are several ways we might try to decrease this disruption: first, by lengthening the time needed to do the scan, so that the patient might spend (say) 10,000 times longer in the scanning process. If this takes 5 minutes now, we might be looking at about a month of scanning. Another method might be to use the same kind of stasis technique I just mentioned above, under embalming. Since the energy density would tend to raise temperatures, we might try cooling by passing liquid N2 or some other cryogenic gas through the patient's brain. If the scanee is unconscious, or better yet, cooled down to just above 0 C, then we might in fact be able to read off the structure of their brain finely enough to record their memories. (If the scanee is conscious during the month the scan takes, a lot of that will simply blur because the scanee will be thinking). Regardless of the methods chosen, this Hires CT Scan would deliver a great deal of radiation to the person's head. This would need antiradiation drugs (probably much more elaborate and effective antioxidants than those we have now) for protection. I will also say that this technology would be very hard to take down to an ATOMIC scale, though we might just get down to the scale of an electron microscope. However, you should know that no one seriously believes that our memories depend on position of specific atoms; some cryonics writing arguing that we can indeed detect and record the position of specific atoms take that approach (justifiably or not) with the aim of showing that we can not only do the essential job but far more. As for politics and quiet: Well, if we COULD make such recordings, with the intention of preserving ourselves for later recreation, then we would have to make that fact public. How else could we find others to keep the storage of our records going after we are just a tape (or other?) in a file? So I personally doubt that such a technology would really remove the problems that cryonicists presently have. And a word on other methods for scanning: Presently we're farther from it than from hires CT scans, but one more method would involve a system in which millions of tiny robots (no, folks, if you are listening note that I haven't made any statement about the chemistry of these robots) which might spread throughout the scanee's brain, record what they see at their location and record their location, and then return. This might be a less disruptive method to achieve the same end as the hires CT scan. Best Thomas Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=726