So you’ve done it.
Your heart is stopped. As far as the law and most of society is concerned, you are dead. But you are not gone… not yet anyway. Before you died, you had a number of long talks with your loved ones, arranged funding for cryosuspension, made all the legal arrangements to “donate your body” to whatever firm currently has you immersed in liquid nitrogen, and so forth. Will you really be coming back though?

This is a tricky question, and one I glossed over briefly in Cold Storage I. What it boils down to is this: What is death, really, and are you actually dead? To put it succinctly, death is the point at which your memories, personality, and sense of identity have degraded past the point at which any conceivable science (short of time travel) would be able to restore you to life. So, death is related to information.

It’s All About Information
Your brain contains quite a lot of information. It contains a huge number of neurons (about 100 billion) and each one of those neurons is connected to (on average) between one and ten thousand other neurons, and in some cases up to about one hundred thousand, for a total of about 100 trillion connections. The connections themselves are not “binary” in fashion (either on or off) - they each have a certain amount of strength. If you ever wanted to know the total possible number of states that the human brain could assume, it would be about 100 trillion squared times the number of possible distinct potential levels in a synapse. According to Carl Sagan, there are more possible brain-states than atoms in the entire universe. Pretty heavy, isn’t it!

Data Integrity and Recovery
Now, at the moment the heart stops, all of those 100 billion neurons and their 100 trillion connections are in peril. Without oxygen and nutrients, the brain will begin to degrade. Here are some question marks I’ve identified:

• What is the half-life of a synapse during warm ischemia? In other words, once blood flow stops, how long does the average synaptic connection take to turn into unrecoverable mush?
• To get more precise, what are the statistics on this, beyond just the average? How about the standard deviation? The distribution? Is it a bell curve or has it got two peaks or does it go all over the place like a seizmometer during an 8.0? Do the connections in the cerebellum tend to go faster? Or in the limbic system, or in the neocortex?
• Again, a question of statistics: If we cool down the brain by ten degrees, by how much do we slow the degeneration of the brain? And how much can we lose (and in which areas) before the person’s memory, personality, and individuality are harshly impacted? How much can a given brain compensate for this loss?
• What is the effect of glycol perfusion followed by vitrification? Will it randomly scramble the synapses, and if so, to what extent?
• How effective will nanorobots be at examining damaged neurons and synapses, forensically determining their correct (in-vivo) operating state, and restoring them to that state?
• If the person had some kind of brain disease or injury, such as Alzheimer’s or some other form of dementia, could nanorobots untangle that mess as well, and perhaps assist the brain’s natural ability to heal its white matter?
• Might it be necessary to bring the body up to operating temperature and run it on life support, and allow the brain to at least partially restart, so that the nanorobots could obtain more information about the neural network? What would the risks be in this?

Evidence of resiliency in the human brain
People have survived brain ischemia for periods lasting from several minutes to over half an hour. Whether a given person will survive seems primarily based on age. Young children have been immersed in icewater, and been pulled out “dead.” (Heartbeat flatlined, no brain activity.) But a few of those children have been revived and come back without appreciable brain damage. Of course, the resiliency of youth is widely known, and it seems probable that the young brain is able to repair damage more easily since it doesn’t have as many established neural connections to worry about. Any adult who has been in icewater for half an hour, and is pulled out without a heartbeat or brain activity, is not likely to be brought back with CPR alone.

Caveat Emptor
These are the kinds of questions that should be asked by brain-only patients. Full-body cryosuspension is naturally more complicated, since there are many organ systems beside the brain that may require extensive repairs. There may also be more damage since a full-body suspension cannot be perfused as thoroughly as a head-only suspension given a certain amount of time.

Broken China
No, not the Middle Kingdom. Dinner plates! You take a dinner plate and smash it. With enough time, patience, and super glue, you can get it back to its original state. Nanomachines would be able to do an extremely good job of that sort of task. With the brain, it’s a similar problem. There may be a perception among some that since adult brains can’t restart themselves after prolonged ischemia, they must be irretrievably damaged. That isn’t necessarily so. With nanotechnology, someone who’s been “iced” long enough for them to be “dead” and cold, might still be retrievable.

Why science is likely to develop cryo-resuscitation technology, regardless of “medical time travellers”
It seems probable that future scientists will be motivated to try to revive cryosuspended patients, once the technology is good enough. But what if that challenge alone isn’t enough to motivate a competent organization to develop this technology?

Even if nobody had ever bothered with cryosuspension, and no one does all the way up to the point at which nanotechnology becomes competent to revive such a patient, medical science will still have use for the ability to resuscitate people who have recently “died” (or who will soon.) I’ve already mentioned drowning victims. They alone are reason enough to develop brain-related nanotech. Another possibility is deliberate cryosuspension before the heart has stopped. Let’s say that someone manages to contract ebola, and the nanotech treatment for this requires three days to cure the patient. But let’s say that by the time the patient gets to a competent hospital, the infection is so advanced that he or she only has two days to live at most. The hospital could cryosuspend the patient (and the ebola infection along with them), and at that point, nanorobots would have all the time they needed to go in, destroy the infection, and repair the damaged organs. The suspended patient would then be revived, and wake up feeling perfectly fine.

So, even if no one cared enough to work on this technology for the sake of “medical time travellers,” there would still be plenty of motivation to develop it for the sake of those who will be alive when the technology is finally mature.

Last In, First Out
Cryopreservation techniques continue to improve. The first patients (from the 1960s) have quite a lot of ice damage. This may be difficult and perhaps even impossible to reverse. Since that time, the technique has improved. Someone suspended today will have a much more well-preserved biostructure than the older “time travellers.” Obviously, if there is much less ice damage, it will be all the easier to restore the patient. So the first people to come out of cold storage are likely to be the last who went into it, with progressively earlier cases being revived as the technology continues to improve. Someone preserved in, say, 2028, might be brought back in 2040, whereas someone preserved in 1968 might not be brought back until the 2060s.

In Cold Storage III, I will discuss a few scenarios for cryosuspended patients who are eventually restored to full life.

Introduction
This is the first in a series of Big Articles that will cover cryopreservation and discuss possible future events that may make it feasible to revive cryonically suspended humans.

You can’t spend very much time reading about futurology without running across mention of “medical time travel” - having one’s body (or just one’s head) placed into cold storage just after the heart stops beating. People have been doing this since the 1960s. What is the outlook for actually bringing any of these people back? Well, one thing’s for sure - we all know the chances of coming back for those who are not thusly preserved.

There are several organizations which, for a fee, will preserve your head and/or full body. The organization I’ve studied the most is Alcor, which claims to be the foremost human cryonics provider. There are other cryonics organizations, of course, and a cursory Google search will turn them up. Be forewarned: I think they must have cryogenically preserved the webmasters who created these sites circa 1996, as their designs are mostly throwbacks to that era, and much of the online material appears to be stale by a few years.

I requested Alcor’s information packet by mail and have read most of the materials inside, which include: a letter to prospective members; a black-and-white glossy concerning Dramatic Advances in Brain Preservation at Alcor Foundation; a large-format “pamphlet” with a short introduction to the concept of cryonics and the company itself; a normal-sized pamphlet about becoming an Alcor member; a membership application (and addressed envelope for same); a memo to applicants about the signup fee; a vinyl Alcor sticker, and finally, a 100-page softbound book with a footprint of roughly 8 1/2 x 11 inches. (The entire book is available as a PDF, sans pictures.)

Why go with cryopreservation?
If you have an inoperable disease, or some terminal illness - or if you are simply getting on in your years - you may not live long enough to benefit from nanomedicine and other future technologies. These inventions may very well give humanity the ability to cure ANY disease, including the biggest killer of all - aging. Yes, aging. If we can manipulate cells at the molecular level, and rewrite DNA itself, there is no reason why we can’t do just that. These are some of the biggest hitters projected for the Singularity. Wouldn’t it be terrible to die of old age just before humankind eradicates aging itself, or of some disease that might soon have been cured with nanomedicine? It would be a huge waste. Cryopreservation offers the only plausible solution that I know of: Putting the body (or the brain, at the very least) into suspended animation, based on the projected capabilities of nanomedicine.

Why NOT go with cryopreservation?
Maybe you’re content with the concept of getting old and gray and dying. Maybe you think it would be impious to reach out for eternal life in this world rather than passing to the next (assuming it exists.) Maybe you’ll live long enough to see the elimination of disease and old age. Maybe you will die in a foreign country and simply decay too much by the time the rescue team can get to you. Maybe you’ll get Alzheimer’s and your brain will turn into mush long before your heart gets around to stopping. Maybe nanotech and medicine will not develop to the point necessary to retrieve cryosuspended individuals. Maybe it’s a huge waste of money (or perhaps you don’t have enough.) Certainly, there are many pros and cons that a prospective patient must evaluate before making the decision to arrange for cryosuspension.

At the Moment of Death
As soon as the patient’s heart has stopped, their body must be cooled as quickly as possible to slow the process of decomposition. Optimally, the patient flatlines in the presence of a cryonics “rescue team” which immediately begins to cool the body. Some organizations will begin to flush out the blood system immediately with glycerol (see the next section.) Alcor has a few different methods they use, depending on whether the patient has died near their facilities or elsewhere. They may put the patient on a heart-lung machine to restore life support for a time. For transporting the patient to their facilitity, they may flush out the circulatory system, replacing blood with a metabolic support solution.

Perfusion and Vitrification
The actual business of cryopreservation currently revolves around the practice of vitrification. The patient’s full body (or just their head) is perfused - that is, their blood is flushed out and replaced - with glycerol. This helps to suppress the formation of ice crystals, which tend to cause severe damage wherever they form. When that happens, huge voids are ripped around arteries and cells can be seen to have lost their membranes. Significant research has been conducted into determining the best sort of glycerol to use (as glycerol itself is available in different molar weights.) A few years ago, Alcor switched to a solution that produces “virtually” (quoting them here) no ice damage. The idea behind using glycerol is that A) it is dehydrative, and B) it gets in the way of water molecules so effectively that they can’t get together fast enough to form ice crystals.

After the circulatory system has been flushed with glycerol to the desired extent, the process of “temperature descent” can begin. The patient is cooled to the glass transition temperature - roughly the boiling point of liquid nitrogen - at which point the entire preserved biostructure is immobilized. All metabolic processes (including those of the microorganisms attempting to decompose the body) are halted, and as long as the patient is maintained at that temperature, no appreciable change in structure is likely to occur for hundreds of years (possibly longer.)

There is an important distinction to note here: Vitrification is not freezing. Freezing is something that can be done with water, or with something that contains a significant amount of water. Vitrification brings the entire biostructure to a glasslike state instead.

Ischemic and Reperfusion Damage
Ischemia is a state in which blood flow is greatly reduced or stopped completely. Obviously this causes tissue damage. If you have ever had an arm or leg “go to sleep” - and you have - that limb has actually undergone ischemic damage. Fortunately, this sort of damage is easily repaired when it happens to muscle and skin tissue, as long as the length and extent of ischemia isn’t too great. The brain, however, has a tougher time of it. White matter is capable of repairing itself to a certain extent, but gray matter is not. Once those cells run out of oxygen, they die.

Reperfusion damage happens as a result of flooding tissues with oxygen after they have depleted their supply of it. The high concentration of oxygen actually oxidizes the tissue somewhat. I’m not certain, but there may also be some damage from restoring hydraulic pressure after it has been totally lost.

In any case, ischemic and reperfusion damage must be repaired before the patient can be revived. The belief is that future nanotech will be able to handle this satisfactorily.

The full body, or just the head?
This is a fairly complicated question. Do we preserve the whole body, or just the head? There are advantages and disadvantages to both schemes.

Full Body

• More expensive
• Harder to perfuse the body as quickly thoroughly as the head alone; there are viscosity limits that get in the way
• “Muscle memory” may be better preserved if the entire body is kept
• The shock of being revived may be less if the patient is still in the same body they remember; age can be regressed (or the entire body replaced with a fresh clone) at a later stage
• Preserving an old, diseased body may be less efficient than simply cloning a new one

Head Only (i.e. “Neurosuspension”)

• Less expensive
• Easier to perfuse a head to the desired concentration
• Assuming the patient wishes to resume life in the normal fashion, a whole new body would need to be cloned
• If the patient wishes to be “uploaded” and run in a computer, preserving the whole body is probably a waste; any avatar (representation of themselves) they might want to use in a virtual world could either be synthesized by DNA analysis or simply put together from old photographs and other biometrics
• Any peculiarities of the original body - that is, things influenced by environmental factors, such as specific shape, scars, tattoos, etc. - will not be present in the cloned body, and may make the patient feel somewhat alienated when they are revived
• It may be simpler to clone a new body and artificially age it to some biological state (e.g. a few years after the end of adolescence) than to reverse the aging process in an old body, not to mention repairing damage caused by any diseases

The Long Wait
After the patient has undergone temperature descent, and been stabilized at liquid nitrogen temperatures, the “medical time travel” begins. How long will it be until we have nanomedicine capable of repairing damage from ischemia and vitrification, let alone restoring the biostructure to normal operating temperature while restarting the metabolic fire and bringing the patient’s brain up to a safe operating state? It could be a long time. Decades, maybe. Perhaps even a century, but at the current level of development I suspect it won’t be that long. Of course the world will have to avoid destroying itself and our societies will have to remain prosperous enough to maintain funding into medical and nanotech research.

What motivations will future society have to bring back these Rip van Winkles? Why will medical science develop technologies that will enable us to retrieve cryosuspended humans? I will discuss these questions in my next Big Article.

One of the cool things that could be done with this technology, aside from helping people with brain or spinal cord injuries to gain more independence, might be figuring out how to decipher signals from the human brain in general. Let us say that we implant these devices into the brains of a hundred people, and get a profile for how each person’s brain composes control signals. Let us then analyze each profile, and try to figure out the strength of correlation between profiles. What would we come up with? How much variance would be introduced by differences in placement of the electrodes? Would the profiles be nothing but noise compared to each other, or would there be similarities? What would that similarity be? 10%? 47%? 99.7%?

As this technology advances, it isn’t inconceivable that we could learn how to make it work in two directions. Neural pacemakers are already used by many epilleptics to help control brain activity. A BCI could be used to transmit data into the human brain, which could then synthesize it into useful information, in much the same way that it synthesizes analogue signals from the senses into sound and vision. The deaf might hear, the blind might see, and the paralyzed might get “force feedback” from their own limbs. The brain is capable of adapting to the implants; after a while, it figures out how to move the cursor around by thought alone, without involving the metaphor of moving one’s limbs.

Advances in this field could provide an incredible yield in the coming decades - and not just for people with brain injuries, or rich technology enthusiasts. I’ll probably write more on that in a future article.

“…the ever accelerating progress of technology and changes in the mode of human life, which gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue.” — Stanislaw Ulam, May 1958, referring to a conversation with John von Neumann

Picking Up Speed
Over the next few decades, the thinking goes, our world will be witness to the most astonishing leaps in technological prowess in all of human history. Nanotechnology, once mature, will be capable of repairing biological damage at the DNA level itself. (Getting it cheap enough to deploy on a scale large enough to heal a whole human body is another matter, but I am confident it will happen, just as I am confident that one-terabyte hard drives will be considered old-hat in five years.) Artificial intelligences may match or even excede human intelligence within the same time frame. Technology, in general, will continue to improve at an ever-increasing rate. What will life be like in 2030? Hard to say, but I’ll say one thing: Look at the rate of technological improvement between 1980 and 2005, and know that all of that incredible progress is but a shade of what we will do next.

Accelerating Returns
Alright, let’s get down to brass tacks. One of the strongest predictors for the Singularity is Kurzweil’s Law of Accelerating Returns. In short, technology develops on an exponential curve, rather than the somewhat straight line it may appear to develop on. It is very easy to look at what has changed in technology over the last year and project what will happen over the next, and to see something like a straight line between a year ago and a year from now. However, if you look at technology over a longer timescale, you will see that it is, in fact, on an exponential curve. Every comptuer scientist has heard of Moore’s Law, which states that transistor density in semiconductors is able to double about once every 18 months. Quoting the Moore’s Law article linked above:

As of Q4 2004, current PC processors are fabricated at the 130 nm and 90 nm levels, with 65 nm chips being announced by the end of 2005. A decade ago, chips were built at a 500 nm level. Companies are working on using nanotechnology to solve the complex engineering problems involved in producing chips at the 45 nm, 30 nm, and even smaller levels—a process that will postpone the industry meeting the limits of Moore’s Law.

This is not really a prediction that can be generalized to all technology - just semiconductors. However, it does form the basis of Kurzweil’s Law of Accelerating Returns, which states that the rate of technological progress - overall - doubles once every decade.

According to Kurzweil, you can assume that a hundred years of technological progress - at the current rate of development - will actually take just 25 years, since we continue to learn things that allow us to do things faster, better, more reliably, more cheaply, etc.

For Example…
Let us say that in order to design Deep Thought using today’s computers and other technology, design and research methodology, and so forth - never using any newer technology, etc. - it would take 100 years. If we periodically upgrade the computers we are using to design Deep Thought, and migrate to newer and better ways of doing research and development on the project, it will actually wind up taking just 25 years to design Deep Thought. This is because computers will continue to increase in power over time, and new efficiencies will be achieved with better R&D processes.

Artificial Intelligence
The physical basis of the human mind - that is, the majority of the brain - is a neural net. It is a learning computer. It starts out almost completely blank, with only a number of sensory inputs and neuromotor outputs and some built-in instincts to cause it to do anything more than sit in a catatonic state. As the owner of the neural net progresses through life, its internal state changes in ways that are informed by the senses and instincts innate to human existence. I believe that strong AI - that is, AI capable of tackling general problems around or above the level of a human, rather than just a single problem domain, such as playing chess - will eventually come together. This will arise from advances in neural net research, knowledge bases such as Cyc, genetic algorithms, our increasing understanding of the human brain, and other areas.

The thought process here is that strong AI may play a pivotal role in the Singularity. Let’s say we design an AI that is as intelligent as the human mind, and then set it to work designing more and more intelligent AIs. One day we have an AI that is a thousand times more intelligent than a human. What do we do with that AI? How do we control it? How do we harness its power? What happens when there are two of them, and then six, and then a thousand, and then a million? Tricky, isn’t it.

Alright, what’s the score here? What’s next?
The term “Singularity” is meant to imply that as we get closer to the actual event itself, any assumptions we have about what the future will hold will become increasingly unreliable. We may have a general idea, in much the same way that people in 1980 had some inkling that computers weren’t just a passing fancy. However, the specifics become rather fuzzy; there were few in 1980 who had even heard of the Internet (as, in this case, a use for computers), much less had any idea that it would become a pervasive element in the human experience, as television and radio did in the twentieth century.

To use the same analogy, we can look at current technology and how it integrates into society, and make some projections about what the future may hold. We probably won’t be dead-on with our projections, but it is arguably worthwhile to at least make some attempt at figuring out what the world might be like in the future. I think the next 25 will be - as Zaphod Beeblebrox would say - Amazingly amazing.

In my next Big Post About Fantastic Things, I will write about… the future!

About Me
I am a twentysomething computer programmer. When I am outside, I like things like hiking and martial arts. When I am inside, I like to program (& read books about programming) and to spend time in a shared 3-D environment called Second Life. I also like all the usual Internet stuff like IRC, various Web forums, etc. I read Jerkcity every day because it is the height of webcomic humor, and I read Rands In Repose because Rands writes interesting things.

My pet peeve is people who IM me with something like “hi” or “:)” out of the blue, and then expect me to invent and carry a conversation, even though it was their idea to contact me. I usually like to answer with something monosyllabic, like “what.”

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