See You Again Soon, Leela! A Two-Hundred Year Cryogenic Love Story

…some of the tools and techniques emerging from neuroscience laboratories were beginning to bear some resemblance to those long envisioned in futurist fantasies.

Neuroscientists were starting to map the connections between individual neurons believed to encode many aspects of memory and identity.

The following story is remixed from an article by Amy Harmon for the New York Times 1 and a rebuttal of sorts by Michael Hendricks for the MIT Technology Review 2.

. . .

Times Is Hard

It was Tom who told her she had cancer, after she awoke from surgery to remove the tumor. “Are you kidding?” she asked him, three times, until she could tell he was not. They learned a few weeks later that the tumor was glioblastoma, virulent, incurable. Terminal.

It was impossible to know on that cloudless Arizona morning which fragments of Leela’s identity might survive.

The infinite scenarios seemed overwhelming. Might she be back in a hundred years, or a thousand? Would Tom be there? In what form? If damaged, could the connectomics of her biological brain be repaired?

There was already some neuroscience research that made piecing together a damaged connectome seem conceivable.

Memories, for instance, appear to be stored in multiple places. Certain areas of the brain responsible for tasks like attention might be replaced with off-the-shelf spare parts. The molecular identity of neurons hold clues to which should be connected where. And broken ones might be digitally pieced back together.

Leela tried to make light of it all. “You’ll have to enhance me,” she told Tom. Amid the few fantasies they allowed themselves, she made a point to tell him something more tangible, too: “I want you to be happy,” she said. “You’ll find a new person, and you’ll be O.K.”

Freeze Me

Less than two years later, at the Hope Lodge Facility for Experimental Medicine provided by the American Cancer Society, Leela’s pulse monitor sounded its alarm and her breath grew ragged. Tom stood bolt-upright from his bedside chair at the high-pitched alert; he cast aside the video game controller where he had been playing Ocarina of Time and reached into a pocket, fumbling for his phone.

As a tear rolled down her face and Tom completed the emergency call, Leela clutched his hand and silently mouthed “thank you”, before closing her eyes for what hopefully would not be the final time.

Tom looked down to his phone screen as the private ambulance’s geobeacon overlaid its serpentine progress through dense midday megacity traffic.

“I’ll show you the ropes,” Tom whispered to Leela’s still form, making morose half-mocking reference to the possibility of her return to a far-future world. He lightly stroked her still-warm face and fought back tears of his own, waiting the agonizing six minutes before the emergency cryonurse team arrived.

Soon, Leela’s breathing ceased and her body became eerily still.

Upon arrival, the Alcor Life Extension Inc. paramedic estimated Leela’s time of death and immediately began the vitrification process. Alcor’s preferred antifreeze was liquid nitrogen, a cryoprotectant so cold that it prevents decay in biological tissue for millenniums. Once pumped through the blood vessels, the liquid begins its transition into a glassy preservative substance.

Leela’s body was placed in an ice bath and loaded into a truck for transportation to the nearby cryonics center.

. . .

As per her cleverly dry, gallows humour, a widget at the top of her social media page read, “IS LEELA ALIVE?” That night it autocorrected due to inactivity, changing from “Yes!” to:

“Nope, sorry. I hope this isn’t how you found out.”

For the remainder of that week, Tom’s social network status read simply, “Damn.”

The Age of Spiritual Machines

Subzero storage kept Leela’s brain in a state of neuropreservative stasis for the next two centuries.

Roughly two hundred years later, Leela’s billions of interconnected neurons were scanned, analyzed and converted into computer code that mimicked how they once worked.

Her brain, although poorly preserved through a crude procedure (salvaging whatever synapses they could — it was the best and only viable option back in the mid-21st century), underwent extensive digital reconstruction and rehabilitation. Microscopic nanorobots inserted in the bloodstream formed intelligent swarms to scan, assemble, and wirelessly upload their information to neural repair and reconditioning systems.

One day, after over two hundred years of dreamless slumber, Leela woke up.

Her first words upon returning to consciousness:
“Am I alive?”

Her second sentence:


In Silico

The dominant dream of cryonics had long since been achieved, a dream that she might rejoin the world after making a choice: an artificial body or a computer-simulated environment. In fact, as with all “sleepers”, she was able use both, feeling and sensing through a networked silicon substrate in addition to her new biomimetic brain. In the event of a sudden death, she could now and forever be rebooted from her last backup.

Enhancements for memory, intelligence and empathy were available, as was the option to merge with other minds through the synapses of the Internet. The very interiority of human life had become virtualized, for a price.

There were even the beginnings of research into “one-way” consciouness transfer, as robots had begun to colonize Mars and conduct experiments beyond the solar system. The limitations of light-speed meant that once a spacecraft left orbit, there was no way to download an entire mind back to Earth. A digital self could, however, sleep indefinitely; astrorobotic avatars could be retrieved via rescue craft at a future date and rebooted into a human body with all of the marvels and stories of space travel intact.

“The brain is a suberbly efficient computing platform, and those computations can be simulated”, doctor and chief technologist Miriam Jenson told Leela soon after she woke. “You are a pattern of electrical signals, and the potential reach of those signals is effectively limitless.”

Show You The Ropes

Leela left the Alcor Institute’s Hospital for Reanimation and Rehabilitation on December 3rd, 2315.

The previous evening’s snow crunched satisfyingly beneath her feet. Where was Tom, she wondered. A blink of the eyes brought a three-dimensional map up straight ahead, upon which she saw herself as a blinking blue dot. Raising her gaze to the stars, Leela waved to the invisible satellite array high above as it beamed down an unmistakable sign that she was here. On Earth. Alive.

With those first ginger footsteps, Leela’s life began again.


Support For Cryonics

The research, limited so far to small bits of dead animal brain, had the usual goals of advancing knowledge and improving human health. Still, it was driving interest in what would be a critical first step to create any simulation of an individual mind: preserving that pattern of connections in an entire brain after death.

“I can see within, say, 40 years that we would have a method to generate a digital replica of a person’s mind,” said Winfried Denk, a director at the Max Planck Institute of Neurobiology in Germany, who has invented one of several mapping techniques. “It’s not my primary motivation, but it is a logical outgrowth of our work.”

Dr. Hayworth, a Harvard neuroscientist working with the Howard Hughes Medical Institute, believes that is possible. Hayworth was once described by The Chronicle of Higher Education as “an iconoclast with legitimate research credentials”. He was, as of 2011, perhaps the only mainstream neuroscientist to openly acknowledge that he would like to upload his brain to a computer.

If the connectome, laid down by genes and altered by life experience, turns out to be the repository of the identity information that neuroscientists widely believed it to be, he argued, there was no reason that uploading a mind should not ultimately succeed, “especially when we can now see how to save it by expanding on today’s neural mapping technology.” 1

Arguments Against Cryonics

Other neuroscientists do not take that idea seriously, given the great gaps in knowledge about the workings of the brain. “We are nowhere close to brain emulation given our current level of understanding,” said Cori Bargmann, a neuroscientist at Rockefeller University in New York and one of the architects of the Obama administration’s initiative seeking a $4.5 billion investment in brain research over the next decade.

“Will it ever be possible?” she asked. “I don’t know. But this isn’t 50 years away.” 1

While it might be theoretically possible to preserve these features in dead tissue, that certainly is not happening now. The technology to do so, let alone the ability to read this information back out of such a specimen, does not yet exist even in principle. It is this purposeful conflation of what is theoretically conceivable with what is ever practically possible that exploits people’s vulnerability. 2

Cryonics and Cryogenics: The Science

Storage capacity needed to map a mouse connectome: 450,000 terabytes
Storage capacity needed to map a human connectome: 1.3 billion terabytes
Global hard drive storage, 2014: 2.6 billion terabytes

The mapping technique pioneered by Dr. Denk and others involves scanning brains in impossibly thin sheets with an electron microscope. Stacked together on a computer, the scans reveal a three-dimensional map of the connections between each neuron in the tissue, the critical brain anatomy known as the connectome.

Still arduous and expensive, the feat had so far only been performed on tiny bits of brain from euthanized laboratory animals, and it would be only one of many steps required to get to a simulation.

Moreover, the brain preservation methods scientists have used to perform such scanning, which involves encasing pieces of brain in hard plastic, had failed for anything larger than the size of a sesame seed. Nor could current methods for cooling and preserving brains at cryogenic temperatures, the only other known means to forestall decay, ensure that their fragile wiring was not damaged.

“We have to recognize that there are many huge gaps that have to be leaped over,” said Stephen J. Smith, a neuroscientist at the Allen Institute for Brain Science in Seattle. “The brain is holding on to many of its secrets.”

Jeffrey Lichtman, a Harvard University neuroscientist, said, “Nothing happening now is close to a reality where a human patient might imagine that their brain could be turned into something that could be reproduced in silico.”

Accurately simulating a functioning brain from a static circuitry map, many scientists say, will require a grasp of how living brains work that is orders of magnitude better than what we have today. Even then, it may be necessary to identify the molecular identity of each neuron, in addition to knowing how they connect to one another.

Moreover, to scan and analyze a human connectome with today’s technology would cost billions of dollars and take thousands of years. And of course, no one knows if even a perfect simulation of a mind would retain the self-awareness of the original.

“You’d ask yourself how many mistakes could you make and still have the same person,” Joshua R. Sanes, director of the Center for Brain Science at Harvard University, said in an interview. “The ability of us to keep being ourselves in the face of changes in our nervous system is pretty amazing.”

Sebastian Seung, a Princeton University neuroscientist who had treated cryonics seriously in his book, “Connectome: How the Brain’s Wiring Makes Us Who We Are.” If the brain’s connections remain intact in the cryonics procedure, or can be pieced back together, he had written, “then we cannot rule out the possibility of resurrecting memories and restoring personal identity.”

But Dr. Seung, an adviser to the Brain Preservation Foundation, cautioned that he hoped his advice would help others “make informed decisions.”

Even though three-dimensional maps of partial bits of brain had become relatively easy to produce, Dr. Seung observed, there were no published 3D images available — even of animal brains preserved under its protocol. Only two-dimensional images had been published. That raised questions about how well preserved their clients’ brains were.


Neuroscientists first insert a needle filled with a chemical fixative into an anesthetized animal’s heart while it is still alive to pump the fixative through the brain, essentially gluing its structure in place. The brain is then soaked in a heavy-metal stain so the neurons can be seen under an electron microscope, drained of water, and embedded in a hard plastic.

That method has the considerable benefit of allowing for storage of the brain at room temperature. But some neuroscientists argue that the chemicals erase information that would be required to devise an accurate simulation of the brain.

(source: 1)


Cryonics, in which human brains and bodies are stored at somewhere below minus 300 degrees Fahrenheit, has since the late 1990s employed a thick, viscous antifreeze to replace the blood and water in the brain in an effort to preserve it before storing it.

The antifreeze is needed to avoid the formation of jagged ice crystals between brain cells that can tear through the fragile web of the tissue. But since cryonics can begin only after a formal declaration of death, clots can form and vessels can start to collapse before the process is started. Even with no delay the liquid can take hours to circulate.

Some proponents of this procedure, known as cryopreservation, have long wanted brains preserved for uploading to a computer. But most proponents hope that the biochemical damage to brain cells will one day be reversible, allowing brains to be thawed and repaired.

(source: 1)

From Anatomy to Activity: Would an upload really be you?

Science tells us that a map of connections is not sufficient to simulate, let alone replicate, a nervous system, and that there are enormous barriers to achieving immortality in silico.

I study a small roundworm, Caenorhabditis elegans, which is by far the best-described animal in all of biology. We know all of its genes and all of its cells (a little over 1,000). We know the identity and complete synaptic connectivity of its 302 neurons, and we have known it for 30 years.

If we could “upload” or roughly simulate any brain, it should be that of C. elegans. Yet even with the full connectome in hand, a static model of this network of connections lacks most of the information necessary to simulate the mind of the worm. In short, brain activity cannot be inferred from synaptic neuroanatomy.

The presence or absence of a synapse, which is all that current connectomics methods tell us, suggests that a possible functional relationship between two neurons exists, but little or nothing about the nature of this relationship—precisely what you need to know to simulate it.

The colossally hard problem of simulating any brain [meets] the stupendously more difficult task of replicating a particular brain, which is required for the promised personal immortality of uploading.

Whatever our subjective sense of self is, let’s assume it arises from the operation of the physical matter of the brain. We could also tentatively conclude that such awareness is substrate-neutral: if brains can be conscious, a computer program that does everything a brain does should be conscious, too. If one is also willing to imagine arbitrarily complex technology, then we can also think about simulating a brain down to the synaptic or molecular or (why not?) atomic or quantum level.

But what is this replica? Is it subjectively “you” or is it a new, separate being? The idea that you can be conscious in two places at the same time defies our intuition. Parsimony suggests that replication will result in two different conscious entities. Simulation, if it were to occur, would result in a new person who is like you but whose conscious experience you don’t have access to.

Would an upload really be you? This is unanswerable, but we can dip our toes in.

(source: 2)

Further Reading:

1. Harmon, Amy. (2015, September 12). A Dying Young Woman’s Hope in Cryonics and a Future. Retrieved from

2. Hendricks, Michael. (2015, September 15). The False Science of Cryonics. Retrieved from

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