Thursday, September 17, 2015

Cryonics and connectomics

I woke up on Saturday to a heartbreaking front-page article in the New York Times about a terminally ill young woman who chooses to freeze her brain. She is drawn into a cottage industry spurred by “transhumanist” principles that offers to preserve people in liquid nitrogen immediately after death and store their bodies (or at least their heads) in hopes that they can be reanimated or digitally replicated in a technologically advanced future.

Proponents have added a patina of scientific plausibility to this idea by citing the promise of new technologies in neuroscience, particularly recent work in “connectomics”—a field that maps the connections between neurons. The suggestion is that a detailed map of neural connections could be enough to restore a person’s mind, memories, and personality by uploading it into a computer simulation.

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. First, what information is required to replicate a human mind? Second, do current or foreseeable freezing methods preserve the necessary information, and how will this information be recovered? Third, and most confounding to our intuition, would a simulation really be “you”?

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...

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.

That means that any suggestion that you can come back to life is simply snake oil. Transhumanists have responses to these issues. In my experience, they consist of alternating demands that we trust our intuition about nonexistent technology (uploading could work) but deny our intuition about consciousness (it would not be me).

No one who has experienced the disbelief of losing a loved one can help but sympathize with someone who pays $80,000 to freeze their brain. But reanimation or simulation is an abjectly false hope that is beyond the promise of technology and is certainly impossible with the frozen, dead tissue offered by the “cryonics” industry. Those who profit from this hope deserve our anger and contempt.

http://www.technologyreview.com/view/541311/the-false-science-of-cryonics/

1 comment:

  1. Earlier this year, a two-year-old Thai girl became the youngest person to be cryogenically frozen, preserving her brain moments after death in the hope that she will one day be brought back to life. The BBC's Jonathan Head visited her family outside Bangkok to ask why they chose to grieve this way...

    It has the feel of a shrine to a young life tragically cut short. Matheryin, or Einz as her family nicknamed her, developed a rare form of brain cancer just after her second birthday. She died on 8 January 2015, just before she turned three.

    But by then her parents, both medical engineers, had made a decision that they hope may give Einz another chance of life...

    That idea was to preserve Einz through technology known as cryonics. The body, or in Einz's case just her brain, is put into a deeply frozen state at the point of death, and kept that way until, at some point in the future, extraordinary advances in medical technology allow her to be revived, and for a new body to be created for her.

    "As scientists we are 100% confident this will happen one day - we just don't know when," he said. "In the past we might have thought it would take 400 to 500 years, but right now we can imagine it might be possible in just 30 years."...

    The Naovaratpong family chose Alcor, an Arizona-based non-profit organisation that is the leading provider of what it calls "life extension" services, to carry out the preservation of Einz's brain. The family was closely involved in the preparations, designing the special coffin in which she would be transported to the United States.

    A standby team from Alcor flew to Thailand to supervise the initial cooling of the body. As the little girl deteriorated, she was moved from hospital to her own room. The moment she was pronounced dead, the Alcor team begin what is known as "cryoprotection"; removing bodily fluids and replacing them with forms of anti-freeze that allow the body to be deep frozen without suffering large-scale tissue damage.

    After arriving in Arizona her brain was extracted, and is preserved at a temperature of -196C. She is Alcor's 134th patient, and by far its youngest...

    In his mind, Einz's thoughts and personality are preserved with her brain at Alcor, and may at some stage be enough for her life to be reconstructed. He and his wife also plan to have their own bodies preserved cryogenically, although he acknowledges there is little chance they will be able to meet Einz again in their new lives.

    http://www.bbc.com/news/world-asia-34311502
    Courtesy of a colleague



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