Earlier this year, when the Brain Preservation Foundation—headed by neuroscientist Kenneth Hayworth of the Howard Hughes Medical Institute—awarded a prize to researchers for preserving all the neural circuits of a pig’s brain, Hayworth found himself in the media spotlight. The only problem was, the popular media simplified things a bit too far. They took the brain preservation technology to be all about euthanasia. Since the method used to preserve the pig’s brain only works with a recently deceased brain, if the technology became available to humans, anyone wishing to preserve their own brains this way would need to die, ideally when the brain is in good shape. So, reporters reached the conclusion that the technology was about taking the opportunity to die knowing your brain would be preserved. As we shall see, that wasn’t the point.
The sensational euthanasia angle crowded out the scientific story about the remarkable advances being made in connectomics—the science of figuring out a brain’s complete wiring diagram—and the once-absurd dream that it might one day be possible to upload a mind into the cloud, Ray Kurzweil-style, achieving cyber-immortality. Although “it will be at least 50 years before the first human mind is successfully uploaded and 100 years before it’s routine,” Hayworth said, he regards it as not only scientifically possible but ethically imperative.
But first, the science.
Just as genomics studies genomes, so connectomics studies connections in the brain. The ultimate goal of this 21st-century biological cartography is to map the location of every neuron and every connection: the synapses that, neurobiologists believe, encode what we call “mind,” from every memory to every facet of personality, beliefs, and consciousness.
Determining the connectome—or, a connectome, since each brain’s is unique—is the prerequisite for uploading and “emulating” (presumably in silicon) a person’s mind, as Hayworth and others dream. A decade after scientists unveiled the first such wiring diagram—of the roundworm C. elegans (302 neurons, 7,000 synapses)—connectomics is hot in pursuit of its Everest: the connectome of the 86-billion-neuron, 100-trillion-synapse human brain.
Last year one of Hayworth’s colleagues, Davi Bock, led a team that obtained electron microscopic images of the fruit fly brain and its 100,000 neurons, the initial step in mapping the first connectome of an actual brain. (C. elegans has a primitive nervous system, not a brain.) At the Allen Institute for Brain Science in Seattle, neuroscientists are taking the first steps toward a mouse connectome: They slice a one-cubic-millimeter chunk of mouse brain into 25,000 pieces, imaging each with an electron microscope that shows the neurons and axons.
One cubic millimeter is one-thousandth of a mouse brain, or one-billionth of a human brain, Bock said. You begin to see why some scientists doubt this will ever work. The mouse project—again, just 0.1% of the brain, and 100,000 neurons—is costing tens of millions of dollars, and is only a baby mouse step toward a full mammalian connectome. But it took $3 billion and more than a decade to sequence the first human genome, compared to hours and $1,000 today. So, some would like to assume that massive technological advances will bring a human connectome within scientific reach.
Because synapses fall apart quickly once life ceases, imaging a connectome requires a brain that’s just barely dead.
To prepare for that day, a tech start-up called Nectome proposes to preserve brains with glutaraldehyde, as its founders did with a pig brain, winning an $80,000 science prize from the Brain Preservation Foundation. Because, as noted above, synapses fall apart quickly once life ceases, imaging a connectome requires a brain that’s just barely dead. This of course triggered the euthanasia fracas. Euthanasia is not, however, a requirement of this technology (should it ever come into being). People who die of natural causes could presumably have uploaders standing by.
Before you dismiss this as sci-fi nonsense, note that Nectome has a $1 million grant from the National Institutes of Health for its preservation and connectome R&D. The preservation technique that won the prize from his foundation, Hayworth says, “appears to preserve the full range of structural and molecular features that modern neuroscientific theories postulate underlie the encoding of all of the types of longterm memories that make a person unique.” Someone undergoing the procedure “is electing to ‘hit pause’…in order to optimally preserve the full informational content of their brain.”
Just to be clear, we’re not talking about reanimation, cryonics-style. Hayworth and Nectome believe the future lies not in reviving the dead but in full-brain “emulation,” or recreating in digital form a brain’s wiring diagram and thus its information content. Nectome describes its mission as preserving a brain “well enough to keep all its memories intact: from that great chapter of your favorite book to the feeling of cold winter air, baking an apple pie, or having dinner with your friends and family. If memories can truly be preserved…we believe that within the century it could become feasible to digitize your preserved brain and use that information to recreate your mind.”
The scientific questions about brain emulation are as fascinating as they are unanswered. In addition to knowing which neurons connect with which—the basic connectome—do you also need to know the strength of each synapse? the firing patterns? the distribution of neurotransmitters? the subjective sense the brain’s owner gets when a particular synapse operates?
In the unlikely event that neuroscience learns everything there is to know about the brain, will it have explained every ineffable mystery about the mind?
Oh, and one little detail: The information content of a cubic millimeter of brain tissue is about 1 petabyte of data, Bock says. An entire mouse brain comes to 1,000 petabytes. At 1 billion petabytes—1 petabyte being equal to 1 million gigabytes—the informational content of a single human brain exceeds the total storage capacity of the cloud today!
But would-be brain emulators don’t let such details deter them. Instead, they predict, as a 2018 study did, that “eventually the reading of memories…will become the daily routine of connectomics.” Those wiring diagrams, including in preserved brains, will “capture functionally relevant features of brain circuits from which mind and cognitive functions emerge”—possibly by 2075 to 2100—neuroengineer Randal Koene told the 2017 SharpBrains summit. But if brain emulations built from connectomes come to pass, is the emulation you? Or is it “just” a copy?
That and related questions echo those that I explored in my very first Brain Science column in Mindful in April 2013: Is there is a mind separate from brain? Is mind “only” what the brain does? In the unlikely event that neuroscience learns everything there is to know about the latter, will it have explained every ineffable mystery about the former? If someone does emulate a brain in silicon, will the silicon version of you sleep and dream, and if it doesn’t, will that degrade its information content? If the brain upload is in the cloud, does it have consciousness? If consciousness is an “emergent property” of brain activity (essentially a happy accident), then it might. Will it suffer something like the mental and sensory deprivation of solitary confinement? Will it wonder where it is and how it got there, tormented by existential despair? It boggles the mind!
Hayworth envisions installing the brain upload in a sensory-enabled robot, so as to avoid at least the last two questions. And to those who argue that the upload couldn’t be the person whence it came, he asks, if C-3PO’s hard drive were transferred to a new droid, would anyone doubt that it is still C-3PO? No. How about if the hard drive were copied perfectly, and put into a second robot; would that be C-3PO also? Yes, he said: “Making copies of C-3PO doesn’t raise philosophical questions for most people. But if we accept the materialist neuroscience view (in which the mind is the brain), we have to accept that a simulation will be you.”
Failing to pursue research that might make brain emulation possible is therefore unethical, Hayworth argues. “There are moral implications to knowing you could have preserved the information content of a human brain but instead said, ‘nah, screw it’” he says. If we do not at least try to develop the technology to preserve the unique patterning of neural circuitry that encodes an individual, including “the memories and knowledge of Holocaust survivors before they all die, that, to me, would be as if we again burned the library of Alexandria” and lost an incalculable store of human experience.
SCI-FI | Heaven on Earth?
An unusually romantic view of connectomic innovation appears in the Netflix hit Black Mirror. In the episode “San Junipero,” two women meet in a simulated California party town (circa 1987): a paradise for the dead and dying, where, if they choose to have their minds uploaded, they can leave behind their lonely end-of-life. San Junipero gives them not only good times, but a second chance at human connection, self-expression, and healing. The question remains whether this use of tech represents a far extreme of escapism or a compassionate, human-made heaven.