According to Philip Jaekl, a writer with neuroscience training, the connectome is the “ complete network of neurons and all the connections between them, called synapses.” Taking a leaf from Sebastian Seung’s book, Connectome: How the Brain’s Wiring Makes Us Who We Are, he argues, “You are your connectome.”
In that case, Seung’s “you” is very complex. Many types of memory are mediated through the connectome. Jaekl writes,
Thus, a key to unlocking the correspondence between the connectome and memory is to elucidate the entire circuitry of the brain. Tracing the wiring at this scale is no easy task when considering the sheer complexity involved. A mere cubic millimetre of brain tissue contains around 50,000 neurons, with an astonishing total of around 130 million synapses, according to some estimates. An entire human brain, however, is more than 1 million cubic millimetres and contains around 86 billion neurons, nearly equivalent with estimates of the number of stars in our galaxy.
The most relevant number is the one representing the total sum of synaptic connections, which comes in at a mind-numbing c100 trillion. Once the possible paths that electrical neural signals can run on across these connections are determined, only then might it be possible to comprehensively know the patterns of activity integral to memory and to subjective experience.Phil Jaekl, “Am I my connectome?” at Aeon (March 19, 2021)
Commenting at TED on the idea of mapping the connectome, Emily Singer of Technology Review notes, “[Seung and his colleagues] will need to make their technique a million times faster to finally bring larger maps — like that of a cortical column — into the realm of reality.” That could be a significant limitation.
When it comes to technologies, we are accustomed to a folk version of “Moore’s Law” of exponential growth (next year, things are bound to get faster even faster than this year). But some constraints in the real world are just plain limits, especially if they are the boundaries of physics. So we do not know for certain that any technology can just be sped up a million times and produce useful results.
But now, what was this about immortality?
Jaekl points out that, shortly after death, the connectome begins to decay. But what, he asks, if it could be preserved?
And so, to actually maintain the exact structure of the entire connectome, you need a preservation method where every single neuron and each of its synaptic connections are held in place – a requirement that must succeed about 100 trillion times over, for an individual human.
The implications surrounding a human brain-preservation technique that can keep the entire connectome intact are profound. If indeed, you are your connectome, defined by all the memories and essences of you imprinted in its structure, then it’s essentially you that’s preserved. Your connectomic self.Phil Jaekl, “Am I my connectome?” at Aeon (March 19, 2021)
Such considerations led to the formation of the Brain Preservation Foundation (BPF) in 2010, complete with cash prizes for the best methods of preserving the connectome. They have learned from animal studies that the connectome can be preserved indefinitely via cryogenic freezing at -135°C (-275°C).
The idea, sponsored by 21CM, is to eventually preserve memories for future immortality by killing a person under controlled circumstances and preserving the connectome, as researchers Ken Hayworth and Robert McIntyre told Jaekl,
The treatment (death) is worse than the problem: living memory lost. Yet both Hayworth and McIntyre believe that vitrifixation, though fatal, offers a type of immortality, if the essence of someone can be scanned for all the relevant information and then somehow transferred to an artificial medium; one that essentially replaces the brain, from a functional standpoint. Crucially, this medium, when ‘running’ would have to accurately and sufficiently conduct the patterns of neural activity that support one’s memory, identity and experience to evoke their unique consciousness.Phil Jaekl, “Am I my connectome?” at Aeon (March 19, 2021)
The next step in the proposed techo-immortality would be to upload the brain’s memories into a computer. It’s not impossible in principle because neurons can work with electrical currents in prostheses; if so, electrically based systems might work with neurons. Jaekl goes into detail about proposed approaches. But the best scenarios face many constraints:
Obstacles to a non-invasive, or minimally invasive, brain-computer interface that can actually do something are many. You need to make your device as small as possible, as flexible as possible, and as biocompatible as possible, which is hard enough. For medical use, to stimulate and sense brain activity—to record intention from the central nervous system and simultaneously deliver it through the peripheral nervous system, like Burkhart’s brain-computer interface does—“is actually very difficult to do, since neural signals are very small,” said Rikky Muller, assistant professor of electrical engineering and computer sciences at UC Berkeley. Few methods can gather a lot of information from the brain quickly enough to operate the thing you connect the brain to—be it prosthetic arm, flight simulator, or drone. The more data you collect, the slower you become, and the faster you get the less data you can grab. Muller pointed to other problems. To pick just one: “It’s very hard to squeeze a high data rate out of a wireless device, because it costs power you don’t necessarily have when you’re in a power-constrained environment, like inside the human body,” she said.PAUL TULLIS, “THE BRAIN-COMPUTER INTERFACE IS COMING—AND WE ARE JUST SO NOT READY FOR IT” AT BULLETIN OF THE ATOMIC SCIENTISTS (SEPTEMBER 15, 2020)
A much bigger issue is the Hard Problem of consciousness. Assuming, as a thought experiment, that a person’s lifetime of memories could be frozen and thawed in this way, what use would it be if no consciousness is associated with it?
Jaekl observes that we change through life anyway in the sense that we are not really the same person when we are old as when we were young. We are, however, a continuous person, and the unfrozen memories might well be just that — a jumble of information with no conscious person to connect them.
One thing that researchers of near-death experiences (NDEs) have noted is that a human being can be conscious while clinically dead. But that implies that consciousness is not, in any event, the sort of thing that can be preserved by these researchers’ methods. As Jaekl notes, “The claim that the self can be found in the connectome is still a long way from being proven, and there might never be any way to determine if consciousness can exist in a machine.”
True, and there’s also a philosophical question: In our universe, everything is transient and the general direction is slowly winding down toward chaos. Is immortality in this universe a reasonable goal? Near death experiences certainly hint at survival — but in a frame of reference that is not strictly this universe as we know it. New technology did not cause NDEs; it only brought back enough people from various states of death to enable researchers to study them.
And that may be all we can know about it for now.
You may also wish to read: Can human minds be reduced to computer programs? In Silicon Valley that has long been a serious belief. But are we really anywhere close?
Why our minds can’t really be uploaded to computers. The basic problem is that human minds aren’t “computable.” Peter and Jane are not bits and bytes.