Neurons of the retina

Ray Kurzweil and other so-called transhumanists have promised that in coming decades we will be able to transfer a digital copy of the trillions of connections among nerve cells in our brains into a computer. We would essentially reincarnate ourselves as non-biological beings that persist for eternity inside a laptop, on the endless links of the Internet or as avatars inside a television set. After achieving the ultimate copy and paste, we would wave goodbye to death as we know it.

For fairly evident reasons, biologists tend to dismiss out of hand the ideas of Kurzweil and the transhumanist lot as the ravings of computer jocks who know nothing about the real workings of the DNA and cells that make up living tissue. Into this debate comes Sebastian Seung, a young and well-regarded computational neuroscientist from MIT, who has taken a serious look at some of the questions put forth by the transhumanists.

In Connectome, due in February, Seung conveys the excitement of studying the complete circuit diagram of the brain for which the book is named. A full connectome might provide telling insight into what goes goes awry, for instance, in an autistic child or an Alzheimer’s patient (definitely worth reading for these bits alone). In the last chapters, though he takes up the claims of the transhumanists who desperately would like to get their hands on a full connectome for the ultimate upload into binary immortality.

Seung tries to come to grips with the controversial assertion that someday you might be able to transfer the equivalent of a connectome.doc file to computer hardware, software or any other robot or avatar that you can pick from back issues of Analog.

Seung strikes a pose that mixes skepticism with fascination. The advance reading copy that Scientific American received acknowledges some doubts :

"In his book Live Long Enough to Live Forever, the inventor Ray Kurzweil predicts that immortality will be attained in the next few decades," Seung writes. "If you can manage to live long enough to survive to that point, you will live forever. Personally, I feel quite confident that you, dear readers, will die, and so will I."

But Seung remains intrigued by the notion that a unifying mechanism drives the workings of the meat machine between our ears and its mechanics might be decipherable and reproducible. And he is at least willing to cast a critical eye on the prospect of a 2.0 version of the self that, when transferred into a supercomputer, laptop, or software avatar, might then live on as an electronic ghost. (Yes, some would say that ESPN and Facebook have already brought us there, but Seung doesn’t address social media as immortality.)

The central question for Seung—and the one that also keeps the transhumanists on tenterhooks—is whether you are your connectome. If you could deduce every connection point of every brain cell, the strength with which each neuron fires, and the way these firing patterns change as the cells interact with each other, would, in fact, you be left with a copy of you?

In a chapter called "To Freeze or to Pickle," Seung undertakes, from multiple perspectives, an earnest and unsmirking analysis of the connectome as a pathway to immortality. All of his conclusions point to obstacles that could very well prove insurmountable.

First he considers what might called the meatlocker problem. Because it may take a while to create that complete wiring diagram, many transhumanists have plans to place their heads or whole bodies in a cryonic liquid nitrogen Dewar soon after death—or, as alternatives, to preserve themselves in a glassy solid or by another process called plastination. (Plastination is the form of preservation used in the Body Worlds tour of skinless corpses.)

Once the uploading technologies are perfected, the idea goes, the preserved tissue could be used for piecing out the wiring plan. On its own, this expectation may be a showstopper because of the difficulty of maintaining the integrity of the brain's unfathomably complex circuitry. "At the present time, cryonics is closer to religion than to science," Seung writes. "Its members believe that a future civilization will be able to resurrect them, based only on their faith in limitless technological progress."

Even if this niggling detail can eventually be resolved, there remains the unresolved issue of what information the connectome contains exactly. To better understand brain connections, scientists have been trying to simulate at least parts of the brain for decades. They are now also taking on the larger question of recreating the whole thing. The Human Brain Project in Europe has targeted the task of crafting a model of the entire organ a decade from now. The model would, in principle, simulate the thousands of different neuron types as well as the connections among them—and their changing structures as the brain learns and forgets.

The Human Brain Project is intended as an exploration of basic science, not a preparation for eternal life. But Seung points out that even an impressive endeavor of its magnitude might fail to capture all the necessary information.

One potential flaw: The model of the brain might have to take into account the way neurons communicate outside known channels—foregoing the transmission of chemical and electrical signals across the small gaps, called synapses, between brain cells. To overcome this hitch, it might be necessary to create a simulation of each atom in the brain, an undertaking of such unimaginable complexity that it would verge on the impossible. “It seems absurd to even consider the enormous computational power required, and is completely out of the question unless your remote descendants survive for galactic time scales,” he writes.

Seung ends his book with an epilogue that calls for a "return to reality"—a recognition that "grand challenges" remain, beyond quixotic quests for eternal life. A 10-year effort to find the connectome of a mouse brain is on his wish list. Such a quest lacks the box-office appeal of contemplating eternity as a file on a flash drive. In the end, though, Seung believes a project of this more modest scale would, like The Human Genome Project push researchers to the limit but vastly deepen our knowledge about an organ that remains largely a mystery.

One thing that I didn’t understand after reading the book was why he didn’t end the chapter about uploading with a blanket condemnation of a seemingly absurd endeavor, a conclusion that would have been fully justified from his arguments.

I e-mailed Seung and asked him whether he thought these far-fetched technologies might ever materialize. He replied that he has received this question before but prefers not to respond. "People often think I'm being coy by not answering the question you ask," he writes. "I'm not being coy; I just don't want to waste my readers' time with matters that are purely matters of opinion. It's impossible to predict events so far in the future, and my opinion is no more likely to be correct than those of other people. In the book, I address questions that can be discussed scientifically."

He continues later: "In my book, I compared transhumanism to religion. Effectively, you'd like to know whether I belong to this religion. (i.e. perhaps you're just asking me a personal question.) Strangely enough, the answer doesn't matter...I've realized that transhumanists view me as working for their cause, whether or not I believe in it. I'm part of their vision of manifest destiny, whether I like it or not."

Seung undoubtedly retains a lingering fascination with the possibility of an intersection between connectomics and transhumanism. At a TED talk given last year, he commented that connectomics might eventually put to the test whether a technology like cryonics will eventually be feasible. And Seung is a member of an advisory board to the Brain Preservation Foundation, which is offering a prize for technologies that would successfully preserve the structure of either a mouse or large animal brain after death for "science," "memory donation" or "continued life."

Don't let any of that deter you, though. Even without meditations on crossover dreams between science and fiction, this is a great book if you want to know where neuroscience is going during the next 10 years and maybe far beyond.

Source: Aleksandar Zlateski and Sebastian Seung