The Immortal Brain: Would You Go For It?

Sep 16, 2015

Last Saturday, two-time Pulitzer prize winner Amy Harmon published a fascinating article in The New York Times about a young dying woman who chose to have her brain preserved in case neuroscience could one day restore her mind back to life.

Harmon accompanied her article with another one, on what it would take, scientifically, to achieve such a feat and how close (or far) we are from it. Could science one day beat death? And, if it could, would you choose to do it?

The science involved is extremely difficult. One could choose to preserve his brain, hoping that one day another "he" could be genetically cloned and the information could be uploaded into his new copy. This requires at least two amazing things: first, that the brain could be preserved long-term without damage; and, second, that human cloning becomes acceptable and feasible. If human cloning would be banned indefinitely (and how could such a law be enforced around the world?), perhaps the info in and of the brain could be uploaded to a robot.

Preserving the brain is complex, since low temperatures damage the tissue and finding the right coolant is tough. Another way of preserving the brain tries to get a mold of its structure (neurons and their connections, called synapses). It uses a heavy metal to trace the neurons and then get rid of the fleshy stuff, using plastic as a filler.

The hope, either way, is that a preserved brain would be scanned and the positions of the neurons and their synapses would be mapped in amazing detail. Presently, this means breaking the brain into little cubes of one-millimeter size, slicing each into about 30,000 sheets, and reading the information with an incredibly accurate electron microscope. There are millions of such cubes in a brain, making the task horribly daunting, even for the fastest electron microscope in the world. However, optimists may argue that reading the human genome was equally daunting in the recent past and is now perfectly feasible.

Let us assume that we could reconstruct the architecture of someone's brain in great detail and with a small margin of error. This would be only part of the task, however, given that the brain is not a static collection of stuff, but a thriving hive of flowing neurotransmitters busily crisscrossing synaptic links in different directions at different rates in separate regions. With some 85 billion neurons and thousands of trillions of synapses, the traffic would be quite messy.

But these are all technical challenges — and technical challenges don't represent an a priori barrier to progress. If reconstructing someone's brain is just a technical challenge, then we shouldn't be surprised if it gets done one day, although that day may be very far away. But is this all that it would take?

No one really knows, since we don't understand the nature of consciousness or how the brain generates what we call mind, the sum-total of the experiences we define as the self. This difficulty has nothing to do with going beyond materialism or invoking the soul as part of the mystery. If we were reconstructing a TV it would be easy, since all that courses through the wiring is an electric current, a flow of the same stuff, electrons. But the brain is not like a TV. There is complexity, not just at the cellular level but also at the biomolecular level — the chemical reactions happening across synapses, for example.

It's hard to imagine that higher-level cognition is the product of local neuronal activity; it seems that the more complex things we do depend on many interlocking parts — and also on separate parts working in tandem, trading information in ways that reinforce one another, including complex connections with the body. It may be impossible to reconstruct you without including information about your whole body.

Whatever the difficulties, the search must go on — and it's heartwarming that the Obama administration has slated $4.5 billion to deliver a "comprehensive, mechanistic understanding of mental function" by 2025. (I'm troubled by the word "mechanistic," though. Why is it there?) We will only find it if we look, and what we don't or can't find will also teach us something.

In the case of understanding the brain, it's safe to bet that we don't even know what the major challenges ahead will be. Still, faced with an early death, should one not believe?


Marcelo Gleiser is a theoretical physicist and cosmologist — and professor of natural philosophy, physics and astronomy at Dartmouth College. He is the co-founder of 13.7, a prolific author of papers and essays, and active promoter of science to the general public. His latest book is The Island of Knowledge: The Limits of Science and the Search for Meaning. You can keep up with Marcelo on Facebook and Twitter: @mgleiser.

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