Could that let you live forever?
Here’s what you’ll learn when you read this story:
- A neuroscientist survey shows that 40 percent think it might be possible to preserve a human brain, potentially well enough to decode its long-term memories after death.
- That opens the door to rebooting a person someday, complete with their memories, using whole brain emulation.
- However, scientists have yet to figure out how to map the complete neural patterns of a human brain, and ethical issues abound if someday we do preserve and then decode a brain.
The idea that physical changes in the brain enable us to store memories has been around for thousands of years. More recently, scientists started thinking that it could be possible to preserve structures in the brain that contain memories and other information representing our identity—and access them in the future.
Some scientists say that provides a slim chance of someday reviving a person from their preserved brain.
During life, when you have a particular experience, scientists think it creates a memory by causing chemical and physical changes in a group of neurons, or nerve cells, in your brain. They call these engrams. The stronger the memory, the greater the number of connections between the cells in an engram. The strengths and patterns of these neural connections formed over a lifetime are known as the connectome.
Theoretically, we recall a memory when appropriate cues—perhaps a sight or smell—reactivate neurons that were active at the time we encoded the memory.
If we could access memories from preserved neural tissue long after someone is gone, brain preservation becomes a potential means of extending life. A recent survey of neuroscientists found that 40 percent think it might be possible to preserve a human brain, and that a well-preserved one could retain enough information to eventually decode long-term memories from it.
“That’s no guarantee, but it’s far from trivial,” says Ariel Zeleznikow-Johnston, PhD, a neuroscientist at Monash University in Melbourne, Australia and lead author on the paper reporting survey results. “Scientists often are very cautious and unwilling to be drawn into speculation about what might be possible in the future. [The finding] says that neuroscientists think this has a reasonable shot at working, if done correctly.”
It might work using a method called whole brain emulation.
This process would preserve the structure of a brain at a resolution sufficient to capture everything that encodes a person’s psychological properties. If scientists could do that, then maybe they could create an artificial digital version of the brain that’s so close to the structure of the original that its behavioral responses would be indistinguishable. A virtual you, in a sense.
Survey respondents also estimate the possibility of creating a whole brain emulation from a preserved brain at 40 percent. They think we may achieve this feat with worms around the year 2045, mice around 2065, and humans around 2125.
“We’re talking about potentially changing our relationship with death itself, shifting from death as an absolute endpoint to preservation as a potentially temporary condition.”
High-quality preservation of the physical brain is possible with animals already; the best validated technique is bathing the organ in a fixative chemical and keeping it at very low temperatures. Zeleznikow-Johnston says preserved brains can be imaged at very high resolution that shows individual synapses or nerve connections.
Preserving a recently deceased person’s brain is tricky, though, given the realities of clinical settings and ethical and legal constraints, he adds. “The fundamental issues here aren’t that there’s new technology that needs to be developed, it’s the implementation details of the existing techniques when applying them to the real world.”
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