But he was still very much interested in the idea that cryonics represented. To stimulate research in this area, Dr. Hayworth founded the Brain Preservation Foundation , and raised funds for prizes meant to drive development of the technology. To win the prize, according to Dr. Hayworth, the entrant had to demonstrate that "the synaptic connectivity of an entire large mammal brain can be preserved.
The winner was a group led by Dr. Robert McIntyre , an AI researcher-turned-neurobiologist, who developed a technique to flood the brain of a pig with a chemical called gluteraldehyde.
Gluteraldehyde bonds to the proteins in the brain, fixing the neurons, synapses and most of the large proteins and important molecules in the brain in place.
These are, as far as neuroscientists know, all of the important molecules and structures that encode our memory and personality. If they're preserved, then, at least in theory, all of the information that was encoded in the living brain could also be retained. The brain could then be frozen without damage for long term storage. Canadian neurobiologist Dr. Michael Hendricks , a researcher at McGill University, admits that the technique can likely preserve all the information in a brain, but it's not going to be possible to bring a brain preserved this way back to biological life.
Hayworth agrees, but has a different vision for brain preservation. Because these preserved brains may retain all of the information in a mind, then it could be possible to retrieve that information. These include whether such brains have any consciousness and if so deserve special protection, or whether their technique could or should be used by individuals to extend their lifespans - by transplanting their brains when their bodies wear out.
In a commentary published in the Journal Nature this week, Prof Sestan and 15 other leading US neuroscientists called for clear regulation to guide them in their work. Certainly, today's experimental models are far from having such capabilities. But various models are now being developed to better understand the human brain, including miniaturised, simplified versions of brain tissue grown in a dish from stem cells.
And advances keep being made. The researchers say that ways of measuring consciousness need to be developed and strict limits set for them to be able to continue their work with the public's support. Prof Colin Blakemore, of the School of Advance Study at the University of London, backs the research team's call for a public debate on the issue.
But the more likely it would also be for the brain to have some sentience and consciousness, which would be deeply worrying".
The brains, which are not conscious, are kept alive through the circulation of an oxygen-rich fluid through the organs. Researchers in the US say they have managed to keep the brains of decapitated pigs alive outside of the body for up to 36 hours by circulating an oxygen-rich fluid through the organs.
While the scientists, led by Yale University neuroscientist Nenad Sestan, say the brains are not conscious, they add the feat might help researchers to probe how the brain works, and aid studies into experimental treatments for diseases ranging from cancer to dementia.
However others were quick to stress that the development did not mean humans could expect to cheat death any time soon, noting that it is not possible to transplant a brain into a new body. That is restoring a human being. If that person has memory, I would be freaking out completely. Today in the journal Nature , 17 neuroscientists and bioethicists, including Sestan, published an editorial arguing that experiments on human brain tissue may require special protections and rules.
These include brain organoids blobs of nerve tissue the size of a rice grain , human-animal chimeras mice with human brain tissue added , and ex vivo human brain tissue such as chunks of brain removed during surgery. Hyman, who also signed the letter, says he did so reluctantly, because he thinks most of the scenarios are exaggerated or unlikely. Funders of a deep-pocketed new "rejuvenation" startup are said to include Jeff Bezos and Yuri Milner.
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