The human brain rapidly dissolves after death due to the break down of proteins and putrefaction. Decomposition often occurs within minutes after death, which is quicker than other body tissues, likely because the brain is about 80% water. Rotting starts in normal ambient temperature at about 3 days, and the brain is essentially vaporized within 5-10 years. For this reason, anthropologists can study the skulls, teeth, and bones of our distant ancestors, but we cannot study their brains.
The advent of “deliberate mummification”, using chemicals, has allowed long-term preservation of soft tissues. We see this in the Egyptian mummies at museums. Of course, the Egyptians also performed “excerebration” in which they removed the brains with iron hooks through the nose prior to embalming, so we don’t have the pharaoh’s brains to examine. “Natural mummification” can also occur at extreme temperatures. Freezing has been shown to preserve rare brains of icemen in glaciers. On the opposite side of the spectrum, extreme heat has “preserved” certain aspects of the brain tissue. Recently described in the New England Journal of Medicine was an ancient brain from Pompeii which was vitrified (turned into glass) from the extreme heat of the Mount Vesuvius eruption in 79CE. Due to the sudden exposure to heat greater than 9680 Fahrenheit and then cooling, the proteins and fatty acids can be thermally preserved.
Interestingly, microscopic examination showed that this ancient Heslington brain had more densely packed nerve cells, which were both shorter and narrower than a modern brain. Enigmatically, the brain was the only tissue remaining from the individual. This may be explained by analysis of the cerebral proteins showing certain characteristics which resisted decay. The average person does not have this brain cytoarchitecture to allow auto-preservation.
So without access to priests versed in mummification, without getting trapped in a glacier, or without a rare genetic predisposition resisting proteolysis, how can the average person leave their brain for research in a few thousand years?
Modern-day brain preservation at the molecular level has been around since the 1960s with “cryonic preservation”. There are numerous “institutes” which will cryopreserve you. Internet advertisements liken it to a spa menu… full-body costs about $200,000 while head-only is just $80,000. If you bargain shop, one company is currently offering a $28,000 early-bird special. A few hundred people have been known to freeze themselves, presumably with the hope that medical science will cure their ailments and bring them back to life. The United States and Russia are the only countries in the world offering human cryopreservation.
Overall, there is no evidence that freezing a body and/or brain will promise immortality. Short-term hypothermia after brain injury has suggested mildly improved function in some studies, although most show no meaningful benefit. Long-term freezing may cause damage as the temperature drops, but the thawing process invariably creates ice crystals that damage the cells. Interestingly, most organs cannot handle cold temperatures for long. One of the biggest challenges in organ transplant is not the number of donors, but the ability to transport the organ in time. Over half of donated hearts and lungs are unfortunately thrown in the trash each year.
However a new chemical, glutaraldehyde, using a technique called “aldehyde stabilized cryopreservation”, may provide a small advancement in cryogenics. Glutaraldehyde bonds to, and protects, the proteins in the brain, so in theory, all of the information encoded in the living brain could be frozen without damage for long-term storage. Unfortunately, this may preserve the information but still does not offer an avenue back to biological life.
However, if aldehyde-preserved brains retain information, the data theoretically could be “extracted” and uploaded into a computer. Of course, a brain scanned at the molecular level is likely to take up at least a trillion, trillion pixels. Currently, the entire world’s estimated data storage capacity is 295 billion gigabytes.
A Silicon Valley company, Nectome, was developed in 2015 to research this. “Nectome” is Latin for, “I bind myself”. Social media satirized the Latin meaning to be, “I have been killed”. Again, uploading your brain into a computer still requires dying first.
In summary, we can freeze the human brain in 2020, but we can’t do much after that. Scientists may eventually be able to upload your thoughts into a computer, but your chances of being the next Lazarus are low. You have a better chance of being attacked by a grizzly bear and a polar bear in the same day… and the mortal outcome would be the same…