Prehistoric Human Brains Baffle Scientists

The most delicate organ in the human body is the brain, which is why it’s protected by a thick-boned skull. What’s baffling is that this squishy mass, out of all the organs, can survive the most time without decay.

Researchers have cataloged over 4,000 naturally preserved human brains, some as old as 12,000 years. This archive includes Inca sacrificial victims, prehistoric people, and North Pole explorers. And yet, the discovery of a preserved brain is perceived to be a very rare incident.

Human soft tissue, including the brain, can be preserved by some well-understood processes such as dehydration, freezing, and tanning. These methods can be the result of human actions or natural factors. It’s not unusual for brains to survive when other internal organs are well-preserved, such as in dried-out remains of desert burials, frozen bodies from mountain passes, and tanned bodies from bogs.

However, preserved brains have been found without other soft tissues, such as floating alongside bones in sunken shipwrecks, or sitting alongside ancient bones from a swampy pond.

Until now, there has been no systemic study to determine why brains last longer than other soft tissues.

This new archive allowed researchers to determine the prevalence of intact brains, to study how they persisted, and the diversity of their preservation conditions. They also mapped their distribution worldwide across time. Finally, the researchers studied the brains to understand ancient diseases and genetics.

About a quarter of the brains were discovered in bodies lacking any other preserved soft tissue. Known processes that preserve all types of tissue can’t explain why these brains endured.

The reason why these brains were preserved is a mystery, but it might be because of the brain’s chemical composition. The brain has a 1-to-1 ratio of proteins to lipids, while other soft tissues have different ratios. This ratio could mean that if metals like iron are introduced, it could cause the proteins and lipids to bind together and last longer. Many preserved brains were found to contain iron oxide (rust).

The team is employing new techniques to study the molecular interactions leading to the preservation of brains. The brains could also offer an opportunity to study neurological diseases in ancient humans.

 

https://www.msn.com/en-us/health/other/thousand-year-old-intact-human-brains-baffle-scientists-and-there-are-thousands-of-them/ar-BB1knvV8?ocid=mailsignout&pc=U591&cvid=e61c919954d04db49bab96e09d0a1bfa&ei=54