The mystery of the ancient human brain remained intact for 2,600 years without decay

Thousands of years ago in the Heslington area of ​​England, a man's body began to decompose. Meat and offal became muddy, hair turned to dust, but bones remained and more specifically, the existence of a small piece of brain.

After months of patiently investigating brain tissue proteins, an international team of researchers has finally come up with a clue that explains this remarkable conservation case and that it could help us better understand it. about how healthy (and unhealthy) brains actually work.

The 2008 discovery of the Heslington brain - one of the oldest neurological tissue specimens ever discovered in Britain - led researchers to solve a challenging puzzle.

Thousands of ancient brain specimens are causing scientists headache because of refusing . decomposition.

In the instant of a death, brain tissue will begin to decompose. Compared to other body parts, this decay is especially quick, with different types of proteins destroying cellular infrastructure.

So when archaeologists looked inside of a mud-laden skull pulled from an Iron Age site, they were shocked to see the withered remains of what looked like a human brain. can recognize.

According to the carbon dating method, the middle-aged man had his last breath somewhere between 673 and 482 BC, most likely the result of a fractured spine, resulting in hanged.

Exactly who he is, or why he died, will probably never be known. However, later, after being executed as speculated, the victim's severed head was thrown into a pit, where it was covered in fine-grained sediments.

Soft tissues can usually be preserved if they are hygroscopic, frozen or kept in anaerobic, acidic environment. But what is especially strange in the case of Heslington skull is that it does not preserve any other parts of the victim's body, including hair.

To find out what makes the remaining organic material so special, the researchers took a closer look at the nature of the protein.

Unlike most organs, the brain needs good support at the cellular level to function and maintain connections within the complex structure of nerve cells.

A matrix of intermediate fibers (IF) performs this task in the living brain and it seems that under the right circumstances, they can retain some kind of integrity quite long after the cells have been reduced to ashes. molecule.

We know a little bit about these IFs based on various pathological studies. Different types of cells have their own fibers, and this specificity has attracted research to uncover biomarkers for neurological diseases.

In the case of the Heslington brain, the microscope showed that IF fibers like long axons make up a living brain, only shorter and narrower, while antibody markers match the axon protein recognizing that they once contained quite long neuron tails.

Further analysis with specific antibody markers showed that an unbalanced amount of nerve structure belonged to cells such as astrocytes, with less protein marking tissue thinking about gray matter.

However, determining why these specialized astrocytes IF do not follow the usual decay pathway will not be simple.

There are no signs of preserving tannins commonly found in UK bodies and while the sample's pH is lower, researchers do not believe they can use it to estimate the acidity of a grave.

Moreover, proteins that stick around at relatively warm temperatures tend to form stable structures and stable proteins don't easily open like unstable proteins.

So over the course of a year, the researchers patiently measured the slow release and degradation of proteins in a modern specimen of nerve tissue and compared it to the decay in the Heslington brain specimen.

The results showed the existence of a chemical that prevents enzymes from destroying called proteases in the months after death, allowing proteins to combine into stable aggregates that can survive at warm temperatures. than.

"In combination, the data suggests that proteases of the neck brain may have been inhibited by an unknown compound that diffuses from outside the brain to deeper structures , " the researchers write in the journal. fox.

There is nothing special about the brain of this Iron Age friend. Instead, something in the environment may have inhibited the chemical processes that often break down the protein strands responsible for supporting astrocytes, at least long enough for it to contract into their own form. I know.

Of course, only with this extremely unique research sample, the researchers say it is still difficult to draw even more solid conclusions than conjectures.

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