Scientists Reveal the Secrets of Britain's Oldest Brain
Mon, April 19, 2021

Scientists Reveal the Secrets of Britain's Oldest Brain

Since its discovery, the so-called Heslington Brain has puzzled researchers because of its unusually intact condition. Researchers at University College London spent a year studying tissue samples using an array of molecular techniques / Photo by: Sergey Nivens via 123RF

 

Since its discovery, the so-called Heslington Brain has puzzled researchers because of its unusually intact condition. Researchers at University College London spent a year studying tissue samples using an array of molecular techniques.

Published in the Journal of the Royal Society Interface, the results identified how the brain preserved itself—considering that neural tissue rapidly disintegrates after death. The results also reveal properties of the ancient organ and suggest applications for modern neuroscience and archeology.


A Puzzling Find

The ancient brain once belonged to an Iron Age man 2,600 years ago and was unearthed in 2008. Archeologists were puzzled to find that the brain was incredibly well-preserved as it was the only tissue matter in the skull that didn't decompose.

Rachel Cubitt, a researcher from York Archaeological Trust, told CNN the "bright yellow spongy material" was  "unlike anything I had seen before."

The Heslington Brain isn't the only example of uniquely preserved neural tissue in the archeological record, but it's still notable since there was "no sign of hair, skin, or any other soft tissue” that came from its discovery.

After confirming it was well-preserved brain material, the archeologists removed the top of the skull to further study the matter and found that it was dated between 482 and 673 BC. The researchers noted it was impossible to preserve human brain proteins in ambient temperature for millennia in free nature.

The breakdown process, known as autolysis, begins immediately following death and sees enzymes break down the brain. Since the brain is 80% water, CNN says this quickens the already rapid degradation process.

Thus, Britain's oldest brain "offers a unique opportunity to use molecular tools to investigate the preservation of human brain proteins."

The ancient brain once belonged to an Iron Age man 2,600 years ago and was unearthed in 2008. Archeologists were puzzled to find that the brain was incredibly well-preserved as it was the only tissue matter in the skull that didn't decompose / Photo by: fotokvadrat via 123RF


The Brain's Afterlife

In identifying the mechanisms that led to the brain's incredible preservation, the researchers observed how the tissues from the ancient specimen decomposed over an entire year and compared the results to that of a modern brain.

They also examined samples using an array of precision techniques such as mass spectrometry and observed the behaviors of antibodies from the ancient brain cells, digital media and broadcasting company Vice Media reports.

The researchers were able to isolate intermediate filaments as the preserving element of the Heslington Brain. Intermediate filaments are a type of neural connective structure commonly found in the cells of vertebrates and most invertebrates.

Images from electron microscopy showed 5-10 micrometer long and 0.2-0.6 micrometer thick filamentous, electrodense structures with diameters ranging from 0.2 to 4 micrometers.

The researchers noted that, compared to the modern brain sample, the Heslington brain has more densely packed axons. Filaments in the modern brain sample were longer, reaching up to 17.3 micrometers, and had a larger diameter of 0.8-7.5 micrometers.

These findings suggest that these proteins in the ancient brain were resistant to the effects of the brain-degenerating enzymes known as proteases. Instead of breaking down, Vice Media says the filaments established strong protein aggregates that helped the organ maintain its overall structure and preservation.

Unique Brain Structure

Study leader Axel Petzold said that, if stored in a certain way, the brain proteins are likely to stay "very stable over time." He noted that the specific way is an aggregate formation, in which proteins clump together.

"It was interesting to learn that brain protein aggregates were more stable than DNA," the lead researcher noted.

The filaments are mostly found in the brain's inner area or white matter. However, the case of the Heslington brain shows the opposite: the proteins were found to be highly concentrated in outer brain areas known as grey matter, CNN reports.

It's this high concentration that prevented and deactivated the autolysis breakdown process from outside the brain. Folding themselves tightly together further helped the preservation process, which explains why the ancient brain appears shrunken and compact compared to a normal brain structure.

Preservation Process

There was no evidence of any artificial preservation techniques, analysis shows, only "naturally occurring chemicals" to preserve the material.

The researchers believe there must have been some type of acidic fluid that entered the brain that prevented the enzymes from breaking it down. They have yet to establish if this fluid was the cause of the brain owner's death or if it breached the brain after he died.

"The manner of this individual's death, or subsequent burial, may have enabled the brain's long-term preservation," Petzold explained.

As part of the study, the researchers also examined the duration of the tightly folded proteins in the Heslington Brain to unfold. While it took a full year for the folds to completely unravel, it still stimulated an immune response to produce antibodies.

"A contemporary brain just dissolved, but the Heslington brain continued to reveal more and more proteins," the lead researcher said.

Petzold and his colleagues noted the benefits of the findings of the brain's preservation and its proteins on current research on protein biomarkers, archeology, medicine, and the biomedical field.

Findings specifically have implications for neurodegenerative diseases like Alzheimer's and dementia, which see adverse folding of brain proteins.

The researchers believe there must have been some type of acidic fluid that entered the brain that prevented the enzymes from breaking it down. They have yet to establish if this fluid was the cause of the brain owner's death or if it breached the brain after he died / Photo by: Aleksei Lagutkin via 123RF