Once an undertaker, Alexandra Morton-Hayward’s fascination with brain decomposition steered her academic path.
“Working with the deceased for years, I noticed brains liquefy rather fast after death,” she remarked. “Imagine my astonishment finding a study citing a brain from 2,500 years ago.”
Presently a forensic anthropologist and doctoral candidate at Oxford University, Morton-Hayward has noted brains, though less often intact than bones, are remarkably preserved in archaeological contexts.
She’s assembled a database of 4,405 brains unearthed globally, from European peat bogs to Andean summits, from shipwrecks to deserts and even Victorian poorhouses, with the eldest dating back 12,000 years.
Morton-Hayward’s research delves into the survival of these brains through time, identifying at least four preservation methods.
This archive, according to Martin Wirenfeldt Nielsen, a pathologist at South Denmark University Hospital not involved in the study, paves the way for novel research avenues. It could reveal ancient diseases and offer insights into how contemporary lifestyles might contribute to present-day brain conditions.
Morton-Hayward compiled this information from three centuries’ worth of literature and interviews with historians and archaeologists, though some physical specimens are now lost.
Among the oldest are two 12,000-year-old brains from a Russian site in the 1920s, found alongside woolly mammoth teeth, Morton-Hayward noted, but their current whereabouts are unknown.
In Oxford, England, Morton-Hayward’s lab houses 570 ancient brains, stored in fridges within securely-lidded jars and takeaway containers. The lab’s most ancient brain is an 8,000-year-old specimen from Stone Age Sweden, found buried on a spike in a lakebed.
Morton-Hayward and her team pinpointed four preservation tactics for these typically discolored and shrunken brains, often related to the climate or environment of discovery. Their study was published on March 19 in the journal Proceedings of the Royal Society B Biological Sciences.
Deserts’ dry heat dehydrated brains resembling mummification, acidic peat bogs effectively tanned them, freezing occurred in cold climates, and in some instances, brain fats converted to “grave wax” through saponification.
However, in about 1,328 cases, the persistence of brains without other soft tissues remains a mystery, sparking curiosity about this organ’s unique resilience.
“We’re considering a fifth, an unidentified mechanism which might involve molecular crosslinking, potentially with metals like iron facilitating it,” she explained, suggesting proteins and lipids in the brain might fuse in the presence of metals, aiding preservation.
The study suggests the skull’s enclosure isn’t solely responsible for brain preservation, as preserved brains have been found in damaged skulls.
“It’s truly remarkable that such delicate, vulnerable central nervous system tissue could survive for millennia,” Wirenfeldt Nielsen observed.
The potential of extracting ancient DNA and proteins from these brains is exciting, Morton-Hayward believes, as it could offer insights beyond what bones and teeth can reveal.
“The brain’s complexity and metabolic activity make it a treasure trove of biomolecular data,” she stated. “The preservation we’re seeing might especially protect high-quality DNA.”
Morton-Hayward stressed the human stories these brains carry, from Polish saints to Inca sacrifice victims. Her undertaker background keeps her connected to the humanity of her research subjects.
“I’m deeply thankful for that experience,” she expressed. “One must always remember, these remains were once living people.”
