by Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on exciting discoveries, scientific advances and more.
An entrepreneur turned academic, Alexandra Morton-Hayward has been interested in brains – specifically how they work – during her previous job.
“I worked with the dead for years. My experience is that the brain is quite quick to liquidate (after death),” she said. “So it was quite a shock when I came across a (scientific) paper that referred to a 2,500-year-old brain.”
Now a forensic anthropologist studying for a doctorate at the University of Oxford, Morton-Hayward has discovered that brains, although not found intact like bones, make a surprising contribution to the archaeological record.
To understand why, the anthropologist has compiled a special archive of information about 4,405 brains discovered by archaeologists. Brains emerged from the peat bogs of northern Europe, from the mountain tops of the Andes, from shipwrecks, from desert tombs and from Victorian slums. The earliest found were 12,000 years old.
Morton-Hayward is working primarily towards understanding how these brains have survived the ravages of time, with at least four preservation mechanisms in place.
However, the database will also open up new areas of study, said Martin Wirenfeldt Nielsen, a senior physician and pathologist at the University Hospital of Southern Denmark, who was not involved in the research. He is also in charge of the medical brain collection of the University of Southern Denmark.
“This database will enable scientists to study brain tissue from ancient times and determine whether diseases known today existed many years ago in civilizations completely different from the ones we live in now,” a Wirenfeldt Nielsen said via email.
“Examining tissue from brains not exposed to the environment and stimuli of modern society may help us understand whether some of the brain diseases we face today may be at least partially caused by the way we live now.”
A collection of free ancient brains,
Morton-Hayward examined scientific literature going back three centuries and interviewed historians and archaeologists to catalog the brains. However, not all the corresponding physical specimens are yet available for study.
The oldest were two 12,000-year-old brains reported from a site in Russia in the 1920s, which researchers said were found with woolly mammoth teeth, Morton-Hayward said.. It is not clear what happened to the brains, she said.
Morton-Hayward works in a laboratory in Oxford, England, where she has helped build a collection of 570 ancient brains. They are kept in refrigerators in jars and plastic containers such as take-out because they have secure lids. The oldest specimen in the lab is an 8,000-year-old brain from Stone Age Sweden, which was mounted on a spike before being buried in a lake bed.
Morton-Hayward and her colleagues identified four ways in which the brains, which were typically discolored and shrunken, were preserved – factors often related to the climate or environment in which they were found. The results were published March 19 in the journal Proceedings of the Royal Society B Biological Sciences.
Dry, hot conditions mimicked the dehydration of the brain the mummies were deliberately embedded, and in acidic peat bogs the body was essentially tanned like leather. In cold places, the brain was frozen, and in some cases, the fats found in the brain were transformed into “grave wax,” a process called saponification.
However, in about 1,328 cases, brains survived in the absence of other soft tissues, prompting questions as to why this organ could continue to decay while others decay. Interestingly, many of the oldest brains preserved in this way are unknown, said Morton-Hayward.
“We have this fifth mechanism, this unknown mechanism that we call a hypothesis could be a type of molecular cross-linking, perhaps triggered by the presence of metals such as iron,” she said, referring to the possibility that proteins and lipids present in the brain. of elements such as iron or copper, which allows the brain to be preserved.
The researchers do not believe that the protective shell of the skull is behind the preservation of the brain in the absence of other soft tissues because preserved brains were found in skulls that were damaged from trauma or the fossilization process, according to the study.
“Tissue from the central nervous system is extremely fragile and fragile and it is amazing to find that brain tissue has been preserved for so many years,” said Wirenfeldt Nielsen.
Secrets waiting to be spilled?
It is possible that ancient DNA and proteins could be teased out of the brain – shedding secrets about the people they once belonged to. If successfully recovered, the material may be able to reveal things that molecular information extracted from bones and teeth cannot, Morton-Hayward said.
“The brain is the most metabolically active (organ) in the human body. It makes up 2% of our body weight, but consumes 20% of our energy, constantly doing things. It is an extremely complex organ, and therefore has this very unusual biomolecular composition. So the wealth of information is much greater to begin with,” she said.
“Ancient DNA could be very well preserved within these brains because of how brains of at least unknown type seem to be preserved,” she said. “They’re condensing and shrinking and driving the water out. And that is to form this kind of closed system that could, in theory, protect high-quality, high-yield DNA.”
Many of the people whose brains have been removed have inspiring stories that have attracted more attention, said Morton-Hayward. One of the brains she documented belonged to a Polish saint. Another was a victim of the Inca sacrifice. As a former businesswoman, she said she never forgets the people behind the body parts.
“I’m so grateful to have that experience,” she said. “The important thing is not to lose sight of the fact that these examples are human beings.”
For more CNN news and newsletters create an account at CNN.com
