A piece of the preserved Heslington brain after it was removed from the skull in which it was found
In 2008, when The University of York in the UK was planning to expand its Heslington East campus, the archaeological work carried out in advance of construction yielded an exceptional find: an Iron Age human skull. The remains of a 2,500-year-old skull were found in a waterlogged pit at one of the excavation sites.
However, the most surprising fact about the find was what the skull had in it: a well-preserved brain, which showed no chemical signs of deliberate preservation. "It was just amazing to think that a brain of someone who had died so many thousands of years ago could persist just in wet ground," said Dr. Sonia O’Connor, team lead and a Research Fellow in Archaeological Sciences at the University of Bradford.
Brain material shows as dark folded matter at the top of the head in this computer-generated view into the skull. The lighter colours in the skull represent soil.
As Dr. O’Connor points out, usually when a person dies, the very first organ that deteriorates is the brain, due to its high fat content. So, how had the brain survived all those years of burial?
“The lack of putrefaction and survival of gross morphology indicate a quick death to burial and the anoxic waterlogged ground seem then to have provided an environment where rather than the brain decaying in the normal way it has instead developed into this persistent material,” said Dr. O’Connor in an email.
Dr Sonia O’Connor, from the University of Bradford, examines the remains of the brain using an endoscope.
DNA sequencing of samples from the brain and carbon dating suggest that it is one of the oldest surviving brains in Europe. The man was the victim of a ritual killing, was aged between 26 and 45 when he died, and the remains date from between 673 and 482 BC. It is further suggested that the man died from hanging and that the burial occurred very rapidly after his death.
Dr. O’Connor added: “This is the most thorough investigation ever undertaken of a brain found in a buried skeleton and has allowed us to begin to really understand why brains can survive thousands of years after all the other soft tissues have decayed.”
A representation of the skull generated from the CT scans taken at York Hospital.
Funded by the University of York and English Heritage, the research was published in the March edition of the Journal of Archaeological Science. The research team included scientists from the UCL Institute of Neurology in London; the departments of Archaeology, Biology and Chemistry at the University of York; the Department of Archaeological Sciences at the University of Bradford; and the Biocentre and the Department of Laboratory Medicine at Manchester University.
In Dr. O’Connor's opinion, “This is not the first time that brains preserved in this way have been found but it is the first time that we have had the opportunity, funding and a first class team to really try to understand what has occurred and the archaeological significance of such survivals.”