London: Scientists have uncovered what they say is the oldest ever human brain preserved in a decapitated skull that dates back more than 2,500 years.
The discovery of the yellowish, crinkly, shrunken brain by British researchers now prompted questions about how such a fragile organ could have survived so long and how frequently this strange type of preservation occurs.
Except for the brain, all of the skull`s soft tissue was gone when the skull was pulled from a muddy Iron Age pit where the University of York was planning to expand its campus.
"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," Sonia O`Connor, a postdoctoral research fellow at University of Bradford, was quoted by LiveScience as saying.
O`Connor led a team who assessed the state of the brain after it was found in 2008 and looked into likely modes of preservation.
"It`s particularly surprising, because if you talk to pathologists who deal with fresh dead bodies they say the first organ to really deteriorate and to basically go to liquid is the brain because of its high fat content," O`Connor said.
When it was found, the skull, which is believed to be of a man probably between 26 and 45 years old, was accompanied by a jaw and two neck vertebrae, bearing evidence of hanging and then decapitation.
Cut marks on the inside of the neck indicate that the head was severed while there was still flesh on the bones, O`Connor said, adding that why he was hanged is not yet clear.
More than a decade earlier, O`Connor was involved in the discovery of 25 preserved brains within medieval-era remains from Kingston-upon-Hull in England.
According to him, the Heslington brain and the other remains are quite different from mummies, frozen bodies, or intentionally preserved remains as in these cases other soft tissue -- skin, muscles and so on -- is also preserved.
None of the recently discovered remains showed any signs that they were intentional preserved, O`Conner said.
The Heslington remains appear to have been buried quickly after death in wet environments where the absence of oxygen prevented the brain tissue from putrefying.
But while the oxygen-free environment seems key, it is not possible to rule out other factors like certain diseases or physiological changes that might predispose the brain to being preserved this way, O`Connor said.
After being deposited in the water-logged pit, she believes, the brain began to change chemically and developed into a durable material, shrinking to just a quarter of its size. The chemicals in the new material are still under investigation, she said.
The new findings are to be published in the Journal of Archaeological Science.