London: A human brain in the UK, believed to be the oldest ever discovered, may have been preserved for over 2,500 years by mud, archaeologists say.
The brain was found inside a decapitated skull, with the jaw and two vertebrae still attached, at an Iron Age dig site near York, UK, in 2008.
A team of 34 experts have been working to study and conserve the brain since its discovery.
By radiocarbon dating of a sample of jaw bone, researchers determined that this person probably lived in the 6th Century BC, which made the brain about 2,600 years old.
By looking at the teeth and the shape of the skull it is likely this person was a man between 26 and 45 years old.
An examination of the vertebrae in the neck shows that he was first hit hard on the neck, and then the neck was severed with a small sharp knife.
York Archaeological Trust said the skull had been buried in wet, clay-rich ground providing an oxygen-free burial.
The trust said the burial location could have helped conserve the brain, although the exact reason for its survival is unknown, 'BBC News' reported.
The skull was discovered face down in a pit, but it was only when it was being cleaned that the brain was found inside.
"I peered though the hole at the base of the skull to investigate and to my surprise saw a quantity of bright yellow spongy material. It was unlike anything I had seen before," said Rachel Cubitt, collection projects officer.
Research suggests that the head was cut from the body very quickly after the person was killed.
Over time the skin, hair and flesh of the skull did undergo chemical breakdown and gradually disappeared, but the fats and proteins of the brain tissue linked together to form a mass of large complex molecules.
This resulted in the brain shrinking, but it also preserved its shape and many microscopic features only found in brain tissue.
As there was no new oxygen in the brain, and no movement, it was protected and preserved, the trust said.