Scientists have reversed memory loss in mice by injecting them with brain fluid.
Researchers took cerebrospinal fluid (CSF) from young adult mice and infused it into the brains of older mice. The treatment improved the memory recall of the old mice in a task where they learned to associate a small electric shock with a tone and a flashing light.
It is hoped that the findings could be applied to humans and raises hope for future dementia treatments.
Study author Professor Tony Wyss-Coray, from Stanford University in California, said: "Brain ageing underlies dementia and neurodegenerative diseases, imposing an immense societal burden.
"Memory improvements that are seen in old mice receiving CSF from younger animals may be attributed to growth factors that are shown to restore natural cell function.
"The findings demonstrate the potential rejuvenating properties of young CSFfor the ageing brain."