The scientist who claims to be about to carry out the first human head transplant by next year says that he has successfully done the procedure on a monkey in China.
Maverick neurosurgeon Sergio Canavero said he tested the procedure in experiments on monkeys and human cadavers.
The monkey head transplant was carried out at Harbin Medical University in China, Canavero told New Scientist.
The monkey survived the procedure "without any neurological injury of whatever kind," he said, but that it was killed 20 hours after the procedure for ethical reasons.
Canavero says that the success shows that his plan to transplant a human's head onto a donor body is in place.
He says that the procedure will be ready before the end of 2017 and could eventually become a way of treating complete paralysis.
"I would say we have plenty of data to go on," Canavero told the science magazine.
"It's important that people stop thinking this is impossible. This is absolutely possible and we're working towards it."
The team behind the work has published videos and images showing a monkey with a transplanted head, as well as mice that are able to move their legs after having their spinal cords severed and then stuck back together, The Independent reported.
Fusing the spinal cord of a person is going to be key to successfully transplanting a human head onto a donor body. The scientists claim that they have been able to do so by cleanly cutting the cord and using polyethylene glycol (PEG), which can be used to preserve cell membranes and helps the connection recover.
It is not the first time that a successful transplant has been carried out on a monkey. Head transplant pioneer Robert J White successfully carried out the procedure in 1970, on a monkey that initially responded well but died after nine days when the body rejected the head.
The newly-revealed success is likely to be an attempt to help generate funds for the ultimate aim of giving a head transplant to Valery Spriridonov, the Russian patient who has been chosen to be the first to undergo the procedure.
