Ahead of a controversial plan to carry out the first human head transplant later this year, scientists have attached the head of a rat onto the body of another.

In the disturbing experiment, researchers in China affixed the heads of smaller, ‘donor’ rats onto the backs of larger recipients, creating two-headed animals that lived an average of just 36 hours.

The team, which involved the Italian neurosurgeon who is set to perform the hotly-debated procedure on a human, managed to complete the transplant without causing blood loss-related brain damage to the donor.

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In the disturbing experiment, researchers in China affixed the heads of smaller, ‘donor’ rats onto the backs of larger rats, creating two-headed animals that lived an average of just 36 hours

HOW THEY DID IT The researchers used three rats for each operation: a smaller rat, to be the donor, and two larger rats, acting as the recipient and the blood supply. To maintain blood flow to the donor brain, the connected the blood vessels from that rat to veins of the third rat using a silicon tube, which was then passed through a peristaltic pump. Then, once the head had been transplanted onto the second rat’s body, the researchers used vascular grafts to connect the donor’s thoracic aorta and superior vena cava to the carotid artery and extracorporeal veins of the recipient. Advertisement

In the study, researchers from Harbin Medical University in China and controversial neurosurgeon Sergio Canavero built upon earlier head-grafting experiments to figure out how to avoid damage to the brain tissue during the operation, as well as long-term immune rejection.

Previously, scientists have attempted the procedure on dogs and monkeys, which helped to test neural preservation when blood flood to the brain had been cut off, they explain in the paper published to CNS Neuroscience & Therapeutics.

But, long-term survival of the specimens was not a priority.

The researchers used three rats for each operation: a smaller rat, to be the donor, and two larger rats, acting as the recipient and the blood supply.

To maintain blood flow to the donor brain, they connected the blood vessels from that rat to veins of the third rat using a silicon tube, which was then passed through a peristaltic pump.

The researchers used three rats for each operation: a smaller rat, to be the donor, and two larger rats, acting as the recipient and the blood supply. To maintain blood flow to the donor brain, the connected the blood vessels from that rat to veins of the third rat using a silicon tube

CRITICS OPPOSE THE HEAD TRANSPLANT Critics say Dr Canavero's plans are 'pure fantasy'. The Italian has been compared to the fictional gothic-horror character Dr Frankenstein and Arthur Caplan, the director of medical ethics at New York University's Langone Medical Centre, has described Dr Canavero as 'nuts'. Dr Hunt Batjer, president elect of the American Association for Neurological Surgeons, told CNN: 'I would not wish this on anyone. I would not allow anyone to do it to me as there are a lot of things worse than death.' Advertisement

Then, once the head had been transplanted onto the second rat’s body, the researchers used vascular grafts to connect the donor’s thoracic aorta and superior vena cava to the carotid artery and extracorporeal veins of the recipient.

According to the team, there was no injury to the donor brain tissue as a result of blood loss in the experiment.

And, after the surgery, the donor head was still able to blink and feel pain.

The two-headed creatures lived 36 hours on average following the procedure, Business Insider reports.

Still, with the addition of the peristaltic pump and vascular grafting to the technique, the researchers say long-term survival could be a possibility.

In the past, Dr Sergio Canavero has said the controversial human head transplant will take place in December 2016.

But, many experts are opposed to the plan, with skeptics arguing that this type of operation is still years away from reality despite successful trials with animals.

Canavero, however, appears to be pressing on.

Ahead of a controversial plan to carry out the first human head transplant later this year, scientists have attached the head of a rat onto the body of another. The team managed to complete the transplant without causing brain damage to the donor

THE CONTROVERSIAL PLAN FOR A HUMAN HEAD TRANSPLANT In September, the controversial neurosurgeon outlined plans to conduct 'Frankenstein' experiments to reanimate human corpses to test his technique. Dr Canavero and his collaborators discussed trials to test whether it is possible to reconnect the spinal cord of a head to another body with tests that will stimulate the nervous system in fresh human corpses with electrical pulses . However, the Russian man who has volunteered to have the first transplant also revealed that his girlfriend is opposed to him having the operation. The aim of the surgery is to first cut the spinal cord and then repair it before using electrical or magnetic stimulation to 'reanimate' the nerves and even movement in the corpse. Dr Sergio Canavero plans to conduct tests on human corpses before performing a human head transplant next year. Russian Valery Spiridonov has volunteered to be the first person to have the operation (pictured right with Dr Canavero, centre, on Good Morning Britain) In an article for the Surgical Neurology International, Dr Canavero and his colleague in South Korea and China drew parallels to the infamous story of Frankenstein, where electricity is used to reanimate the fictional monster. He pointed to experiments conducted in the 1800s using the corpses of criminals who had been hung as proof such tests could be successful. Dr Canavero and his colleagues said: 'A fresh cadaver might act as a proxy for a live subject as long as a window of opportunity is respected (a few hours). 'It also implies that the process of deathly disintegration is not an immediate process. We name this effect the "Frankenstein effect." Advertisement

In November, the neurosurgeon unveiled a virtual reality system that will 'prepare patients for life in a new body.'

The doctor says the procedure could ultimately help people who are paralyzed from the neck down to regain the ability to walk, and Russian wheelchair user Valery Spiridonov has volunteered to be the first patient.

The operation would see his head 'frozen' to stop brain cells from dying and tubes connected to support key arteries and veins.

Created by Chicago-based firm Inventum Bioengineering Technologies, the VR system would enable patients to take part in sessions for months before an operation.