Head transplant

There are three main technical challenges. As with any organ transplant, managing the immune response to avoid transplant rejection is necessary. Also, the brain is highly dependent on continuous flow of blood to provide oxygen and nutrients and remove waste products, with damage setting in quickly at normal temperatures when blood flow is cut off. Finally, managing the nervous systems in both the body and the head is essential, in several ways. The autonomic nervous system controls essential functions like breathing and the heart beating and is governed largely by the brain stem; if the recipient body's head is removed this can no longer function. Additionally each nerve coming out of the head via the spinal cord needs to be connected to the putatively corresponding nerve in the recipient body's spinal cord in order for the brain to control movement and receive sensory information. Finally, the risk of systematic neuropathic pain is high and had largely been unaddressed in research. The challenge of grafting the nervous system remained in early stages of research . ==History==

by Vladimir Demikhov on 1954 Alexis Carrel was a French surgeon who had developed improved surgical methods to connect blood vessels in the context of organ transplantation. In 1908, he collaborated with the American Charles Claude Guthrie to attempt to graft the head of one dog on an intact second dog; the grafted head showed some reflexes early on but deteriorated quickly and the animal was killed after a few hours. Carrel's work on organ transplantation later earned a Nobel Prize; Guthrie was probably excluded because of this controversial work on head transplantation. In 1954, Vladimir Demikhov, a Soviet surgeon who had done important work to improve coronary bypass surgery, performed an experiment in which he grafted a dog's head and upper body including the front legs, onto another dog; the effort was focused on how to provide blood supply to the donor head and upper body and not on grafting the nervous systems. The dogs generally survived a few days; one survived 29 days. The grafted body parts were able to move and react to stimulus. The animals died due to transplant rejection. In 2016, he announced his plans to do the procedure on Valeriy Spiridonov, a disabled Russian software engineer suffering from spinal muscular atrophy, who volunteered for the surgery. Canavero claimed that there was a 90% chance of success. In the proposed procedure, a body would be donated from a brain-dead living patient. However, Spiridonov later cancelled his participation after getting married and having his first child. In 2015, Ren published work in which he cut off the heads of mice but left the brain stem in place, and then connected the vasculature of the donor head to the recipient body; this work was an effort to address whether it was possible to keep the body of the recipient animal alive without life support. All prior experimental work that involved removing the recipient body's head had cut the head off lower down, just below the second bone in the spinal column. Ren also used moderate hypothermia to protect the brains during the procedure. ==Ethics and popular opinion==

Arthur Caplan, a bioethicist, opined in 2017, "Head transplants are fake news. Those who promote such claims and who would subject any human being to unproven cruel surgery merit not headlines but only contempt and condemnation." Robert J. White became a target for protestors because of his head transplantation experiments. One interrupted a banquet in his honor by offering him a bloody replica of a human head. Others called his house asking for "Dr. Butcher". When White testified in a civil hearing about Sam Sheppard's murder case, lawyer Terry Gilbert compared White to Dr. Frankenstein. The People for the Ethical Treatment of Animals described White's experiments as "epitomizing the crude, cruel vivisection industry". In general, the field of transplantation medicine has been met with resistance and alarm from some quarters as advances have been made; Joseph Murray, who performed the first kidney transplant in 1954, was described as doing something unnatural or as playing God. These continued as other organs were transplanted, but perhaps became sharpest as hand transplants and face transplants emerged in 1998 and 2005 respectively, as each of these are visible, personal, and social in ways that internal organs are not. Popular opinion about Canavero's plans for head transplantation has been generally negative . Many of these criticisms focus on the state of technology and the timeframe in which Canavero says he will be able to successfully conduct the procedure. ==Popular culture==

Literature • ''Professor Dowell's Head'' (1925), science-fiction novel by Alexander Belyaev, a mad scientist performs head transplants on bodies stolen from the morgue, and reanimates the bodies. • Arthur Nagan or "Gorilla-Man", Marvel Comics scientist character whose head was transplanted onto a gorilla's body. • NOGGIN (2014) by John Corey Whaley; Travis Coates wakes up after undergoing a head transplant after five years of being cryogenically frozen. • Dog Man (2016) After a dog and a cop are injured in an explosion, a nurse transplants the dog's head onto the cop's body. Film and television • ''The Brain That Wouldn't Die'' (1962), science-fiction/horror film • The Incredible Two-Headed Transplant (1971), science fiction/horror film • The Thing with Two Heads (1972), science fiction film • ''Professor Dowell's Testament'' (1984), Soviet film based on the A. Belyaev story mentioned above • "Donor" (1999), an episode of The Outer Limits • The X-Files: I Want to Believe (2008), science fiction film • In May 2024, a realistically animated rendition of a head transplant became a viral video on social media Video games • B.J. Blazkowicz, protagonist of the Wolfenstein series, has his head transplanted on to a genetically engineered body in Wolfenstein II: The New Colossus (2017). ==See also==