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categories: ["bodies"]categories: ["bodies"]tags: ["transplantation", "spinal cord", "neurosurgery", "medical ethics", "identity", "fringe science"]tags: ["transplantation", "spinal cord", "neurosurgery", "medical ethics", "identity", "fringe science"]summary: "The proposed transfer of a living human head onto a donor body, blocked chiefly by the inability to reconnect a severed spinal cord and rejected by mainstream neurosurgery."summary: "The proposed transfer of a living human head onto a donor body, blocked chiefly by the inability to reconnect a severed spinal cord and rejected by mainstream neurosurgery."updated: "2026-10-29"updated: "2026-10-30"humanEvidence: "No human attempt has been made; living-subject work stops at Demikhov's 1950s dogs and White's 1970 rhesus monkeys, whose cords were never joined, and the 2017 human procedure was a rehearsal on two cadavers."humanEvidence: "No human attempt has been made; living-subject work stops at Demikhov's 1950s dogs and White's 1970 rhesus monkeys, whose cords were never joined, and the 2017 human procedure was a rehearsal on two cadavers."------ lines 53–59 → 53–5939 unchanged lines not shown
Restoring function would require far more than membrane fusion. Millions of axons would have to reconnect, each to a target of the appropriate class, in a topographically correct arrangement, and the resulting circuit would have to be usable by a brain whose motor map was built for a different body. Polyethylene glycol can fuse the membranes of adjacent cut axons in laboratory preparations; it does not perform routing.Restoring function would require far more than membrane fusion. Millions of axons would have to reconnect, each to a target of the appropriate class, in a topographically correct arrangement, and the resulting circuit would have to be usable by a brain whose motor map was built for a different body. Polyethylene glycol can fuse the membranes of adjacent cut axons in laboratory preparations; it does not perform routing. The scale of the difficulty was underlined by a 2023 transplant at NYU Langone in which a patient received a partial face transplant that included an entire eye. The globe survived with perfused retina, which was itself a first.[^ceradini2024] Vision was not restored, because the optic nerve is a central tract and could not be reconnected, even though it was a single nerve, handled under ideal circumstances, with the world's attention on it. Restoring sight after optic nerve loss currently requires bypassing the nerve altogether, which is what a cortical visual prosthesis attempts and why the devices in [[retinal-implant]] exist.The scale of the difficulty was underlined by a 2023 transplant at NYU Langone in which a patient received a [[face-and-hand-transplantation|partial face transplant]] that included an entire eye. The globe survived with perfused retina, which was itself a first.[^ceradini2024] The surgeons joined the donor optic nerve to the recipient's, and the retina still responded to light, but at one year the patient had no light perception in the transplanted eye.[^ceradini2024] The optic nerve is a central tract, and joining it did not restore sight even though it was a single nerve, handled under ideal circumstances, with the world's attention on it. Restoring sight after optic nerve loss currently requires bypassing the nerve altogether, which is what a [[cortical-visual-prosthesis|cortical visual prosthesis]] attempts and why the devices in [[retinal-implant]] exist. ## Other barriers## Other barriers removed, struck through added, underlinedLine numbers count the serialised markdown of each revision, frontmatter included.
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