Can you transplant a head to another body? - Max G. Levy

On March 14th, 1970, Robert White and his team carted two small monkeys into an operating room. The neurosurgeon lay on the verge of an ambitious experiment, decades in the making, which was bizarre, if not pulled straight from his own fever dream. White’s objective? Connect the head of Monkey A to the body of Monkey B, in what he considered a whole-body transplant.

White’s ultimate goal was to one day perform this surgery on humans. While disturbing, the idea of a body transplant raises ethical, biological, and philosophical questions— on the nature of life and the limits of science— that are still discussed today. But first, is it even medically possible?

White's surgery faced several technical hurdles. For one thing, it guaranteed paralysis as no doctor then— or now— could reconnect a severed spinal cord. But White, a practicing neurosurgeon, thought the surgery could be life-saving for his patients with spinal cord injuries or progressive mobility diseases like ALS. These patients often face multi-organ failures and paralysis, so with a body transplant, he hoped to save their lives by replacing all of their organs at once.

But paralysis wasn't the only challenge. Due to their high energy demands, brain cells require a constant supply of oxygenated blood to survive. Yet the transplant surgery would likely interrupt the brain’s oxygen flow for hours. But White had an idea. When the brain is cold, its metabolism slows down and it relies less on oxygen.

Experimenting on dogs and monkeys, White optimized a brain-cooling technique where the brain’s blood flow was selectively chilled and halted, while the rest of the body’s blood remained warm and circulated. Then, in 1964, White successfully cooled the brain of a human patient with a life-threatening brain tumor into “suspended animation” at 11°C. Whereas normally the surgical team would have just 3 to 5 minutes to remove the tumor, with this new technique, they operated for over an hour without causing damage.

Brain cooling revolutionized the field of neurosurgery and put White one step closer to his body transplant goal. But this vision was fraught with serious ethical concerns. What conditions would justify such an experimental surgery, that could result in debilitating pain and neurological damage? And how many animals would have to die to prove it was possible?

At the time, bioethics was still an emerging field. Nevertheless, numerous critics, including many in the scientific community, recognized the cruelty of White's research and strongly opposed it. Yet White continued to gain approval from agencies like the NIH. And by 1970, he was ready to attempt a monkey body transplant.

First, Monkey A was installed with temporary blood vessels— coils of plastic tubes that tethered the head to the body. Plastic tube by plastic tube, the team connected Body B to Head A, and then waited for the subject to awake from anesthesia. The monkey did— alive, paralyzed, and extremely distressed. According to the team, the monkey could see, smell, hear, and even tried to bite off one of the doctors’ fingers.

White felt this proved that the operation could work. The brain appeared to survive a head transplant and, with high doses of drugs, could live without immune rejection. But had White performed a body transplant on Monkey A? Or was it a head transplant on Monkey B? The surgery raises questions about the mind-body divide that have been debated for millennia.

While modern neuroscience supports the central role of the brain in building out our consciousness, discoveries about gut neurons and the microbiome suggest that the answer may be more complicated. Does part of the “self” reside outside of the mind? The body and brain are interconnected by circuits and signaling systems; so, what is lost by separating the two?

As a neurosurgeon, White performed more than 10,000 brain operations before retiring in 1998— but never the human head transplant he dreamed of. Since then, several scientists have expressed interest in picking up where White left off, reviving unfinished debates. Even if a doctor could successfully connect a patient’s head to a donor’s body, who of the two would emerge? And is extending a life always worth the cost?