Jun 28 2013

Head Transplantion

Here’s a fun one to finish out my vacation week – I recently received the following question:

I recently listened to a podcast dedicated to an often forgotten Skeptic, H.P. Lovecraft. (www.hppodcraft.com). In listening to the episode devoted to “Herbert West: Re-animator”, they mentioned historical experiments where animal heads were transplanted to other bodies, and survived. This set off a ping on my SkepDAR, and I researched it further. (Read: Wikipedia)

I found reference to a journal article in Surgical Neurology International, in which the author claims to lay the ground-work for the first successful surgical transplant of a human head.

As a lay-person, it seems like a plausible medical intervention. That being said, I’d love to hear the SGU tackle both the plausibility of the procedure and the ramifications such a procedure could have on our society. Could this be the key to Bob’s immortality?

In a word, no. At least not anytime soon. The technical hurdles are still too great.

Surprisingly, however, there has been some experimentation in this direction. The most famous such experiment was performed by Dr. R.J. White, who in 1973 transplanted one monkey head onto the body of another monkey. The experiment was declared a “partial success,” because the resulting monkey survived for a few days.

In the 1950s Soviet surgeon Vladimir Demikhov conducted a series of experiments in which he attached the head and shoulders of one dog onto another, creating two-headed dogs. (Watch the video if you’re not sensitive to that sort of thing.) Apparently this was done to demonstrate the Soviet Union’s superior medical technology.

In 2002 Japanese scientists transplanted the heads of infant rats onto the thighs of adults. This was done to create an animal model to study the effects of ischemia (lack of oxygen) on the development of the brain.

None of these experiments, however, constitute a head transplant – or more accurately, in my opinion, a body transplant. I think it is more accurate to describe these procedures as grafting a head onto the body of another animal, which then serves as a life support system for the head.

These are not true transplants because the head is never functionally connected to the body. In the case of the monkey, for example, the spinal cord is severed and it never attaches to the host body. The monkey head received blood supply from the body it was attached to, but it was functionally still a completely isolated head. It could have been attached to a heart-lung machine for all it knew.

In a 2001 interview with BBC news, Professor Robert White who conducted the monkey experiment is quoted as saying:

“People are dying today who, if they had body transplants, in the spinal injury community would remain alive.”

Head transplant is not a treatment for a severed spinal cord, and probably never will be. If we could get the spinal cord from the transplanted head to connect to the spinal cord of the recipient body, then we would have the technology to repair damaged spinal cord in the first place. The severed spinal cord is the main problem with head transplants and will likely not be solved anytime soon.

Other technical aspects of the transplantation process are challenging but not insurmountable. Obviously there is a lot of anatomy to connect. The arteries would be a serious challenge. The brain would need to be cooled to a low temperature to prolong survival during the process, and there would need to be a way to keep blood circulating to the brain while all the main arteries are connected – two carotids and two vertebrals.

The alternative to a full head transplant is a brain transplant. I don’t think this would be any easier, however. You still have the problem of severing the spinal cord (probably just below the brainstem, from inside the skull). You also have all the cranial nerves to reattach. You would still need to attach the blood supply – two carotids still, but further up inside the skull, and perhaps the basilar artery (formed by the union of the two vertebrals).

It seems likely to me, however, that by the time we have the technology to successfully transplant either a brain or a whole head, we will by necessity have the technology to repair whatever it is that is wrong with the original body in the first place.

We have to postulate some very advanced medical technology, in my opinion, before you get to a scenario with any kind of head/brain transplant is useful. For example, I can imagine growing cloned bodies, but somehow keeping the brain from developing or just keeping it unconscious and not functional, then transplanting the brain of an old or dying person into a young fresh version of their body.

The limiting factor here is the brain itself – it ages too. So, once again, if we have the technology to keep the brain young and going, this might also provide the same technology to keep the rest of the body going. Perhaps, however, there will be a period of time when the lifespan of the brain will be significantly greater than the lifespan of the body, or when the body will be unavoidably decrepit, and a body transplant will be desirable.

I’m going to stick my neck out, however, and predict that such a procedure will not be developed in time to benefit anyone alive today over 40.

9 responses so far

9 thoughts on “Head Transplantion”

  1. DOYLE says:

    The stuff great fiction is made of.

  2. Kawarthajon says:

    Woohooo! I’m only 39 1/2, meaning that I should start saving for my head transplant. Phew, just made it in under the wire!

    All joking aside, this is a great, very interesting question and I really appreciate your answer Steve! Something that might cross your mind, but I don’t have the ability to answer.

    It seems like stem cells will come to play a big part in reconnecting severed nerves. Would they not also play a role in head transplants in the future, say if your body was crushed? You hear about rats/mice having abilities restored with the help of stem cells. Are we really far away from that in humans as well?

  3. Jared Olsen says:

    Awesome! Great question and amazing answer. This is now one of my favourite posts!
    I remember in the film of the Lovecraft short story, the head was kept alive (and talking!) by sitting in a tray of fresh blood. At the time I thought that was probably insufficient…

  4. BillyJoe7 says:

    “I’m going to stick my neck out…”

    Good one, Steve. (:

  5. Bill from Fallbrook says:

    FYI… Just saw this story this AM, don’t know if it’s legitimate or not: http://nextbigfuture.com/2013/06/technical-hurdles-have-been-overcome.html

  6. Hi Steven,

    There’s another interesting angle to the idea of a brain transplantation. According to Anthonio D’Amasio’s last book (and probably others), he postulates that much of our sense of self is due to hierarchical spatial maps – maps of our limbs in space, maps of our internal organs, maps of our location relative to the ground, to danger, etc. A brain that has matured in one body would then have spatial maps appropriate for that body. There might well be an initial incompatibility with a new body; perhaps a sense akin to vertigo, or “outer body experience,” or who knows what. Perhaps the brain would need a (long?) period of re-mapping via new functional/anatomical connections. The new brain might have to learn how to “drive” the new body just as infant brains have to learn how to interact with their world. I only mention all of this to give voice to the notion that a brain and a body may not be as functionally separable as we might think at first blush. As a neuroimager I do tend to treat the body as a life-support system for the organ of interest, but I concede that neuro-centric view could be highly misleading!



  7. Davdoodles says:

    “The alternative to a full head transplant is a brain transplant.”

    I’d have thought that would be more difficult as it would invovlve all the same spinal comnections as a head-to-body graft, but also connecting up the optic, auditory, olfactory nerves etc.

    Even re a head-to-body graft, certainly at the moment, a spinal re-connection seems beyond our abilities. But, assuming that all the other plumbing issues (connecting up veins, lymphatic and ventriculalr systems, meninges), etc can be overcome, would the head be conscious? ie would it be effectively like a person with a complete upper spinal break – a quadriplegic but otherwise able to see, hear, smell? Talk?

    If so, I wonder if a person with massive body damage but an intact head (eg someone run over by a train), would want to be transplanted onto a healthy body with a destroyed head (eg a suicide-by-gunshot victim), even if it meant living as a quadriplegic?

    Happy thoughts…

  8. Mlema says:

    I didn’t look at any of the articles or watch the video, but I’m really troubled by the fact that people would kill animals in this way: cutting the head off and keeping the brain alive by transplanting the head. This sounds like torture to me. Anyone who’s ever had a pet knows that animals have emotions, and I suspect living for even a few days in this fashion would involve fear and pain.

    I hope I’m misunderstanding the experiments and that the animals were effectively dead, and the research was just showing circulation or something, and no brain function in the transplant.

  9. Billzbub says:

    But, what about heads in jars Futurama-style?

Leave a Reply