Brain Transplant

[CraigD]

When an amputee has lost a foot or similar appendage, they often report "phantom limb" sensation, where they feel tingling or even pain in an area where they no longer have that appendage.

 

I wonder if they'd have a sense of "phantom brain," where they get tingling sensations where the former brain was connected. This is wildly thought provoking topic for me I must admit. :)

I think they’d be more likely to experience a sense of “phantom whole body”, where their mental image of the precise shape of their body was out-of-whack with their new one. I imagine this would be something like the “coltish” awkwardness rapidly growing children experience, where they seem unsure of the length of their limbs and mass of their bodies.

 

The visual experience would likely be strange, as well. If you’ve ever worn extensive costume makeup, you’ve likely been startled when you failed briefly to recognize your own reflection in a mirror, or caught a glimpse of you disguised hands. Getting a whole body transplant might be like this, but couldn’t be washed off with a bit of cold cream.

[InfiniteNow]

I imagine this would be something like the “coltish” awkwardness rapidly growing children experience, where they seem unsure of the length of their limbs and mass of their bodies...If you’ve ever worn extensive costume makeup, you’ve likely been startled when you failed briefly to recognize your own reflection in a mirror, or caught a glimpse of you disguised hands.

Good call with both examples. Clear and easy to follow... Although I'm none too pleased with the possibility of bumped and bruised toes, legs, and arms all over again... :doh:

 

I was impacted greatly by this during puberty, where my body grew faster than my own awareness of the space it occupied. :)

[Deepak Modak]

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[CraigD]

Dr. Robert J. White, now retired, from Cleveland, Ohio has already performed countless successful head transfer experiments on monkeys …

Wow. I consider my self pretty rational and emotionally well-controlled, but found this a bit disturbing.

 

At first reading, I suspected Deepak, Buckyball, and others were victims or perpetrators of a hoax. Argument’s such as

A human body is severely tapped keeping one brain alive. Brains have huge exclusively aerobic metabolism and enormous heat production. Getting raw materials in and wastes out is a near thing.

seemed credible to me.

 

However, it appears White really did transplant the head of a rhesus monkey onto the body of another rhesus (see http://en.wikipedia.org/wiki/Head_transplant#Actual_instances, attached image.) in 1971, with considerable success – afterwards the monkey was conscious, able to perceive the world, and control the muscles of its head. The monkey survived for “hours”. I’ve found no evidence to suggest that any effort was made to attach the spinal chord nerves, so the monkey could not control the new body, or the body live long without artificial life support. Detailed descriptions of this surgery appear to be difficult to find electronically.

 

The claim that White performed “countless” such operations appears unfounded – one side describes him as performing “more than 30” such operations, but it is a site supporting bans on medical experimentation on animals that makes several clearly false claims, so I don’t consider it credible.

 

There’s also good evidence that it’s possible to reduce brain metabolism to levels that would permit a similar operation to be done with a human patient – presumably including an effort to connect enough spinal nerves so that the transplanted head could control the new body, and the heart and lungs operate without artificial assistance.

 

The people who would most benefit from the development of such a surgery appear to be the quadriplegic victims of severe neck injuries. Such people usually have much shortened lifespans (they rarely live to be 50) due to non-brain organ failure resulting from their injuries. Even if such a surgery could not provide full or even partial use of the donor body limbs, it would permit these people to have more normal lifespans. There is, unfortunately, no shortage of healthy bodies with irreparably injured heads, and the brain (though not necessarily the rest of the tissues of the head) appears to be “immunologically sound” – that is, not prone to attack by the donor body’s immune system.

[Deepak Modak]

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[CraigD]

The people who would most benefit from the development of such a surgery appear to be the quadriplegic victims of severe neck injuries.

Brain transplants can probably also be used for patients with cancer, …

For certain forms of cancer – ones with low probability of metastasizing into brain and spinal tissue - head (or “whole body”) transplants do appear to offer a potentially valuable treatment. If such an operation becomes possible, however, I expect it will be a surgery of last resort, used only after all other cancer treatment options are exhausted.

… people without limbs etc.

I doubt whole body transplants will become a viable limb replacement option. Attaching the patient’s head to the donor body – particularly the spinal cord – appears more difficult than would be attaching a new donor limb, and poses much lower risk of injury to the patient’s brain, or risk of loss of function of their remaining limbs. There’s no reason to expect that head or whole limb transplant recipients would experience greater function than patients who have had severed limbs and appendages reattached. In all cases to date, these patients have experienced significant (sometimes as great at 100%) loss of sensation and mobility of the reattached part. Until reattachment surgery outcomes has reached a state of the art that most patients regain nearly 100% function, I doubt that patients will be willing to give up the perfect function of their remaining limbs in order to replace one or a few lost ones via a whole body transplant.

 

Note that reattachment surgery has not yet advanced to the point where it can reattach an entire limb. The majority of reattachment surgeries involve severed fingers. There have been a small number of successful hand transplants – see http://www.handtransplant.org

 

Unless the donor is the patient’s identical twin, both head transplants and whole limb transplants would require the patient to receive immunosuppressant therapy for the rest of their life. Although the brain and spinal cord appear to be “immunological sound”, and are not attacked by the donor body’s immune system, other tissues in the head are not, and would remain at risk or rejection. This is a very daunting prospect, as it equates to the risk of the patients head literally “rotting alive”.

 

“Quality of life” is always an important consideration when deciding to undertake any major surgery. As a case in point, Clint Hallam, the first hand transplant recipient, was so unhappy with his outcome that he refused to continue taking his immunosuppressant drugs, requiring his hand to be amputated and replace with a prosthesis. Hallam reports that he is much happier with a prosthesis.

 

Head transplants would introduce many new complications not experience in current organ and limb replacement surgeries. For example, the brain is the source of many important hormones (proteins) that vary importantly in fine structure between individuals. A whole body transplant recipient would likely require life-long hormone replacement therapy of a kind currently unknown to avoid serious endocrine disease.

 

Actually, the people who would benefit from brain transplantation the most, would be everyone - we would all have a chance to live for ever (until at least the brain itself deteriorates) or for much longer.

Unfortunately, the brain senesces (deteriorates) at about the same rate as other body tissues. Brain tissue is subject to the same major causes of senescence as other tissues (eg: the breakdown of mitochondria due to their activity in metabolism, loss of DNA telomeres). In many functional areas, brains appear so senesce faster than other organs.

 

The belief that aging and death is accurately described as “a young brain trapped in an aging body” is, I believe, incorrect.

[Deepak Modak]

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[billg]

There is no way the technology currently exists to peform successful brain OR head/body transplantations (whatever you want to call it). Currently we cannot even heal damaged spinal cords. Even if nervous tissue can be made to grow, we are only able to control our body by a particular setup of neural links between the brain and spinal cord. Getting the nervous tissue to grow is actually the easy part - getting it to grow in the right way in the right places is currently impossible. You can't just put the brain or head in place and hook it up to the blood and expect it to work. Even assuming you can attach the spinal cord and cranial nerves, it may well be that one brain outputs and inputs CANNOT match a bodies outputs and inputs. You could end up being hooked up in ways that will never actually allow you to perform any useful action.

 

Also as far as transferring memories from one brain to another, it's again much more complex than what's being proposed in this thread. Aswell as a lifetime of semantic memory (i.e. "facts you know" like 1+1=2, blue is spelled B L U E) and episodic memory (as in "when I was 15 I dated Melinda Bruns for a year"), there is a massive part of the brain devoted to organising sensory information into meaningful things and turning abstract "move arm there" signals into the complex muscle movements that actually allow us to move. There's also huge amounts of information you're not ordinarily even aware you know because it's below the threshold of consciousness, like what certain facial movements or inflections of voice mean. You can't just right the information down and then read it into your new brain.

 

And finally, whoever this scientist is who did the Rhesus monkey experiment should be imprisoned. A pointless experiment with no medical applications. I think it's profoundly unethical. According to wikipedia he did it once in the 70's, which I can almost understand, but repeated it in 2001. What ethics board allowed that experiment to go ahead? It's insane.

[CraigD]

There is no way the technology currently exists to peform successful brain OR head/body transplantations (whatever you want to call it). Currently we cannot even heal damaged spinal cords. Even if nervous tissue can be made to grow, we are only able to control our body by a particular setup of neural links between the brain and spinal cord. Getting the nervous tissue to grow is actually the easy part - getting it to grow in the right way in the right places is currently impossible. You can't just put the brain or head in place and hook it up to the blood and expect it to work. Even assuming you can attach the spinal cord and cranial nerves, it may well be that one brain outputs and inputs CANNOT match a bodies outputs and inputs. You could end up being hooked up in ways that will never actually allow you to perform any useful action.

Billg summarises the gap between current medical technology and the requirements of a fully effective brain or head/body transplant well. It’s informative to note that current technology can sometimes, but not always, restore partial use of a reattached finger, let alone an entire body.

 

Note, however, that much of the interest in head transplants is on the part of victims of high (cervical) spinal cord severing injuries who already have no control over the voluntary muscles of their bodies. Such people typically die due to widespread organ failure within a decade or two of their injuries. For these people, a “body transplant” offers additional years or decades of life, in the form of a “full set of organs transplant”.

 

People who are about to die are eager for technologies that can postpone death, even if the technologies are immature.

Also as far as transferring memories from one brain to another, it's again much more complex than what's being proposed in this thread.

Again, I think, right on. I’d summaries the state of the art necessary for “brain recording”, which spans the disciplines of Neurology, for an understanding of brain function, and Physics, for the next-generation imaging (enhanced MRI, positron beam, etc) likely to be required, to be in the “can’t even accurately predict when or if” stage.

And finally, whoever this scientist is who did the Rhesus monkey experiment should be imprisoned….

I must strongly disagree and condemn, both as a point of US (where the experiment was performed) law, and scientific advocacy, suggestions that scientists should be imprisoned for experiments performed with the proper approval and oversight of available government and academic institutions. From a cultural perspective, such suggestion are calls to a “witch hunt”, and are historically associated with some of the darkest and most appalling failures of law and social order every recorded. From a legal perspective, one simply cannot be imprisoned because some people feel one is unethical or “insane”. None of Robert White’s experiments were, in the opinion of any recognized jurist, violations of US law.

[Deepak Modak]

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[Deepak Modak]

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[jeremy]

Human cloning and a full body transplant has definitely already been achieved but not released.. I mean, really if you could live forever, would you tell the rest of the world? If you did then you definitely wouldn't be able to live forever.. It is unrealistic to think everyone can live forever and keep making babies.. Only a few of the smartest most advance people should be allowed to maintain the human race and ensure evolution