Brain Transplant

[Yahweh]

We can transplant everything else, but is it possible to put one persons brain inside another persons head successfully?

And if this was possible, what would happen if we were to put a mans brain inside a womans body (some people feel like that already, but forget that for a second), would it work?

 

[jmercer]

The obstacles are enormous. Setting aside rejection issues, we can't even mend severed nerves yet, let alone reconnect a brain to a spinal cord.

 

[John Bentley]

We can transplant everything else, but is it possible to put one persons brain inside another persons head successfully?

And if this was possible, what would happen if we were to put a mans brain inside a womans body (some people feel like that already, but forget that for a second), would it work?

It would be easier to just transplant the whole head. Interestingly enough, this would certainly be possible, but you would be a quadraplegic, as jmercer has pointed out. Until we find some way to reconnect spinal cords, this will have to wait. I, for one, am not looking forward to the day when it is possible. I've read too many bad SF books based on the premise.

 

[Yahweh]

The obstacles are enormous. Setting aside rejection issues, we can't even mend severed nerves yet, let alone reconnect a brain to a spinal cord.

Functioning arms and limbs have been reattached, doesnt that involve reconnecting nerves as well?

 

[roger]

My girlfriend is a neuroscientist, so we get to have fun conversations about stuff like this all the time.

Basically cognitive science is still at such an infancy that there is no way to answer the question. I'm not talking about the biological issues of fusing a brain stem, coping with tissue rejection, etc.

As an example, one of her colleages invinted a technique to help cure phantom limb disorders. You know, when somebody has the feeling of pain or other sensation in an amputated limb. The technique is actually pretty simple - a mirrored box is used to reflect an image of the remaining limb over to the missing limb. The person who was cured felt like their missing hand was clenched so tight that their fingernails were pressing through their skin. So the therapy consisted of starting with the good hand clenched, and then slowly releasing it, massaging, etc. Over time the pain in the phantom limb abated!

So there is obviously a vast store of body knowledge in our brain that goes off kilter when the body is grossly modified. It's anyone's guess how it would deal with an entire body transplant, though my guess is "not well, not well at all." But there is really no way to say at this point.

 

[John Bentley]

Functioning arms and limbs have been reattached, doesnt that involve reconnecting nerves as well?

Yes, I had noticed that as well. jmercer wasn't quite correct. We can reattach severed nerves. However, the limb never functions quite as well.

The nerve you see in severed limbs with the naked eye is not like a single electrical wire. It is more like a conduit containing thousands of microscopic wires. To make matters worse, even if you were somehow able to connect each one of these wires back to its severed end perfectly, it still wouldn't work, because when a nerve is severed, it's long "strands" - called axons - die, and sometimes the whole cell dies. All the connecting strands would have to grow back perfectly, and any dead cells would have to be regenerated. Most of the nerve strands are in little tubes, so if the nerve cell is still alive, the nerve can grow back down those, but you would still have to connect every single one perfectly.

The spinal cord is several orders of magnitude more complex, because not only are there millions of nerve axons travelling up and down it, there are millions of nerve cell bodies as well. Each of these would have to be reconnected and regrown.

And that's just trying to reconnect your own spinal cord. Imagine trying to connect you to someone else's, whose pathways are just a little different, different number of nerves, different number of cell bodies.

I personally think it will take nanotech to make it practical.

 

[Bikewer]

I read a speculative article in OMNI years ago about a possibly more practical approach; uploading your personality into a computer.

This would imply vastly more capability than we have now, of course, but if quantum computing becomes a reality, that might be do-able.

I speculated at the time that at best you'd just be creating another "you", but the author (sorry, long since forgotten) said that the individual would essentially switch "viewpoints" back and forth from the physical body to the computer, so that at some point it would be the same.

Lots of sci-fi guys have had fun with the idea, notably Fred Pohl.

 

[davidhorman]

It would be easier to just transplant the whole head. Interestingly enough, this would certainly be possible

It's been done at least once with monkeys. It lived for a few days, if I remember correctly.

Lots of sci-fi guys have had fun with the idea, notably Fred Pohl.

Greg Egan, too.

David

 

[Rolfe]

Greg Egan, too.

Robert Heinlein was the one I first thought of. I Will Fear No Evil. That specifically dealt with the fact that the male patient had received the body of a young female. (In fact, someone he had known.)

Not going to go anywhere useful until the problem of getting CNS nerves to regenerate has been cracked.

Rolfe.

 

[Hellbound]

Just to toss a couple pennies in the pot, there is at least one application for this so far (even assuming we can't regrow all the nerves): for those who are already quadraplegic.

One of the problems with a quadraplegic patient is degeneration of the body. As I understand it, often the parts of the body degenerate because the body is not used. Lungs weaken, heart gets smaller, etc, etc, etc. A body transplant (more appropriate term than head transplant, IMO) could extend lifespan. IIRC, this was suggested when the monkey experiment was performed.

Now, questions as to the ethicality (is that a word?) of such a procedure, or the logistical side of it, I leave as an exercise for the reader

 

[Drooper]

We can transplant everything else, but is it possible to put one persons brain inside another persons head successfully?

And if this was possible, what would happen if we were to put a mans brain inside a womans body (some people feel like that already, but forget that for a second), would it work?

12,000 miles and mines still working fine

By the way, Albert says hi.

 

[Bikewer]

Transplant a brain? No problem for sufficiently advanced technology:

"A child could do it!" Dr. McCoy, in Spock's Brain.

 

[jmercer]

Yes, I had noticed that as well. jmercer wasn't quite correct. We can reattach severed nerves. However, the limb never functions quite as well.

The nerve you see in severed limbs with the naked eye is not like a single electrical wire. It is more like a conduit containing thousands of microscopic wires. To make matters worse, even if you were somehow able to connect each one of these wires back to its severed end perfectly, it still wouldn't work, because when a nerve is severed, it's long "strands" - called axons - die, and sometimes the whole cell dies. All the connecting strands would have to grow back perfectly, and any dead cells would have to be regenerated. Most of the nerve strands are in little tubes, so if the nerve cell is still alive, the nerve can grow back down those, but you would still have to connect every single one perfectly.

The spinal cord is several orders of magnitude more complex, because not only are there millions of nerve axons travelling up and down it, there are millions of nerve cell bodies as well. Each of these would have to be reconnected and regrown.

And that's just trying to reconnect your own spinal cord. Imagine trying to connect you to someone else's, whose pathways are just a little different, different number of nerves, different number of cell bodies.

I personally think it will take nanotech to make it practical.

Agreed, 100%... I was thinking of complex nerves (as in Christopher Reeves, etc.).... and yeah, nanotech will certainly be a big boon to this sort of thing. (And possibly stem cell research as well.)

 

[jmercer]

I read a speculative article in OMNI years ago about a possibly more practical approach; uploading your personality into a computer.

This would imply vastly more capability than we have now, of course, but if quantum computing becomes a reality, that might be do-able.

I speculated at the time that at best you'd just be creating another "you", but the author (sorry, long since forgotten) said that the individual would essentially switch "viewpoints" back and forth from the physical body to the computer, so that at some point it would be the same.

Lots of sci-fi guys have had fun with the idea, notably Fred Pohl.

Yeah - it's a cool concept. Makes the Matrix seem rather weak.

However, the only way to make it work without creating doppelgangers (with only one "original") would be to erase the original as it vacates either perspective.

 

[jmercer]

Just to toss a couple pennies in the pot, there is at least one application for this so far (even assuming we can't regrow all the nerves): for those who are already quadraplegic.

One of the problems with a quadraplegic patient is degeneration of the body. As I understand it, often the parts of the body degenerate because the body is not used. Lungs weaken, heart gets smaller, etc, etc, etc. A body transplant (more appropriate term than head transplant, IMO) could extend lifespan. IIRC, this was suggested when the monkey experiment was performed.

Now, questions as to the ethicality (is that a word?) of such a procedure, or the logistical side of it, I leave as an exercise for the reader

Good point, Huntsman. I was thinking about the ethical side of things over the weekend after my initial response. I suppose that transplanting a viable brain into a viable body (who happens to be brain-dead) might be ethical.

I have dibs on Brad Pitt, btw.

 

[Demo]

I just recently finished a book (Stiff: The Curious Lives of Human Cadavers by Mary Roach) which discussed this same topic. Apparently some whole-head transplant experiments were carried out with dogs. In some cases, instead of actually transplanting the head, they would just add a puppy head to a grown dog. None of them lived more than a few days, IIRC.

The book is a great read and I highly recommend it.

 

[yersinia29]

There is a huge difference between peripheral nerves and central nerves.

Central nerves found in the spinal cord and brain do not regenerate teh way peripheral nerves do. Peripheral nerves respond to growth factors that cause the axons to sprout and reform synapses. Central nerves dont respond to growth factors like that.

So that explains why limbs can be reattached whereas re-attaching spinal cord or any cerebral matter is infinitely harder.

 

[Hellbound]

There is a huge difference between peripheral nerves and central nerves.

Central nerves found in the spinal cord and brain do not regenerate teh way peripheral nerves do. Peripheral nerves respond to growth factors that cause the axons to sprout and reform synapses. Central nerves dont respond to growth factors like that.

So that explains why limbs can be reattached whereas re-attaching spinal cord or any cerebral matter is infinitely harder.

What about the feasibility of transplanting the entire CNS (brain and spinal column)?

 

[Brown]

It seems to me that the feat is possible in the sense that technology could be developed to do it. It could not be done using today's technology.

I have mused with the idea of enhanced brain power, in which the brain is given access to an implanted device that acts like a little computer. With such an implant, a person could make calculations virtually effortlessly, remember vast amounts of information, learn a subject in no time flat, speak and understand as many languages as desired, and so on.

The brain itself would still be responsible for matters of judgment. But it would have enormous resources at its disposal.

It would not surprise me to see technology like this developed within my lifetime.

If, as has been suggested, a person's "essence" could be converted into a file and placed into such an implant, then it would be akin to transplanting one person's brain in another.

 

[jmercer]

I refer you to a recent Sci-Fi series by David Weber and John Ringo. They refer to such devices as "toots". (I forget what it's shorthand for), and "toots" do much of what you have identifed.

The can also act as translators... provide hardware reactions to force the body to move quickly without thought in combat situations; and all sorts of other interesting things.

Weber and Ringo also have suggested that "toots" could lead to "toombies" - people who's bodies are taken over by hacked "toots", to the horror of their proper owners.

March Upcountry (Prince Roger Series)