Hi all. What biological problems need to be overcome before we can start doing brain transplants? Just curious 
The biggest problem ATM is that we can’t cure paralysis caused by a severed spinal cord. Once we can cure all the world’s paraplegics and quadriplegics we can start to think about brian transplants. Until then it’s pointless to even consider.
Remember that to transpllat the brian you need to detach it form the spinal cord, and thtameans severaing the spinal cord, which is just a fancy of way of saying that you’ve broken the patient’s back. Even if the transplant were perfectly succesful the patient would be totally paralysed fom the neck down.
Of course the transplant would also require severing all the cranial nerves so the patient would also have no sense of balance, taste, sight no ability to talk or hear and so forth. Total sensory isolation. But without that spinal cord connection the host body would need to be kept alive entirely artifically. And of course once we’ve worked out how to regrow severed nerves for the spiinal cord the rest should be relatively simple. 
Heck, once we can regrow/splice together/replace nerve connections and the spine, it’d probably just be easier to simply transplant the head onto a new body, like the good Doctor White has done. (I wouldn’t want to screw around with cutting the brain out of a skull, manhandling it around an operating room, and hooking it back into a new cranium if I didn’t have to. And god only knows what you’d have to do the the “donor” head to install the new brain…how much of the skull would they even be able to salvage?)
You’re thinking of the brain floating inside the skull, maybe rattling around like some people we read… er know of.
When you transplant a kidney, in order to make it work you have to hook up three things: 1) artery 2) vein 3) ureter. We’re pretty good at hooking up the stump of the transplanted kidney artery to the cut end of the recipient’s renal artery branching off the aorta. I seem to recall the ureter gave us problems very early in transplant surgery, scarred closed sometimes and things like that, but now our surgeons have got the technique down, and it’s easy (if you are skilled) to reconnect the three things that make the kidney work.
When I detach a brain, I have to break each of twelve pairs of cranial nerves, sever the spinal cord, and rupture the pituitary stalk. At this time we have no idea how to make those nerves regenerate the way they do in lower life forms. We cannot connect millions of microscopic axons from neurons in the brain, through the spot where we have severed them, to the axons in the nerves in the recipient. So we cannot hook up the donor brain. So it won’t work and the recipient will be brain dead and, shortly thereafter, really most sincerely dead.
Suppose we did know how to tell axons that have been rudely severed in mid-nerve to go find severed axon ends that belong to another person, and hook up, and mind you, hook up correctly - don’t make the wrong choice out of millions available to you - a much harder thing than merely understanding total fetal and embryogenesis to make new nerves grow in the first place - then we could have some really interesting experiments. Do the transplanted brains carry the whole memories and central feeling of “I” of the transplanted person? I suspect so. Or is there some body memory too, like in I Will Fear No Evil where he can’t play piano any more, but can run the stenographer’s machine?
We sure as hell won’t know in my lifetime. Oh well.
Bumbling assistants and interfering townspeople with their pitchforks and torches.
I suspect we already have the technology to do a head transplant - it would achieve many of the same goals (i.e. transfer of a functioning mind to a (mostly)new body, at the same time as removing many of the obstacles such as reconnecting all the cranial stuff and the general complexities of handling the brain without destroying it).
But we would have to lower our expectations for the recovery and long-term survival of the patient; consciousness might be regained, but there would be no recovery of sensation or motor control below the point at which the join was made, and I think it would also necessitate life support such as an iron lung or other mechanical ventilation, plus tube feeding, etc, for the rest of the patient’s life.
There would also be the rather tricky logistical problem of procuring an entirely intact donor ‘body’ onto which the patient’s head could be attached; maybe if the donor was a condemned criminal, it could be done, but that introduces further difficulties in ethics etc.
[McCoy]A child could do it.[/McCoy]
Damn straight.
Semi-Hijack
What is the current state of keeping brains alive inside jars? OTTOMH There are two arteries in, and two veins out connecting them to a bypass machine should be easy. We’d need transfusions and dialisys of course. We could leave the eyes intact. We’d have to have some way to keep them pointed in the same direction. Obviously, the patient could only look straight ahead. Keeping the room sterile would be a problem. We should be able to implant many tiny electrodes for a very detailed EEG. This would probably allow for a kind of crude communication. Work on using EEG to move cursors is already being done.
Like that Steve Martin movie, huh?
“This is brain surgery, Smithers, not rocket science!”
Sorry, I’ll stop.
OK, one more.
“Look at me! I’m Davy Crocket!!”
Old Laugh-in skit:
Rowan: What are you doing?
Martin: I’m washing up to do a brain transplant.
Rowan: Don’t you know there has never been a succesful brain traknsplant?
Martkn: Oh well, then, no sense washing up. 
I was reading somewhere lately that there have been successful tests of prosthetics moved by nerve impulses. If you can do that I would seriously wonder if neural jumpers of sorts could be created to bridge a cut nerve bundle like a spinal cord.
ok not exactly what i saw before but related and cool by its own right
I seriously doubt it; reconnecting all of the right ends back together in a severed spinal cord is a hideously complex prospect; connecting the right ends of the severed spinal cords of two different people is far, far worse.
As I understand it, the nervous system, although it develops as a result of broadly the same set of processes for everyone, we all get a custom wiring job; I don’t think there will ever be a way to fully map and connect the axon ends of two disparate spinal cords, especially when factors like the survival of the patient (while you’re doing the mapping job) are also in the mix.
True, but I was not assuming it would be tomorrow, give us 50 years of playing with advanced neural controlled prosthetics and you know someones going to want to try.
Dayum, gabriela! I just love having you here!! 
Practical knowledge, folks. It’s priceless.
Dr. White has done something similar with Dog brains, as I recall. Though he didn’t use an artificial life support system—he grafted the victim brain’s blood supply to a “host” dog, like a parasite. It was, obviously, completely unable to receive sensory information or anything, but it did live for a day or so. (As I recall, it didn’t die on it’s own. They terminated the experiment.)
There was a Russian film I downloaded awhile back where they kept the head of a dog alive on a life support system. (For awhile, at least.) I’ll try to dig up a link later.
And, like I said, monkey heads have been swapped, successfully. Again, it was paralyzed, but it was alive and conscious.
I don’t know, have we figured out that the connection between the spinal cord and the brain stem is standardized? What I know about neural networks such a connection would be individual-specific so when you have a million nerves to connect you might get some rudementary function but by just connecting things you would never get full function.
Makes a boy quiver, reading the phrase " pituitary stalk".
We’re forgetting the basics. Forget paralysis, forget sight, forget the other neato things.
When we transplant a heart, we do a bit more than we do with a kidney. Dicey work, but still lots of folks move around with transplanted hearts, god bless 'em. And yet the heart is kept oxygenated through that most devilishly clever device, the heart-lung machine.
Oxygen. The heart is a hardy muscle, pardon the pun. I cannot imagine a method by which one could remove a brain from a cranial cavity with no loss of oxygenated blood the entire time. And- we don’t know what kind of effect the cold blood would have on the brain. ( heart-lung machines tend to run blood cold ).
Hmmm. Oxygen.
Cartooniverse- a lifelong user and abuser of our friend O2.
Eh? Generally speaking, when you remove a heart for transplant, you don’t keep it hooked up to a life support machine the whole time…it usually goes in a cooler. Heart-lung machines, to the best of my knowledge, are used on a patient’s body while the heart is being worked on or replaced. :dubious: