Medical Advancement - Brain Transplant Possible?

This - albeit odd - subject has always fascinated me.

Every time I read about brain trauma injuries, old age, cryogenics, et al coupled with just how far we have advanced medically in the past 100 years I often wonder if say 100 years from now, brain transplants would ever be possible, moral issues notwithstanding.

Before you say no, just think about what we have done in the last century. If I told you in 1912 that we could transplant a heart and the person would live for years, I would have been locked up. Remember in 1912, we were not even sure that infections spread by bloodied towels and hands!

While it seems unlikely to ever happen due to the fact that most of believe that the “person” IS the brain and the rest is just a container, you have to wonder if there is any scenario where this might be useful.

While the more fascinating question is how that person is no longer that person. They look like “John” but are really “Dave” with all his memories.

Who is he legally since his fingerprints say John?

So yeah, not going to happen, probably ever due to social and moral issues, but does anyone think it will be technically possible in 50 or 100 years? I know the major medical challenge is a lack of oxygen for even a few minutes destroys the brain but there have been cases of deep hypothermia limiting that damage and who knows what another century gives us medically.

Transplanting the brain is easy.
Re-connecting all of the nerves in the spinal cord - not so easy.

A brain transplant is a contradiction in terms. I would call it a body transplant. And while it might be possible in 100 years, where would you get the donated bodies? Maybe from someone dying of a brain tumor.

It all depends on just what it is that makes us who we are.

A guy I know had this topic of discussion. It seems that there is a part of the brain that assigns where memories are stored. He proposes that one could plug in to that part of the brain, and have it store memories in a digital device instead of in the meatspace. Over time, the memories would all be transferred to this digital analogue. Then the digital box could be duplicated, or removed, etc.

But does that really move the identity, or just the memories? Are we more than our memories?

A lot of our personality is tied to the meatspace, and the biochemical reactions going on. Extracting one element of our identity (what we’ve done and what we know) seems to me to be incomplete.

Whole brain transplant requires connections of nerves. We don’t really do that surgically right now. If you can figure that out, then you can conceivably find a way to transplant a brain.

Alternately, there’s trying to come up with a “brain pattern” of some sort that encapsulates the identity. Replicating that “brain pattern” would, by definition, duplicate the personality and identity. Would that equate to transferring the identity? Then you get the philosophical discussion of whether duplication is transferring if the original is destroyed, or if it is a new identity with the memories of the old identity.

Maybe. Scientists have already had some success with whole head transplants in monkeys in in 2001 and in this really gruesome expoeriment in 1963 (not for the squeamish).

Brain only transplants add yet another level of complexity but the hardest part is the spinal cord connections as noted. We can’t even heal people who suffer spinal cord injuries yet let alone attach all the connections from the brain to the rest of the body. It is unknown when these issues will be solved but they will take some extreme breakthroughs in micro-neurosurgery.

Indeed - and not just because of the practical difficulties of rejoining two neurons, but also, because it’s quite likely that individual nervous systems are a bit different in their specific organisation - it’s a self-organising system that builds itself into a generally similar end result, but the detail emerges on the fly.

Connecting brain A to spinal column B would involve mapping every single neuron on both ends, then building an interface to connect the right ends together. If we ever get to that level of medical/biological technology, we’ll just be able to custom-build a brand new body onto the stump of your existing neck.

Also… what are the supply/demand dynamics? - What problem demands the solution of being able to transplant brains? Where is the supply of donor bodies?

If you seat the identity in the brain, then yes, that makes the most sense.

Well, conceivably cloning might be developed such that bodies could be grown that don’t have identities in them, so that they aren’t conscious people, but empty shells. But the reality is that that is probably more science fiction than the body transplant in the first place.

The reality is that cloning technology for medical purposes is going in a different direction, anyway. Instead of the sci fi concept of a body in storage you pull out at will (such as used in Robert Heinlein’s The Cat Who Walked Through Walls), we are much more likely to see cloning of individual organs grown in vats. While that might make limb transplants difficult (who is going to work out the muscles, to grow them strong?), there is already research for growing tissues like skin, and organs like hearts or livers. There are real technical issues for keeping the tissues together while growing, but it is active research.

I think the major source for brainless bodies will probably still be motorcycles, i.e. head trauma.

Some background information from Cal Meacham

Well, there are any number of physical impairments where the person might be happy to start over in a new shell. Think of cyctic fibrosis, or parapalegics, for example. Of course, the technology to allow body transplants would probably be directly applicable to curing parapalegics without the transplant, so there’s that.

Then think of aging, where it might be nice to get rid of a 60-70 year old body that has been used hard and get back into a 20 yr old body in prime shape.

But that kind of market will rapidly exceed the available bodies from head trauma and the like. So you definitely need a different source of donors.

I should also mention a work of fiction, Robert Heinlein’s I Shall Fear No Evil, where an old billionaire gets a brain transplant, into the body of a young woman. However, it is not regarded as one of his better works.

They also show a considerable lack of brain activity after the accident.

I don’t think this semantic niggle is very useful; from the point of view of the patient, it’s “transplant my brain into that body over there”. From the POV of the surgeon, it’s “transplant this brain into this other body”.

There’s no particular reason why the seat of personality matters to the terminology of the operation.

Didn’t Heinlein also do one about a brain transplant on Hitler?

Dr. Michael Hfuhruhurr: I can envision a day when the brains of brilliant men can be kept alive in the bodies of dumb people.

I suppose the main issue is the brain is a huge consumer of oxygen and nutrients. (One stat I read said that it uses 30% of our energy, thus - the reason why high intelligence is a rare occurence in the animal kingdom, you’d better have a really good evolutionary advantage to put that sort of need onto the system). I suppose one could take advantage of the “drowning reflex” which allows chilled brains (cue zombie jokes) to survive 10 minutes to half an hour without oxygen.

The trope has been beaten to death in SF. IIRC, one of the Gil Hamilton ARM stories by Larry Niven uses it, wasn’t there some stupid movie (The Island?) where clones were raised as a future receptacle for rich people to transplant their brains; several other such stories over the years…

The law does not have a provision for this simply because it is currently impossible. When it is a real situation, there will be laws drawn up, or else the courts will decide in lieu of the legislators.

No doubt the obvious will prevail - the brain is the source of all personality, it seems to us. Therefore, just as brain death determines the termination of the person, even if their heart, liver, kidneys, etc. live on… the person is legally dead when the brain stops functioning. So yes, it will be a body transplay.

(I think it was another Gahan Wilson cartoon, the older couple talking to the brain floating n the tank - “We were wondering if you want us to sell the motorcycle?”)

There was also a SF story about this, a while ago, where the brain transplant worked, it seems to be the brain’s personality in the new body - then the doctor observes the patient making the sign of the cross backwards, Eastern Orthodox style - like the donor body used to, not the current brain’s standard procedure.

of course, there are more interesting situations; what if we can regenerate deteriorating brain with new brain cells grown from stem cells? What effect does this ahve on the personality? What if over time your personality and memory fades with the old cells, so you the 2,000 person don’t remember what happened 1,000 years ago? What’s the statute of limitations? What if we could cure behaviour like rape or murder by adding missing parts to the brain? Is the cured person with complete memory still legally responsible, or was that a disease and so not guilty by reason of mental defect?

For example, what is the legal status of a clone?
Is it a child of the source person who initiated the replication?
Or is it like an identical twin, legally a child of the source’s parents and entitled to a child’s share of the parents’ inheritance? Are the Source’s parents then obligated to provide child supporrt, be the legal guardian, or does the source person have that role?

Or since the source is effectively the complete set of parents of the clone, having initiated the life and being the source of both sets of chromosomes, should a clone get a double share of the source “parent’s” inheritance over regular children, who are half the source parent’s and half their partner’s?

I hope a lot of future judges have a serious science background. God knows there’s a lot of screwey decisions related to science and patents today…

Did he undertake to explain how those memories would be digitized?

No, of course not. They never do despite that being a popular idea. We still don’t know how the brain works very well but what we do know indicates that is almost totally unlike a digital computer.

Clearly, then, the seat of one’s identity is not the brain, nor even the heart, but the fingers! If “Dave” gets his hands whacked off, then gets then hands of “John” transplanted onto the ends of the arms – well, then, that is John now!

Better do a thorough background check on your donors first!

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An even stranger question, with perhaps weirder possibilities, would be: What about partial brain transplants. What happens if you get a donor medulla, or frontal cortex, or visual cortex, or other part of a donor brain, transplanted into a host body, joining it with the remainder of the host brain? What kind of strange hybrid brainish outcome would happen then? And who would the resulting organism be?

It seems to me that current technology would allow a brain “transplant,” although the patient would be completely paralyzed. The vascular hookups are not that complicated.

More importantly, without the cranial nerves (at least), it would be the worst case of locked in syndrome you could think of.

So while a donor body could keep the brain alive, you would have nothing but that original brain identity without any means whatsoever of communcation between the brain and the outside world.

There’s also a DS9 episode where a friend of Kira suffers brain injury and has part of his brain replaced