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First-ever human head transplant is now possible, says neuroscientist
- tsukikage 13y ago"The Head of Professor Dowell" vs. reality ;)
- devindotcom 13y agoThis is pretty pie-in-the-sky stuff. Having studied spinal cord anatomy a bit, it seems to me that "full use" of the donor body is absolutely not an option. Cord cross sections are similar on a gross level but when you get down to specific pathways and such, there's huge variation. And you can't just rely on natural mending processes and neural plasticity to make up the difference. I'm not saying we'll never have something like this, but the "cut the cord and put it on top of the other cord" method described here seems massively, massively naive, like pre-enlightenment level medicine.
- dclowd9901 13y agoAbility to control different parts of the body (assuming there is a connection) seems like it would be more a "software configuration" issue than a "hardware issue" (if such an analogy is at all appropriate). Are you saying that even if the connection is there, the brain can never learn to utilize it if it doesn't jibe with the way the brain "is"?
- Retric 13y agoThe brain has zero software it's 100% hardware. Basically each neuron in the spine is independent and really long so a local cut breaks connections several feet from the break because the cells die. You can't fix things because unlike fiber optics or cable each side does not line up even in the original person let alone someone else.
- lostlogin 13y agoIt does remap functions as needed however - avoiding damaged areas.
- enraged_camel 13y ago>>The brain has zero software it's 100% hardware. I'm not sure if we can say this with any level of certainty. If anything, the nature vs. nurture dichotomy could translate directly to hardware vs. software. What nature gives you is hardware, and what you learn is software.
- skaevola 13y agoNope, learning physically changes the brain. For example, learning to juggle will increase certain portions of their brain. [1] It's like running Crysis, and having your video card's capability increase, 1. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002669 http://www.plosone.org/article/info:doi/10.1371/journal.pone...
- Zarel 13y agoYes, and hard drives physically change when they're modified, too. I think it's more like installing Crysis, and having more of your hard drive devoted to Crysis than before.
- skaevola 13y agoMemories are stored in the hippocampus, the changes took place in the occipito-temporal cortex. I'm not a neuroscientist, but my understanding is that the changes were directly related to processing, not memory.
- Zarel 13y agoI'd imagine it's the difference between writing to executable code and writing to data files. It's still just the files inside the hard drives that's changed.
- devindotcom 13y agoIn the brain, the hardware is the software. (Kind of like an FPGA, if I'm not mistaken?) Neural plasticity, which is essentially the extent to which the software can be modified by reforging connections between neurons, has its limitations, both in magnitude and rate. If you cut off someone's hand and put a foot in its place, chances are you could get a little basic functions, but rewriting the area of the motor cortex corresponding to that hand takes a good long time and will likely never be complete. It's not inconceivable that the brain could successfully send an action potential all the way from the cortex to the tip of the toe in a new body, but the 'rewiring' that would need to take place to make it happen in concert with the million other neurons (and many times that number in connections and networks) necessary for basic control or locomotion is simply not feasible on this scale. Putting a new finger where an old finger was removed is hard enough, and the brain has enough trouble rewiring itself to make that halfway decent. Rewiring for a whole limb or body, to say nothing of all the viscera, I really just don't see happening without some kind of massive assistance on a nano level, stuff that's sci-fi for now.
- waps 13y agoAlso keep in mind that your brain does not learn the same things at the same age. When your brain first forms and starts operating (< 18 days after conception) it will start learning very fast relations. It learns about the high frequency components of the human body, presumably things like how the electrical signals for a touch look like, or what the carrier signals are for your eye and the like. This also results in very, very fast sleep-wake cycles. When you "wake up from nothingness" so to speak, the cycle is less than a second. By 2-3 months it's about 5 minutes, and as any parent will know and complain about, at birth it's 2-3 hours. Obviously it eventually synchronizes to the sun, but that takes more than a year. Then as you mature, the myelin sheath starts to grow, which "locks in" the high frequency stuff it's already learned. By the time you're born you've lost the ability to learn about events that takes less than 3-4 ms to complete. By the time you're twenty, it will be at about 50ms. This is why people who start learning a sport at 3-4 years at most effectively have an insurmountable advantage. This has all sorts of effects that you will recognize in a growing human being. Short-term memory starts using progressively longer frequency signals to store itself. Reaction speed for anything new goes down (reflexes, and trained behaviors learned earlier stay in force though). Your ability to reason about things far away massively increases (a 4 year old kid cannot plan more than 20 minutes or so ahead without adult help, which mostly consists of reminding them what they were doing every 10 minutes or so). Furthermore the way your brain compresses signals is by distributing itself. There are small parts of your brain everywhere in your body, and several big blobs in your head. Every muscle has a cluster of neurons on it, and things like the heart, bigger muscles (like stomach muscles, biceps, triceps, ...) have large clusters on them. Those are clusters that do the same learning process as the rest of your brain, they're not preprogrammed. So your brain does not directly control your body, it negotiates what should be done with those local clusters. Because of this your body is able to have very short feedback loops controlling your muscles despite the fact that the decision process itself takes tens of milliseconds (and happens 1-2 meters away from the actual muscle). Now these clusters start out as blank as the rest of your brain, but they grow together, and they learn to communicate together. Different people send signals differently (well, the basic structure of the signal is the same, the semantic meaning, such as which muscle it affects, what timeframe it's talking about, ... is not). This is why if you connect a robot arm to a human, they cannot use it for fine motor control, even after months of practice, it improves to a pretty pathetic level, and just doesn't improve further (certainly not enough to write at normal size with it). If you want to be pedantic, there is more than one level of indirection. The first is the "brain region" -> spinal cord interface, and then every 15 cm or so in your spinal cord is another layer of control, and every point where neurons split up is another control point. Here's a rather basic introduction : http://en.wikipedia.org/wiki/Motor_control#Sensorimotor_feedback http://en.wikipedia.org/wiki/Motor_control#Sensorimotor_feed... All this means that your brain's lower level body control is effectively a ROM by the time you've grown up, and it is very dependant on tiny variations in the length of neurons to various parts of your body. Every single human body has a custom protocol for controlling the muscles that's different from everyone else's (so it's not possible, like in the movies, to mount something on the spinal column and take over motor control). Connecting up a brain to a new body, assuming you can keep it stable until the person wakes up, will immediately lead to a seizure (because the brain will be sending wrong signals to the heart), extremely rapid breathing, violent convulsions, ... until the patient is dead.
- agumonkey 13y agoI wonder if the nerve subsystem is generic at all. My bet is that genetic differences, life experiences and brain storage~ will be far too coupled for connecting two different bodies and expecting it too work. But I just remembered that there has been successful hand transplants so I'll just take the door.
- fumar 13y agoMy sister has a brain tumor. They attempted to surgically remove the tumor, it rests at the base cerebellum, where it meets the spinal cord. In order to do this surgery, they had to cut a piece of her spine and in the process cut some nerve pathways. Post surgery, she still has trouble walking and other general motor skills. The brain is the software and hardware, any changes to it will alter its software.
- smosher 13y agoAnd you can't just rely on natural mending processes and neural plasticity to make up the difference. I wonder about that. I can see healing and plasticity going a very long way over time, but intuition is telling me there's not enough plasticity in the wiring of critical autonomic functions.
- devindotcom 13y agoIt goes pretty far, and it is amazing, but the limitations are real and are encountered even on seemingly "simple" transplants like a finger. Critical autonomic functions, actually, may work fine, because they are more self-contained - the heart regulates itself, the gut in many ways as well, and many actions like breathing and basic drives are, to my knowledge, rather "standardized" between humans in the lower part of the brain. That's why we all have similar reactions to touching something hot or sharp, being hungry, out of breath, etc.
- kghose 13y agoDid you get down voted for voicing an opinion about a non-political, scientific topic? Only among nerds...
- sp332 13y agosmosher got downvoted because intuition is not helpful here. We can sit around and talk about what we feel might be an answer, but if we don't have any information, it's just random noise.
- smosher 13y agoI have a good bit of information about neurology, and that's exactly what my intuition draws from. I am extremely thankful I don't have the attitude you're endorsing.
- petegrif 13y agoThis guy is a neuroscientist so presumably he has given this question some thought and I would imagine he too has 'studied spinal cord anatomy a bit.'
- jessriedel 13y agoThere are plenty of crazy doctors out there who make nutzo claims not backed up by evidence in their field. One neuroscientist chosen at random is probably reasonable and competent, but a neuroscientist chosen conditional on publishing an astounding claim that isn't shared by any of his colleagues is almost certain to be cray.
- snorkel 13y agoGood point. I imagine the spinal cross connecting step would have to be preceded by some careful electrical probing and labeling of which spinal pathways are connected to which nerve endings.
- devindotcom 13y agoYes, but unfortunately our microelectrodes are nowhere near good enough for this kind of thing. The bleeding edge is the arrays being implanted in retinas and visual cortex for prosthetic vision, and they're like a couple orders of magnitude too bulky and imprecise to be effective.
- bennyg 13y agoAs a person who had retinal detachment and ended up being blind in one eye, this is what I'm hoping for within about ten years. A way to get to my depth perception back would be great.
- thorum 13y agoHasn't it been shown that the body, especially the gastrointestinal system, has a huge effect on cognitive function? I wonder if a procedure like this is possible without dramatically changing the personality of the subject.
- chc 13y agoHas it? I have never seen anything to that effect. Do you have any reading on the subject?
- devindotcom 13y agoIt certainly can affect your moods and drives, but it's feedback, not origination. If such a procedure were in fact carried out successfully (and I have grave doubts about that) the person may certainly have different habits when it comes to eating, tiring, and so on, but they wouldn't suddenly start liking spicy food or jazz.
- speeder 13y agoWell... there are a couple of reports of heart transplants suddenly changing one taste for soccer team so... I am not so sure about that. I guess it might relate to hormonal response or something.
- codereflection 13y agoAll I can think is this is one step closer to Futurama's Head in a Jar. ;)
- gliese1337 13y agoPrevious HN Discussion: https://news.ycombinator.com/item?id=5956301 https://news.ycombinator.com/item?id=5956301 And the technical details: http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2013;volume=4;issue=2;spage=335;epage=342;aulast=Canavero http://www.surgicalneurologyint.com/article.asp?issn=2152-78...
- VladRussian2 13y agothis seems to be thought experiment on throwing together of the old experiment on monkey head transplanting technicalities and the recent discoveries about PEG and some other compounds stopping the typical inflamation process that makes spine cord cuts into unrestorable connection breaks. That begs a question - why wouldn't before head transplant we'd try to transplant a piece of spine (one or few vertebrae) with a cord to the people with traumatic damages of the spine (like bullet or some sport injuries)?
- Udo 13y agoYou just have identified the primary reason why this entire head transplant thing is badly thought-out fiction right there: we haven't mastered reconnecting nerves yet. At least not reliably and not on that scale.
- danso 13y agoCrazy. I don't think we as a society have even gotten used to the implications of face transplants. My prediction: we'll be arguing for a long time whether this is a head transplant or a body transplant...at least in Philosophy 101 courses.
- bennyg 13y agoNo, it's a head transplant. The head is part of the body. There is nothing metaphysical about a head. That's not where the philosophical language problems come into play. The problems start when you talk about WHO the combinated person is.
- danso 13y agoRight...but the head is sometimes considered to be the center of someone's identity...case in point, brain death is often considered to be the standard of actual death. So if I find my head atop a different body...why shouldn't I label it as a body transplant? For those currently in cryogenic cranial freeze and who successfully are revived, would we not think of them as having new bodies, rather than the bodies having new heads?
- benatkin 13y agoBecause "head transplant" is more fun to say. It's a self-deprecating joke to say "I need a head transplant". https://twitter.com/search/realtime?q=%22I%20need%20a%20head%20transplant%22&src=typd https://twitter.com/search/realtime?q=%22I%20need%20a%20head... It probably is incorrect, though, as a head transplant would mean that the head would be assuming the identity of the person carrying the body. While amusing it seems a lot to ask of the person with the head. Edit: even more people say "I need a brain transplant" https://twitter.com/search/realtime?q=%22I%20need%20a%20brain%20transplant%22&src=typd https://twitter.com/search/realtime?q=%22I%20need%20a%20brai...
- nsxwolf 13y agoIf you were diagnosed with brain cancer, would you be pleased if you were offered a head transplant as a cure? No, you would not. Now if you had terminal cancer spread all over your body, would you accept a body transplant as a treatment option? It's a body transplant.
- ejain 13y agoIt's not a head transplant, it's a body transplant.
- ewrwerwerw 13y agoI imagine it'll be easier eventually to simply move the head to an android body.
- mdda 13y agoOne benefit of this is avoiding many sources of cancer, since there would be a whole lot less cell-machinery to go wrong. To me, this seems like the most obvious (though drastic) means of life-extension.
- hfsktr 13y agoWhat would we do with all the spare android heads then? :P
- deleted 13y ago[deleted]
- bobwaycott 13y agoPut them back on our abandoned human bodies so as to allow the machines to fully integrate and understand the human experience as a defense against them misunderstanding our collective craziness and rising up to destroy us. :)
- devindotcom 13y agoI agree. This is way, way more likely than human transplants, for a dozen reasons. And to be honest, it could be done in a few years. Moving around using the body would be relatively easily accomplished but expression via tapping the spinal cord... not so easy.
- drKarl 13y agoSounds like Avatar B to me! http://2045.com/ http://2045.com/
- blaze33 13y agoThere is a related video http://vimeo.com/20230127 http://vimeo.com/20230127 (14min) with an interview of Robert White and some footage of animals head transplants in the 70s.
- Pitarou 13y agoHas anyone sat down and tried to itemise all the taboos this would break? I don't consider myself especially squeamish, bit this concept creeps the hell out of me!
- jlgreco 13y agoI don't see why it should be an issue in a world where we already do transplants. It is just more of the same, an iteration, albeit a very impressive advance.
- Dylan16807 13y agoAre you creeped out by the idea of an arm transplant?
- agumonkey 13y agoWas there no resistance to the first organ transplants ? I bet many people weren't willing to allow it or even benefit from it.
- Pitarou 13y agoHeart transplants caused a lot of upset at first, because folk beliefs about the heart as the seat of the soul still lingered.
- deleted 13y ago[deleted]
- conexions 13y agoHere's a short story on a similar subject, the ethics of a brain transplant. Won a Hugo in 1973. http://docs7.chomikuj.pl/1852561988,PL,0,0,Frederik-Pohl---The-Meeting.txt http://docs7.chomikuj.pl/1852561988,PL,0,0,Frederik-Pohl---T... Ignore the first 2 paragraphs. Its the end of an introduction by Issac Asimov from an anthology of Hugo winners.
- Pitarou 13y agoSome people appear to be trying to use rational arguments to persuade me that I shouldn't feel creeped out. You'll fail. Rational arguments reach an entirely different part of my brain.
- tracker1 13y agoAT a $13 million dollar cost, that's a barrier to entry... I'll take SuperMan's body please... http://www.tv.com/shows/lois-and-clark-the-new-adventures-of-superman/ordinary-people-29116/ http://www.tv.com/shows/lois-and-clark-the-new-adventures-of...
- pessimizer 13y agohttps://www.youtube.com/watch?v=KDqh-r8TQgs https://www.youtube.com/watch?v=KDqh-r8TQgs https://en.wikipedia.org/wiki/Experiments_in_the_Revival_of_Organisms https://en.wikipedia.org/wiki/Experiments_in_the_Revival_of_...
- swamp40 13y agoHere's the only important sentence: Connection of a spinal cord from the head of one creature to the body of another has never been attempted even in animals, so Canavero’s paper must be taken as an exercise in speculation.
- dhughes 13y agoNot quite ever it's been done with dogs. https://www.youtube.com/watch?v=lICXAFFxWgk https://www.youtube.com/watch?v=lICXAFFxWgk edit: I guess that's part 1 of the procedure, there is another video of the transplant. There are pictures of it too https://www.google.com/search?q=russian+soviet+transplant+dogs+head&safe=off&qscrl=1&tbm=isch&tbo=u&source=univ&sa=X&ei=RdHRUZeNEvay4AOE6oGQCw&ved=0CE0QsAQ&biw=1280&bih=687 https://www.google.com/search?q=russian+soviet+transplant+do...
- nollidge 13y agoNit: isn't "first-ever" kind of redundant, since "now possible" necessarily implies it wasn't possible before?
- ebbv 13y agoSweet I'm putting my head onto a baby's body next week I'll totally own the other kids in chess club this time through school!
- jessaustin 13y agoI'm no bioethicist, but there seem to be several ethical problems with your plan.
- arbuge 13y agoThis could be the way to go in the future if you have any major incurable trouble, so long as it's below the neckline... it's a whole new spin on attaining immortality. Of course, heads too must die some day, but this certainly would push your runway out quite a bit.
- tsenkov 13y agoShouldn't this be called "body transplantation", instead?
- dbg31415 13y agoPlease try this on a monkey first. Show me a monkey with a transplanted head and we'll talk.
- sampk 13y agohttp://vimeo.com/20230127 http://vimeo.com/20230127
- freshyill 13y agoHow would you like to be the guy on the waiting list who gets the call? "Mr. Doe, we have a suitable donor. Be at the hospital in 30 minutes so we can decapitate you before this corpse goes bad."
- YZF 13y agoGives new meaning to brushing your teeth. Now we need to figure out how to grow bodies with no brains.
- tsotha 13y agoI wonder what kind of quality of life the new body would provide.