Conciousness and cutting a brain in half, what would happen?

[Ross PK81]

Okay, say there was a body stood next to me, without a brain inside it's head.

Let's just say this is possible: If someone were to open my skull, cut my brain in half and put half of it in the other persons empty head, and connect it to the things it needs to be connected too and that half of a brain is still alive.

Where would I be? You know, I as in me that's here right know experiencing reality.

This certainly is mind boggling. I can't see myself being in two bodies at once experiencing what both bodies are seeing and hearing, but then I can't see how I could split into two seperate me's because I'm only one. If I could, what would determine which of the two me's is me, if there is another me, that would suggest there is already another person in my brain that I'm unaware of.

[antoniseb]

Hi Ross PK81,

Please only ask questions about Astronomy and Spaceflight in our Q&A section. I have moved this post from there to General Science.
Also, if the question is about commercial astronomy equipment or cameras, ask that in the Astronomical Observing, Equipment, and Accessories section.

[HenrikOlsen]

Apart from the transfer to a different body, the Split-brain situation has been studied intensely, perhaps you can get some answers from the link.

[Larry Jacks]

Split brain surgery has some interesting side effects. I've seen examples where a test subject has been shown a picture of something to one eye following the surgery. Depending on which eye saw the image of an object, he might not be able to speak the object's name but could write it or draw a picture of it.

There is a procedure called hemispherectomy where half of the brain is removed. It is still a rare procedure but has proven useful in treating people who suffer many seizures every day. It is most often performed on young children. IIRC, the recovery is more problematic after puberty.

One side effect Canadian neurosurgeon Kenneth McKenzie reported in 1938 after a hemispherectomy on a 16-year-old girl who suffered a stroke was that her seizures stopped. Nowadays, the surgery is performed on patients who suffer dozens of seizures every day that resist all medication, and which are due to conditions that mostly afflict one hemisphere. "These disorders are often progressive and damage the rest of the brain if not treated," University of California, Los Angeles, neurosurgeon Gary Mathern says. Freeman concurs: "Hemispherectomy is something that one only does when the alternatives are worse."

Anatomical hemispherectomies involve the removal of the entire hemisphere, whereas functional hemispherectomies only take out parts of a hemisphere, as well as severing the corpus callosum, the fiber bundle that connects the two halves of the brain. The evacuated cavity is left empty, filling with cerebrospinal fluid in a day or so.

The strength of anatomical hemispherectomies, a specialty of Hopkins, lies in the fact that "leaving even a little bit of brain behind can lead seizures to return," Freeman says. On the other hand, functional hemispherectomies, which U.C.L.A. surgeons usually perform, lead to less blood loss. "Our patients are usually under two years of age, so they have less blood to lose," Mathern says. Most Hopkins hemispherectomy patients are five to 10 years old.

Neurosurgeons have performed the operation on children as young as three months old. Astonishingly, memory and personality develop normally. A recent study found that 86 percent of the 111 children who underwent hemispherectomy at Hopkins between 1975 and 2001 are either seizure-free or have nondisabling seizures that do not require medication. The patients who still suffer seizures usually have congenital defects or developmental abnormalities, where brain damage is often not confined to just one hemisphere, Freeman explains.

Another study found that children that underwent hemispherectomies often improved academically once their seizures stopped. "One was champion bowler of her class, one was chess champion of his state, and others are in college doing very nicely," Freeman says.

Of course, the operation has its downside: "You can walk, run—some dance or skip—but you lose use of the hand opposite of the hemisphere that was removed. You have little function in that arm and vision on that side is lost," Freeman says.

[grant hutchison]

It's probably a mistake to think that there's a single, persistent and coherent "you" inside your brain in the first place, even though it feels that way.
From cognitive science, the picture is really more like a loose and varying affiliation of various "consciousness applets", hosted in both hemispheres.
So the result of your thought experiment would likely be two impaired versions of your original consciousness, each lacking certain facilities but perhaps both enjoying a sense of continuity with the original "you". We know, for instance, that people can have improbably large chunks of cortex removed under local anaesthesia and retain a sense of continuous "self" throughout the process.

Grant Hutchison

[ravens_cry]

True, but this is our brain we are talking about, there is a you. behind the conciseness curtain, yes there is a lot of things happening, but just like we only have one body, but many parts and organs and cells, we only have one mind. Of course, this is a barrier to studying the mind, just like thinking of the body as a whole in and of itself can make understanding the different parts problematic.

[grant hutchison]

My point is that it just feels like you have one mind: but in reality "you" are just a series of neural patterns that share a sense of continuity. Bits of your brain light up, other bits go dark, but "you" persist.
If we put bits of that "you" into two heads (or two separated hemispheres in the same head), then we shouldn't be surprised if both bits share a sense of continuity with the original "you".

Grant Hutchison

[Bozola]

True, but this is our brain we are talking about, there is a you. behind the conciseness curtain, yes there is a lot of things happening, but just like we only have one body, but many parts and organs and cells, we only have one mind. Of course, this is a barrier to studying the mind, just like thinking of the body as a whole in and of itself can make understanding the different parts problematic.

Are you saying that Mr.Spanky and all the other voices in my head aren't real? Well, that's a bit of turn up for the plus-fours, I can tell you.

[Noclevername]

My point is that it just feels like you have one mind: but in reality "you" are just a series of neural patterns that share a sense of continuity. Bits of your brain light up, other bits go dark, but "you" persist.
If we put bits of that "you" into two heads (or two separated hemispheres in the same head), then we shouldn't be surprised if both bits share a sense of continuity with the original "you".

Grant Hutchison

You only feel like you have one body, but it's actually made up of millions of cells and dozens of organs.

You think you drive a car, but actually you're driving hundreds of separate bits of metal, plasic, rubber, and gasoline.

One thing can be made up of parts, y'know. Minds included.


ADDED: And you can change the tires on it without making it a "different car".

[grant hutchison]

One thing can be made up of parts, y'know. Minds included.


ADDED: And you can change the tires on it without making it a "different car".

My point, exactly.

Grant Hutchison

[Fazor]

Well, technically since the areas of your brain that control vital operations of your body not on both hemispheres, likely both bodies would be dead. I know, that's no fun.

Consiousness, best I can tell, is really just a collection of different sensations brought about by various senses. Or, as others have said with less words and more clarity; it's not a single thing, but a collection of things. Therefore, if you did manage to "split brain" transplant into an empty body, you'd have two un-shared consiousnesses, though they'd each be made up of whatever senosory abilities they ended up with.

To look at it another way, say each half devlopes into a fully-functional brain. Now you're still standing next to the other body. You experience the pain from the surgery to open your skull. You smell the aneseptic smell of a hospital room. And you see your friend Bill looking at you with his one un-decomposed eye.

Bill feels the pain from his skull being opened (and from the various body parts that decomposed partially until you generously donated your brain). He feels a draft, because the nurses forgot to tie closed his hospital gown. He smells the aneseptic smell of the hospital room, but also the gas he just passed that hasn't wafted your way quite yet. And he sees you, looking at him with an expression of pure horror as you realize you just brought a zombie to life.

There you have two completely seperate consiousnesses. Now you may ask if you two will "think alike"...but our ability to reason is learned, and based off our life experiences. Assuming those were transfered aswell, then yes, at first you'd probably think pretty much alike...but personalities would diverge based on the experiences you have after the split.

That's my best stab at it, but I'm not a doctor (and I don't play one on tv!)...so take it for what it's worth.

[Ross PK81]

I think I'm understanding this better (now I've started having a drink, go figure).

Half of me, my conciousness would be in one body, the other half in the other body. There wouldn't be any connection between the two halfs, the conciousness in one half will think 'What has determined 'me' to jump into this body but not the other one?', and vise versa.

But you've got to be half of what you are, so maybe you would only be half as self aware as what you were if that makes any sense, as in you're more zombiefied.

I mean where does it stop and why, what about cutting one of the halfs into another half, then that half into half until you end up with an atom? Are atoms concious? Maybe, but the self awareness is so small that it's almost as though it doesn't exist.

[HenrikOlsen]

Since the two halves of the brain "think" in fundamentally different ways, from the moment they are split into two they will have completely different ways to react to the situation, though both will be "you" to their own understanding.

[Van Rijn]

Some folks have had a corpus callosotomy. That severely reduces the communication between the hemispheres. I believe I remember one story where a fellow started strangling his wife with one hand, and used the other hand to pull it off of her. Apparently, he was of two minds on the subject. (And, no, he wasn't Dr. Strangelove.)

[Ross PK81]

Some folks have had a corpus callosotomy. That severely reduces the communication between the hemispheres. I believe I remember one story where a fellow started strangling his wife with one hand, and used the other hand to pull it off of her. Apparently, he was of two minds on the subject. (And, no, he wasn't Dr. Strangelove.)

So I guess, If every human being on earth had their brains connected to each other, we'd just be 'one' conciousness. I wonder if it'd feel any different? Would that one conciousness be way way way more aware of reality than what any one single person is? It's got to if it would lessen with a brain continually being cut into half.

[Ross PK81]

You only feel like you have one body, but it's actually made up of millions of cells and dozens of organs.

You think you drive a car, but actually you're driving hundreds of separate bits of metal, plasic, rubber, and gasoline.

One thing can be made up of parts, y'know. Minds included.


ADDED: And you can change the tires on it without making it a "different car".

If conciousness can be made up of several parts, I guess that would mean it can be created from a replica brain made out of microchips and circuit boards.

It's still hard to imagine that happening though.

[Joe Durnavich]

I suppose that those who have had hemispherectomies have been lucky that the surgeon in each case removed the hemisphere that did not have the mind in it. Or, should we say the patients had a half-mind afterward?

[grant hutchison]

I suppose that those who have had hemispherectomies have been lucky that the surgeon in each case removed the hemisphere that did not have the mind in it.

In each case, the surgeon removed about half the resources available to sustain consciousness. Fortunately, that doesn't seem to disrupt the sense of self that is a part of consciousness.

Grant Hutchison

[Joe Durnavich]

Fortunately, that doesn't seem to disrupt the sense of self that is a part of consciousness.

Grant, how do we know that to be true? What criteria tells us this "sense of self" is intact?

[HenrikOlsen]

What criteria tells us this "sense of self" is intact?

We ask that "self" if it feels intact.
If the answer is "yes", the conclusion is that the "sense of self" is intact.

Note that this doesn't mean the "self" is identical to the one before the operation, just that it feels itself(pun unavoidable) to be, which is really all the "sense of self" is.

[grant hutchison]

Grant, how do we know that to be true? What criteria tells us this "sense of self" is intact?

See HenrikOlsen, above.
Hemispherectomies have been carried out in teenagers and adults as well as in small children, so we can talk to them afterwards about such subtle matters as selfhood. Major cortical resections have been carried out in continuously conscious adults, under local anaesthetic, and we can talk to them during the loss of brain tissue.

Grant Hutchison

[grant hutchison]

Note that this doesn't mean the "self" is identical to the one before the operation, just that it feels itself(pun unavoidable) to be, which is really all the "sense of self" is.

Yes, it's that sense of continuity which convinces us that we are a single, continously existing "self". It's remarkable the insults that selfhood can withstand. I can fill you with barbiturates until your EEG is a flat line punctuated by uncoordinated bursts of electrical activity, and keep you that way for days; I can shoot you in the frontal lobes; I can remove half your cerebrum; I can chill you into hypothermia and stop your heart for half an hour; I can pass a current through your brain so that your whole cortex lights up with uncoordinated electrical activity: and yet you still reboot with a sense that you are the same person who existed before the disruption of processing.

Grant Hutchison

[HenrikOlsen]

It does rather give credence to the idea that the "self" is really a rationalization of what's going on instead of something "real".

[FriedPhoton]

It does rather give credence to the idea that the "self" is really a rationalization of what's going on instead of something "real".

I'm going to disagree with this based upon my belief that consciousness is self-awareness. We understand our self to be that which we feel is connected to us and providing feedback via our nervous system. Inside our heads it's dark and there is no way to perceive anything aside from perhaps a lack of oxygen or chemical imbalance, but even those things we understand as happening to ourselves because we can detect the change. And the rest of our senses we understand are a part of self because we perceive the stimulus they send our brain. I do not look at my neighbor's eye and wonder if her eye is a part of me. I know it isn't because I do not perceive input coming from it. There is a clear distinction between myself and other people, the boundary of which is the extent of my nervous system. A sense of self is about as real as anything in the world. No rationalization is required.

[Noclevername]

If conciousness can be made up of several parts, I guess that would mean it can be created from a replica brain made out of microchips and circuit boards.

It's still hard to imagine that happening though.

More like 100 billion computers in a massively parallel network, each linked to at least ten to twenty thousand others at a time. But of course, we aren't sure how much the actual pattern of our own hundred billion neurons plays in consciousness, so just having the networks and links may not be enough.

[Joe Durnavich]

We ask that "self" if it feels intact.
If the answer is "yes", the conclusion is that the "sense of self" is intact.

Well, I am not sure I know what "asking the self" means. I don't know if I was to take that literally or not.

What criteria does this "self" examine to determine if it is intact? Is it some sort of direct awareness of intactness? Under what circumstances would the self feel disrupted? Could it identify what was missing?

And finally, how do you know this to be true?

[Joe Durnavich]

Hemispherectomies have been carried out in teenagers and adults as well as in small children, so we can talk to them afterwards about such subtle matters as selfhood.

Which of the following would indicate to us that their selfhood was reasonably intact?

(1) They insist that it is.

(2) Their behavior is pretty much the same after the operation as it was before it.

(1 is actually encompassed by 2, but the general idea here is that 2 clearly has criteria on which to base a judgment.)

[Joe Durnavich]

If conciousness can be made up of several parts, I guess that would mean it can be created from a replica brain made out of microchips and circuit boards.

It's still hard to imagine that happening though.

Not really. Consider that you consider yourself and the rest of us here conscious, yet you haven't cracked open a single skull in your life. You would never look at a clump of neurons and call that "consciousness." To date, you have applied that term only in the context of yourself or of other people doing or accomplishing something without regard to the exact nature of the physiological details.

[Disinfo Agent]

Yes, it's that sense of continuity which convinces us that we are a single, continously existing "self". It's remarkable the insults that selfhood can withstand. I can fill you with barbiturates until your EEG is a flat line punctuated by uncoordinated bursts of electrical activity, and keep you that way for days; I can shoot you in the frontal lobes; I can remove half your cerebrum; I can chill you into hypothermia and stop your heart for half an hour; I can pass a current through your brain so that your whole cortex lights up with uncoordinated electrical activity: and yet you still reboot with a sense that you are the same person who existed before the disruption of processing.

You -- you get away from me, you!

[HenrikOlsen]

Which of the following would indicate to us that their selfhood was reasonably intact?

(1) They insist that it is.

Note that my posts wasn't about the "selfhood" being intact, but the "sense of self" being intact which specifically is the feeling by the individual that their self is the same, so for the area I was talking about it's definitely 1.