Consciousness and half a brain

[GreenDestiny]

There is this story of a boy who had half of his brain removed because of serious damage, but developed quite normal afterwards. Information can be found here: http://news.bbc.co.uk/1/hi/health/880478.stm

 

And there is also a book about his story and his rehab: http://www.amazon.com/exec/obidos/tg/detail/-/0521783070/

 

EDIT: I just re-read the two links and I think those are in fact two different boys - one named Harrison and the other named Nico. Well, whatever, doesn't really change anything regarding my questions.

 

Very interesting story, but I recently had some additional thoughts about it. The brain seems to be most important regarding consciousness - but which part of the brain is actually responsible for that? If they removed half of his brain, wouldn't they remove part of his consciousness as well? How does this work?

 

Would it also have worked, if the boy had had a healthy brain and they had removed half of it?

 

Or another very interesting, though only theoretical scenario: What if they had made a clone of him, removed the brain of the clone and then transplanted half of the brain into the clone - could this work? But what about his consciousness, his personal experience of the world? Which of the two boys would be him? Everyone perceives the world from his personal position, but this boy could not be inside two bodies at the same time, could he? Or maybe they would actually rather be two new persons then...

 

Can anyone give some answers about this?

[AlexT]

well in the brain is composed off many parts for example the cortex , thalamus, hypothalamus etc.. the most important parts of the brain are in the center the cortex is only used for thinking and a few other things and it is the hypothalamus that regulates breathing, heartbeat and other vital functions. while if you remove half of the cortex the other half would be responsible and take over the other halfs functions. the result would most likely be the same if the boy had a heathy brain although removing half of it for no reason would not be advisable.also removing part of a clones brain wouldnt make much of a difference first off you couldnt attach the brain without a very lucky stem cell transplant and still the neurons wouldnt work very well as brain connections grow over time so it would be pointless to transplant. and no a person can not be in two places at one unless they were siamese twins with a conjoined brain but thats probably not what you mean by your last question.

Hope this helped you GreenDestiny

[gib65]

The left brain and right brain are responsible for different mental functions. The left brain is primarily responsible for logical/analytical thinking and the right brain for artistic/creative think. This is overly generalized, but the point is if you remove the right brain, the individual will continue to function but will not be able to think creatively. If you remove the left brain, the individual will not be able to think logically. There are other functions that would be thrown out too. The left brain is responsible for speach and language comprehension, so removing the left brain would render the individual speachless and incapable of understanding speach. On the other hand, the right brain can identify objects visually and solve visual problems, so the individual would still be able to carry out these tasks. I'm not sure how much the left brain would be able to learn to take on these tasks should the right brain be remove, or the right brain learn to take on language tasks should the left brain be removed. AlexT, when you said the left/right brain could take over the tasks of the other, did you mean it could actually do this?

[dna mauro]

they removed half of the big brain.The important side of big brain is left side,,right side is mostly for art etc. i knew people who got brain insult one got 3 times at right side, and was after that ok.but other got once at left side and died.left side seems to control a little also organs(mostly it is done with hormons and other brain parts)

dunno, but left side insuries are more dangerous.So these boys where very lucky. i saw a serial on TV (Calling 119), there was one boy from a gang and half of his brain was shooted out with magnub, but he lived and after 4 years he was pretty smart at maths etc and weak at art(right side was gone).

[Kygron]

What if they had made a clone of him, removed the brain of the clone and then transplanted half of the brain into the clone - could this work?

 

You can do that this way: Look up something on people who have had their [group of neurons that connect the cortex hemispheres] cut. A researcher can ask the person to write the answer to a question, and he may write DIFFERENT answers with each hand. It's as if there's two people that share one body.

[GreenDestiny]

Is this really true? Do you have a source for it?

 

At least that sounds very strange... so that person's two brain halves aren't connected anymore? Does one half always control one arm then or how does the experiment work?

 

Still I'm wondering, if this would happen to me... right now I have the conscious experience of being me - what it feels like to be me. This seems to be a unique experience, at least I can't have the experience of being my neighbor or anybody else. So if they removed the connecting neurons between my brain halves - which of the two persons would I be then? I mean, you can't be two persons at the same time.. you can't be yourself and your neighbor as well and have both conscious experiences.

 

Or would it be more like two new persons with new unique personal conscious experiences?

[gib65]

Or would it be more like two new persons with new unique personal conscious experiences?

 

I think that would be it. Each half would retain the memories, skills, ideas, etc. that you had on that particular side of the brain before the split. Each half would probably remember being you, but now feel parts of itself are missing (at least, if it still retained the ability to introspect and ponder such things). The actual "you" from before the split would be gone, and two new "you's" would fill the void. Because they'd probably share some of the memories of the old "you", they'd probably still feel like they are the same "you" as before.

[Guest cheesyamoeba]

...

[Guest cheesyamoeba]

"Can anyone give some answers about this?"

 

 

The question you asked "What is consciousness?" is the most difficult question being attempted answers in the feild of neuroscience/psychology.

 

Right now I have discovered that my current single-moment comprehension (theoretically speaking) research (on executive functioning of cognitive control) for a publication I am doing is synonymous to the act of being effectively conscious. There are many approaches being done in order to inderstand the physical definition of what consciousness truly is (and it's alternate states). In this sense, based on what you have said (I don't have time to read the articles, but I wanted to help you and answer our question) they are reffering to the boys being able to function in GENERAL.

 

Although one is able to function at all, when portions of their brain have been removed there is always something that they are less capable of performing (or, in most cases, not at all) one the incision/lesion/removal has been made.) Therefore, although he may be functionable, the extent to the boys' functioning may lack greatly concerning right-brain specific functions and left-brain right-brain dependant functions.

 

here is a link to specific current consciousness research:

 

http://www.sciencedirect.com/science?_ob=IssueURL&_tockey=%23TOC%236752%232005%23999859998%23580930%23FLA%23Volume_14,_Issue_1,_Pages_1-232_(March_2005)%2BMNeurobiology_of_Animal_Consciousness&_auth=y&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=a16ee52f048475adb0dae3bcdf00b73d

 

Hope this helped.

[Mag]

Is this really true? Do you have a source for it?

 

At least that sounds very strange... so that person's two brain halves aren't connected anymore? Does one half always control one arm then or how does the experiment work?

 

 

 

it is strange, but when you do cut the corpus callosum the hemispheres work alone.

 

Therefor, you may do one thing, and your other hand may do another, because they are not interacting. With your right hand you may go to take a fork to eat, but your left hand may go and do something else, like take a cup of water.

 

its pretty hard to describe, but it does happen. Its usually after a surgery that requires the corpus callosum to be severed.

 

edit: ill come back to this thread with a better example.

 

and on topic: conciousness is, as i learned, a comination of all the parts of the brain. YOu can still have it if part of your brain is missing. in other words, if i remember correctly, its a "joint effort" (between all the parts of the brain, not just 1).

[GreenDestiny]

Wow, that's interesting and indeed rather strange.

 

This is really like two distinct persons living in the same body. How do these persons react to the situation? Do they know that there is somhow someone else in their head? Seen from the perspective of one of those persons...

 

I think that would be it. Each half would retain the memories, skills, ideas, etc. that you had on that particular side of the brain before the split. Each half would probably remember being you, but now feel parts of itself are missing (at least, if it still retained the ability to introspect and ponder such things). The actual "you" from before the split would be gone, and two new "you's" would fill the void. Because they'd probably share some of the memories of the old "you", they'd probably still feel like they are the same "you" as before.

 

Well, thinking of those boys who had half of their brain removed - wouldn't it be a bit like killing them? I mean, in a way they would not be the same person they had been before... their old "I" would no longer exist.

[Mag]

Wow' date=' that's interesting and indeed rather strange.

 

This is really like two distinct persons living in the same body. How do these persons react to the situation? Do they know that there is somhow someone else in their head? Seen from the perspective of one of those persons...

 

[/quote']

 

The person is still them, but they may do things that one side of the brain doesnt want to because the two hemispheres are working alone.

It is still the same person, because both sides of the brain know the person, its just that things wont work in unison and they normally did.

 

Oh yeah, and i looked it up in this prinout i still had.

Its called a Split-brain operation, because the people who need these will have epileptic seizures, so by cutting the Corpus Collosum, it will stop.

 

basically, as i said, the Corpus Collosum permits the two hemispheres to know what each one is doing. So when it is cut, they dont know what the other is doing, so they act on their own, because the other side isnt telling it what it is doing.

 

so, an example is (someone converses with their left side, therefore operations of the right hemisphere are diffcult to detect) that someone puts down a book with their left hand (right side of the brain) even though they have been reading it with great interest.

 

and other things like that.

[Kygron]

Is this really true? Do you have a source for it?

 

I had previously read the book "The User's Guide to the Brain" but it was returned to the local library and I don't have the details for you (You'll notice I didn't even remember the term "corpus collosum").

 

The other half of that was that the person had a (spoken) reason for the action performed with the left hand, it was a good reason, but, as this was a controlled expirement, it was the wrong reason. The person felt normal!

 

I think there are other coordinating brain processes that connect the hemispheres lower down the "chain of command", so these people are able to walk and dress and perform most habitual actions without problem. I'm not certain of this though.

 

My guess is that to each side of the brain, the commands of the other side appear to be habits, when in fact they are reasoned actions. This is not unusual for the brain, just try catching something thrown to you. So this wouldn't feel any different from anything else.

 

I'd be interested to hear what happens to these people 20+ years later, when each side has been developing on its own. I'll have to look it up sometime.

[GreenDestiny]

Well, at the moment it seems that these split-brain patients still remain one person rather than become two new ones.

 

I found an interesting link about this operation: http://www.indiana.edu/~pietsch/split-brain.html

 

Also, from another site:

As discussed in the experiments on split brain patients, if a perception does not go to the left hemisphere (our center for speech) the patient says they are not conscious of it. (see a standard experiment for a review) However, his right hemisphere is aware of it and can respond accurately. For example, if the person in the experiment was asked to use the object, he would be able to accurately use the key, or if asked to write down the name of the object, the left hand would be able to write the names of simple objects. Even so, the person says they do not know what the left hand is doing. This seems to tell us that we may become conscious of something only if the information about it reach the circuits that control speech in the left hemisphere. It seems that the consciousness of the right hemisphere is largely disjoint from that of the left, the right forms a kind of unconscious mind for the left. It can be disputed that the right hemisphere is not as conscious as the left because it manifests its consciousness in other ways. The right hemisphere has an unconscious knowledge of the stimuli that is presented to it.

 

[...]

 

It is important to note that in these patients the hemispheres are not completely disconnected, the right hemisphere can inject ideas into the left through the brainstem. Split brain patients experience these communications as unexplainable hunches from the unconscious.

 

This brings us to an interesting question, are the right and left hemispheres of a split brain patient of different consciousness? Sperry rejected this notion, and most scientists agreed with him. While split-brain patients could be manipulated into displaying two independent cognitive styles, the underlying opinions, memories, and emotions were the same. This could be explained anatomically. As discussed earlier, deeper structures of the brain that are critical to emotion and physiological regulation remained connected. Split brains, actually, are not really split into two but instead form a Y.

From: http://www.macalester.edu/~psych/whathap/ubnrp/split_brain/Consiousness.html

 

Very interesting, really. So there still seems to be one unified consciousness, but some part of it works on its own, like some kind of subconsciousness.

 

Also, the brain isn't really split into two completely seperate parts, but as the text says still connected through other parts below. Thinking of the original question of this thread, what would happen if you took out half of the brain of a person and transplanted it into another body (where the brain had been completely removed before): Maybe this wouldn't work the way I thought it would, because you can't really take out one complete half - thinking of that 'Y', the bottom is important for the forming of a personality as well, I guess. I was wondering which of the two new persons the original person would be, if one half of the brain were transplanted, but I think that the person would remain in the original body then (with several disabilities of course).

 

I'd be interested to hear what happens to these people 20+ years later, when each side has been developing on its own. I'll have to look it up sometime.

 

If you find out something more, just post it here.

 

Also, something else I asked myself: If the two brain halves don't work together very well after they have been split, why don't these patients have difficulties with three-dimensional vision? After all you need the information from two images to create a three-dimensional picture - why aren't there any problems when each half of the brain gets an image from one eye only?

[Kygron]

why aren't there any problems when each half of the brain gets an image from one eye only?

 

Firstly, there's people without depth perception that see "normally", so this may not be an issue.

 

But, secondly, if I recall, the eyes don't feed into seperate hemispheres, in fact one side of each eye feeds into one hemisphere and the other side into the other hemisphere. So each hemisphere actually gets full visual data of half your field of view.