Why is our brain split in two halves?

Why don't you have the video chip on/in your CPU?
Because they have separate functions, and it's better that way (less heat, for example).
Similarly, the brain needs specialized functions. If they are further from eachother is better, as there is some better damage control, heat dissipation, etc.
And if you are an 'evolutionist', ask Darwin. If not, ask God :D

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Original post by Raduprv Why don't you have the video chip on/in your CPU? Because they have separate functions, and it's better that way (less heat, for example). Similarly, the brain needs specialized functions. If they are further from eachother is better, as there is some better damage control, heat dissipation, etc. And if you are an 'evolutionist', ask Darwin. If not, ask God :D

Ok, good, but a PC has a processor, a video card, a sound card, a network card, etc..., those are all totally different things, while the two hemispheres of the brain are kinda similar (mirror images of each other).
Now you could mention "dual processors", but then why two and not four, for example...

EDIT: please avoid darwin vs god discussions, let this thread be purely about the hard- and software of the brain :D

It might be just an artifact of the way human embryos develop. We have bilateral symmetry in many other parts of our body; it seems to me that this would be the simplest way to make a human out of splitting cells. One goes to two, so unless you do something interesting you are going to end up with bilateral symmetry.

42.

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Original post by King of Men It might be just an artifact of the way human embryos develop. We have bilateral symmetry in many other parts of our body; it seems to me that this would be the simplest way to make a human out of splitting cells. One goes to two, so unless you do something interesting you are going to end up with bilateral symmetry.

Then why don't we have 2 livers, hearts, dicks, etc.?
I don't think this is the reason. My guess is that having two parts that communicate with eachother is better because there is some redundancy involved.

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Original post by Raduprv Then why don't we have 2 ...dicks...etc.?

Speak for yourself!

I don't know if this will help explain anything, but have you ever read anything about split-brain cases? It's where they cut the connection between the two halves to (i think) try to prevent seizures from spreading from one half to the other.

"Split-brain is the condition where the corpus callosum connecting the two halves of the brain is severed to some degree. This is often done to treat epilepsy.

A patient with a split brain, when shown an image in their left visual field (the left half of what each eye sees), will be unable to say what he or she has seen. This is because the speech control center is in the left side of the brain in most people and the image from the left visual field is sent only to the right side of the brain. Since the two sides of the brain cannot communicate, the patient can't say what he or she are seeing. The person can, however, pick up a corresponding object with their left hand, since that hand is controlled by the right side of their brain."

from wikipedia

I think the brain as we know it actually developed from way back in the day of primordial fishlike creatures, when neurons clustered in the head for olfactory and maybe vision purposes. So these clumps of neurons that were originally paired (two eyes, two nostrils) started to kind of get more closely linked over time as they turned into a generic learning/processing system, but the fundamental symmetry and fact that they aren't just a single lump of unbroken neurons didn't change. So the rift has been there for a really long time, as far as I know.

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Original post by Raduprv Quote: Original post by King of Men It might be just an artifact of the way human embryos develop. We have bilateral symmetry in many other parts of our body; it seems to me that this would be the simplest way to make a human out of splitting cells. One goes to two, so unless you do something interesting you are going to end up with bilateral symmetry. Then why don't we have 2 livers, hearts, dicks, etc.? I don't think this is the reason. My guess is that having two parts that communicate with eachother is better because there is some redundancy involved.

The whole nervous system is symmetrical, just like our body. It most likely is "the reason" it is symmetrical in appearance. The hearth and genitalia are located in the middle of the body, and are already somewhat symmetrical. Of course the symmetry of our internal organs is not perfect, but that is most likely the result of evolutionary specialization... Our brain might not be perfectly symmetrical in its internal wiring either since the functions of both hemispheres are not identical.

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Original post by nicksterdomus I don't know if this will help explain anything, but have you ever read anything about split-brain cases? It's where they cut the connection between the two halves to (i think) try to prevent seizures from spreading from one half to the other. "Split-brain is the condition where the corpus callosum connecting the two halves of the brain is severed to some degree. This is often done to treat epilepsy. A patient with a split brain, when shown an image in their left visual field (the left half of what each eye sees), will be unable to say what he or she has seen. This is because the speech control center is in the left side of the brain in most people and the image from the left visual field is sent only to the right side of the brain. Since the two sides of the brain cannot communicate, the patient can't say what he or she are seeing. The person can, however, pick up a corresponding object with their left hand, since that hand is controlled by the right side of their brain." from wikipedia

That was interesting.

Since the left side of the brain is the one that controls speech and verbal communication, I would assume that when you communicate with a person with a split-brain, we're communicating with his/her left brain side.
Since his/her right brain side is disconnected, we can't communicate with that person's right brain side anymore, and the person's verbal part can't do that either.
So have there then appeared two different concious beings in that person, namely the left side that we can talk with, and the right side that's trapped in the brain forever and is unable to talk, only able to see things and keep them for itself?

EDIT: another thing. It sais that the right part of the brain sees the left part of each eye. So does that mean the right part of our visual field goes to the left brain side? But since the left brain side is better at verbal things, I would think it wouldn't be able to do much with that information. But despite that, I exerience no difference in the left and right side of my own visual field... So I'm confused, can anyone clear up the confusion?

2 ideas:

A) One half does emotional/judgement stuff. The other half does stuff like logic, etc.
B) Your brain is like a ship. If a cannonball hits it, it is going down. Wouldn't it be better to have 2 ships, such that if one gets shot down, the other still works.

idk, if we knew for sure, we would be a lot further in AI.

Neat eh? Makes you want to do all kind of weird experiments with your own brain just to see how it feels.

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Original post by nectarine Neat eh? Makes you want to do all kind of weird experiments with your own brain just to see how it feels.

Well, I tried covering up the right side of my vision so that everything I read would go to the right side of my brain, which should be unable to read texts. But I could read and understand everything perfectly. Probably because the right half used the connection with the left half to ask it to read it for him. The cheater.

Actually your right eye is connected to the left half of your brain, I think. At least that's the case with arms and such. Don't ask me, I didn't design the damn thing.

As for hearts and dicks, you'll note that both are quite close to the centerline of the body and bilaterally symmetric anyway. I admit my theory breaks down for the liver. :)

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B) Your brain is like a ship. If a cannonball hits it, it is going down. Wouldn't it be better to have 2 ships, such that if one gets shot down, the other still works.

Why not 4 then? 3? 6? 100 micro-brains?

I don't think questions like this matter. Why is anything? Why is are planets round? Why do we have two ears. Whilst you can answer them to an extent by giving advantages of having things that way, you can not really give any reason why they should not be any other way.

(you may think its absurd to even consider the other variations such as with the 'shape of planets' question, but if all planets were cuboid and laws of gravity and other forces allowed this, spherical planets would sound just as ridiculous)

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Original post by Access Quote: B) Your brain is like a ship. If a cannonball hits it, it is going down. Wouldn't it be better to have 2 ships, such that if one gets shot down, the other still works. Why not 4 then? 3? 6? 100 micro-brains? I don't think questions like this matter. Why is anything? Why is are planets round? Why do we have two ears. Whilst you can answer them to an extent by giving advantages of having things that way, you can not really give any reason why they should not be any other way. (you may think its absurd to even consider the other variations such as with the 'shape of planets' question, but if all planets were cuboid and laws of gravity and other forces allowed this, spherical planets would sound just as ridiculous)

Planets are round because the gravity pulls the particles in that shape.

But most of the things about the human body are there for a useful reason, for example two ears to be able to know the direction a sound came from.

But for the two halves of the brain I can't really think of a reason why that would be more useful that one whole brain, or a brain with 16 parts.



Another question I find interesting: I read that, unlike the left side, the right side of the brain can communicate with the reptilian part of the brain that controls the body functions. It communicates with it through images, because the right side of the brain is the one that's good with images, and because the reptilian brain knows nothing about words.

-Is that true or false?
-How would this communication through images happen? I mean, I know what the inside of the body looks like because I saw pictures of it in books. But the reptilian part of the brain probably hasn't seen these pictures, so what sort of images would be used for the communication with it??
-(I wanna know because I want to give my reptilian brain commands about how to improve my body that way and so I must find images to think off that it can understand ;))

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Lode: Planets are round because the gravity pulls the particles in that shape.

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Whilst you can answer them to an extent by giving advantages of having things that way, you can not really give any reason why they should not be any other way. (you may think its absurd to even consider the other variations such as with the 'shape of planets' question, but if all planets were cuboid and laws of gravity and other forces allowed this, spherical planets would sound just as ridiculous)

Please read me carefully. I am also having a hard time explaining my view so its not entirely your fault.
What I am trying to say is, things could have been different, and there would still be rational explanations to explain the way they are.

If the world had been made with only planets of a different shape and NO spherical planets, i'd still be asking why planets are square and not spherical. And you'd still be telling me it because of something.
So while there are reasons for why things are this way, had they been a different way, there would still be reasons to support them.

My point is that reasons come AFTER things exist. Reasons are just our way of justifying the way things are.

My point is that nothing is really rational. Why should anything be the way it is? It could have easily (had God chosen to make it that way) been different and there would still reasons to support them.

So are things the way they are for any reason? Or do the reasons justify the way things are?

From my view, things arent the way they are for any reason.

Things just are.

I hope at least one person understands what I'm trying to say.

It's like dual core CPUs. You can't get enough brain cells to do everything on just one block of brain, so we have two.

consider this;
As creatures evolved cells started to group together to perform tasks, things such as your eyes are a result of this.
So, groups of cells started to group together to react to stimuli, noteably from the visual cells, which where positioned at the 'head' end of the creature in question.
Over time more sense evolved but they needed to coordinate with each other, thus they all moved into one section of the body, again the head end (although adaptions on this do exist, for example worms have nerual clusters in each segment of their body). As these cells evolved they cross connected and remained together in groups, which is why things tend to clump together in the brain functionality wise.

Why the two halfs. Well, while the brain might be massively parallel not all parts of the brain need to talk to each other, as such having everything interconnect is a waste of resource, instead a fast 'trunk' between the two halfs evolved, connecting the sections which needed connecting and while allowing the everything else to talk to only what it needs to talk to.
The brain burns alot of resources, so while some redundancy is usefull excess connections wouldnt be usefull, it would be like setting up a telephone system where each neightbourhood had a direct line to every other one and can be routed via them to other places as well, while the extra redudancy might seem like a good idea the waste in resources doesnt make it viable.