Severed Corpus Callosum

[Grayman]

I have always thought this video was interesting. Its about a man who had his brain cut in half and how he manages to function after that procedure.

One thing I don't understand is how his left side of his body still acts in coordination with his right side. Each side of your body is controlled by one half of your brain. So how does he manage to walk and talk wtihout the other foot deciding to change direction or half his mouth deciding to say something else?

Lastly what does this mean for consciousness? He seems to still have one consciousness but at times he seems like two different people. Maybe there is a soul and that is what allows him to function mostly as one person and not two people in discord.

 

[Black Rose]

He still has his thalamus connecting both sides.

This is what keeps him coordinated without the corpus callosum intact.

 

[Hadoblado]

Split brains are incredibly interesting.

AK is right, while the Corpus Callosum is the main highway between hemispheres, there are backroads too, and new paths can be adapted with neuroplasticity. I can't remember the details (it's been a while).

As a general rule, the brain can be incredibly adaptive (e.g. it can remap sensory processing of one region to another within minutes of losing a limb) and will kind of just make up a solution. While it's true that motor control is contralateral, it's actually a lot more complicated than that (for instance, the inhibition for motor movement is a bilateral endeavor).

So rather than thinking of it as a static control system, it's probably better to think of it as a society of neurons, where the very structure of the system can shift and adapt to meet different needs. If you cut off the internet yes communication between geographic regions would be hurt, but there are other, less efficient ways that we would get by.

I would be very hesitant to suggest that this is evidence for the soul. There aren't many better ways to come to reject the notion of a soul than to study neuroscience. I think your curiosity is admirable and your questions are good, I just don't think they'll lead you to where you want to go. Just remember: Everything you hear about the brain from sci articles or docos is going to be extremely low-resolution information in order to make it even a little bit accessible. Neuroscience is a pile of seeming contradictions that take enormous time and effort to parse due to the complexity of the system they're nested in.

 

[ZenRaiden]

Well as far as I know there is brain stem that has some impact on whole body function.
There is even reflex loop for instance for lower limbs right in the spine cord if I understand that makes your foot go up if you step on a lego. Its better that way because that reflex can do it faster than your brain and thus protects you from injuring your foot which would be death sentence for primitive human with no medicine.
Corpus callosum is above that.
Then there is the back brain that controls motor movement.
Then there is some bit somewhere like corpus callosum that does something similar, but is different.

 

[ZenRaiden]

I would be very hesitant to suggest that this is evidence for the soul.

Yeah. What is it like being a creature with multiple brains like a starfish.
No one knows what soul it has.