There is such a thing as callosal disconnection syndrome. It can happen by sheer incredibly unlikely and unfortunate accidents but mostly is done through a corpus callosotomy. And although I thought corpus was Latin for body, a corpus callosotomy is actually a surgery to severe the corpus callosum in your brain. Thanks to science’s penchant for keeping the Latin language alive that all sounds very much like too much jargon. Put simply it is a surgery that is performed as a last resort for severe epilepsy sufferers (so severe the seizures are in danger of doing them serious harm and medication and previous surgeries haven’t worked). The surgeon opens up the head and cuts the bundle of nerves that connects the two halves of the brain.
I have done zero research into why exactly this is done but I would have to assume that faulty connections between the two hemispheres is what causes seizures so preventing the connections altogether stops the seizures. Once the surgery is complete the patient is left with what is colloquially termed split brain syndrome and scientifically termed callosal disconnection syndrome.
Personally I find split brain syndrome fascinating but I am in no doubt that it’s somewhat less fascinating if you have to live with it. Both sides of the brain are left working independently, how could they not? They have no means of connection anymore.
If you were to show a patient suffering from split brain syndrome some pictures, things get pretty interesting. Put an image of anything you like in the left visual field and they will recognise what they have seen and know what it is but they will not be able to tell you what it is. The images seen in the left visual field are transmitted to the right side of the brain (why does biology always have it’s lefts and rights muddled?). For most people Broca’s area (the part of your brain responsible for speech) is on the left side of the brain. So when the right side of your brain is shown an image it doesn’t do the talking, ordinarily it would let the left side know what it’s seen and the left side will verbalise it. But there’s no connection, only the right side knows what it’s seen.
In rare cases this syndrome means that the two hemispheres are fighting for control. One patient experienced one side of his brain (the side that wanted to get dressed) using the corresponding hand to pull up his trousers, while the other side (the side that didn’t want to get dressed) was pulling them down. But most of the time a more dominant side emerges and takes charge.
Having had no experience of this scientific gold mine of information on the brain’s inner workings, I can’t say for sure what it’s like to live life with two brains. But I do know quite a bit about having two minds in my head. It’s not unnatural for people to flip flop with decisions and have difficulty choosing one way or another. That’s the whole reason ‘I’m of two minds’ exists as a phrase. But with depression it’s not just a little bit of uncertainty and trepidation. It very often feels as though there’s a whole other mind inside my head, and frequently it’s the dominant one as well.
Half of me wants to go outside, enjoy the sun and find happiness. The other half likes it in my dark cavernous flat, hidden away from anything that could make me happy. It attempts persuasion first, reminding me I’m literally allergic to the sun (it’s called polymorphic light eruption or PMLE, and it pretty much makes me like a modern day vampire… not one of those shitty sparkly ones). Sometimes just that works. Sometimes I say ‘No, fuck you depression! I’m going out anyway. Exposure to lots of sun is also a temporary cure.’ At that point it drops all semblance of friendship and cooperation. It takes control of my body and much like the guy both pulling up and pulling down his trousers I never get very far.