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A clinical study conducted by researchers at Georgetown University Medical Center found that, for children who had a major stroke to the left hemisphere of their brain within days of their birth, the infant’s brain was “plastic” enough for the right hemisphere to acquire the language abilities ordinarily handled by the left side, while also maintaining its own language abilities as well.

The left hemisphere of the brain is normally responsible for sentence processing (understanding words and sentences as we listen to speech). The right hemisphere of the brain is normally responsible for processing the emotion of the voice — is it happy or sad, angry or calm. This study sought to answer the question, “What happens when one of the hemispheres is injured at birth?”

The findings appear in PNAS the week of October 10, 2022.

The participants in this study developed normally during pregnancy. But around birth they had a significant stroke, one that would have debilitating outcomes in adults. In infants, a stroke is much rarer, but does happen in roughly one out of every 4,000 births.

The researchers studied perinatal arterial ischemic stroke, a type of brain injury occurring around the time of birth in which blood flow is cut off to a part of the brain by a blood clot. The same type of stroke occurs much more commonly in adults. Previous studies of brain injury in infants have included several types of brain injury; the focus in this study on a specific type of injury enabled the authors to find more consistent effects than in previous work.

https://www.pnas.org/doi/full/10.1073/pnas.2207293119

We actually learned a lot about this because for a brief window we'd cut the brain in half to treat seizures.

Based on the changes the brain could make and the age of the patient, we learned a lot about how brain placisty changes over time.

Wait, so you're saying they would actually separate the two hemispheres?

When you altered the title of the paper, you introduced fresh nonsense. Language normally only exists in one hemisphere (usually the left, although which side matters less). When people have language in both hemispheres, they have a mental health problem. They identify one of the sides with "self" and think that the other side is someone else. In addition to explaining much about religion, this is one possible cause of some forms of psychosis.

Split brain patients. Some cool experiments with fascinating results to be seen there.

They would cut the major pathway between the the hemispheres. This was a last resort treatment. It slows and or stops the wave of seizure "signals" from propagating through the whole brain and overwhelming it.

It was effective and people were able to have mostly normal lives, with a few interesting side effects, including possible split consciousness...

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strokes are pretty wild when you really start to read into them. most people known of the slurred speech, one sided weakness symptoms but it depends on where the bleed or clot is in the brain and that'll change symptoms of the patient. like one guy i had was completely unable to see but could speak and move fine.

also, people who have had strokes in the past have a better chance of recovery from their next one because their brains develop what's called collaterals. they have develop extra vasculature to keep parts of their brain perfused with fresh blood and o2 for when they incase they have another one.

Reminds me of Emilia Clarke. She suffered two brain aneurysms in 2011 and 2013 but looks relatively okay. It's obvious she has some memory and speech issues during interview afterwards but literally everyone thought she's just an airhead. They "indulge" (patronize, actually) her "eccentricities" because she's beautiful and famous.

https://www.nbcnews.com/pop-culture/pop-culture-news/emilia-clarke-says-scan-brain-shows-quite-bit-missing-rcna38864

"To be seen there".. settle down there Dr evil.

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There have been children with complete hemispherectomy's develop cognitively and otherwise with much success.

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Neuroplasticity is truly incredible

Did they have delayed speech?

Yeah, there was also a thing called an ice-pick lobotomy. It was very popular throughout the mid 1900s (think 40s and 50s) as a way of (if we're being cynical) making peoblematic mental illness cases go away, as well as a way of treating seizures.

The procedure was pretty simple and "safe": it's just a small tool they inserted through the eye socket on the inner side of your eye (your eye would be fine) to reach the connective tissue between your hemispheres, and they'd swich it arround until large portions of this connective tissue (and also your frontal lobe) were severely damaged.

This was done in essentially outpatient settings, and the doctor that invented it was highly prolific, and did like thousands of these procedures over the years: most to people who shouldn't be treated with brain surgery. It usually left people halfway between mildly impared and vegetable, but it did frequently "cure" the worst symptoms of a lot of mental illnesses by essentially erasing half their personality.

I'm grossly oversimplifying here but it was nasty business. Not medicine's best chapter

Edit: more ethical versions of this survived the ice pick lobotomy era, for specifically only seizure treatments that had fewer adverse side effects, although it's a very radical treatment for pretty severe cases as I understand it

This is reallly fascinating, thank you.

Do you have any articles about the interesting side effects? :)

There’s a great Oliver Sacks book that talks about this procedure (severing the corpus callosum) and the split conscious thing is utterly fascinating. Literally made me rethink what identity and personality are. Definitely read up on it

Hemispherectomies are still performed today for intractable seizures, particularly in children. It's not an archaic medical practice. At the stage that the procedure is performed, there has usually already been a lot of brain damage to one side of the brain so the loss of function isn't as much as you'd think.

Yes. While over simplified, think of the brain as 3 major parts. Left, right, and lower. Think of the brain as a giant circle with the connections. Left and right are connected, and both are connected to the lower part.

We have cut the connection between the left and right parts. From it some pretty interesting experiments, studies, and realization have shown up.

Like the theory that each of your brain hemispheres are both conscious in some way, having their own likes and dislikes. Like experiments where they would be asked to reach out with both hands and pick their favorite color... And yet each hand would choose a different color.

They did and for those that didnt die it often really stopped epilepsy.

So yes. If we hadnt stopped researching it cuz its "inhumane" we might have a solution to epilepsy as a whole now.

> Emilia Clarke

Given that her career basically started with game of thones, what was her personality before the aneurysms?

It is. The more we do research the more i think we just need to find a way to synthesize stem cells and find a way to start injecting ourselves with it. It basically overcomes any injury.

Should be 'The Man Who Mistook His Wife for a Hat' by Oliver Sacks

I heard somewhere that every stroke case is unique

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its talking about me :D

They would cut their corpus callosum (I probably botched that spelling). It's the biggest and most important communication network between the hemispheres. Without it they struggle to/can't communicate in real time. However, it can cure epilepsy.

It creates a ton of interesting quirks. For instance, the hemispheres can't share everything about what they're seeing with their respective eyes. Sometimes one hand can do something without the opposite hemisphere even knowing about it. The person will generally attempt to explain away the behavior, but the truth is that they don't know exactly what their left hand was doing when they couldn't see it with their right eye.

I have hemiplegia. Diagnosed as a child. Immediately had someone try to reverse a medically file as a psych doctor not understanding a single thing about how the brain and spine work. I also had someone hop on when the primary concern later was indicative of brain or upper spine insist on rudimentary imaging of the lower back having asked a specific question about minor back ache knowing that right sided weakness was still present.