What Happens When You Split Someone's Brain in Two?

The brain reacting to danger. Did you do any interviews with people who are soldiers or interview fighters or people that are involved in extreme activities that... Yeah, no, I haven't done a lot of interviews. I mean, I have talked to people like that. You know, individual cases are interesting because they give you stuff, but it's not data, so the data you have to go out and collect. Yeah. What do you got there for notes? You got a pile of notes there. Oh, I don't know. Do you have anything you want to discuss? I just thought... Just brought this... I think we covered most of what I want to say. The amygdala is not a fear center. Behavior is not primarily a tool of the mind. It's a tool of survival. We think we know why we do the things we do and others do them, but we don't really because our conscious mind is not privy to all of the things that the body and brain are doing. Now, when you wanted to examine danger and you want to examine the mind and how it reacts to danger and fear and threats, what were you trying to get out of this? Well, I started out thinking this was a way to study emotion. At the time, I'd been studying these human patients with split brain surgery. Can you explain that? You've lost over that earlier, but the split brain surgery is alleviation of epilepsy? It's a way to control epilepsy that can't be controlled in any other way. Medications are not working. So you have young kids, teenagers that have lived most of their life paralyzed by epilepsy and not being able to lead a life. There was one patient who basically his parents were constantly having to hold him down on a mattress he was seizing so often. This is only done in a very extreme set of conditions. It's not done that much anymore, but when it's done, the connections between the two sides of the brain are separated. So information on one side doesn't cross over to the other. How do they do that? They open up the skull, pull the two ... You've got two loaves of bread sitting next to each other and they're connected by threads, which are axons that go between them. So you pull apart here and you can see where those axons are when you open up from the top. So imagine like a hot dog bun. So you open it up at the top and you can look down in the center and imagine that there was like a bunch of wires crossing between the two sides of the bun. So those wires would then be surgically sectioned. And so now you end up with two sides of the brain separate and independent. So typically language is on the left side, so you can talk to that side. The right side doesn't have language, so you have to ask, well, what can it do? So if you present a stimulus that only the right hemisphere sees and you do that by flashing a picture of an apple on the left side of space because everything to the left of center goes to the right hemisphere and everything to the right of center goes to the left hemisphere. So you send a stimulus to the right hemisphere and you say, what did you see? And the left hemisphere answers because that's where the language is. He says, I didn't see anything. So, okay, you said, reach into this bag and see what's in there. If the right hand goes in, that's connected to the left hemisphere, can't find it. The left hand goes in, connected to the right hemisphere, which saw the apple, it pulled out the apple. So the right hemisphere has information that the left hemisphere can't talk about. What is life like for people once they've done that operation? Well, slowly, the left hemisphere kind of comes to dominate again. And they come to live with it. And how does it prevent seizures? Well, the folklore of it, I don't know if this is actually true, but what is often said is that it prevents the seizures from jumping back and forth and having, because the electrical activity, jumping back and forth sort of gets into kind of an endless loop that can't stop. But cutting that isolates the seizures in the two hemispheres and makes each one more controllable by taking a medication. Jesus. So... Imagine being the first guy to try that out. Yeah, really. I got an idea. Split your brain like a hot dog bun. So what we were interested in in these patients that we were studying, this was my mentor, Michael Gazzaniga, and I were studying these at Dartmouth Medical School. We were at Stony Brook out on Long Island. We would drive up to Dartmouth to see these patients. How does the left hemisphere cope with the fact that the right hemisphere has performed a behavior that the left hemisphere that you talked to didn't commend? So we would put information in the right hemisphere. The guy would stand up and say, why'd you do that? I needed to stretch or scratch his hand and say, oh, I had an itch so I needed to scratch it. And so time after time, the left hemisphere would generate a narrative that made its behavior make sense. Oh, wow. That's why I got interested in how non-conscious systems would be generating behaviors that we generate narratives to explain. Because at the time that we were doing this, the idea of cognitive dissonance was very popular. And what that means is that when cognitively, when you do something behaviorally that is incongruent with what you cognitively know, it's disturbing. It causes dissonance. And so you have to engage in some kind of dissonance reduction. So our hypothesis was these narratives that the left hemisphere is generating about right hemisphere behaviors was a way of the left hemisphere's conscious mind kind of keeping it all together. Consciousness thinks that it's in charge, that the brain and body are its. That's the control center and everything else is there to satisfy its whims. And so it generates these narratives to keep that sense of unity going even though it's no longer unified. That is so fascinating that the brain tries to seek some sort of an explanation for the actions that you provoked externally. And that's why I got into emotion because, well, maybe emotion systems produce these. You got something, Jamie? When I'm looking this up, alien hand syndrome came up. Do you know anything about this? I don't. I'm sorry. There's a long article explaining this thing called alien hand syndrome and also known as Dr. Strangelove syndrome. Picture Dr. Strangelove. The explanations are very strange about people's hands doing something that they're not explaining. I don't know why it did it. It's kind of the same. Do they generate an explanation when they do that? It just explains different scenarios. People have had like a leg walk in the wrong direction or buttoning up your shirt with your left hand, the right hand starts unbuttoning it. That seems to be like some sort of a neurological problem. Well, these split brain patients would, you know, right after surgery when things are really like fucked up. It would be like pulling the pants down with one hand and pulling them up with the other. Oh, wow. There's one patient I saw in the hospital, a young kid. The left hand reaches out to grab the nurse on the ass. Can I say that? Yeah. You're going to grab the nurse. And the right hand is pulling it back. Oh my God. Oh my God. So there's like a physical struggle. You know, and it all kind of like over time, they don't come back together, but they negotiate something where it's not so dramatic. The woman who thinks her alien hand wants her to be a better person. Yeah, see, I'm thinking these are some sort of a physiological. Yeah. Well, it's a what a crazy solution to epilepsy. I know there's other solutions that, but that is a last ditch effort. Yeah. And so for severe, severe cases. Do those people go on? It's not done that often. To eventually sort of achieve some sort of a normalization? Yeah. You know, the kids have lived so long in the state by the time they get their brains changed like that. I don't know really, ultimately, what became of all these people because I moved on to other fields. But I think in general, they live a somewhat better life, but I doubt they ever live a completely full normal life. I mean, how could you after all that? I'm really interested in the brain creating these narratives to explain. Yeah, there's so many people that do things like that. Right? They'll try to explain their life away and give themselves excuses and give themselves reasons for behavior. And one of the things you see with the more rational people is it's never their fault. It's always someone else's fault. Well that's the four billion year story that I tell. Yeah. How we got to these narratives. That's what it's all about.