The ancient history of coma and consciousness research

7:34that we I think understand the least out of everything. So, any any light that is shed on this mystery, I think is uh certainly welcome. All right. So, with that in mind, let's get into some of the history behind this type of research. >> Yeah, yeah, yeah. And we'll start all the way with the ancient Greeks. Always. Okay? Because the ancient Greeks they had some crazy ideas. Like Aristotle thought that the cool the brain was just a cooling organ for the blood. And consciousness actually lived in the heart. We're going to we're going to let that slide because other people like Hippocrates the guy from the Hippocratic oath, right? >> Yes. Yes. He noted that patients who fell into deep unresponsive um sleep

8:18after a head trauma rarely ever recovered. Okay? And the word coma comes from deep sleep Mhm. >> in Greek. >> Mhm. So, they had already sort of classified normal sleep versus this pathological deep sleep coma. >> Yes. >> They'd already kind of figured that out. But again, it was just sort of an observation, right? Then um in the Renaissance there came the anatomical revolution with Vesalius. He published um this massive manuscript called De humani corporis fabrica in 1543. Mhm. >> basically like really into dissecting um human bodies and gave us incredible drawings of human

8:58anatomy. So, from there now we've got an understanding of brain structure, right? But it's kind of like the machine is getting cataloged, but we don't really know what any of the parts are doing. So, already by the early 1600s, we both had like a philosophical framework or concepts developing about classifying what these different parts of the body are doing and how that like uh how that translates behaviorally as well as sort of a very detailed cataloging of the physical structures, at least as it related to the brain and other key parts of the human body you know, four or 500 years ago. >> Yes, yeah, exactly. It was a catalog. We didn't know what each thing did, but there was a pretty good catalog already,

9:39right? And then in the 1800s, we had some pretty revolutionary ideas. Um Paul Broca in 1861, he discovered this idea of cortical localization. There's um an area of the brain now called Broca's area, and now we know that that damage to that area causes language loss. We also know that electrical stimulation in the motor cortex causes muscle movements. So now we're starting to get into the brain, it turns out, is a machine that has specialized parts, and each of these parts is doing something right? The other invention in the 1800s was electrophysiology. In the 1870s, Richard Caton placed electrodes on exposed

10:19skulls of rabbits and found that there was electrical activity. And then we see Hans Berger in 1929, he develops the EEG, the electroencephalogram, which is you put leads on the skull and you can actually read electrical activity. And he found that the brain electrical activity dramatically changes with the state of consciousness. Okay? So different patterns mean waking, sleep, and anesthesia. So already now it's like, okay, the brain is doing different things during unconsciousness. So perhaps the brain is really the seat of, you know, consciousness. That kind of makes sense. Um Finally, 1949, Giuseppe Moruzzi and

11:00Horace Magoun, they published this landmark paper, and this demonstrates something called the reticular activating system. It's a diffuse system that runs in the brainstem. The brainstem is where your brain meets the rest of the body with the spinal cord. So it's kind of like the connecting part of the brain. And they found that that part of the brain, the part that connects the brain to the spinal cord, that is essential for maintaining wakefulness. So now we've honed in on this is the sort of general area where consciousness is probably happening. So so to make a crude analogy, uh we figured out the brain is the factory and we now know that different

11:42parts of the factory have different workers. Yeah. The engineers are downstairs, the the the sort of manufacturing line is upstairs, the finance department's over here. And and but but we didn't really know where the boss's office was. >> Yeah. Yeah. Where is the boss's office? >> Yeah. Yeah. It seems like that's where it's the brainstem. Right. It's that part, right? And over the following decades, we've mapped out that brainstem in more and more detail. So, we figured out there's something called the locus coeruleus, there's something called a basal forebrain, there's something that's part of the brainstem, there's the hypothalamus, there's the raphe nuclei. And so all of these like sort of parts, you see where the spinal cord is going in, that junction Mhm. is where

12:25all of this is happening. Which it's it's it's almost like even just from a crude structural, like just looking at it, you would imagine if the things that are most sensitive have the most protection, just locationally. >> Yes. Kind of >> Locationally, that makes sense from one perspective of evolution. And the other perspective of evolution, I think is that like the brain sort of grew out from that part, right? Yeah. Yeah. Yeah. >> like the oldest part of the brain is the part that connects it to the rest of the body because I mean, let's face it, like the brain evolved to control movement, Mhm. right? And so the brain controlling the rest of the spinal cord is sort of probably how it started. And then like higher and higher cognition formed around that, right? It's like, "Oh, okay, I need a sense of

13:06place. I need a sense of play a sense of time. I need a sense of problem