Redefining the Neuroscience of Fear

I'm Wendy Zuckumman and you're listening to Science Fverses. Today on the show, we are opening up a case file. This is where we report on case reports, which are curious stories from the scientific Nerd literature. Basically in N of one, a patient wears something weird as to them to go on this adventure. We have science channalist and friend of the show, Joel Wedder. Hello. Hello. I'm a curious nerd. This is perfect. Let's go. All right, Joel, to kick us off today Can you tell me about a time that you felt fraid Very afraid. Look, it's a long list My fear runs deep Are you afraidy cat? Oh ye, absolutely. I think the last time I felt truly afraid was when I found out how many people listen to podcasts at double speed. What's wrong with you people? This is supposed to be a fun thing. You're supposed to relax. Don't rush through it. No, but seriously, growing up in Australia, I spent a lot of time in the ocean as a kid And it's really easy for the ocean to go from being like an idyllic, beautiful day to being a near death experience. And like I have this one memory of being at a surf beach. and I had gone to the beach with some friends and we'd sort of swam out beyond the first breakers, like the shore break where the first waves crash And we're catching some wes, you know, frolicking in the it's like a soda commercial, you know. And then yeah suddenly get dumped by a wave, get thrown around underwater, stick my head up, take in a breath, and as I come up, there's another wave crashing on me straight away. And so it happens again. And then I think when the waves hit in a particular frequency, then you suddenly just like every gasp of air is a little bit shallower than the last wave. Yeah. And you start panicking a little bit. Is that what you were doing? Oh, definitely ye, yeah yeah It went from feeling like, you know, o, I've been thrown around for one or two waves to being like, if this keeps going, if I don't get out of this, then There's a good chance that something bad could happen. So what did you do? How did you get out? Well, I ended up being able to swim with the waves. so I kind of caught a wave through to that shorebak area. and then once you can stand, you can kind of like stand up and battle the surface with your les as well. But I think it's that feeling when you're just floating in the ocean and getting pummeled by the waves Yeah, it's pretty intimidating. Well today on the show We're telling you about someone who would be in that situation And their heart might not even skip a bait. They wouldn' they wouldn't be scared at all. Wow Someone who has nerves of ste, not the Freidy cat that I am, I guess. Someone the complete opposite And it's all coming up after the break Adobe Firefly is the all in one creative studio with AI powered image and video editing for today's creative process. buuilt for creators of every kind Firefly helps you generate, edit, and experiment fast Because the asks aren't getting smaller budgets aren't getting bigger, and the timelines, oh yeah, still tight With all the best creative AI models in one place, Firefly brings your ideas to life. Unlock a better way to make with Adobe Firefly. This episode is brought to you by Quaker Oats. The pace of the morning, the rhythm of the commute, the energy for whatever the day throws your way However your day unfolds, it all starts in the morning. So start with Quaker oats, one hundred percent whole grain oats with a good source of fiber to support digestive health and energy to keep you going. Stay in sync throughout the day Quaker, the official sponsor of the FIFA World Cup twenty six, brringing you fuel to start whatever's next. Visit Quakeroats dot com slash FIFA to learn more todayod on the show. We're bringing you a case file, strange report Case Reports from the literature and we're here with Joel Werner. Hello, hello. Hello For we're gonna jump right in This is a story about a woman who we're going to call SM And years ago, she started getting these strange spells where she would smell a funny odor And it was followed by this sensation of being deted or feeling like she was watching herself from above And so she gets a referral to the University of Iowa for a checkup. seeee what's going on She had there and in a paper about SM and kind of this moment really Doctors describe her as pleasant and cheerful. but also quick to become friendly with examiners and experimenters. whichich is exactly how Dr. Justin Feinstein, who worked at the University of Iowa D sccribe s She's extremely friendly She's very trusting. She starts Speaking to you right away as if You have this long history as if she's already your friend The next thing you know, she's asking personal details about your life and she's telling you very personal details about her life So she's a bit too much. We all know people like this though. This isn't, you know, we don't need to study people who are just like don't know boundaries. donon't understand social boundaries, right? But there's some other reasons we might want to study E, right? So doctors start running tests to see what's going on with these spells And they give her a CT scan. which uses a kind of x ray on your brain and Normally with the CT scan, you just want to see a lot of gray. brain That's how, you know, you don't want to see like white patches in there suggesting there's some bones somewhere in your brain they saw when they looked at SMs sprad It's quite exquisite. What they saw was very much unprecedented at the time It was these two bean shaped patterns Hyper intense, bright white patterns. So weird. It's so weird. Loo at the CT scans, it's so specific. It's really bizarre. Even neurosurgeons said how How is nature you know, carving out this little almond shaped nucleus and leaving the rest of the brain mostly intact So Bright white patterns, like with an X ray does suggest there's something hard in your brain Let me show you this SitA scan So you see those little? Oh, yeah. Like they jump out at you. It's almost like two sort of eyes within the brain.. Yeah, little poked out eyes. Yeah. Not meant to be there. For you and me, presumably. Yeah, that should look great So it turns out that SM has a genetic mutation Halcifies this very particular part of her brain. So the rest of her brain is fine if just these specific almond shaped bits get calcifized. Yes, it's so weird. It's so weird. The condition is called Urbach Vitee disease It does other things to your body, but in the brain. It's just really calcifying those two almond shaped bits. That's so bizarre. And the bits that this disease is going after. Very interesting, it's the amygdala A, okay. J didn you' have beenabbled in neuroscience in the past. Yes. what does the amygdala mean to you? Well, given the story we were talking about before as well, which is like maybe a big clue, it sort of has something to do with the way that we process fear. Yes, Yes, exactly The amygdala, we have two on each side of our brains. but for SM, she has none And it's really the amygdala is considered the fear center of the brain. It does other stuff, but as one paper put it in the minds of many scientists, the amygdala is synonymous with fear and basically many researchers have thought that you need it to feel fear So we use the amygdala to recognize fear, to feel fear. When you look at pictures of threatening animals and threatening people, your amygdala lights up There have been studies. into like what happens if we mess up an animal's amygdala. So rats who have lesions in their amygdala will go up to a cat. In fact, one of the rats in this very particular study nibbled on the cat's ear Cat didn't like that? No no, not a wise decision if you're a rat. No No. So do they think that so say when I'm out in the surf and I'm getting pounded by these waves and then I start to think, o maybe I can't get out and that panic feeling overwhelms my brain. That's the neurons in my amygdala are firing offinging Yeah. Yeah, they're playing a big role in that that whole reaction that you're feeling. if I have these calcified almonds in their place, then maybe I'm just like, lovely day for a serf today. Well, the question was How would she react? particularly at this stage when doctors are just meeting her. and this is exactly what they wanted to know because she is so Unakeia in the world of like brain science. Justin said that at this University of Iowa, they basically collected patients with weird brain lesions and brain stuff going on. It's like a very specific type of Pokemon card. Like you gott to collect them all. They had like thousands of people with different brain conditions. amazing. And with SM SM is one of the only living humans Walking around this earth without an amygdala So researchers wanted to study her and researchers like Justin to find out what does this mean? Does she really not feel fear? Would she really go into that water? And how would she react to? She's bungee jumping every weekend, going skydiving. Well Great, great example because just to give you a bit of context about what's possible here Do you know who Alex Honnold is? He's a climber climbed El Capitan. Oh, the free solo guy. Yes, yes, yes yes. Okay. so he for those who don't know, there was a documentary about him called Free Solo. He climbed this Biff three thousand feet up into the air without a harness without a rope. Just him on his own I feel like Maya Mygdala was like working overtime just watching that documentary. I was having sweaty palms, like that sinking feeling in your stomach. And so he has a functioning amygdala, but researchers have found that it's a little bit Camped down So when they did some studies on him, they were like, they showed him images that with you and me, Aram Mcdilliz would be like, bing, bing, bing, b, bing, and his was like, bom, bong bom So that is what's possible. and yet he still has mingala Wow. And I just do want to say that The reason scientists wanted to get to the bottom of this, it's not just as a medical curiosity of what is SM capable of, but understanding what the amygdala does, understanding fear It could help us with many different things. It could help us understand how we all understand fear. it could help us unravel treatments for PTSD and anxiety, which in some cases are thought to be where your fear response is maybe a little different to other people. So The researchers start doing experiments on SM. and they start simple, like at first they'll show her these photos of people's faces with different expressions on them. This's a very of classic experiment surprise and disgust and anger and happiness and fear She clearly could see the picture. She could tell if it's male or female. She could tell you all the description of what color hair they have, what color eyes they have. She could recognize anger and happiness and disgust But then fear she had this whopping deficit. Wow. Yeah, she couldn't recognize when someone else was afraid It's not that she just can't recognize emotion generally in people, that she's picking up all of these other emotions But then fear, nothing. Yeah, the whopping def is, it's very strange, right? Next, they wanted to know basically Could we scare her And they really wanted to do what's called condition this fear response into SM. So what they do is they show her slides with different colors. And when a blue square would appear The shape would be paired with a very loud boat horn Wow. L, I had I vote h and then forgot it at home So Look, I'm not gonna lie. I'm kind of thankful that I didn't get pranked by a blowhorn. This isn't like early two thousand reality TV. This is serious science journalism here. It was really loud. was I also feel like what else are they conditioning? Well, the thing is, if you for you and me, it wouldn't take that long to show us the blue square, pair it with the loud sound Th then as soon as we see the blue square, we'll be like, But for SM Never flinched. What? Never had any reaction. they could not condition her to feel fear. Amazing All right, they ask her questions out in the real world. Have you ever been scared? And they get into specifics asking her Qestions about things that you know, a lot of people are scared of What kind of animals do you not like? Is there anything that Mbe you're afraid of or you just don't find very pleasant. And she goes, well, I'm not really afraid of any animals, but I just don't like snakes. She kept saying that Fair Now It's interesting here because Justin and his colleagues think that SM's brain wasn't always the amygdala wasn't always calcified in that way and that it actually started in her adolescence And maybe when she was younger, She had an amygdala because she had stories that when she was little, she did feel fear. And she told this story that when she was on a hike with her dad, she actually fell into this pit of baby snakes And she remembers at that time being extremely scared and yelling for her father to come get her out of it. But Justin Figures, wow, fast forward Let's see how she reacts to snakes now. so he takes her to a exotic pet store. Picture it I don't know, fifty or so cages of different snakes. They had small ones, very like tiny sllythern snakes. They had really large ones that probablyrob we're almost Eight to ten feet. Did she share any sign of fear? She did not. It was so fascinating. In fact, it was the exact opposite. She was extremely curious. You know, I willll never forget her holding one of the snakes and touching its flicking tongue and looking right into its eyes and going almost nose to nose Wait, so she intellectually understood that she should have some kind of fear of snakes based on this early childhood experience. actually didn't feel the ear when confronted with this eight foot snake Yeahet, even though Even though she had said, I'm, you know, I don't like them, She showed no sign of that. And in fact, at one point, the employee at the store had to tell her like, stop trying to touch the snakes because we think you're going get biten and some of these snakes are actually quite dangerous. Wow and Justin thought maybe there was something about being in the pet store. That made her kind of blaset about snakes. likeike maybe You know, it felt like a safe environment. And so he asked her son, one of her sons Has she ever showed, you know this kind of fear in the real world? And her son actually told this story of a time where he and his other brother were playing in the yard and they see this really big snake And they say, Oh my go. and again, SM just grabs the snake rorows it onto the grass, get it away And the sun said, she seemed sort of feel this. Wow There's like some Steve Owen level snake handling. Yeah. it's like, let's just get it out of here. I know. Justin takes it up a notch and takes her to a very scary spot I can't believe you took out to a haunted house as part of a study. You know And it wasn't just any haunted house, it was Waverly Hills Sanitarium, which is considered one of the most haunted places in the world Okay, so Waverly Hills Sanatorium In Kentucky, used to be a hospital for tuberculosis patients and a lot of people died there. A lot of people died. And it closed down decades ago, was abandoned, but now you can go on tours there The Sanatorium even has a TikTok account. So Joel, I want you to describe this video It is scary. It looks like I mean, I'm not into haunted houses, but this looks like a scary place. What are you seeing? Okay, so there's like it's a very gothic looking building. There's gargoyles on the top We're going down some creepy stairs Yeahet, oh, what's that on the walls Yeah, o I'm out already. Like if I'm there, I'm just like scary right. That's pretty weird. Yeah I gotta say though, it's kind of weird hearing a scientist talk about like one of the most haunted places in America. it's like, buddy, come on. What's fun is that other papers have cited this paper with quite seriousness and been like, look, they even took her to a haunted house guys. So I was rating a nine on the haunted scale, was that deeply haunted It's a freaky place. It's areeaky place. And when Justin took SM, it was actually Halloween when the owners of the sanatorium really go to town and they create this very intense experience. It was extremely creepy. Imagine you know going in through very dark corridors into rooms that you can't really tell what's on the other side, Really loud bangs and startling sounds going off chainsaws coming out, the stroping lights, the people hiding in weird corners. was It was managing to scare me, but there was SM leading us into battle saying this way guys, follow me, Go through this hallway. Now let's go through this She was having a blast Amazing. She's just like cocktail hour. Exactly. Can we get that chainsaw on some lines? I want' a hito She never screamed, never jump backwards, never flinched. Justin wrote she would gaze with amusement at the monstrous creatures smiling or laughing at them in one instance, even scaring an actor. She's given it back. She's just like, I'm here to party.' go And I to say that at this point reading about SM, I was a little bit jealous about what it would be like too have no Aicto, to live like that. Just to think of all the things that I haven't done in my life because I've been afraid And she feels no fear. How are you feeling I don't know. L I feel like fear Like and you know, correct me if I'm wrong, but I feel like fear plays an important part in like our survival, you know? Like it's good to be afraid of things. That is exactly what Justin said Justin was like, you know We need that spidey sense telling us, don't jump into that water, donon't eat those poisonous berries. Don't believe the myth of trickle D down economics. Yeah, I mean, don't go down that street. Don't approach that person or that snake of he's Justed again The whole point of fear is to teach you something, right So the amygdala's role is really to keep you alive to keep you away from the things that can kill you And not having a functioning amygdala at times for SM It has been rough Her life has actually been at risk quQuite a few times So researchers like Justin who study SM have protected her privacy very carefully and no journalists have ever been able to talk to her But several years ago, when Alex Spiegel was co hosting the MPR podcast Invisibilia, she was able to send a short list of questions. to one of the neuroscientists who's been studying SM for the last few decades. His name is Daniel Tranll SM told him this story. So it's nightt timee. She's walking through a park N our church I was marketing a store And I saw this man on a park bed What me No I said I'll be coming back in a hry That's okay. it's an intense situation feel will not happen. And And I went home By. What an intense story. She's got a knife held to her throat by a man in a dark park and still doesn't feel fear. Yes. And she told Justin this story too. and she even took him to the park where it happened The way she describes it is she wasn't panicked She could hear the church choir in the background actually practicing And It sounds like the guy may have been a little freaked out by how calm she was and he let her go And she walked home Wow Isn't that it's like it's so And in fact that she walked home, Justin said, she didn't run She just walked And I guess this is what we're talking about before when like, you know fear is very useful because for most of us, if we're in that situation, we're not even approaching the creepy guy on the bench. We're clocking him and just getting out of there as soon as we can. Yeah And it's not just this incident with the knife. At another time, a stranger put a gun to her head, yelled at the top of his lungs, Bam before running away. That didn't scare her SM said she found the whole experience strange So there situations where anyone with a functioning amygdala would be out of there would have sort of sensed the fear in the moment and would have sort of extracted themselves from that situation. But for her becausecause she doesn't have that ability, her brain just doesn't experience that fear She just stays in the situation until it's too late, essentially and people are pulling knives and pulling guns on her. Is that sort of what they think is happening? Why? I mean, she also lives in a in an area that's not She super safe. There is a lot of violence, there's a lot of drug violence where she lives And in that instance with the gun, how it happened is that her kid had found some drugs in the yard. And she suspected who it was in the neighborhood, who was dealing and went to the police and just said, that's that person. and as a result was getting a bunch of threatening letters, including a gun being pointed at her. But it's the sort of thing that if you live in that neighborhood, I don't and you've got. kids I don't think I would be going to the cops. You Keep your head down. Keep your head down. And whereas you don't she doesn't have that level of fear. so she just was like, well, I don't want drugs in my neighborhood Wow. Yeah And like the other really curious thing about these times is if if any of this stuff happened to you and me It would stay with us. We would, you know, for weeks you know, months, maybe maybe years, we would be thinking over this time about how terrible it was. You know, because the amygdala plays such an important role in like capturing those memories Maybe it's not so surprising that with SM The traumatic events do not seem to stick doesn't seem to have an imprint on her. Long term So when you would ask her about these horrible events How would she react She would tell you very matter of factly, what had happened. And in some cases, she would actually tell you it with a bit of pride, like look what You know, I've I've had to overcome in life So By this point when it comes to sort of Justin's journey of trying to scare SM. and doing all these experiments over years I mean, he's really thinking This woman just cannot feel afraid She seemed fearless After the break Forget snakes and haunted houses Justin is gonna try something completely different they just change the way we think about fear. 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Think Green Godddess Chicken, Garlic aioli, crrumbled bacon, corn salsa Protein made to keep up with whatever comes next. New sweetgreen wraps hit different. Order now at order. sweetgreen. com. Okay, welcome back He's where we're Scientists have basically been trying to scare a woman who can apparently feel no fear, a part of her brain, the amygdala, that we think is critical for feeling fear does not work in her brain So this mission is feeling a little bit freugless And as a reminder, scientists Just doing this for kicks, they're doing this to help us all understand how we feel fear I wanted to know, that's why scientists are interested in this Why is What about SM? So I asked Justin. Why was she up for this? Like she's been studied for decades? Why does she let herself do this? You know, I think for her, she's actually quite curious as well about her condition. She knows that she's different. She knows that she obviously has this brain injury. Before this study, she didn't really fully understand Deep her lack of fear when But then Justin starts thinking, maybe I need to take a Totally different approach here. For years, actually decades, all of the the things we had done to probe SM's fear There have been external threats sounds site But what if? in the words of Zeus We need to look inside ourselves Because there is this fear response that we have that has nothing to do with what we can see or hear, but it comes from within and it's called interrosceptive fear. I'm talking about the brain's ability to sense inside of your body, the viscera of the body, so like the heart, the gut your whole respiratory system, for example. So this is this like an awareness of your internal system? Like you're hearing your heartbeat, you're like sensing the sort of breath going into your lungs? Is it Exactly, exactly. And so when things go wrong inside our body, sometimes it can make us feel afraid. Best example of this, I think is is when it comes to braining From the moment we wake up until the moment we go to sleep, and even while we're sleeping, we're just breathing, right? We take it for granted We breathe in oxygen, we breathe out carbon dioxide. It's this beautiful delicate dance A body is happy. But here's what happens if you screw up that dance for just a moment There's this experiment that Justin likes to do. Will you do it with me? Absolutely Breeze normally Th then I want you to exhale all the air out of your lungs. Every last drop, nice and slowly, go ahead Take as big of an inhale as you can through the mouth all the way till you have no room left And hold it And then let go And that's it. That's all it is is you do that. Okay, except There is one very important difference between what we just did and the actual experiment. Instead of breathing in regular air, which is actually quite nice, you breathe in a bag of air that has eight hundred and seventy times more carbon dioxide in it than regular air. Yeah. So there's quite a lot of COU And when people do this experiment, they can get really scared and think that they're going to die Because normally if your CO two levels go through the roof and your oxygen levels dive, it's super dangerous Now this experiment is safe because you're just taking in one big breath of carbon dioxide and you can sort of balance things out quite quickly when Breathe out air you're kind of get rid of that carbon dioxide quickly Also, your oxygen levels are fine throughout the experiment, but still, Your brain, your body gets confused and people can panic Did you must have tried it on yourself, Ryot? Oh yes, definitely. I started noticing that I'm hyperventilating and it was automatic. I'm just going And like all of a sudden the periphery of the world feels is like getting a little darker. And then in my mind, the only thing I could think about at the time was If this continues, I'm going to suffocate. So when I was thinking about these events that have happened in the surf where I've been really afraid, I've thought that the one thing that was driving my fear reaction was the lack of oxygen. was like I wasn't getting enough air into my lungs. I wasn't getting enough oxygen into my body And I think I always felt that if I could just get a really big breath in then I would feel a lot better. R And this sounds like this is what this experiment was Y as well. Yeah, exactly. It was probably both the situation around you, but then this intaceceptive fear probably played a role in it as well Exactly, interestnting And so Now let's go back to SA. becausecause Justin and his colleagues wanted to know how would she reacted this. What did you think would happen with SM going into that day? Keep in mind the context that I had just spent, you know the past five years trying my best to find a way to scare SM And so my expectation is that Her response was going to be blunted. What do you mean by blunt? Like she'd breathe it in and what would you see on her face? You would not see fear. You would not see this extreme hyperventilation response Basically, he suspected she might have some low key reaction, but just like with the snakes in the haaunted house, it was gonna be a bust And when SM walked into the lab that day, she didn't seem worried either She was her normal self. We're hooking her up to all these different sensors to measure different things. We're putting this breathing mask on her No sense of fear or anticipatory anxiety. She seems very calm talking to us, chit chatting and whatnot She just takes a single breath of a bag of air that contains carbon dioxide One breath, That's all it is. And this is where things get interesting Within about a few seconds She starts waving her hand saying, helpelp me, help me. And then she starts trying to tear off her face mask When you look at her eyes, her eyes were wide open like a deer in headlights. Never seen that before in SM And then afterwards, when we talked to her, it took several minutes for her to calm down from this experience We asked her what happened? And her response was I have never felt anything like that before. I felt fear Whoa. must have been so intense for her. Yeah, yeah. I mean, I think so. I think she remembered it Later when Justin would talk to her, she'd say, I never want to do that experiment again. So do they think that this intceptive fear is like modulated by a different part of the brain? Is there different system going on. What's happening? Yeah, Okay. well, so first, he tested it with two other people. It was twin sisters who also had lesions in both of their amygdalas because of the same disease that SM has Both of them got really scared too, gasping for air, looking very distressed, wanting to rip off the inhalation mask It was all this was all quite shocking because it showed that contrary to what science thought that the amenal is essential for fear. I mean all of a sudden it wasn't. So here's Justin I mean If you could have been a fly in the wall in the laboratory that day, our eyes were wide open, our jaw was agpe We were all dumbfounded because this was the exact opposite of what we had expected to happen You know, for the better part of half a century It was always presumed that the amygdala was required to feel fear to feel panic. And for the first time we have a human who is lacking this structure in their brain no longer has the amygdala. yet still felt fear and panic. Where is this happening in the brain? How is this happening in the brain? These were the types of questions spiraling through my head So Ever since this fateful day, I've been racking my brain to try to understand How is this happening Amazing. So generally speaking The reason that all of us can get panicky when we have too much carbon dioxide is because we have these chemical sensors in our blood and throughout our body that detect if the blood is getting too acidic cells that are exquisitely sensitive to even small changes in carbon dioxide That's because we really need to know if there is too much carbon dioxide in our body. If it happens, it makes our blood more acidic Blood gets too acidic organs can fail So when these sensors detect, oh CRT levels are too high. They emit suffocation alarms or as Justin wrote in a paper, quote, Pverbial primal scream aimed at alerting the nervous system of impending demise That's right. You drk the red wine before riding that line, no doubt Well, keep this in mind. It sounds a little hyperbolic, but it turns out it's absolutely true If you breathe that level of CO two for even one to two minutes It could kill you This panic response. this alarm is a real alarm. It's trying to alert you ssentially that the pH of your blood is dropping. It's becoming acidic And so these sensors then emit that suffocation alarm to and that message ultimately gets sent into your brain And now your brain is saying, my goodness, where is all this CO two coming from And that ultimately creates this feeling of fear and panic and oh my gosh, I'm going to die. And so to go back to why did SM have this feeling? well, like the rest of us, she has those senses that Cbon dioxide levels So when the CO two hit the chemoreceptors of SN Those chemore receptors fired like it was a firework show, right And then those messages got sent to the brain and they must have generated that fear response bypassing any amygdala. Perhaps we don't even need the amygdala for this particular kind of fear response So basically they're saying that like for decades, we've thought that the amygdala is necessary for the experience of fear. and now they're saying that fear can be experienced other parts of the brain. Exactly, exactly. And in fact, the study this study of SM with the carbon dioxide, it's since been cited hundredundreds of times. as evidence for this exact thing, that you can experience fear without an amygdala And there's other research. It's not just this that's showing this kind of thing Even when there's no carbon dioxide around, we are seeing people experiencing fear not involving the amygdala. So for example, there's another patient that had damage to both of his amygdala also had that same disease, Ubac Vite disease All of a sudden, with him, he just developed these really nasty panic attacks where he'd get heart palpitations and have a fear of dying And in that case, there was no CO two. It just sort of happened spontaneously. And there are other studies in folks with fully functioning amygdalas that have found that other areas of the brain are lining up in this kind of fear network. And maybe the amygdala isn't This fear center that we thought it was Maybe it's I mean, it is really making us think of fear in this totally new way. You know, we obviously theal is still important for fear Because SM did all of these things. Yeah, it's the idea that there are maybe different types of fear as well, but we've been labeling this whole sort of gamut of emotions with the label fear. but like something like, you know, if you're afraid of a snake, there's a sort of intellectualized component to that, right? Like you have to have learnnt at some point that snakes are bad Whereas like this it sort of seems like a more kind of physiological process where it's like ' got the extra carbon dioxide in your blood, there are these biological sensors that are kind of detecting it. It feels very low brain. very low brain.ight. Well you know, that idea, that's kind of how Justin sees it as well. I think one of the important lessons that SM has taught the scientific world about the neuros signs of fear is that there's probably not one of fear that is all encompassing and is in one specific brain area. Got it