SciShow Tangents - Brains

Episode Date: September 21, 2021

This episode is brought to you by Gates Notes, the blog of Bill Gates. Go to gatesnotes.com to learn about the future of Alzheimer's research.I don’t want to alarm you, but you’ve got a big ol’ glob of pink goop in between your ears right now, and it pretty much controls everything you do. In fact, it might BE you... But try not to think about that too much while you enjoy this episode!Head to https://www.patreon.com/SciShowTangents to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter!A big thank you to Patreon subscribers Eclectic Bunny and Garth Riley for helping to make the show possible!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @slamschultz Hank: @hankgreen[Fact Off]Cetacean brains staying warmhttps://www.nature.com/articles/s41598-021-84762-0https://phys.org/news/2021-03-whale-dolphin-brains-specialfor-production.htmlhttps://phys.org/news/2021-04-whale-dolphin-brains-lots.htmlBrain blood flow measuring devicehttps://www.npr.org/2014/08/17/340906546/the-machine-that-tried-to-scan-the-brain-in-1882https://academic.oup.com/brain/article/137/2/634/284537?login=truehttps://www.umassmed.edu/strokestop/modules/module-3-the-blood-supply-of-the-brain/brain-circulation/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536794/https://www.ndcn.ox.ac.uk/divisions/fmrib/what-is-fmri/introduction-to-fmri[Ask the Science Couch]Brain evolutionhttps://www.newscientist.com/article/mg21128311-800-a-brief-history-of-the-brain/https://www.karger.com/Article/Fulltext/320218https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873165/https://link.springer.com/referenceworkentry/10.1007%2F978-3-540-29678-2_3154https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614228/https://www.scientificamerican.com/article/worm-discovery-brain-evolution/[Butt One More Thing]Bony-eared assfish smallest vertebrate brainhttps://www.researchgate.net/publication/20270929_Acanthonus_armatus_a_Deep-Sea_Teleost_Fish_with_a_Minute_Brain_and_Large_Earshttps://www.fishbase.se/summary/Acanthonus-armatus.htmlhttps://royalsocietypublishing.org/doi/10.1098/rspb.1987.0018 

This episode of SciShow Tangents was made in partnership with Gates Notes, the blog of Bill Gates. Diagnosing Alzheimer's disease as early as possible isn't just important when it comes to caring for individual patients, but also in clinical trials and research that could lead to new breakthroughs in Alzheimer's treatment. Go to GatesNotes.com to learn about promising new advancements in the early detection of Alzheimer's disease. Hello and welcome to SciShow Tangents. It's the lightly competitive knowledge showcase. I'm your host, Hank Green, and joining me this week, as always, is science expert, Sari Reilly. Yeehaw. And our resident everyman, Sam Schultz. Hello. I wasn't crazy about that. I'm going to try out some new interjections. I say hello all the time. So get ready. People love hello. Look, look, look, we need to mix it up a little bit. We've had a lot of the same over the last two years. We need some yeehaws.

I want next time for me to say, and our resident everyman Sam Schultz, and for you to say, wow, motherfucking who? Oh, sometimes I say, what's up? I want wahoo. Wahoo. Like Mario?

Okay, I'll try. Wahoo. And I'll do a Yoshi noise. I'll do Yoshi. Oh no, that was really good. Wow. I can only do like two impressions. I can do Yoshi and Oh, no, that was really good. Wow. I can only do like two impressions. I can do Yoshi and I can do a beagle howling.

And that's it. We're going to save the beagle howling for next week. Every week here on SciShow Tangents, we get together to try to one up, amaze and delight each other with science facts while also trying to stay on topic. Our panelists are playing for glory. They're also playing for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of them will be crowned the winner and they will be able to brag about that and it will be all worthwhile. Now, as always, we introduced this week's topic with the traditional

science poem. This week, it's from me. I can think about my body parts that doesn't bother me. I've got parts that run in circles and parts that make my pee. I can think about my hair that grows in patches here and there. I can think about my hair that grows in patches here and there. I can think about my eyeballs that move and look and stare. It doesn't bother me one bit to think about my knees. They bend and push and hurt sometimes after I climb trees. There's only one part of my body that I like to just leave out. A part that if it's all the same, I'll just not think about.

If you think about it too much, it'll drive a man to drinking. Because the thinking part is thinking about the part that does the thinking. That was very cute. Thanks. So the topic for today's episode of Tangents is brains, the thinking part. And there are all kinds of different ways that thinking parts do the thinking. But Sari, do we know what a brain is? I think so. I think we can draw a circle and say most of the things inside the circle are brains. Well, yeah, I mean, there is some debate about how far the brain extends. Yeah, that's true. But we know that in humans and by extension, all vertebrates and most endovertebrates, it is the center of the nervous system.

It's an organ. It is in our heads, usually close to other sensory organs like our eyes, ears, nose. Other animals have different versions of sensory organs. And it's just chock full of neurons and chock full of glial cells, which are the overlooked, underappreciated cells that stick our brains together and help with a lot of supporting functions. Part of my fact up is about glial cells and I could not figure out what the hell they were for the life of me. So what are they? They're like, so like neurons are usually considered the most important cells in the brain. They're like the ones with the axon and

dendrite and they're where nerve signals get sent along. And then glial cells are just like around. They don't have like different ends. They don't transmit electrical signals, but they're just like the cushioning around the neurons. And if the neurons need a little structural support, they give that. If they need a little biochemical support, they sprinkle some biochemicals. They insulate everything so that the electricity stays in the correct wires and they don't get crossed. They're just like the everyman kind of cell, Sam. Okay. So the ways in which a brain becomes unclear, octopuses, cephalopods, where you end up with

a bunch when there's like multiple brains stemming out, the whole nervous system occasionally is decision making as well as... And also this happens in us. There are ways that our nervous system makes decisions without involving our brain. And then it's like, well, at what point is it brain then? In us, it's pretty clear. It's a big, complicated mass of decision-making. But in other organisms, it's like, well, there's like one end of the nervous system that's

like enlarged a bit. Does that count as a brain? And then there's the other confusing part is where do you draw the line in our own bodies between the brain and the rest of the nervous system? There are people who argue about whether the eyes and optic nerves count as brain or if that's just sort of a separate thing. Which reminds me, if you ever want to have a good creepy giggle, just Google brains and eyes and look at all the image results.

It makes you think, how on earth does any of this work? We made an episode about eyes being brains on SciShow very recently. And like your spinal cord might be part of your brain and stuff like that. There are all kinds of stuff. Yeah, where does it go? Where does it end? Where does it start? Sari, what do you think? Oh, I don't know. I'm not gonna weigh in on this debate. We just got the squishy bits and then we've got the harder parts

to protect the squishy bits. And that's how it all works. And I don't think about it too hard. That's what the science couch is for. Yeah. I just sit here recording my silly little podcast on this silly little rock with my silly little friends. And don't worry where my brain stops and ends. That's probably for the best.

Oh God. Do you know where the word brain comes from? So what's funny about the word brain is that it is not connected to a Greek root. Like the Greek root for mind is phren, which is like phrenology or frenetic. So that is the mind or thought root. But in old English and Germanic languages, the word brain or other forms of it seems to have arisen from who knows where. Influences from other cultures. But any way you trace it, it seems like it is a homonym for words for mush or goop or filth or like pulpy mass.

Because we didn't realize what the brain did. We just cracked open skulls and then it came out and we were like, gross. What's that brain? It says nothing. Yeah.

It's just the goop you keep in your head. Yeah, we just had a head full of mush, huh? That's what we were saying? Like other organs were more like rounded. I don't know.

You could like pull them out of a body, but then we only saw brains when you like really obliterated someone. It was like, look at that body goop. That's a brain. Wow. You really obliterated something.

Yeah. I guess it's like, it's what comes out when you have a particularly violent interaction with a foe. Yeah. And it's like excrement basically, or like garbage. It's just mush. Yeah. Yeah. And it's like excrement basically, or like garbage. It's just the bush.

Yeah. Yeah. That's wild. I always wonder if like the seat of conscience. So like when I think, I feel like I'm thinking out of this part. Yep. Did not everybody throughout time feel that way,

I guess? Nope. Huh. I've read a book among the history, the history of like our understanding of consciousness and like, like understanding of mind at one point. And like, they felt that in their chest. Wow. Which I can, I can get understanding of consciousness and like, like understanding of mind at one point. And like, they felt that in their chest,

which I can, some, I can get like, sometimes I like when I'm having strong emotions, you feel it in your chest. Yeah. Yeah. I think a lot of it was heart based and that's where,

and I'm just guessing at this point, but like humors came from because like, oh, your heart pumps your blood and your soul is like bound up in that system. So you've got to adjust the things that the heart does to your body to make yourself feel better. Okay. Gosh, that is a shocker of an etymology. I did not expect this. Yeah. We really undersold the brain and now it's stuck. And this is like the word that stuck, which I think is hilarious. Like this word where we don't

know where it came from and it means mush. And it's like, this is the center of all human consciousness. It's the mush. Yeah. And we use it to just make iPhones and yell at each other. Wow. What a thing. Yeah. Real bummer on that one.

I don't know. iPhones are pretty cool. Okay, yes. iPhones are cool. The yelling, not so much. Unless it's like fun yelling, like, ha ha, I'm razzing my friend. Then worthwhile. Yeah, yeah.

Unless it's like butt is legs yelling. Yeah. Are we all on the same page regarding butt being legs? This is the origin of the butt and legs conversation. It's tangents. This was something I was thinking about when I was putting together our bonus episode for this month was I couldn't remember what your stance was on it. Me?

Yeah. Butt is legs. That's what I thought. I mean, I'm in the same boat as you, yeah. Butt couldn't be anything else. That'd be ridiculous. I'm indifferent at this point, so. Butt is legs, sure. Again, just here making a silly

conversation with my silly friends. Don't need to think about where things start and end. It's me. Sari Reilly, head empty. Yeah. Head empty, just talk. All right. Well, get head full because now it is time to move to the quiz portion of our show where you will have to think hard because it's time for Truth or Fail.

We use a lot of algorithms every day, and some of them are in our computers. Yes, there are brain algorithms. In fact, many computer algorithms them are in our computers. Yes, there are brain algorithms. In fact, many computer algorithms are based on brain algorithms. So when researchers want to improve computer algorithms, they look to brains sometimes, and sometimes to animal brains. Which of the following three tales of algorithms and their animal muses is the true fact? So we've got three things where an algorithm was inspired by an animal. Two of them are fake. One of them is true.

Are you ready to find out and tell me which one is the thing? Oh, yeah. Yeah. Fact number one. Researchers created an improved search engine that's better able to sort information by designing an algorithm inspired by how fruit fly neurons sort and label smells as edible or not edible when they're foraging for food. So that's fact number one. Fact number two, researchers developed a more effective Spotify

recommendation algorithm that layers information aggregated from external reviews and from in-app usage that was inspired by snakes and how their brains layer infrared and visual information to parse their surroundings. Or you have fact number three. Researchers created a cloud drive that is able to efficiently store more information across multiple servers by designing an algorithm that mimics the way the distribution of neurons and multiple brains throughout an octopus's body allows it to operate its arms independently. So is it the fruit fly search engine, the snake maps, or the octopus server drives? Well, God bless Spotify and hello to everyone listening on Spotify. But I feel like my Spotify recommendations have gotten worse. So snakes may be the best.

Maybe that's what happened. Maybe they were like, let's choose this snake stuff, but then it turned out to be real bad. Snakes don't know anything about music. Fruit flies, that seems like a lot of work for a fruit fly to me. I would think they'd think everything smells food. Is that not the case? Well, no.

It's not everything is food. If you're a fruit fly, you can't just go to anything that smells or you'd have them all up in your armpits. Oh. Do they smell with their feet or something weird like that? I'm sure there's like chemoreceptors. They don't have a big old schnoz on there, I don't think. But I think some receptors on their body.

Isn't it like house flies taste with their feet and then they can like detect chemicals other ways? Yeah. Okay, so here's my guess. A house fly, I think, lands on a thing, goes, taste with their feet and then they can like detect chemicals other ways. Yeah. Okay. So here's my guess with a housefly I think lands on a thing goes ew not food flies away

and then goes I already forgot what I was just doing. So they don't they don't sort anything. That's my guess. But it's a fruit fly not a housefly.

Well both both of them do the same thing. Okay. One's just smaller. And what do you think about cloud storage Sam? Well I'll tell you what I think about cloud storage Sam well I'll tell you

what I think about cloud storage that one seems too obvious to me the octopus brain thing is like I feel like that's one of the first things

you think about when you're thinking about like animal brain it's like oh octopuses have weird brains so now you tell me what you think

Sam's ruled all of them out yeah they're all the retrofacts I know which one i like but um i also this is where you could convince me of anything i understand algorithms so loosely that you could tell me you based it on anything and be like oh you based this on bees swarming you

based this on the groundhog popping up and down out of out ground? Sure. I agree that the octopus one feels too on the nose. It's like, oh, look at the octopus that has different brains and then there are different servers and they're all linked together in the cloud, which is the octopus's head. But great metaphor. Yeah, but when you say it that way,

I mean, it makes a lot of sense. I don't actually know. I don't really use Spotify. I listen to the, when I run, but I have the ads version because I don't listen to enough music. So I get an ad every third song or something. So know nothing about recommendations. I guess there's multiple inputs. There's like what you're searching and whatnot.

I'm writing that one off because I don't understand Spotify. I'm leaning toward fruit flies because it feels like a search engine is something that people like search algorithms are something that people try to work on a lot of the time. Like in my computer science classes way back when we had to learn different ways to sort things. And so I could see scientists tinkering with that. So I'm going to go with fruit flies. Okay. I'm going to go with the snake one. I don't know why. That one just feels like something somebody would try. It may very well be something that someone would try, but so far it is not something that anyone tried. But the

correct answer is the fruit fly search engine. Yes. Congratulations to Sari for getting early point here on SciShow Tangents. This was a pretty complicated computer science situation that went down in 2017 at Salk Institute in California, where they designed an algorithm based on how fruit flies fire up their neurons when trying to figure out whether or not something is edible. So typically, in a search engine, an algorithm is based on what's called a similarity search, where you reduce your data set down to a few key traits. And you tag them and then you put them into, you sort them, as Sari was saying, into buckets, but with like similar tags on them. But fruit flies do that differently.

They actually spread things out into like a ton of buckets instead of just like a few different tags. They gather a ton of information using a ton of neurons and then sort from there. A researcher described the difference like this. If a computer scientist was trying to study relationships within 100 different people, the typical similarity search method would be sticking them all in a crowded room. But the fruit fly method spreads them out over a football field. I don't really get it's computer science and it's hashes and it's algorithms, but they definitely did this. And when researchers

created an algorithm based on the fruit fly method of sniffing out food into a way to search through a data set, the algorithm was performed just as well and sometimes even better

than a normal computer science solution. Wow. All our fancy technology in a little bug beats us. That's right. Well, it turns out that the ways that brains

figure it out is probably pretty good because they work well. Yeah, sometimes. The Spotify thing was fake, but snakes do do this where some of them have special pit organs

that are separate from their eyes and create a heat map. And then the snake is able to sort of like look at the heat map and the visual map that its eyes give it somehow at the same time, either like referenced to each other or literally stacked on top.

And like, we don't know how this works because we're not snakes and we cannot perceive the world the way that they can. But it's very cool that they can, they sort of have two different sets of inputs that are basically visual, though one's infrared. They come from totally different organs, and then they can see them together.

And then the octopus thing, y'all were right. It's just octopus brains are really cool. Do they work similarly? The cloud and octopus brains? No. Okay. Hank apparently does understand cloud computing and just doesn't want to tell us you're right i it could be i mean definitely like things are

stored like my email like my gmail is not all stored on one computer you know right um so there has to be some way that it figures it out but i don't i i don't heckin know all right so we're headed uh out of truth or fail with sari with know. All right. So we're headed out of Truth or Fail with Sari with one point and Sam with nothing. We're gonna take a short break and then it will be time for the Fact Off.

This episode of SciShow Tangents was made in partnership with Gates Notes, the blog of Bill Gates. The way we currently diagnose Alzheimer's is one of the biggest hurdles standing in the way of developing Alzheimer's treatments. See, by the time patients know to get tested for Alzheimer's, their cognitive decline is too far advanced for drugs to work on them, so they can't volunteer for clinical trials. A cheap, non-invasive way to diagnose patients early is key to finding an effective treatment for Alzheimer's.

The good news is that all over the world, technologies are being developed that will allow doctors to do just that. From a blood analysis being developed in Sweden to eye exams being researched in Seattle, easy-to-administer tests could be widely available in the next couple years. You can learn about some of these promising advancements in Alzheimer's diagnostics and more about the future of treatment for Alzheimer's in the new blog post and a video at GatesNotes.com. Welcome back, everybody. Get ready for the fact-off. Our panelists have brought in science facts to present to me in an attempt to blow my mind. After they have presented their facts, I will judge them and award Hank Bucks any way I see fit.

And to decide who goes first, I have a trivia question. The hominid that can claim the largest brain is Homo neanderthalensis. The average Neanderthal brain was about 200 cubic centimeters larger than the average homo sapiens brain how big was the average neanderthal brain in cubic centimeters so it's 200 cubic centimeters bigger than the average human brain so just go based on that how big do you think a neanderthal brain was? Oh, how big is a human brain? It's this big. Oh, shit.

Yeah, I'm trying to figure out what my head is in centimeters. About 200 cubic centimeters could mean literally anything to me. Well, I mean, so you know that a Neanderthal's head is not like three times bigger than yours. Right, right, right. So math your way from there. I'm not. I'm going to let Sari do it first. I'm going to guess that a Neanderthal brain was 1,200 cubic centimeters

because I can do 10 times 10 times 10 really easy in my head. You're like, okay, all right. Yeah, close enough. Gosh, what did you say? 1,000? 1,200. So I'm guessing that you say? 1,000? 1,200. So I'm guessing that our brains are 1,000 cubic centimeters plus 200. Oh, that's 1,400.

Sam is the winner through just cheating. No, just being really smart. Please. The answer is 1,600 cubic centimeters, which is substantially bigger than a human homo sapiens brain. So if only they were around for us to be like, what's up? That would be cool. But they are not. Why?

Don't ask too many questions. Don't ask questions you don't want to know the answer to. So Sam, that means you get to decide who goes first. I guess I'll just go first for once in my life. So whales and dolphins have big old brains. We were talking about big old brains. They got even bigger damn brains. Sperm whales, in fact, have the biggest brains on Earth.

And many dolphins have a larger brain to body ratio than primates, including humans. So one conclusion you might draw from this fact is that since whales and dolphins have big brains, that they are really smart, possibly even smarter than humans. However, they don't really seem smarter than humans. They don't have like underwater cities or anything like that. And the brain to body ratio could, I guess, hypothetically be useful in determining intelligence, I guess, especially like ape intelligence. But the mammal with the largest brain to body ratio is a tree shrew. And they aren't, they ain't that smart probably. So taking these details into account, a paper

published earlier in 2021 proposes an alternative explanation for why whale and dolphin brains are so huge. So the first thing you need to know is that mammal brains have to stay 98.6 degrees to function right. Anything below that can make bad stuff start happening real fast, up to and including death. So one way that animals keep their brains at the right temperature is with brown fat. So when the brain starts to get chilly, brown fat produces proteins called uncoupling proteins or UPCs. And when these proteins hit mitochondria, I'm getting a little out of my depth. This is what I understand. When they hit mitochondria and brain cells,

the cells start making heat instead of ATP, which is a chemical that helps the brain function by helping ions travel in the brain. Is that what ATP does? Does anybody know? ATP is like a chemical energy. You can use it to do whatever inside your body. Okay, my next sentence is,

I think it basically makes the way your brain create energy less efficient and more heat producing. So it's like just a different energy it's making. So the researchers looked at the brains of three species of cetaceans, which are whales and dolphins, and 11 species of land-dwelling mammals closely related to cetaceans, like hippos, pigs, and giraffes, and found that 90% of the neurons in cetacean brains had UPCs in them. So this extra heat-causing molecule. And only 35% of neurons in land mammals had UPCs in them.

And cetacean glial cells, which we talked about before, I won't tell you what I wrote that they are, but mine was a little different than yours. I just said there's support cells in the brain. Is that right? Sure. That's good. So they are also full of UPCs.

Like 30 to 70% of them have UPCs. While in land species, there aren't any UPCs in glial cells. And then also the nerves that control production of UPCs are way denser than land animals. So based on these findings, a team proposes that cetaceans evolved big old brains because they needed to basically have their brains be chock full of like heating elements so their brains wouldn't freeze in the cold ocean. And a brain that's processing UPCs instead of ATPs is probably not working at full efficiency. So the size of the brain is not a good way to tell how smart the animal is. It just needs to be big to be hot.

aren't the animal is just needs to be big to be hot and this all probably happened a long time ago when early cetaceans moved from like closer to land waters out into the cold ocean for millions of years uh and earth's cooling climate but of course millions of years of gradual delicate evolution are no match for a hundred years uh and or so of clumsy man-made climate change so the researchers concluded their paper by saying that if the oceans continue to get hotter, that we're probably going to have a lot of whales and dolphins with really hot brains

and that won't be good for them. Well, in the short term, it would be bad for their brains. But in the long term, if it's warmer, then their giant brains could turn extra powerful

because they don't need to stay warm all the time. They could get super brains. That's true. And then they can make an underwater civilization. Hopefully, their brains

don't just all cook instantly. Probably that's what's going to happen. Yeah. But who knows? There's billions of years left. And maybe not for us and or whales. But sure. But just in general,

like the universe will still be around. Yeah. There'll be more whales on some other planet somewhere else that somebody else can help someday. Yeah, they'll figure it out. One way or the other. Yeah. All right. That's quite cool, Sam. I liked your fact. Thanks. What does Sari have for us? Okay. We all know our brains are important because our central nervous system keeps our bodies going. And that importance comes with a cost, which is energy,

as Sam was talking about with his fact. So in healthy adults while resting, so not after a hard test or a bunch of exercise, it's generally thought that around 10 to 20% of the volume of blood being pumped out by the heart goes to the brain because those hardworking cells need a steady supply of oxygen, biochemical signals, and other nutrients carried by blood. And a lot of brain studies use fMRI,

which is functional magnetic resonance imaging, which basically relies on this fact that brain cells need oxygen and detects changes in blood flow when people are using their brains in different ways. And I've always considered fMRI like a pretty modern development, and it is generally credited to Seiji Ogawa and Ken Kwong in the 1990s. But about a century before then, the Italian physiologist Angelo Masso created a device called the human circulation balance, which was sometimes nicknamed the metal cradle or machine to weigh the soul. And those names sound a little bit mad scientist, but the idea was actually pretty good. He was studying how blood pressure and blood flow changed when we use our brains by strapping people to what was basically a carefully balanced seesaw table.

The idea being tested was that if someone used their brain and that increased blood flow to their head, you could measure that because their head would get heavier and tip the table. And Maso's results got a little hand wavy since his notes claimed that the table tipped clearly

when he rang a bell to stimulate the patient's brain, presumably like you're hearing something as opposed to not hearing something, and that it tipped clearly when he rang a bell to stimulate the patient's brain. Presumably like you're hearing something as opposed to not hearing something. And that it tipped less extremely when someone was doing light reading like a newspaper and more when they were reading a difficult philosophy book. Oh, come on. And those are such subtle differences to measure. So even with a highly sensitive technology like fMRI. So is table?

So even with a highly sensitive technology like fMRI. So his table, eh. But what is incredible to me is that the overall strategy of this machine to weigh the soul is pretty good, that brains need blood flow to work. And scientists thought so too, because two of them, David Field and Laura Inman, recreated a version of this table for a 2014 study using a scale to measure any slight tipping of the table rather than relying on their eyesight. And there was a difference of force around 0.005 to 0.01 newtons when participants were in silence and blindfolded compared to listening to music and looking at the wiggly graphics of Windows Media Player. That's fun.

So the initial takeaway here is go humans. We understand the basics of the brain and blood flow, even 100 years ago. But the deeper takeaway is that even though we've come a long way, we constantly face problems with brain measuring devices. In Maso's device, for example, to balance it, he had to use pressure monitors to account for normal things like breathing, changes in heartbeat, and humans just being fidgety when we're lying down. And in fMRI, we have to understand that brain regions serve multiple functions, and we have to decide what normal blood flow is relative to statistically significant shifts. So maybe to our future selves, fMRI will seem as quaint as the machine to weigh the soul because while blood flow is sort

of quantifiable our brains are just weird mush well now you have an unfair advantage where you can tie in your effect to the to the definition because you wrote the damn definition too oh yeah sari has an unfair advantage because she did more work i connected it back using my own brain because in my script that i wrote for myself i said our brains are so freaking complex but then i just decided woozing my what's the word improvisation improvisation improvisational skills please cut out all the bad takes there wasn't a a good take, Siri. They're all bad. You should have just said improv.

Using my improv skills. I wowed you. You're wowed. I'm wowed. That's redemption. Oh, boy. Oh, that's super cool. Like the TikTok frame, which one of these makes a better TikTok, makes this so much easier.

Because like I can sense out like story to tell. And both of those would be great TikToks. But Sari's is a better TikTok. Yeah. That is really weird because it's got like mad scientist vibes. But it turns out that the mad scientists were kind of right. And that if you look at, if you listen to music, that your head gets heavier. Yeah.

All right. Well, congratulations, Sarah. That means you are solidly the winner for this episode with the 200 points that you got for this versus Sam's 180. And that means that it's time to ask the science couch where we've got listener questions for our couch of finely honed scientific minds. This one is from at Dr.

BFF. Is there any evidence that a brain or brain-like organ evolved multiple times independently or are all brains related? Definitely not all related. Brains have, in fact, I believe, by some crazy, evolved multiple times, right? I don't know. Maybe. I think it's very contentious is what I found. Oh, all right.

It's a fight. Yeah. So we know what side found. Oh, all right. It's a fight. Yeah. So we know what side of the fight you're on. I have found at least more readings and more literature from the people that are all brains traced back to a central ancestor. Just like a worm with like an enlarged nerve spot. Exactly. Yeah. And it's not only just a worm with an enlarged area of thought, but it is a made

up worm. It's one of those situations where people like trace back taxonomic trees and they're like, there is probably an ancestor here. We probably will never find one. There was a worm. Yeah. We won't find it in the fossil record, but there was a worm. And they've named it the Erbilaterian or Erbilateria. Bilateria meaning like bilateral symmetric because they think it's the, or this proposed ancestor is the ancestor of all animals that have bilateral symmetry. So like vertebrates like us, but also other kinds of flat worms that now have brains like the invertebrates that have brains as opposed to radial symmetry which is like jellyfish that have nerd net nerve nets um or and worms worms are radially symmetrical oh yeah yeah not all not all flat worms are not really well i mean worms are a lie. There's no actual group. Oh, we just point to tubes?

Yeah. Well, yeah, then some tubes are radially symmetrical and don't have brains. Anyway, the Urbilateria, there are multiple different hypotheses of what it might look like, either if it's like a very simple worm or like it actually started differentiating body parts more similarly to like more complex bilaterally symmetric animals most people are in the camp of the simple blob which makes sense because there's a lot of complex things going on in evolution i guess the main counter argument to this being the one time brains evolved or the the original brain from which all other brains diverged is the fact that other bilaterally symmetric animals that we were joking

about but like acorn worms or nematodes or that are also radially symmetric um that don't have a brain so if they all came from this common ancestor then maybe it didn't have a brain and then brains evolved multiple times or it's possible that they evolved and lost their brains because it was not energetically favorable to have one around. And all the worm scientists seem to say, we simply have no way of knowing. But it is very controversial to say that there is a worm ancestor that had a brain. And worm scientists are up in arms at that concept, that you would say something so bold and so definite.

All right. Well, see, I was of the opinion that maybe this doesn't count, that the erbilitarian nerve cluster at the front of the worm, is that a brain? I don't know. There's just very different brains, but it does make sense to me to sort of like start at a nice solid spot, which is like, when did a nervous system first happen? And then when did a sort of centralized location of that nervous system first start to develop. Yeah, as opposed to like scattered neurons

around your body. There's like a clump. Like C. elegans neurons, which are just like basically evenly distributed throughout the organism. Sam's looking like he's not a huge fan of this kind of thought. I don't know anything about this.

There's a worm. Maybe it might've had a brain. Might thought. I don't know anything about this. There's a worm. Maybe it might've had a brain. Might not. We don't know. Is that what you said? Yeah. Yeah. In so many words.

And it kind of sounds like the scientists were also just like, don't worry about it. It's just a little worm living its little worm life. Well, they're worried about it. They want to know the answer, but sometimes you got to say like, we don't know. You got to just let it go.

Yeah. And maybe we'll find it. I think it's fine. I don't know what, I don't know anything about nematodes or brains. I got nothing to offer you. Would you time travel to find the first organism with a brain, Sam? Or would you time travel to something more interesting? I'd time travel to something considerably more interesting.

I'd time travel forward as like far as I could. Skip past some bullshit. I think that's probably what I'd be doing. Wow, that's bold. That's brave. I think time traveling any more than 100 years is like will there be anything there? Oh, when did Star Trek happen? I'd go 500 years,

minimum. Sir, Star Trek isn't like a definite. Yeah, well maybe though. You don't know until you get there. It's true. I'd rather go someplace definite where I know what I'm signing up for. And I like the idea of going back to Earl Balletaria because nothing's got teeth then. Nothing's going to eat me.

You got to be so careful. You're going to squish something that's important. They're everywhere. This whole area is covered in them. They'll just squirm all up my legs and i'll be like hello little buddy i'm taking you i'm taking you back to the present i'm gonna i'm gonna get a nobel prize it'll just be a planet of hanks and i'll be like good job hank thanks hank here's the hank prize that's how it works yeah oh lord well if you want to get the science couch to answer your question you can follow us on sci show tangents where we tweet out topics for upcoming episodes every week

several people did that uh including dr bff but also at ff55818 and at hearth homes and a bunch of other people so thank you for your questions if you like this show and you want to help us out you can do that in a bunch of different ways. But the main one, and that you will like this because you can get access to things like Poopy Peepypedia, our patron-only podcast, and Q and Bidet, our other butt-focused patron-only podcast. Look, we love butts here at SciShow Tandem. And you can become a patron and get access to those things. Also, we have a newsletter for you. We've got illustrated poems that Sam does. Just the newsletter

has an extra answer to a science question from Sari. It's great. Yeah. So much information packed into it. Yeah. You can also leave us a review wherever you listen.

We're approaching, I think, a thousand reviews on Apple podcasts. And I love to read them. I don't know if you know this, everybody, but SciShow Tangents is climbing up the charts. People are discovering us.

They love us. We're amazing. People are talking about that little science podcast. Yeah, nobody can shut up the charts. People are discovering us. They love us. We're amazing. People are talking about that little science podcast. Nobody can shut up about it. It's so good. And finally if you want to show your love for SciShow Tangents just tell people about us. Thank you for joining us. I've been Hank Green. I've been Sari Reilly. And I've been Sam Schultz.

SciShow Tangents is created by all of us and produced by Caitlin Hoffmeister and Sam Schultz who edits a lot of these episodes along with Hiroko Matsushima. Our social media organizer is Paola Garcia Prieto. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Medish. And we couldn't make any of this without our patrons on Patreon.

Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. When talking about brain sizes, like Sam was saying, scientists try to take body mass into consideration. So a given animal might have a big or a small brain on average relative to its size. And it turns out the current record holder for vertebrate with the smallest brain compared to its body is a deep sea fish called the bony-eared ass fish. I feel like we talked about this guy before for different reasons. I feel like I've heard about the bony-eared-and-ass fish, too.

There was some other humiliating thing that was wrong with him. That was not his brain, I don't think, though. But the ass part, as far as we can tell, comes from its scientific name. Right. Acanthonus armatus. Armatus referring to the weapon-like spines on its head. Acanthosus armatus, armatus referring to the weapon-like spines on its head, acanthos referring to prickly, and onus either meaning relative of a cod or donkey, which is also known as an ass. Anyway, the wrinkly preserved specimens do kind of look like pieces of shit.

Well, this was our dumbest episode yet.