{"version":"1.0.0","segments":[{"startTime":0.0,"endTime":5.84,"body":"[Music]"},{"startTime":5.84,"endTime":9.28,"body":"Welcome to episode 35 of the Language Neuroscience Podcast."},{"startTime":9.28,"endTime":14.48,"body":"I'm Stephen Wilson and I'm a neuroscientist at the University of Queensland in Brisbane, Australia."},{"startTime":14.48,"endTime":19.44,"body":"Just a quick heads up, I have a research position available in my lab right now at the University of Queensland"},{"startTime":19.44,"endTime":25.76,"body":"to work on imaging aspects of our NIH-funded project, Neural correlates of recovery from aphasia after stroke."},{"startTime":25.76,"endTime":31.52,"body":"This is a level A or B research focused postdoctoral position, which is open to international applicants"},{"startTime":31.52,"endTime":34.88,"body":"and UQ will sponsor a visa for the successful applicant."},{"startTime":34.88,"endTime":40.0,"body":"If you or anyone you know is interested, please go to langneurosci.org/join to learn more."},{"startTime":40.0,"endTime":44.88,"body":"Okay, well my guest today will need no introduction for most of our listeners."},{"startTime":44.88,"endTime":49.44,"body":"I'm really pleased to be joined by Greg Hickok, distinguished Professor of Cognitive Sciences"},{"startTime":49.44,"endTime":54.16,"body":"and Language Science at the University of California, Irvine. Greg is one of the most brilliant and"},{"startTime":54.16,"endTime":59.12,"body":"influential scientists in our field and he has a brand-new book coming out, \"Wired for words"},{"startTime":59.12,"endTime":64.96,"body":"The neural architecture of language\", coming out from MIT Press on November 25th, the same day that I'll"},{"startTime":64.96,"endTime":69.6,"body":"release this podcast episode. Today we're going to chat about the book, which lays out Greg's"},{"startTime":69.6,"endTime":74.08,"body":"up-to-date model of language processing in the brain, building on his previous work and of course"},{"startTime":74.08,"endTime":79.12,"body":"150 years of findings in our field. We'll talk about the dual streams, the sensory theory of speech"},{"startTime":79.12,"endTime":84.8,"body":"production, dorsal and ventral precentral speech areas and last but not least our diverging views"},{"startTime":84.8,"endTime":89.52,"body":"on the laterality of the ventral stream. Okay, let's get to it. How's it going?"},{"startTime":89.52,"endTime":94.08,"body":"It's going well. As well as can be trying to do science in the United States these days, but"},{"startTime":94.08,"endTime":100.8,"body":"how are things with you. Pretty good. As you know, I moved to Australia a few years ago"},{"startTime":100.8,"endTime":106.8,"body":"and how about you? Like how's your life going apart from, you know, science challenges?"},{"startTime":106.8,"endTime":111.84,"body":"Life’s pretty good. Life's pretty good. I can't complain. We have a grand kid now."},{"startTime":111.84,"endTime":118.08,"body":"Oh wow. Yeah. He is already three years old, living in Nashville, oddly enough."},{"startTime":118.08,"endTime":123.36,"body":"Oh, okay. Older daughter lives in Nashville. What's she doing there?"},{"startTime":123.36,"endTime":130.8,"body":"She's, they were in Arizona and didn't want to be in Arizona and didn't want to come to California"},{"startTime":131.36,"endTime":136.88,"body":"and settled on Nashville as a place. Okay. Is it affordable and interesting in some ways, so…"},{"startTime":136.88,"endTime":142.88,"body":"It is. Well, it's not affordable anymore, but you know, so your daughter has like really replicated"},{"startTime":142.88,"endTime":148.96,"body":"my life of moving from California to Arizona to Nashville. (Laughter) Yeah, exactly. Yeah, clearly that was"},{"startTime":148.96,"endTime":155.68,"body":"yeah. Maybe she'll hit Australia next. It'll be good for her. Not so good, but maybe not for you."},{"startTime":158.0,"endTime":163.28,"body":"Yeah. So, are you still getting to the beach a lot and taking advantage of Southern California?"},{"startTime":163.28,"endTime":170.56,"body":"Oh, yeah. Yep. I head down to the beach a couple times a week, not surfing much anymore,"},{"startTime":170.56,"endTime":178.24,"body":"but paddling. I have like a racing style canoe, like the surf skis they call them, that are just"},{"startTime":178.24,"endTime":184.24,"body":"kind of like an outrigger without the outrigger. So, I go paddle that around for a few hours"},{"startTime":184.24,"endTime":189.76,"body":"a couple times a week. Okay. So, that's more your speed than surfing these days? Well, yeah, it's just"},{"startTime":189.76,"endTime":195.04,"body":"easier to get out there and you know, it's gotten crowded in the water and sharky, you know, it's gotten,"},{"startTime":195.04,"endTime":201.2,"body":"it's, you see sharks out there now. Oh, wow! More like Australia. So, yeah, great whites. So,"},{"startTime":201.2,"endTime":205.84,"body":"oh, goodness. Yeah, I'm good with, with paddling and canoeing around here and out."},{"startTime":205.84,"endTime":212.24,"body":"Kayak around. Okay. Yeah, there's been quite a few shark attacks in Australia this year."},{"startTime":212.96,"endTime":219.68,"body":"Pretty, pretty shocking ones sometimes. But it doesn't stop my family from playing in the water."},{"startTime":219.68,"endTime":229.28,"body":"Right. Yeah. Yeah, exactly. Okay. So, you've got a book that's coming out. We're going to chat about"},{"startTime":229.28,"endTime":233.84,"body":"that. When is the, do you know when the book is coming out? Like when's it going to be officially released?"},{"startTime":233.84,"endTime":239.76,"body":"Yes, it’s coming out I think the 24th or something. Okay. A couple weeks from now."},{"startTime":239.76,"endTime":244.72,"body":"Okay. So, just for context, we're talking on the 13th for me, 12th for you."},{"startTime":244.72,"endTime":248.72,"body":"And so, yeah, it usually takes me at least a week to edit anyway. So, we'll"},{"startTime":248.72,"endTime":253.12,"body":"release our conversation on the same day that your book gets released."},{"startTime":253.12,"endTime":258.96,"body":"That's awesome. And yeah, it was really fortuitous because like I emailed you to see if you wanted"},{"startTime":258.96,"endTime":264.96,"body":"to chat and not knowing that you had the book coming out and then learned that you did and"},{"startTime":264.96,"endTime":270.48,"body":"that was perfect because I've got a chance to, you know, read your current opinions about all these"},{"startTime":270.48,"endTime":277.12,"body":"things that you've been working on for 25, 30 years. And then it gives us kind of, you know, a big,"},{"startTime":277.12,"endTime":282.88,"body":"big picture thing to talk about. So, yeah, thanks for making the time to talk with me."},{"startTime":282.88,"endTime":288.56,"body":"Yeah, of course. I'm excited to do it. I think you're the first person I've talked to about the book"},{"startTime":288.56,"endTime":297.84,"body":"besides a few couple students. Oh, that's cool. Yeah. Media. The first and only podcast about the"},{"startTime":297.84,"endTime":306.8,"body":"scientific study of language in the brain. So, what is your book? Is it a textbook, a memoir,"},{"startTime":306.8,"endTime":313.6,"body":"or something in between? I think it's definitely not a textbook, although it's, so I wrote it,"},{"startTime":313.6,"endTime":318.48,"body":"I wrote it with my students in mind. I've been teaching this course, Language in the Brain at UCI,"},{"startTime":318.48,"endTime":326.16,"body":"since 1997. And there's no textbook; there wasn't what I thought of writing this book and I"},{"startTime":326.16,"endTime":333.12,"body":"decided I would write a textbook myself and pitched it to MIT Press back in probably 1999 and"},{"startTime":333.12,"endTime":341.04,"body":"it got approved and I got a contract around the year 2000 to do it. But then that was around the"},{"startTime":341.04,"endTime":345.12,"body":"time when David Poeppel and I were developing the dual street model and I'm like, oh my god,"},{"startTime":345.12,"endTime":349.6,"body":"I had to figure out how this stuff is working before I can write a textbook on brain and language."},{"startTime":349.6,"endTime":354.8,"body":"And then time got away, and I kept working on other things and"},{"startTime":354.8,"endTime":363.68,"body":"wrote a book in between but then decided I owed MIT Press this book. So, I got back to it in 2016 or so."},{"startTime":363.68,"endTime":369.36,"body":"And by then David Kemmerer had his book out textbook, which is quite good and there was no point"},{"startTime":369.36,"endTime":375.2,"body":"of writing another textbook. So, I decided to make it a kind of, that's a pretty high paise, to David"},{"startTime":375.2,"endTime":379.44,"body":"Kemmerer, by the way. Like, he'd already written one, so there's no point writing another one, but yeah."},{"startTime":379.44,"endTime":384.72,"body":"Yeah, I thought it was quite good. David and I joke that his description of the dual stream model"},{"startTime":384.72,"endTime":391.04,"body":"was way better than ours. (Laughter) We thought it was pretty, you know, it was pretty good. So yeah, no one"},{"startTime":391.04,"endTime":396.96,"body":"like his textbook too. Yeah, I asked MIT Press if I could editor there, if I could just write a"},{"startTime":396.96,"endTime":406.48,"body":"monograph kind of my view of the world of brain and language and I wrote it basically as the"},{"startTime":406.48,"endTime":413.04,"body":"following the content of my course and tried to make it accessible to undergraduates at least"},{"startTime":413.04,"endTime":418.32,"body":"with some guidance. So that was kind of my target for this book. Yeah, so it's kind of in between."},{"startTime":418.32,"endTime":423.6,"body":"Yeah, and so having taken a look at it and I can share with our listeners that,"},{"startTime":423.6,"endTime":432.72,"body":"okay, first of all, you should definitely read it. I loved it. It's for many reasons. One of which is"},{"startTime":432.72,"endTime":439.76,"body":"just it's written in such a accessible conversational way, right? So, like I so I know you and I've been"},{"startTime":439.76,"endTime":446.24,"body":"chatting with you for decades, believe it or not. But I really when I read it, I just hear your voice,"},{"startTime":446.24,"endTime":451.12,"body":"you know, like it's just like this is Greg talking and it doesn't, it doesn't read stuffy at all."},{"startTime":451.12,"endTime":455.04,"body":"It just kind of reads like, well, there's what I thought and then I thought I might be wrong. So, then we"},{"startTime":455.04,"endTime":460.8,"body":"tried this and it turned out I wasn't wrong. I was definitely right all along. (Laughter) So, you know what I mean?"},{"startTime":460.8,"endTime":464.48,"body":"Yeah, yeah. Did you do that deliberately or is that just the only way you can write?"},{"startTime":464.48,"endTime":471.36,"body":"It's kind of my style. But yeah, I did want to make it accessible and interesting. I don't"},{"startTime":471.36,"endTime":476.24,"body":"stuffy textbooks are just kind of boring to read and scientific papers are kind of boring to read."},{"startTime":477.52,"endTime":482.08,"body":"And I just wanted something where I could go through this stuff without, without pulling punches on"},{"startTime":482.08,"endTime":487.84,"body":"the details, but trying to make it accessible to people who were interested, really interested in"},{"startTime":487.84,"endTime":493.04,"body":"understanding bits and pieces about this system worked. And it's really not just for it. It's not"},{"startTime":493.04,"endTime":497.84,"body":"just for undergrads by any means, right? I mean, I think that there's like, you know, I think that"},{"startTime":497.84,"endTime":504.16,"body":"all of our colleagues in the field could take a lot from this book. Yeah, that's right. I wrote it"},{"startTime":504.16,"endTime":511.2,"body":"accessible to undergraduates, but I when I was thinking I was writing these arguments and"},{"startTime":511.2,"endTime":517.92,"body":"referencing everything so that it would be a perfectly legitimate argument for the practicing"},{"startTime":517.92,"endTime":524.32,"body":"scientists for sure. Yeah, cool. So, I don't know if you've ever listened to my podcast, but I always"},{"startTime":524.32,"endTime":528.72,"body":"kind of like to talk to people about how they got into the field, how they developed their interests."},{"startTime":528.72,"endTime":532.8,"body":"And you sort of tell us a bit in the start of the book and I'll read a quote here. It says,"},{"startTime":533.36,"endTime":537.2,"body":"\"This is a book about the biology of language, my primary area of research."},{"startTime":537.2,"endTime":540.72,"body":"Oddly enough, I never much liked the topic during my college years.\""},{"startTime":540.72,"endTime":547.76,"body":"And then you go on to explain how you got interested in the neuroscience of language. So can you just"},{"startTime":547.76,"endTime":555.52,"body":"share that back story with us? Yeah, sure. So, I was interested in mind and brain as an undergraduate,"},{"startTime":555.52,"endTime":562.72,"body":"and anything mind and brain fascinated me except the language stuff. I was in psychology classes,"},{"startTime":562.72,"endTime":568.48,"body":"because you take classes and learn about language. And a lot of it is just like, \"Oh, there's these"},{"startTime":568.48,"endTime":572.4,"body":"nouns and verbs, and then there's phrase structure, and there's this and that and it's just like,"},{"startTime":572.4,"endTime":580.0,"body":"yeah, it never excited me. It was nothing I was interested in. So, yeah, it didn't, it bored me,"},{"startTime":580.0,"endTime":585.2,"body":"and like I said in the book, I remember picking up a copy of a neuropsychology book and"},{"startTime":585.2,"endTime":590.0,"body":"realizing that if I wanted to do neuropsychology someday, I'd probably have to learn about these"},{"startTime":590.0,"endTime":595.76,"body":"aphsias and stuff. And I was like, all right, fine, I'll learn about it, whatever. But yeah, but then I"},{"startTime":595.76,"endTime":603.28,"body":"happened to get into grad school at Brandeis University where the advisor that I would be, a, work with"},{"startTime":603.28,"endTime":608.4,"body":"doing neuropsychology was Edgar Zurif. He was a famous aphasiologist, and I was like, Okay, I guess"},{"startTime":608.4,"endTime":615.6,"body":"I'm learning language. But how did you get paired up with Zurif if you weren't interested in language?"},{"startTime":617.44,"endTime":623.12,"body":"That's an accident, actually. So, I was applying to grad school. I applied to MIT, Johns Hopkins,"},{"startTime":623.12,"endTime":629.84,"body":"I wanted to work with the neuropsychologist in those kinds of places. My undergraduate advisor"},{"startTime":629.84,"endTime":635.92,"body":"was someone named Mary Louise Cain, who was an aphasiologist, and I was doing face perception"},{"startTime":635.92,"endTime":641.68,"body":"research with her because that was interesting to me. And I was applying to programs, and she said,"},{"startTime":641.68,"endTime":646.56,"body":"Hey, you should apply to Brandeis. That's a good program, and Edgar Zurif is there. And I was like,"},{"startTime":646.56,"endTime":651.84,"body":"Well, I don't really want to do language, but okay. And that's the program I got into. I didn't get"},{"startTime":651.84,"endTime":657.28,"body":"in at any other place. And so that's where I went. And so, I started learning language."},{"startTime":657.28,"endTime":664.08,"body":"That's like just an interesting little side note there. Isn't it? For those listeners who are struggling"},{"startTime":664.08,"endTime":667.92,"body":"to get into grad school and wondering what grad school they're going to get into and sending"},{"startTime":667.92,"endTime":674.96,"body":"all these applications. You only got into one grad school and then go on to become you. (Laughter)"},{"startTime":674.96,"endTime":681.84,"body":"Yeah, it was my backup plan, and I got in and said, Okay, I'm going to do this, I guess."},{"startTime":681.84,"endTime":687.92,"body":"That's great. That's a great story. So, I mean, so did Edgar you interested in it?"},{"startTime":687.92,"endTime":694.0,"body":"You know who got me interested in it? I tried to read some of his papers before arriving in"},{"startTime":694.0,"endTime":699.92,"body":"Massachusetts in Boston. And it was just this still wasn't that interesting to me. I was reading his"},{"startTime":699.92,"endTime":706.32,"body":"papers and, alright, whatever. But I took a course on graduate syntax by Jane Grimshaw."},{"startTime":706.32,"endTime":716.56,"body":"And she's a well-known linguist doing syntax. And I just jumped in, and she taught the course and"},{"startTime":716.56,"endTime":720.96,"body":"I remember the very first assignment, homework assignment I got where we had to analyze some"},{"startTime":720.96,"endTime":727.28,"body":"sentence structure. And I remember going to one of my fellow grad students and saying,"},{"startTime":727.28,"endTime":731.92,"body":"I don't even have any idea what format an answer is supposed to look like. It was a phrase"},{"startTime":731.92,"endTime":738.64,"body":"structure kind of set of rules that they were looking for that she was looking for. And that was my"},{"startTime":738.64,"endTime":744.4,"body":"beginning. But what I learned from Jane was really important things. That language is this kind"},{"startTime":744.4,"endTime":749.76,"body":"of internal system that generates these things. It's part of how the mind works and how language"},{"startTime":749.76,"endTime":756.64,"body":"gets learned and processed. And I realized that it was really interesting. That it wasn't what I"},{"startTime":756.64,"endTime":762.4,"body":"thought it was. And so, I got interested. And then kind of went into hardcore, not syntax syntax,"},{"startTime":762.4,"endTime":768.32,"body":"but I did straight up psycholinguistics. And when I finally did start diving into aphasiology,"},{"startTime":768.32,"endTime":776.16,"body":"it was grounded in serious, Chomskyan kind of theoretical syntax, if you read my early papers."},{"startTime":776.16,"endTime":783.52,"body":"Yeah, I have done. Sorry, my dog's just decided to start barking at nothing probably."},{"startTime":783.52,"endTime":792.72,"body":"Molly! I can edit that out. I can't even hear it. Yeah, Zoom cancels these things."},{"startTime":792.72,"endTime":798.48,"body":"Okay, so yeah, no, I've read those papers of yours from the late 90s. It doesn't read like later"},{"startTime":798.48,"endTime":807.76,"body":"Greg, but like it's like formative, right? Yeah, yeah, I was another interesting story. So, I took,"},{"startTime":807.76,"endTime":815.2,"body":"as a third year graduate student at Brandeis, I took a course by Steve Pinker and Ellen Prince,"},{"startTime":815.2,"endTime":821.52,"body":"who were then all about the past tense and, you know, connectionist and critiques and all that sort of"},{"startTime":821.52,"endTime":830.4,"body":"thing. And as my project, my paper project for that course, I did a paper proposing an experiment"},{"startTime":830.4,"endTime":838.96,"body":"in aphasia studying past tense production. And Steve liked it and eventually invited me to"},{"startTime":838.96,"endTime":844.56,"body":"become a postdoc at MIT with him, the new McDonnell-Pew Center for Cognitive Neuroscience,"},{"startTime":844.56,"endTime":850.24,"body":"which I went and did. But I wasn't terribly interested in doing aphasiology,"},{"startTime":850.24,"endTime":855.04,"body":"ended up working with Ted Gibson on some straight up psycholinguistic stuff. And at the end of my"},{"startTime":855.04,"endTime":861.44,"body":"first year, they were going to kick me out of MIT because I wasn't doing neuroscience, but I was"},{"startTime":861.44,"endTime":865.52,"body":"just doing straight up kind of cognitive stuff. Why didn't they kick Ted out then? (Laughter)"},{"startTime":865.52,"endTime":871.84,"body":"Well, he, yeah, no, he was a graduate student, no, he was a postdoc. I don't know, he probably should"},{"startTime":871.84,"endTime":878.08,"body":"have. (Laughter) He might have been in under a different program or something, I don't remember. But anyway,"},{"startTime":878.08,"endTime":884.32,"body":"so, I decided that I would start doing syntax and brain and that's kind of the, they told me that I"},{"startTime":884.32,"endTime":889.84,"body":"could stay another year if I just started doing that. So that's how it started. Yeah, I didn't know"},{"startTime":889.84,"endTime":894.96,"body":"that. I didn't know that back story. That's interesting. So then, so that's how you kind of got into it."},{"startTime":894.96,"endTime":901.84,"body":"Now, in the book you talk about, in the preface, you say, you have a tendency, I wouldn't"},{"startTime":901.84,"endTime":908.32,"body":"quote again, like, you have a tendency to frame the issues in historical context. And I really like that"},{"startTime":908.32,"endTime":916.08,"body":"approach. That's, that's the way that I think too. But as you note, I quote, some readers don't necessarily"},{"startTime":916.08,"endTime":920.4,"body":"want this kind of framing, preferring instead to just get the facts of the modern understanding without"},{"startTime":920.4,"endTime":926.48,"body":"mulling over the old ideas and results. So why do you think it's good, why do you think it's good"},{"startTime":926.48,"endTime":933.36,"body":"to think this way? And why do you think this way? I naturally like history. So, I'll go back and see,"},{"startTime":933.36,"endTime":938.72,"body":"you know, what happened back in the day. That's just fun for me. But I found that it's useful because"},{"startTime":938.72,"endTime":945.52,"body":"it shows you things about where these ideas came from and what kinds of ideas got rejected,"},{"startTime":945.52,"endTime":950.56,"body":"why, and sometimes for the wrong reasons. So sometimes what happens in a field is,"},{"startTime":950.56,"endTime":956.08,"body":"is someone comes along and says, Oh, no, that's a bad idea. And here's why and everyone buys it. But"},{"startTime":956.08,"endTime":963.6,"body":"the argument is bogus. But then the idea is gone, and everyone's forgotten it. So, going back and seeing"},{"startTime":963.6,"endTime":969.76,"body":"what the ideas were, where they came from originally, why they were rejected or accepted. And then,"},{"startTime":969.76,"endTime":974.72,"body":"you know, moving forward, it gives you a broader perspective on the various, the range of ideas and"},{"startTime":974.72,"endTime":980.88,"body":"arguments. And I found plenty of flaws in old arguments as I try to detail in the book"},{"startTime":983.12,"endTime":989.04,"body":"that helped me understand why we have the biases that we do today and how we can move forward"},{"startTime":989.04,"endTime":996.64,"body":"most productively. So, I'm happy to tell. Yeah, I appreciate that framing of everything in your"},{"startTime":996.64,"endTime":1004.8,"body":"in your book and in your work in general. And so again, at the start of the book, you talk about"},{"startTime":1004.8,"endTime":1009.92,"body":"how the human brain is specialized for language, which is something that we would obviously agree on"},{"startTime":1009.92,"endTime":1014.72,"body":"and the most of our listeners would probably agree on. And you raised this interesting question about"},{"startTime":1014.72,"endTime":1021.12,"body":"whether it evolved from scratch or did it evolve by tinkering with what was lying around. So, can"},{"startTime":1021.12,"endTime":1024.96,"body":"you kind of share like, what's your perspective on that and what ramifications does it have for"},{"startTime":1024.96,"endTime":1032.4,"body":"understanding the neurobiology of language? Yeah, so it's always been difficult to be a student"},{"startTime":1032.4,"endTime":1036.8,"body":"of the neurobiology of language. Whereas if you're a setting vision, we can go and study cats or"},{"startTime":1036.8,"endTime":1043.44,"body":"macaques or we have all this information from other homologous visual systems where we can kind of"},{"startTime":1043.44,"endTime":1048.16,"body":"jumpstart the process of understanding how things are working in humans. I grew up with the"},{"startTime":1048.16,"endTime":1056.24,"body":"the idea, the belief that there was no homologue. There was no animal model for language."},{"startTime":1056.24,"endTime":1062.48,"body":"You know, obviously, because we're the only speaking animal, at least at the level of sophistication"},{"startTime":1062.48,"endTime":1070.08,"body":"that we have in the world. So how do we make progress? And then if that's true for the only speaking"},{"startTime":1070.08,"endTime":1075.6,"body":"animal or linguistic animal, how did we get it? How did it start? And that's been, of course, a fundamental"},{"startTime":1075.6,"endTime":1084.64,"body":"question that people had wondered about for a long time. So, it's just a fundamental question about"},{"startTime":1084.64,"endTime":1090.96,"body":"how language evolved. And the problem is that evolution doesn't really work like that. It doesn't"},{"startTime":1090.96,"endTime":1096.56,"body":"work by inventing brand new things. It tinkers with existing systems, modifies them, and it can"},{"startTime":1096.56,"endTime":1103.68,"body":"modify them through descent quite substantially so that they become quite unique. But they have to"},{"startTime":1103.68,"endTime":1107.84,"body":"come from somewhere. So where did language come from? And people that propose various ideas. But"},{"startTime":1107.84,"endTime":1115.84,"body":"yeah, that's kind of the, the basic problem with that issue. And why I think the approach that I've"},{"startTime":1115.84,"endTime":1123.12,"body":"taken kind of helps solve that in some ways. Yeah. So, you basically, you're perspective, and which I"},{"startTime":1123.12,"endTime":1130.16,"body":"share is that it evolved by tinkering. And that ends up having, then as you kind of explore all the"},{"startTime":1130.16,"endTime":1135.36,"body":"different aspects of the language network, you always kind of relate them to other principles of"},{"startTime":1135.36,"endTime":1140.96,"body":"neuroscience or principles of brain organization in different modalities and systems. Yeah."},{"startTime":1142.48,"endTime":1149.04,"body":"Yeah, for sure. I think this was a natural thing for me to do. I didn't consciously"},{"startTime":1149.04,"endTime":1157.36,"body":"start doing this. But back in the 90s, I was reading Milner and Goodale’s book on the two visual"},{"startTime":1157.36,"endTime":1165.04,"body":"streams, the visual brain in action, I think it's called. And I saw a lot of parallels to language."},{"startTime":1165.04,"endTime":1170.88,"body":"And so that's kind of drew me to start thinking about language in those terms. And it helped me"},{"startTime":1170.88,"endTime":1178.32,"body":"organize how I thought about very a wide range of data in aphasiology and in functional imaging."},{"startTime":1178.32,"endTime":1183.52,"body":"And ultimately led to the dual stream model that David and I proposed in the 2000s."},{"startTime":1183.52,"endTime":1189.36,"body":"And so, I realized that that kind of approach, thinking in terms of evolutionary homologies,"},{"startTime":1189.36,"endTime":1195.84,"body":"was helping me think of things that I wouldn't have thought of otherwise and to develop hypotheses to"},{"startTime":1195.84,"endTime":1204.56,"body":"test. And they turned out to be reasonably accurate in my view. So yeah. I think it's a really helpful"},{"startTime":1204.56,"endTime":1209.84,"body":"approach. Yeah, cool. So, let's kind of start talking about the model that you develop in this book."},{"startTime":1209.84,"endTime":1214.96,"body":"And it's got several different components to it. But like you just mentioned the dual stream model."},{"startTime":1214.96,"endTime":1219.84,"body":"And obviously that's what you're very well known for. And it's also a prominent part of this book."},{"startTime":1221.44,"endTime":1228.56,"body":"You know, your 2007 paper has almost 7000 citations and the earlier papers have many thousands as well."},{"startTime":1228.56,"endTime":1235.68,"body":"And this kind of like pervades, I'd say the first half of the book. So can you talk about,"},{"startTime":1235.68,"endTime":1241.12,"body":"you know, the dual stream concept in the visual domain just for, you know, briefly for those that"},{"startTime":1241.12,"endTime":1248.8,"body":"are familiar with it and then kind of talk about how you develop those concepts in the language domain."},{"startTime":1249.68,"endTime":1256.32,"body":"Yeah, sure. So, in the visual domain, it's conceptually the argument is pretty simple. So, as you're looking at"},{"startTime":1256.32,"endTime":1261.28,"body":"Stephen's image in the video here, you see a microphone sitting there in front of him."},{"startTime":1261.28,"endTime":1267.2,"body":"And there's two things you can do with that information. You know, conceptually, one is that you can"},{"startTime":1267.2,"endTime":1272.88,"body":"look at it and understand what it is and map it to some semantic representation and understand that it is a"},{"startTime":1272.88,"endTime":1278.8,"body":"a recording amplification device and it's doing something. It's meaningful to you. On the other"},{"startTime":1278.8,"endTime":1284.24,"body":"hand, if you are in the room with Stephen, you could reach out and grab it. Now, those two tasks are"},{"startTime":1284.24,"endTime":1289.92,"body":"fundamentally different. It's going to be a microphone, whether it is in its place now, whether it was"},{"startTime":1289.92,"endTime":1296.08,"body":"above Stephen's head, lying on the table, upside down, it's still a microphone, no matter its position"},{"startTime":1296.08,"endTime":1301.52,"body":"in space or orientation, and maybe there's a little mini microphone. That's, you know, same semantic"},{"startTime":1301.52,"endTime":1308.08,"body":"category, but different size and shape. So, it doesn't change the semantic content, but what it does do is"},{"startTime":1308.08,"endTime":1313.04,"body":"change the way you might interact with that if you're going to reach and pick it up. So, all those features"},{"startTime":1313.04,"endTime":1318.56,"body":"that don't matter for categorizing semantically, suddenly matter for everything when you're trying to"},{"startTime":1318.56,"endTime":1325.84,"body":"reach and grasp it. So, the idea there is that the brain perceives information and processes it"},{"startTime":1325.84,"endTime":1331.44,"body":"along two different streams, one for concept, conceptual understanding. That's the ventral stream"},{"startTime":1331.44,"endTime":1336.4,"body":"and one for motorically interacting with that object. So that's ‘the what’ and ‘the how’ stream"},{"startTime":1336.88,"endTime":1342.72,"body":"respectively. So that's the visual domain and arguments were laid out nicely by Milner and Goodale."},{"startTime":1342.72,"endTime":1350.16,"body":"I encourage folks to read it. And it occurred to me that something very similar is happening in"},{"startTime":1350.16,"endTime":1354.64,"body":"in speech and language. So, as you're listening to my words, there's two different things you can do"},{"startTime":1354.64,"endTime":1363.6,"body":"with them. You can hear them for and understand them, or you can take those perceptual signals, those"},{"startTime":1363.6,"endTime":1369.2,"body":"phonemic sequences and map them onto your own motor system so that you can say the same words. And"},{"startTime":1369.2,"endTime":1375.6,"body":"obviously, we do that in development as part of learning because you hear speech words and speech"},{"startTime":1375.6,"endTime":1380.48,"body":"sounds in the environment and you figure out not only how to make sense of them in terms of their"},{"startTime":1380.48,"endTime":1385.36,"body":"meaning, but you figure out how to be able to reproduce those words in those phonemic patterns"},{"startTime":1385.36,"endTime":1392.96,"body":"yourself. So those are two separate kind of mappings, which we hypothesized were a ventral and"},{"startTime":1392.96,"endTime":1401.44,"body":"a dorsal stream system. And that was kind of the foundation for thinking about speech processing"},{"startTime":1401.44,"endTime":1407.68,"body":"in terms of these two streams. Yeah, cool. And so, you know, you talk about that historical"},{"startTime":1407.68,"endTime":1413.04,"body":"perspective that you bring to everything, and you know in your papers from the first decade of"},{"startTime":1413.04,"endTime":1418.8,"body":"century as well as in this book, the relationship between the dual stream concept and"},{"startTime":1418.8,"endTime":1423.2,"body":"Wernike-Lichtheim model. So can you talk a bit about like, you know, to what extent were those old"},{"startTime":1423.2,"endTime":1429.52,"body":"guys barking up the right tree and what and where did they kind of not quite have it right?"},{"startTime":1429.52,"endTime":1437.12,"body":"Yeah, so Wernike sometimes doesn't get respect in the modern world. We all know that it's not"},{"startTime":1437.12,"endTime":1443.12,"body":"right in all details and there's a tendency when you know models aren't working very well for this"},{"startTime":1443.12,"endTime":1449.2,"body":"or that you toss them out. They don't do anything for syntax, or you know any of the more complicated"},{"startTime":1449.2,"endTime":1455.36,"body":"linguistic things that we think about these days. But they were onto something. That Wenike’s"},{"startTime":1455.36,"endTime":1460.88,"body":"model was the first dual stream model that predates the visual. We always think of the Hickok-Poeppel"},{"startTime":1460.88,"endTime":1467.52,"body":"dual stream model is derivative of the, I always thought this derivative of the Milner-Goodale"},{"startTime":1467.52,"endTime":1472.32,"body":"two visual streams going back further, Ungeleider and Mishkin model with the ‘What, Where’ system."},{"startTime":1473.12,"endTime":1478.8,"body":"But Wernike proposed essentially a dual stream model where you had information coming into"},{"startTime":1478.8,"endTime":1483.76,"body":"the auditory cortex. It was sent in two different directions. One was to the motor system, one was to"},{"startTime":1483.76,"endTime":1489.6,"body":"the conceptual system. That is essentially the dual stream model. And in fact, our dual stream model"},{"startTime":1489.6,"endTime":1495.84,"body":"was merely an elaboration and reframing and updating of Wernike’s original model. So, I don't"},{"startTime":1495.84,"endTime":1500.8,"body":"take credit for that at all. I think it was already there in the literature. And he even talked about"},{"startTime":1500.8,"endTime":1508.56,"body":"important concepts like what we today call feedback control in motor planning. He talked about it in"},{"startTime":1508.56,"endTime":1514.72,"body":"terms of a corrective function of the auditory system on motor cortex. So, it was quite advanced at the"},{"startTime":1514.72,"endTime":1522.32,"body":"time. Absolutely. Yeah. I like how you always draw those connections throughout the book to the"},{"startTime":1522.32,"endTime":1529.28,"body":"history of all the ideas that you talk about. So, I think that probably most people would,"},{"startTime":1530.0,"endTime":1534.08,"body":"I'd like to talk more about the ventral stream. And that's kind of the question that I raised"},{"startTime":1534.08,"endTime":1541.04,"body":"that I wanted to talk to you about, especially laterality. But maybe saving that for later in"},{"startTime":1541.04,"endTime":1548.4,"body":"our discussion. But moving forward with the dorsal stream that perhaps is sometimes a less of a focus"},{"startTime":1548.4,"endTime":1553.6,"body":"of other people reading your work, but I think might be very much a focus of your own interest,"},{"startTime":1553.6,"endTime":1559.28,"body":"especially in this book. I think you really develop your dorsal stream ideas more. So, can you"},{"startTime":1559.92,"endTime":1564.32,"body":"let's, can we talk about what goes on in the dorsal stream and you kind of describe it as the"},{"startTime":1564.32,"endTime":1568.32,"body":"sensory theory of speech production. So, what's that all about?"},{"startTime":1568.32,"endTime":1574.48,"body":"Yeah. So, one important thing just as a prerequisite before we start talking about this is the"},{"startTime":1574.48,"endTime":1580.96,"body":"dual stream model as David and I developed it and as later, Rauschecker and Scott developed it"},{"startTime":1580.96,"endTime":1588.72,"body":"in their version of this, it only makes sense from the perspective of auditory perception. So the"},{"startTime":1588.72,"endTime":1594.48,"body":"dual stream model is a very perceptually grounded model. And I think people misunderstood it and took it"},{"startTime":1594.48,"endTime":1600.64,"body":"as a model of language processing in general. Like some people I remember would say, oh, the"},{"startTime":1600.64,"endTime":1605.04,"body":"dorsal stream is involved in phonological processing. So, the way that we comprehend words"},{"startTime":1605.04,"endTime":1610.08,"body":"is we take phonological information, process it in the dorsal stream, and then you come back into"},{"startTime":1610.08,"endTime":1615.76,"body":"the ventral stream for comprehension. But that's not at all what we were saying. So, it's important to"},{"startTime":1615.76,"endTime":1622.64,"body":"think about the dual stream model as making sense from the perspective of the auditory system."},{"startTime":1622.64,"endTime":1626.48,"body":"From the auditory system, speech information comes in and it can go in two different ways."},{"startTime":1626.48,"endTime":1633.12,"body":"If we're just talking about producing speech, naming pictures, natural volitional production,"},{"startTime":1633.12,"endTime":1636.88,"body":"dual stream model doesn't make much sense because you're going from concepts wherever they're"},{"startTime":1636.88,"endTime":1642.88,"body":"represented and we have ideas that I laid out in the book to kind of morphosyntactic or"},{"startTime":1642.88,"endTime":1649.12,"body":"lemma level things to phonological level things and then on out to the motor system in for speech"},{"startTime":1649.12,"endTime":1657.04,"body":"motor planning and such. And that's just one stream from concept to lemmas to phonological output."},{"startTime":1657.04,"endTime":1661.6,"body":"And there's no dual stream involved at all. It involves in fact both of the systems that we"},{"startTime":1661.6,"endTime":1666.16,"body":"talk about in terms of the dual stream, the ventral and the dorsal part. So that's the first thing."},{"startTime":1666.72,"endTime":1674.08,"body":"So, what's the point of the dorsal stream? So, the idea there is that it was mostly developed to"},{"startTime":1674.08,"endTime":1679.2,"body":"kind of explain the architecture of the phonological system for speech production."},{"startTime":1679.2,"endTime":1686.0,"body":"And the basic idea is derived from another field motor control, that motor control theory,"},{"startTime":1686.0,"endTime":1692.08,"body":"which is all about hitting sensory targets with your actions. So again, let's think about"},{"startTime":1692.08,"endTime":1699.28,"body":"reaching and grasping. So, if you're going to reach for Stephen’s microphone, you are taking a sensory"},{"startTime":1699.28,"endTime":1705.12,"body":"information about its location and its orientation and its size and you're using that to guide some action"},{"startTime":1705.12,"endTime":1711.52,"body":"towards it. So, it's if you didn't know that sensory information, you could never plan the sensory"},{"startTime":1711.52,"endTime":1720.24,"body":"movements or the motor actions to do the coding. So, movement planning is grounded in sensory systems"},{"startTime":1720.24,"endTime":1726.48,"body":"in that sense. So, the idea is that linguistic processing is grounded in a similar way. So when"},{"startTime":1726.48,"endTime":1733.52,"body":"we're producing a word for a microphone, say, even though it's not physically out in the environment,"},{"startTime":1733.52,"endTime":1738.56,"body":"there is a sensory or an auditory related code for that sound pattern that's stored in your brain"},{"startTime":1738.56,"endTime":1744.32,"body":"because you've heard that word over again in auditory related cortex. And so that is the target"},{"startTime":1744.32,"endTime":1749.76,"body":"that your the sensory related target that your phonological planning system is aiming to hit."},{"startTime":1749.76,"endTime":1757.12,"body":"So to speak. And so it relies on this posterior auditory related target that is then translated into"},{"startTime":1757.12,"endTime":1762.64,"body":"motor phonological plans and then executed. So that's kind of what the function of the dorsal"},{"startTime":1762.64,"endTime":1769.84,"body":"stream is, is to integrate posterior targets that are sensory related in an abstract way"},{"startTime":1769.84,"endTime":1778.0,"body":"to motor plans for hitting those targets. Yeah. Okay, that's so fundamental. And you know,"},{"startTime":1778.0,"endTime":1782.96,"body":"you give this really nice example in the book that I think drives home why this is the right way to"},{"startTime":1782.96,"endTime":1788.08,"body":"think about things. And it involves putting a pencil in your mouth. And so, like our listeners are"},{"startTime":1788.08,"endTime":1792.0,"body":"not going to see this because it's an audio podcast, but I have a pencil on going to put it in my mouth."},{"startTime":1792.0,"endTime":1797.84,"body":"And your point is that you put a pencil in your mouth that you can still talk. And so I'm going"},{"startTime":1797.84,"endTime":1802.16,"body":"to try that right now. I'm going to put the pencil in my mouth. Okay, now holding a pencil"},{"startTime":1802.16,"endTime":1808.72,"body":"return why taste and I can still quite effectively produce a sentence that should be intelligible."},{"startTime":1808.72,"endTime":1814.88,"body":"And that shows and I had to make some very dramatic motor accommodations to achieve that which I"},{"startTime":1814.88,"endTime":1821.2,"body":"was completely, which was completely subconscious obviously. But I think it's a powerful demonstration"},{"startTime":1821.2,"endTime":1828.0,"body":"of this concept that like in speech production we are trying to reach sensory goals and that we've"},{"startTime":1828.0,"endTime":1834.4,"body":"got this system that's very flexibly able to do that. Yeah. Yeah, that's right. That's a good example."},{"startTime":1834.4,"endTime":1841.84,"body":"We it's not just that we are controlling the position and trajectory of articulators. We are"},{"startTime":1841.84,"endTime":1846.96,"body":"aiming for an auditory target which is a point that Frank Guenther has made repeatedly and done a"},{"startTime":1846.96,"endTime":1852.48,"body":"great job demonstrating that. And you see that in lots of other paradigms too like ultra-auditory"},{"startTime":1852.48,"endTime":1857.6,"body":"feedback (UAF), where we will quickly accommodate to perturbations and what we think we hear"},{"startTime":1857.6,"endTime":1864.0,"body":"or say or what we are hearing us ourselves saying artificially. So yeah, lots of evidence for that."},{"startTime":1864.0,"endTime":1870.0,"body":"But the pencil test is the easiest demonstration. Yeah, it makes the point very strongly. So how did"},{"startTime":1870.0,"endTime":1878.08,"body":"you get interested in how did you come to work on this particular question of like how these auditory"},{"startTime":1878.08,"endTime":1885.44,"body":"motor transformations in speech production? Yeah, so we had proposed the dual stream model and the"},{"startTime":1885.44,"endTime":1890.96,"body":"dorsal stream involved three main components. There was like a phonological target system which is"},{"startTime":1890.96,"endTime":1897.36,"body":"basically we think of as the superior,  posterior superior temporal sulcus which stores the sound related"},{"startTime":1897.36,"endTime":1903.12,"body":"phonological representations of words. Then there's motor phonological plans that is the motor plans"},{"startTime":1903.12,"endTime":1908.24,"body":"whatever format they are in aimed at hitting those targets and a translation system in between."},{"startTime":1908.24,"endTime":1913.2,"body":"And the reason why I ended up focusing on the dorsal stream so much is because that was the one"},{"startTime":1913.2,"endTime":1919.44,"body":"part of the model that we didn't have direct evidence for. We proposed an in-between area that"},{"startTime":1919.44,"endTime":1925.2,"body":"was doing this transformation and that idea came directly out of monkey research on visual motor"},{"startTime":1925.2,"endTime":1931.76,"body":"grasping where they had identified regions in the intraparietal sulcus (IPS), that were involved in"},{"startTime":1931.76,"endTime":1938.72,"body":"transforming visual inputs into motor plans for controlling eye movements or grasping actions."},{"startTime":1938.72,"endTime":1944.8,"body":"So, we thought well if speech works the same way there's got to be a translation system in between"},{"startTime":1944.8,"endTime":1950.64,"body":"an integration area that's doing this kind of coordinate transformation as they call it in the"},{"startTime":1950.64,"endTime":1959.2,"body":"visual world. And so we went looking for it in fMRI. So, we spent a good chunk of the 2000s identifying"},{"startTime":1959.2,"endTime":1965.2,"body":"this circuit. We called that translation system area SPT for Sylvian, parietal, temporal. Although the"},{"startTime":1965.2,"endTime":1970.72,"body":"lab we just called it informally in the lab the ‘spot’ and that's how we reverse engineered the"},{"startTime":1970.72,"endTime":1982.0,"body":"acronym SPT. (Laughter) So, we had identified this and done what I think is a pretty decent job in arguing that"},{"startTime":1982.0,"endTime":1987.2,"body":"it was doing it was doing in some sensory motor auditory motor function. But then people would"},{"startTime":1987.2,"endTime":1991.92,"body":"always say well what do you mean by transformation? What do you mean by integration? And I would always"},{"startTime":1991.92,"endTime":1997.76,"body":"say I don't know yet. I'm just working on establishing the area first and then I'll figure out what is"},{"startTime":1997.76,"endTime":2003.68,"body":"doing computationally. So, by the end of the 2000s I decided to turn my attention to what it's doing"},{"startTime":2003.68,"endTime":2009.68,"body":"computationally. And I had two places to look. One was psycholinguistics where you had detailed models"},{"startTime":2009.68,"endTime":2016.96,"body":"from Pim Levelt and Gary Dell and other people about how we produce speech. And then you had the motor"},{"startTime":2016.96,"endTime":2022.96,"body":"control people like Frank Guenther and many others who were doing experiments on"},{"startTime":2022.96,"endTime":2026.88,"body":"altered auditory feedback (AAF), and these sorts of things developing computational models."},{"startTime":2026.88,"endTime":2032.64,"body":"So those were the two places I could look for what might be going on computationally. And the odd"},{"startTime":2032.64,"endTime":2038.56,"body":"thing that I discovered was that they seemed to be studying exactly the same thing even at the same"},{"startTime":2038.56,"endTime":2043.76,"body":"level if you look closely. But they were not talking to each other assumed that they were studying"},{"startTime":2043.76,"endTime":2051.44,"body":"different things and used completely different vocabularies. So, I spent a couple of years just going"},{"startTime":2051.44,"endTime":2056.4,"body":"over all the motor control literature including visual motor stuff, going over psycholinguistic"},{"startTime":2056.4,"endTime":2062.88,"body":"literature to see if I could somehow try to integrate these things. And I found that both have"},{"startTime":2062.88,"endTime":2068.16,"body":"truths and that some form of integration was a worthwhile enterprise. And so that's how I"},{"startTime":2068.88,"endTime":2075.52,"body":"started getting into motor control principles and integrating them with my ideas about how"},{"startTime":2075.52,"endTime":2081.6,"body":"linguistic processes work. Yeah, so I mean I think it's a 2012 paper where you first"},{"startTime":2081.6,"endTime":2088.16,"body":"lay out that model, right? And then it gets developed more in this book or maybe not in more detail"},{"startTime":2088.16,"endTime":2094.0,"body":"but like maybe conceptually more. Yeah, it's kind of maybe organized a bit better. My first"},{"startTime":2094.0,"endTime":2101.92,"body":"foray was actually with John Houde, who was a motor speech person at UCSF who was a fellow MIT"},{"startTime":2101.92,"endTime":2107.52,"body":"student with me when I was there, David Poeppel and John Houde, we were there and John was doing"},{"startTime":2107.52,"endTime":2112.48,"body":"this interesting motor speech stuff that I had no idea what it was. But we teamed up because I"},{"startTime":2112.48,"endTime":2116.64,"body":"looked at John's motor speech models and tried to see if we could integrate them. So, we wrote a"},{"startTime":2116.64,"endTime":2123.36,"body":"paper kind of arguing for some form of an integration. And then a 2012 paper extended it a bit and"},{"startTime":2123.36,"endTime":2129.76,"body":"put it in more context. Yeah, but it is kind of laid out a bit more clearly I hope in the book."},{"startTime":2129.76,"endTime":2136.4,"body":"Yeah, I think it's more accessible. I mean, I remember reading the 2012 paper back in maybe 2012"},{"startTime":2136.4,"endTime":2145.2,"body":"or so. And I liked it. But I feel like I understood it better now. Or although maybe that's just me"},{"startTime":2145.2,"endTime":2153.2,"body":"growing up. But yeah, so it ends up being this kind of hybrid of a motor control approach and"},{"startTime":2153.2,"endTime":2160.96,"body":"a psycholinguistic approach. Can you, do you think you can explain like how exactly you"},{"startTime":2160.96,"endTime":2165.76,"body":"meld those things together? Like, yeah, those two different streams of research?"},{"startTime":2165.76,"endTime":2172.0,"body":"Yeah, for sure. It's a fairly simple idea. So, motor control architectures basically have sensory"},{"startTime":2172.0,"endTime":2179.2,"body":"targets. They have three parts, sensory targets, a motor execution or planning system, and then"},{"startTime":2179.2,"endTime":2185.52,"body":"an in between translation system. So, you have these three components. And then you have computational"},{"startTime":2185.52,"endTime":2191.12,"body":"operations like when you're motor planning, you can check to see whether the plans that you're"},{"startTime":2191.12,"endTime":2195.76,"body":"developing will match the targets. And if they're not, you can do some error correction process. This"},{"startTime":2195.76,"endTime":2204.4,"body":"is called feedback control. And there's internal and external forms of that as well. So basically the"},{"startTime":2204.4,"endTime":2210.96,"body":"idea and in psycholinguistics, you have models that propose linguistic levels. Like if you look at"},{"startTime":2210.96,"endTime":2216.56,"body":"Dell's model, you have a semantic layer of processing, you have a word level or a lemma level of"},{"startTime":2216.56,"endTime":2222.4,"body":"processing. And then you have a phonological level of processing. So, three stages of processing."},{"startTime":2222.4,"endTime":2230.16,"body":"The idea that I had was that maybe each level of processing, like focusing on the phonological"},{"startTime":2230.16,"endTime":2236.08,"body":"first, maybe the phonological level of processing in psycholinguistic models is actually"},{"startTime":2236.08,"endTime":2244.8,"body":"composed of three parts. Like a motor control architecture, it has a phonological target system"},{"startTime":2244.8,"endTime":2249.68,"body":"that's more related to sensory systems. It has a phonological motor system that's planning at"},{"startTime":2249.68,"endTime":2255.44,"body":"the phonological level to hit those targets once executed. And then you have a translation system"},{"startTime":2255.44,"endTime":2261.76,"body":"in between. And so that's basically the idea. That's what I proposed for how phonology looks."},{"startTime":2261.76,"endTime":2268.4,"body":"It's not just one box of units. It's three different boxes that are doing different things for"},{"startTime":2268.4,"endTime":2277.28,"body":"phonological output planning. So, what else apart from phonology gets that sort of tri-partite"},{"startTime":2277.28,"endTime":2282.72,"body":"division in your model? Yeah, so I started with phonology, but of course I was always thinking if"},{"startTime":2282.72,"endTime":2289.76,"body":"you look back at the models that I drew, like in that 2012 paper, I have this three part division"},{"startTime":2289.76,"endTime":2295.52,"body":"of labor in multiple, in a hierarchy. So, there's a low level of kind of phonetic control which"},{"startTime":2295.52,"endTime":2301.28,"body":"involves low level motor cortex, low level somatic sensory cortex on the sensory side,"},{"startTime":2301.28,"endTime":2306.88,"body":"and the cerebellum as the in between translation system. And then you go up a level and you're in"},{"startTime":2306.88,"endTime":2312.08,"body":"the part of the, the dorsal stream, traditional dorsal stream as we proposed it. So"},{"startTime":2312.08,"endTime":2320.08,"body":"posterior STG, inferior frontal regions, and then SPT in between. And then I drew a single box"},{"startTime":2320.08,"endTime":2326.24,"body":"for the lemma level, the word level that fed into these systems. And as I was drawing this, I thought"},{"startTime":2326.24,"endTime":2331.12,"body":"I wonder if this can be divided or should be divided into two as well, three parts as well."},{"startTime":2331.12,"endTime":2339.04,"body":"Knowing full well that people doing research on the word level have identified both anterior"},{"startTime":2339.04,"endTime":2345.12,"body":"and posterior regions involved in word selection and planning, but there wasn't enough evidence"},{"startTime":2345.12,"endTime":2352.48,"body":"for me to separate it out yet. So that eventually led to a collaboration with my former student,"},{"startTime":2352.48,"endTime":2360.64,"body":"William Matchin, to develop this idea of a sensory motor-like architecture for morphosyntax"},{"startTime":2360.64,"endTime":2367.68,"body":"And that was our 2020 paper that proposed that. That didn't have a middle part. It only had the"},{"startTime":2367.68,"endTime":2374.48,"body":"posterior side and anterior side. But just recently, and I think it just snuck into as a note in the"},{"startTime":2374.48,"endTime":2381.84,"body":"book that we might have beyond to a in between area for morphosyntax. Where do you reckon that is?"},{"startTime":2381.84,"endTime":2390.24,"body":"Inferior Parietal? Yes, of course. Saying that. So again, this is theorizing based on thinking about"},{"startTime":2390.24,"endTime":2395.84,"body":"how the rest of the brain works, right? You have temporal lobe, coding, sensory stuff for vision,"},{"startTime":2395.84,"endTime":2402.56,"body":"for audition. You have frontal lobe, coding, motor stuff. And the parietal lobe is the seat for"},{"startTime":2402.56,"endTime":2407.6,"body":"visual motor transformation. It's where SPT lives for what we think is auditory motor translation."},{"startTime":2407.6,"endTime":2414.16,"body":"So where would the morphosyntax translation system be? Probably in the parietal lobe. And,"},{"startTime":2414.16,"endTime":2420.24,"body":"you know, I went back and looked at some old ideas from David Gow, who was talking about things that"},{"startTime":2420.24,"endTime":2425.52,"body":"made no sense to me at the time. But looking back, I was like, wait, I think he was on to something"},{"startTime":2425.52,"endTime":2432.08,"body":"here with this. And then really great work by Kathy Price, subdividing the supramarginal gyrus (SMG),"},{"startTime":2432.08,"endTime":2437.44,"body":"and her group into different components. One of them that seems to be very word like,"},{"startTime":2437.44,"endTime":2445.28,"body":"and then turning up facts like people with conduction aphasia who have damage in that general zone,"},{"startTime":2445.28,"endTime":2448.8,"body":"sometimes have pragmatic speech. They always have pragmatic speech."},{"startTime":2448.8,"endTime":2454.88,"body":"Not all of them. Some of them also have comprehension problems. And yeah, it gets a little"},{"startTime":2454.88,"endTime":2461.2,"body":"complicated. But we shouldn’t start talking about how clean or messy aphasia is because that will get"},{"startTime":2461.2,"endTime":2468.4,"body":"out of hand. Yeah. And when I say always, I mean in general. But yes. Yeah, no, that makes sense. So,"},{"startTime":2468.4,"endTime":2475.68,"body":"so just this, the overarching scheme is that all of these different layers of the speech language"},{"startTime":2475.68,"endTime":2483.2,"body":"system involve frontal, parietal and temporal components that are respectively motoric,"},{"startTime":2484.8,"endTime":2491.68,"body":"translational sensory motor, I guess, because I said parietal in the middle, didn't I? And then sensory"},{"startTime":2491.68,"endTime":2499.52,"body":"or connecting to the conceptual system, I guess. Yeah. So it's, I get in trouble for saying stuff"},{"startTime":2499.52,"endTime":2506.56,"body":"like this because the linguists want to say, oh, we're just reducing language to the structure of"},{"startTime":2506.56,"endTime":2513.36,"body":"language to sensory motor systems. But what I'm not saying, and I try to hammer this in the book,"},{"startTime":2513.68,"endTime":2519.04,"body":"I'm not saying that this is just a sensory motor system. I'm saying that this is, has all the"},{"startTime":2519.04,"endTime":2526.08,"body":"richness that, you know, whatever linguistics decides or determines is in the system. It's just"},{"startTime":2526.08,"endTime":2532.8,"body":"distributed over this kind of abstract sensory motor like architecture. Yeah. Which is actually"},{"startTime":2532.8,"endTime":2538.56,"body":"completely orthogonal to the linguistic divisions, right? And it's interesting, right? Because then"},{"startTime":2538.56,"endTime":2543.28,"body":"you end up basically saying, well, yeah, every aspect of language is going to be frontal, temporal"},{"startTime":2543.28,"endTime":2548.24,"body":"and parietal. And that's, there's lots of evidence for that, right? From both imaging and aphasia."},{"startTime":2548.24,"endTime":2554.88,"body":"And it starts, and you start to see how someone like our mutual friend, Ev, can, can come to the"},{"startTime":2554.88,"endTime":2561.2,"body":"perspective that it's like that the language network is a rather unitary kind of structure."},{"startTime":2561.2,"endTime":2567.6,"body":"And I think that both you and I would tend to not agree with her on that final conclusion,"},{"startTime":2567.6,"endTime":2573.12,"body":"but you can kind of see like what you can see the conditions for the evidence that leads her to"},{"startTime":2573.12,"endTime":2579.2,"body":"think that way, right? Absolutely. Yeah. Because all of the facets do kind of end up like,"},{"startTime":2579.2,"endTime":2585.12,"body":"you know, having your anatomical substrates throughout the network."},{"startTime":2585.12,"endTime":2590.8,"body":"That's exactly right. Yeah. It involves the whole that whole system, language involves that"},{"startTime":2590.8,"endTime":2596.8,"body":"whole system at each level. So yeah, depending on how you, you know, what paradigms you use and"},{"startTime":2596.8,"endTime":2602.4,"body":"whatever data you're collecting, you're going to see multiple systems involved. Exactly. Yeah."},{"startTime":2602.4,"endTime":2607.28,"body":"It's a very interesting and new idea. And I think it's like, yeah, made,"},{"startTime":2607.28,"endTime":2614.4,"body":"like the argument, I think, is nice and clear in this book. And so I think everybody should read it"},{"startTime":2614.4,"endTime":2619.28,"body":"just for that reason alone. You also, you have a chapter, and I don't want to get into this in too"},{"startTime":2619.28,"endTime":2625.6,"body":"much detail, but I can't help being really interested in your chapter on the parallel hierarchy"},{"startTime":2625.6,"endTime":2629.2,"body":"of speech production areas in the frontal, the dorsal, ventral division."},{"startTime":2629.2,"endTime":2636.16,"body":"And what you call the dorsal, pre-central speech area, which obviously, you know, that I'm interested in."},{"startTime":2636.16,"endTime":2642.08,"body":"So, can you tell us about, you know, what are your views on the dorsal, pre-central speech area?"},{"startTime":2642.08,"endTime":2650.8,"body":"Where is it? What's it for? What's it doing? Yeah. So this, this is interesting. I got"},{"startTime":2650.8,"endTime":2657.04,"body":"interested in this area because in functional imaging studies and all my SPT auditory motor circuit"},{"startTime":2657.04,"endTime":2662.72,"body":"mapping studies, we would always see this dorsal pre-motor area that is right at the back of the"},{"startTime":2662.72,"endTime":2668.4,"body":"of the middle frontal gyrus. If you had back towards the middle frontal gyros and hop over"},{"startTime":2668.4,"endTime":2674.32,"body":"into the next, the pre-central gyrus, it's right there. It overlaps area 55B, which is in the"},{"startTime":2674.32,"endTime":2681.28,"body":"Glasser Atlas based on human connectome project parcellation, interestingly, and it constantly shows up."},{"startTime":2681.28,"endTime":2686.8,"body":"It is one of the strongest language activations you see in your own study, Stephen. It was the one"},{"startTime":2686.8,"endTime":2692.64,"body":"that showed up in your sensory and motor area in the frontal of the ventral, Broca, traditional"},{"startTime":2692.64,"endTime":2698.88,"body":"Broca’s area didn't show up much. So, it showed up in Kathy Price's early data, her paper on hearing"},{"startTime":2698.88,"endTime":2704.08,"body":"and saying, your work, my work, keep showing up. And I, we always wondered what it was, and I remember"},{"startTime":2704.08,"endTime":2710.24,"body":"a conversation when you first joined my lab for a brief time, and we sat in my office and tried"},{"startTime":2710.24,"endTime":2716.4,"body":"to figure out what this dorsal area was doing unsuccessfully at the time, but we were, you know,"},{"startTime":2716.4,"endTime":2720.56,"body":"interested in what it was doing, and I didn't understand what it was doing until just a couple"},{"startTime":2720.56,"endTime":2729.44,"body":"years ago. So basically, the insights came from, so overall, you have what appears to be two hierarchies"},{"startTime":2729.44,"endTime":2735.2,"body":"of motor control or motor planning. One is their traditional ventral one, which involves broca’s"},{"startTime":2735.2,"endTime":2743.04,"body":"as area, and a lower ventral motor cortex, which also activates in my auditory motor mapping studies."},{"startTime":2743.04,"endTime":2751.2,"body":"But then you have this more dorsal one. One of the breakthrough things came from Eddie Chang's work"},{"startTime":2751.2,"endTime":2757.92,"body":"at UCSF showing that that region showed, in intracranial recordings, showed a correlation with"},{"startTime":2758.64,"endTime":2763.36,"body":"pitch height during vocalization. So, it had something to do with pitch. And interestingly,"},{"startTime":2763.36,"endTime":2770.0,"body":"there's been a lot of great work on mapping laryngeal motor cortex in humans. We have two of them."},{"startTime":2770.0,"endTime":2775.2,"body":"One of them is dorsal sitting right near this area that Eddie mapped, and it shows up in all our"},{"startTime":2775.2,"endTime":2780.88,"body":"studies of sensory motor processes and speech. So that suggested an anatomical, functional anatomic"},{"startTime":2780.88,"endTime":2786.16,"body":"connection between this dorsal speech area and dorsal laryngeal motor cortex."},{"startTime":2786.16,"endTime":2797.36,"body":"And then work by my grad student, Jon Venizia, had identified this area as being particularly"},{"startTime":2797.36,"endTime":2802.96,"body":"auditory in its response properties. It showed spectral temporal receptive fields that coded pitch."},{"startTime":2802.96,"endTime":2811.36,"body":"And so this started me thinking about this area being important for pitch control via the larynx."},{"startTime":2812.16,"endTime":2817.68,"body":"And then thinking about what higher level functions might also be involved because that same area"},{"startTime":2817.68,"endTime":2820.8,"body":"or just anterior to that also seems to be getting,"},{"startTime":2820.8,"endTime":2826.32,"body":"implicating syntax at some level or another. And so, the thought was, well, maybe it's"},{"startTime":2826.32,"endTime":2832.32,"body":"prosody because we know that prosody has something to do with syntax. And this, you have this"},{"startTime":2832.32,"endTime":2839.76,"body":"dorsal, middle-frontal gyrus, dorsal pre-motor speech area, dorsal laryngeal motor cortex hierarchy"},{"startTime":2839.76,"endTime":2850.56,"body":"that's involved in coordinating respiration and prosody for pitch and prosody control via the"},{"startTime":2850.56,"endTime":2855.36,"body":"dorsal laryngeal motor cortex. So that's the separation. Prosody kind of gets parceled out of the"},{"startTime":2855.36,"endTime":2861.92,"body":"speech motor control system. And the rest of it, the phonetic control is the more ventral circuit."},{"startTime":2862.56,"endTime":2869.2,"body":"Okay, so yeah, to summarize that it's sort of, it's related to laryngeal motor, well, it's a"},{"startTime":2869.2,"endTime":2874.64,"body":"adjacent to laryngeal motor cortex or one of the parts of that. It seems to be involved in pitch"},{"startTime":2874.64,"endTime":2880.56,"body":"and prosody in contrast to more ventral frontal speech motor areas that are more about articulation."},{"startTime":2880.56,"endTime":2890.0,"body":"Yeah, this is really interesting. This is actually how I met Eddie, right? So, I met Eddie in 2007"},{"startTime":2890.0,"endTime":2896.96,"body":"and he'd seen our fMRI paper on this area. And he was seeing it in his ECoG recordings and"},{"startTime":2896.96,"endTime":2902.96,"body":"just being quite perplexed by it. Because another thing which I don't think you talk about in the"},{"startTime":2902.96,"endTime":2908.96,"body":"book is that it has a very fast auditory response, right? So, this is a little spot in pre-motor cortex"},{"startTime":2908.96,"endTime":2916.16,"body":"that responds to auditory stimuli within 100 milliseconds. So, you only see that with ECoG, right?"},{"startTime":2916.16,"endTime":2922.24,"body":"We don't see it with our tools that we use. But Eddie was very struck by that and just basically"},{"startTime":2922.24,"endTime":2925.6,"body":"trying to figure out what it was and that's how we became friends and started, you know, gradually"},{"startTime":2925.6,"endTime":2933.2,"body":"developing some collaborations. And you mentioned that you guys found evidence that it"},{"startTime":2933.2,"endTime":2941.44,"body":"has sort of auditory representations rather than motor, yeah? And I know that you've seen Eddie's"},{"startTime":2941.44,"endTime":2949.52,"body":"stuff on that too, right? Where they showed in 2016 that it basically patent like an auditory area"},{"startTime":2949.52,"endTime":2955.36,"body":"rather than a motor area. And so, you know, isn't it just, isn't it? Does it like, why is there a"},{"startTime":2955.36,"endTime":2959.84,"body":"patch of auditory cortex sitting up in the pre-central gyrus? I mean, do you ever thought about it from"},{"startTime":2959.84,"endTime":2965.04,"body":"that perspective? I mean, is this just like, does that need to be there because of the centrality of"},{"startTime":2965.04,"endTime":2971.84,"body":"these coordinate transforms that your model is all about? Yeah, so that's we're thinking as an"},{"startTime":2971.84,"endTime":2977.92,"body":"evolutionary biologist helps a bit. So, if you look in Macaques, their dorsal stream projects up to that"},{"startTime":2977.92,"endTime":2985.12,"body":"general region. And you think about it and it projects up to near the frontal eye fields,"},{"startTime":2985.12,"endTime":2989.6,"body":"which is kind of a misnomer. Frontal eye fields are not just about eye control. They're about"},{"startTime":2989.6,"endTime":2998.16,"body":"orienting and some people think of it as a general orienting response. So in Macaque and in us,"},{"startTime":2998.16,"endTime":3007.84,"body":"the function of that pre-linguistics, pre-language was apparently auditory orienting. So, hearing"},{"startTime":3007.84,"endTime":3012.4,"body":"sounds in space and orienting towards them, controlling head movements, eye movements, attention"},{"startTime":3012.4,"endTime":3018.88,"body":"towards those systems. So that was essentially the frontal control area that was using"},{"startTime":3018.88,"endTime":3023.84,"body":"lower level auditory information. And of course, if you think about auditory localization,"},{"startTime":3023.84,"endTime":3029.04,"body":"you immediately think about interaural level and time differences to orient in the horizontal plane."},{"startTime":3029.04,"endTime":3036.4,"body":"But the cues that are useful for orienting in the vertical plane are spectral. So much more rich,"},{"startTime":3036.4,"endTime":3042.0,"body":"much more of the kinds of things that you'd find coded in primary auditory cortex. So all of that"},{"startTime":3042.0,"endTime":3048.4,"body":"acoustic information would be useful in a pre-motor area that was important for orienting."},{"startTime":3048.4,"endTime":3055.84,"body":"And the idea that I have, that's hard to test, but the idea is that we evolved this dorsal"},{"startTime":3055.84,"endTime":3063.92,"body":"area to control voice pitch where you also need pitch feedback. Because that's where the relevant"},{"startTime":3063.92,"endTime":3068.24,"body":"sensory information was coming in. It was the part of the brain that was getting the relevant"},{"startTime":3068.24,"endTime":3076.8,"body":"information. And so that's the logical place if you're evolving a system to evolve control"},{"startTime":3076.8,"endTime":3082.16,"body":"of vocal pitch. And apparently that's what happened in birds as well, who have vocal learning"},{"startTime":3082.16,"endTime":3087.84,"body":"for bird song. So yeah, I thought about it. It has to do with orienting, I believe, in attention."},{"startTime":3087.84,"endTime":3093.68,"body":"Yeah, I have always thought it was like attention related. I mean, I think that the first really"},{"startTime":3093.68,"endTime":3099.52,"body":"clear evidence for this, the existence of this area was actually from MEG studies, like"},{"startTime":3099.52,"endTime":3106.16,"body":"mismatch negativity where they had this 100 millisecond MMN response. And that was in the late 90s."},{"startTime":3106.16,"endTime":3110.8,"body":"And that was always kind of a scribe to an attentional thing, as it's coming in these like oddball"},{"startTime":3110.8,"endTime":3115.76,"body":"paradigms. So yeah, this is really interesting. And this is a great example of like how you're,"},{"startTime":3115.76,"endTime":3122.0,"body":"you know, you're, you're thinking as always very grounded in this sort of evolutionary perspective."},{"startTime":3122.0,"endTime":3127.36,"body":"So yeah. Yeah, yeah, I do try it helps. Again, it's just another source of constraint. It's really hard"},{"startTime":3127.36,"endTime":3133.28,"body":"to do this work, right? In language neuroscience. And we need all the constraints from all the fields"},{"startTime":3133.28,"endTime":3138.56,"body":"we can get. So, you know, I draw from motor control to cycle linguistics to general neuroscience,"},{"startTime":3138.56,"endTime":3144.72,"body":"to evolutionary biology, anything I can get my hands on to help narrow down the search space,"},{"startTime":3144.72,"endTime":3151.12,"body":"essentially. Yeah. Well, I really enjoyed the chapter on the, what do you call it? The"},{"startTime":3151.12,"endTime":3157.68,"body":"Dorsal Pre-central Speech Area. Yeah, I'm broke. Yeah. Yeah. Okay. So last topic,"},{"startTime":3160.16,"endTime":3166.48,"body":"very interesting, like, let's get back to that, that ventral stream. And I, as I emailed you"},{"startTime":3166.48,"endTime":3171.28,"body":"originally, I wanted to talk about laterality. But before we kind of, you know, to set the,"},{"startTime":3171.28,"endTime":3177.04,"body":"to set the stage, you're talking about laterality, can you talk about like the series of processing"},{"startTime":3177.04,"endTime":3184.32,"body":"steps that happen in the ventral stream, kind of maybe which, Henschen outlined a hundred years ago,"},{"startTime":3184.32,"endTime":3189.36,"body":"and they have further refined yourself and others have further refined here. So, what's that"},{"startTime":3189.36,"endTime":3195.44,"body":"sort of processing hierarchy in your view? Yeah. So there's roughly speaking and it's obviously"},{"startTime":3195.44,"endTime":3200.64,"body":"more complicated than this. But the, the rough sketch is that early on in auditory cortex, say in"},{"startTime":3200.64,"endTime":3206.24,"body":"Heschl’s gyrus, there's coding for spectrotemporal information. That is information that"},{"startTime":3206.24,"endTime":3215.04,"body":"varies spectrally and frequency over time. And that gets, that gets translated or from that you can"},{"startTime":3215.04,"endTime":3221.28,"body":"derive phonological level representations. And I don't think that, that there are phoneme"},{"startTime":3221.28,"endTime":3226.72,"body":"representations and auditory cortex. I think there are demy syllables or little chunks of syllables,"},{"startTime":3226.72,"endTime":3231.84,"body":"but that's a separate issue. But something phonological is happening in the lateral superior temporal"},{"startTime":3231.84,"endTime":3237.84,"body":"gyrus and dorsal bank of the superior temporal sulcus. From there, that information at the phonological"},{"startTime":3237.84,"endTime":3246.4,"body":"level gets input and you can derive some information about word level. And by word, I mean abstract word"},{"startTime":3246.4,"endTime":3254.24,"body":"and psycholinguistic terms. It is referring to lemmas and linguistic terms I'm talking about morphosyntax."},{"startTime":3254.24,"endTime":3260.8,"body":"And that's middle temporal gyrus, kind of regions that are, is coding word level stuff. And then"},{"startTime":3260.8,"endTime":3266.88,"body":"from there, you're mapping it out into the conceptual semantic system. So, so acoustic features,"},{"startTime":3266.88,"endTime":3272.64,"body":"the phonological to word level, the three main stages, I would say that we have a pretty decent handle on."},{"startTime":3272.64,"endTime":3279.44,"body":"Okay. And there's a lot of evidence for that, right? And like, you know, you point out that, you know,"},{"startTime":3279.44,"endTime":3287.04,"body":"Jeff Binder’s 2000 fMRI paper, kind of like provides this really nice picture of what Heschl had"},{"startTime":3287.04,"endTime":3294.88,"body":"come to 80 years before. So, I think we probably mostly, I mean, well, actually we don't all agree"},{"startTime":3294.88,"endTime":3300.56,"body":"because there is dispute over whether it's anteriorly directed or posteriorly directed. But let's just say"},{"startTime":3300.56,"endTime":3310.08,"body":"it's, we think it's mostly posteriorly directed in between us. And that's the basic layout of the"},{"startTime":3310.08,"endTime":3316.08,"body":"the ventral stream. Now, then there's this other interesting aspect that you proposed in your papers"},{"startTime":3316.08,"endTime":3324.08,"body":"in the first decade of the century, whereby the ventral stream is to some extent, which you can"},{"startTime":3324.08,"endTime":3332.0,"body":"state for us, some extent, bilateral. So, what are your current views on the bilaterality of this"},{"startTime":3332.0,"endTime":3338.08,"body":"series of steps? My current view is that at the level of phonological, up to the level of phonological"},{"startTime":3338.08,"endTime":3345.44,"body":"processing, most of us are perfectly symmetric in terms of our lateralization, which is a controversial"},{"startTime":3345.44,"endTime":3353.6,"body":"idea and something that I didn't even believe until recently. So, this site, so that just to state the"},{"startTime":3353.6,"endTime":3358.56,"body":"facts, beyond that, once you get to the level of recognizing words and getting to higher levels,"},{"startTime":3358.56,"endTime":3366.08,"body":"it becomes a little bit more left-dominant. But still, at the level of the ability to recognize words"},{"startTime":3366.08,"endTime":3374.48,"body":"and understand their meaning, that is mostly bilateral in most people. So, in symmetric in many."},{"startTime":3374.48,"endTime":3382.64,"body":"So that's a summary of what I believe now. Okay. So, I don't agree with that. But I know that like"},{"startTime":3382.64,"endTime":3390.0,"body":"you like a good argument. So, what's the evidence that leads you to come to that view? Like what are"},{"startTime":3390.0,"endTime":3396.24,"body":"the main things that really struck you that led to that position? Yeah. Well, it's very hard to find"},{"startTime":3396.24,"endTime":3403.44,"body":"people with unilateral damage to the superior temporal gyrus and has significant single-word"},{"startTime":3403.44,"endTime":3410.16,"body":"comprehension problems. And by that, I mean not comprehension problems where there's lots of"},{"startTime":3410.16,"endTime":3415.12,"body":"semantic foils or other sorts of things. This basic kind of can you tell the difference between"},{"startTime":3415.12,"endTime":3421.92,"body":"bear and bear when you're pointing to pictures? We did a large-scale study on this and found that"},{"startTime":3421.92,"endTime":3429.28,"body":"only about well less than 10% of people in chronic stroke have significant deficits, where"},{"startTime":3429.28,"endTime":3437.6,"body":"significant is below like 85% something like that. So that's the fact. So, you know, most people,"},{"startTime":3437.6,"endTime":3442.64,"body":"if you look at the distribution, most people are at ceiling on tasks like that, even with complete"},{"startTime":3442.64,"endTime":3450.08,"body":"destruction of the superior temporal gyrus on the left. So that's one bit. If it was more"},{"startTime":3450.08,"endTime":3456.48,"body":"lateralized, if it was significantly lateralized, we would expect to see more deficits in more people."},{"startTime":3456.48,"endTime":3460.48,"body":"So that's one argument. The other argument is if you damage the systems bilaterally,"},{"startTime":3460.48,"endTime":3464.96,"body":"you end up with word deafness, that's where the severe deafness syndrome comes in."},{"startTime":3466.08,"endTime":3472.48,"body":"We've also done this in WADA and in acute stroke and we still can't identify severe single-word"},{"startTime":3472.48,"endTime":3479.68,"body":"receptive deficits on these tasks. I'm just interrupting from the future here briefly because we've"},{"startTime":3479.68,"endTime":3484.72,"body":"forgotten to define WADA, which makes this a bit hard to follow otherwise. So, WADA means the WADA"},{"startTime":3484.72,"endTime":3491.6,"body":"test and that's named after a Japanese neurosurgeon named Juhn Atsushi Wada, who invented this procedure"},{"startTime":3491.6,"endTime":3497.28,"body":"in the late 40s. This is a procedure where you use a barbiturate like sodium amobarbital to"},{"startTime":3497.28,"endTime":3502.4,"body":"anesthetize one hemisphere of the brain at a time and this is done prior to surgery to determine"},{"startTime":3502.4,"endTime":3509.12,"body":"lateralization of language or other functions. So, the idea is you transiently take one hemisphere"},{"startTime":3509.12,"endTime":3514.08,"body":"out of the action and you can see what the other hemisphere can do. So, Greg and I are going to talk"},{"startTime":3514.08,"endTime":3518.08,"body":"about some studies that have been done using this procedure to look at language lateralization."},{"startTime":3518.08,"endTime":3523.84,"body":"Okay, let's get back to it. And then I went the next step for this book to look back at the WADA"},{"startTime":3523.84,"endTime":3530.16,"body":"data that I had collected and look to see because overall if you look at whether if people have left"},{"startTime":3530.16,"endTime":3534.8,"body":"hemisphere anesthesia, you put the left hemisphere to sleep, you ask if they can comprehend words,"},{"startTime":3534.8,"endTime":3539.36,"body":"then you do it with the right hemisphere. There are worse than comprehending words when the left"},{"startTime":3539.36,"endTime":3544.56,"body":"hemisphere is asleep on average compared to the right. So, there's some asymmetry there. I never"},{"startTime":3544.56,"endTime":3550.0,"body":"did it by that. But then if you look at the distribution of that asymmetry, it turns out that more than"},{"startTime":3550.0,"endTime":3556.72,"body":"half of the people are perfectly symmetric and it's only a smaller fraction of people who are"},{"startTime":3556.72,"endTime":3562.56,"body":"much more left dominant. So, my view is that the left dominance that we see in the population when"},{"startTime":3562.56,"endTime":3569.12,"body":"we do functional imaging studies or group level stroke studies is being driven by very small biases"},{"startTime":3569.12,"endTime":3576.24,"body":"in most people are pretty symmetric. A few people are slightly left dominant and then a small fraction"},{"startTime":3576.24,"endTime":3581.12,"body":"of people are strongly left dominant. You average all those together and you get a kind of left"},{"startTime":3581.12,"endTime":3586.32,"body":"dominance. Okay. That's what I think is going on at the population and individual level. Okay."},{"startTime":3586.32,"endTime":3592.88,"body":"Thanks. Yeah, that's a great summary. So, I want to kind of think about it from like, okay, things we"},{"startTime":3592.88,"endTime":3601.36,"body":"agree on is that we sort of ask the question that like, I think both of us think about the question"},{"startTime":3601.36,"endTime":3605.12,"body":"the same way. Like when we're asking like, what does it mean to be a bilateral? We're asking like,"},{"startTime":3605.12,"endTime":3611.52,"body":"what can the right hemisphere do if put to the test, right? Is that the way you see it? Like,"},{"startTime":3611.52,"endTime":3618.08,"body":"when you say that we're bilateral or that most people are bilateral, what you mean is that"},{"startTime":3618.08,"endTime":3621.36,"body":"take the left hemisphere out of the picture, the right hemisphere can still comprehend words."},{"startTime":3622.08,"endTime":3628.08,"body":"Yep. Okay. I think another thing that we would agree on is that comprehension is much more"},{"startTime":3628.08,"endTime":3633.44,"body":"bilateral than production, right? So, you've never made claims about the bilateral,"},{"startTime":3633.44,"endTime":3637.52,"body":"bilaterality of speech production. You think that the production system is pretty lateralized?"},{"startTime":3637.52,"endTime":3642.48,"body":"I think, well, that's traditionally my view, but now I'm questioning it because we're taking"},{"startTime":3642.48,"endTime":3647.36,"body":"average it is and we're collecting by a sample. So, I think it is lateralized. I believe that"},{"startTime":3648.8,"endTime":3653.68,"body":"and more so than comprehension, but I think we're overestimating the degree of lateralization."},{"startTime":3653.68,"endTime":3658.64,"body":"Okay. But we think that there's a difference. Yes."},{"startTime":3658.64,"endTime":3665.6,"body":"So yes, and I would agree with that too because like, I mean, what you said initially, the fact that"},{"startTime":3665.6,"endTime":3672.08,"body":"single-word deficits, like word comprehension deficits at the single-word level are quite rare"},{"startTime":3672.08,"endTime":3676.96,"body":"in aphasia. That's, as you said, that is just a fact that we have to grapple with."},{"startTime":3678.24,"endTime":3684.24,"body":"What it means is debatable, but that I would say comprehension is much more bilateral than production."},{"startTime":3684.24,"endTime":3690.56,"body":"I think another thing that we would agree on is that different aspects of comprehension"},{"startTime":3690.56,"endTime":3694.88,"body":"would differ in the extent to which they're bilateral. So, for instance, you said, like,"},{"startTime":3694.88,"endTime":3699.84,"body":"that spectro-temporal stage, we would both agree is fully bilateral."},{"startTime":3699.84,"endTime":3704.48,"body":"And then when you get to mapping and then the phonological word form stage,"},{"startTime":3705.44,"endTime":3710.16,"body":"you think it starts to be maybe a little bit lateralized in some people, whereas I sort of think it's"},{"startTime":3710.16,"endTime":3714.08,"body":"more than that. And then when you get to the stage of mapping and under meanings, you think,"},{"startTime":3714.08,"endTime":3718.16,"body":"oh yeah, there's it's a little bit lateralized in some people, maybe more so in others."},{"startTime":3718.16,"endTime":3723.6,"body":"And I think, well, that's pretty strongly lateralized in my view. But we both agree that there's like,"},{"startTime":3723.6,"endTime":3728.72,"body":"as you go through the hierarchy, it changes, right? It becomes more lateralized."},{"startTime":3729.44,"endTime":3736.16,"body":"Agreed. Yep. And another thing that I think is interesting, you didn't quite say this in the book,"},{"startTime":3736.16,"endTime":3740.96,"body":"but I'm pretty sure you would think the same as me. When you get central, like, you know, as you're"},{"startTime":3740.96,"endTime":3744.4,"body":"going through the hierarchy, like we just said, if you get more lateralized, but when you get central,"},{"startTime":3744.4,"endTime":3750.72,"body":"you actually become bilateral again, right? Because meaning is very bilateral."},{"startTime":3750.72,"endTime":3755.76,"body":"Yeah, central meaning, like once you get up to concepts and yeah,"},{"startTime":3757.2,"endTime":3762.08,"body":"yeah, I honestly never thought too much about it, but obviously, yeah, if you're going to get to"},{"startTime":3762.08,"endTime":3768.88,"body":"the phonological form and then get to the word meaning, then you've got to have some bilateral"},{"startTime":3768.88,"endTime":3772.72,"body":"capacity. Although, well, I'm not saying you have to have bilateral capacity. I'm just saying,"},{"startTime":3772.72,"endTime":3779.52,"body":"if you can get through that bottleneck of sound meaning, you'd then have a semantic representation,"},{"startTime":3779.52,"endTime":3784.56,"body":"which is very bilateral, as we see in stuff like Alex Huth's work, where everything looks"},{"startTime":3784.56,"endTime":3791.04,"body":"really symmetrical. So those are, I think, of the things that we agree on. And I think what we"},{"startTime":3791.04,"endTime":3801.76,"body":"disagree on is the extent of laterality of those mid-range, you know, that kind of that middle"},{"startTime":3801.76,"endTime":3807.44,"body":"of the system, like where it's getting, you know, not the acoustic analysis and not the central"},{"startTime":3807.44,"endTime":3815.36,"body":"representation of meaning, but just that bottleneck. And I guess, like, I guess I want to just ask your"},{"startTime":3815.36,"endTime":3819.76,"body":"opinion about, like some of the, I think, things that are a little bit difficult for your viewpoint."},{"startTime":3819.76,"endTime":3826.8,"body":"So, and things are difficult for my viewpoint, right? So, I think, difficult for my viewpoint,"},{"startTime":3826.8,"endTime":3831.84,"body":"for instance, is the fact that a few people with aphasia have profound word comprehension deficits."},{"startTime":3831.84,"endTime":3836.8,"body":"Difficult for your viewpoint is the fact that any people with aphasia have any word comprehension"},{"startTime":3836.8,"endTime":3843.52,"body":"deficits, right? Like, so, you know, I'm sure you've seen our paper in brain from a couple of years"},{"startTime":3843.52,"endTime":3850.4,"body":"ago. And, you know, like a lot of our people with large MCA lesions or large temporoparietal lesions,"},{"startTime":3850.4,"endTime":3858.08,"body":"they do have pretty profound word comprehension deficits, certainly acutely, and in many cases"},{"startTime":3858.08,"endTime":3863.84,"body":"into one and three months, resolving over time, which is super interesting, but like, what do you,"},{"startTime":3863.84,"endTime":3871.52,"body":"what do you make of that initial single word comprehension deficits that we do see in most of our people?"},{"startTime":3871.52,"endTime":3876.32,"body":"Well, not, I would never say most. I'd say more than half of our people with really substantial"},{"startTime":3876.32,"endTime":3884.08,"body":"left temporoparietal damage. Yeah. Yeah. Yes, your paper is probably one of my favorites in terms"},{"startTime":3884.08,"endTime":3893.36,"body":"of testing these ideas. So, which is why I want to get some of that data. I'm working on it."},{"startTime":3893.36,"endTime":3901.28,"body":"I'm working on it. Yeah. So, initially, so if you have giant frontal lesions, I, you know, I don't,"},{"startTime":3901.28,"endTime":3908.48,"body":"I don't know exactly. I mean, diaschisis is an issue, right? Maybe the right hemisphere is suppressed."},{"startTime":3908.48,"endTime":3914.88,"body":"Maybe, maybe there's some frontal things that are, you know, people are just having trouble with"},{"startTime":3914.88,"endTime":3919.68,"body":"selection processes, something that is not about the recognition of the word."},{"startTime":3923.04,"endTime":3929.6,"body":"Yeah. I'm not sure. In some ways, I think the giant lesions are a little bit hard to evaluate"},{"startTime":3929.6,"endTime":3937.36,"body":"in the acute stage because I, you know, imagine that a lot of things are going on with these"},{"startTime":3937.36,"endTime":3942.64,"body":"different lesions and tell things resolve a bit. But you would know that better than me. So,"},{"startTime":3942.64,"endTime":3950.4,"body":"yeah. So, that's, I mean, the acute stuff is a concern, which is why we did this, the acute study,"},{"startTime":3950.4,"endTime":3954.32,"body":"where we did it more focally. We had a bunch of people with acute stroke"},{"startTime":3954.32,"endTime":3962.88,"body":"measured their blood flow and their lesion acutely and then looked to see whether people with"},{"startTime":3962.88,"endTime":3970.0,"body":"substantial damage to these areas we think, like the STG, basically it was superior middle-front"},{"startTime":3970.0,"endTime":3975.2,"body":"middle temporal gyri. If you had a lot of damage there, independent of how big the lesion was"},{"startTime":3975.2,"endTime":3982.16,"body":"and where everything else was. Do you have a lot of people with significant deficits? And the answer,"},{"startTime":3982.16,"endTime":3988.72,"body":"in that study was more than half of people had no problem whatsoever, despite damage to the ROI"},{"startTime":3988.72,"endTime":3993.92,"body":"that's supposed to be lateralized. And then you start getting a trail off of ability in terms of"},{"startTime":3993.92,"endTime":4002.0,"body":"the distribution where everyone is above threshold and only about, again, 20% are having some clinically"},{"startTime":4002.0,"endTime":4007.68,"body":"significant deficits at single word. So, yes, it does happen acutely, but it's a smaller fraction"},{"startTime":4007.68,"endTime":4013.44,"body":"and the distribution, I think, is what's interesting. So, the way I've started thinking about is rather"},{"startTime":4013.44,"endTime":4019.6,"body":"than debating about whether that counts as lateralization. We just measure the distribution of these things"},{"startTime":4019.6,"endTime":4025.28,"body":"and say, well, this is the degree of lateralization. The modal tendency is symmetric or whatever."},{"startTime":4025.28,"endTime":4030.72,"body":"And then you have 15% of people who are going to be below this level and that is just an empirical"},{"startTime":4030.72,"endTime":4035.84,"body":"measure of lateralization. Yes. Okay. So, that's actually another thing that we agree on that I forgot"},{"startTime":4035.84,"endTime":4041.68,"body":"to put in my list of things we agree on, is that there is very substantial individual variability"},{"startTime":4041.68,"endTime":4047.68,"body":"in the degree of bilaterality. And I think we disagree on what the distribution is. I think we"},{"startTime":4047.68,"endTime":4054.16,"body":"disagree quite significantly because I would never think that bilaterality would be the norm,"},{"startTime":4054.16,"endTime":4060.48,"body":"but I understand that you do. So, I mean, like, from my point of view, when I think about those acute"},{"startTime":4060.48,"endTime":4068.64,"body":"data and yes, it's definitely not inconsistent with what we see. I think that when you talk"},{"startTime":4068.64,"endTime":4073.28,"body":"about an, like, you know, damage to a superior temporal ROI or even if it's in the middle temporal,"},{"startTime":4073.28,"endTime":4079.12,"body":"I think in most people, there's going to be a lot of residuals left temporal function that's still"},{"startTime":4079.12,"endTime":4085.76,"body":"going to be available to interpret the acoustic information from the right hemisphere. If indeed,"},{"startTime":4085.76,"endTime":4091.2,"body":"like, left, if left, if left Heschl is really out of the picture, you need to do an awful lot of"},{"startTime":4091.2,"endTime":4098.96,"body":"damage to take away, like, potential left hemisphere substrates for interpreting that spectrotemporal"},{"startTime":4098.96,"endTime":4105.04,"body":"information that can come in through the right, which we all agree on. And in general, I'd say with"},{"startTime":4105.04,"endTime":4111.68,"body":"functional imaging of people with aphasia, which is sort of basically my thing, there's a few"},{"startTime":4111.68,"endTime":4119.2,"body":"things that strike me again and again. And one of them is that in almost everybody, you will be shocked"},{"startTime":4119.2,"endTime":4124.24,"body":"by how much residual functional activity there is even in people that have huge lesions. So, we'll"},{"startTime":4124.24,"endTime":4128.24,"body":"take somebody that has like a huge MCA lesion and you just think, \"Well, that's just wiped out"},{"startTime":4128.24,"endTime":4132.24,"body":"the language network.\" You look at it on a, you know, there are acute DWI and you're like, \"That person's"},{"startTime":4132.24,"endTime":4137.76,"body":"never going to talk again.\" Then we bring them in and scan them at like one month, three months,"},{"startTime":4137.76,"endTime":4145.52,"body":"12 months is our goal, even at one month, or maybe at three. You'll just see activation right up to"},{"startTime":4145.52,"endTime":4150.24,"body":"the edge of the lesion, you know, like, and then the lesion tries so hard to destroy the language"},{"startTime":4150.24,"endTime":4155.92,"body":"network, but there's always bits of it left and it's very, it's extremely rare to get somebody that"},{"startTime":4155.92,"endTime":4160.56,"body":"literally has no left hemisphere language network because these people, honestly, they don't survive"},{"startTime":4160.56,"endTime":4166.4,"body":"because that would involve an entire hemisphere being destroyed. So, I'm very struck by,"},{"startTime":4167.44,"endTime":4170.56,"body":"you know, I'm not saying that the right hemisphere isn't playing a role in comprehension or"},{"startTime":4170.56,"endTime":4177.28,"body":"doesn't have any comprehension abilities, but I think that you might be overestimating the lack of"},{"startTime":4177.28,"endTime":4182.16,"body":"left hemisphere substrates in some of these people, even if they've got damage to those."},{"startTime":4182.16,"endTime":4186.72,"body":"Yeah. Left hemisphere regions. What do you make of the WADA data then?"},{"startTime":4186.72,"endTime":4192.96,"body":"Yes. Okay. So, the WADA data, well, I think that when in your WADA study,"},{"startTime":4195.04,"endTime":4200.88,"body":"it was, you were testing them for quite a while because you were doing semantic and"},{"startTime":4200.88,"endTime":4207.6,"body":"Phonological distractors, and I think that they were, I don't think that the hemispheres"},{"startTime":4207.6,"endTime":4213.84,"body":"were fully out of the picture for a much of the period that you were testing them."},{"startTime":4213.84,"endTime":4222.16,"body":"And so, I think of what I've seen in our clinical WADA data that we've not published, by the way,"},{"startTime":4222.16,"endTime":4228.64,"body":"so this is just anecdotes and should be not given full, you know, really should be back to"},{"startTime":4228.64,"endTime":4235.12,"body":"publication, but like what we see is pretty complete single word comprehension loss in most people"},{"startTime":4235.12,"endTime":4240.8,"body":"under anesthesia of the left hemisphere. And so, like I said, we haven't published that,"},{"startTime":4240.8,"endTime":4245.44,"body":"but that's what we've seen in our data. But what who has published it is this"},{"startTime":4246.16,"endTime":4253.68,"body":"Risse et al. from the late 90s, and they have, you know, when they, that's there, you know, they"},{"startTime":4253.68,"endTime":4260.24,"body":"basically say that most people have zero single word ability when the left hemisphere is"},{"startTime":4260.24,"endTime":4264.32,"body":"anesthetized. And I know that's quite different to what you found. But I think that there's a"},{"startTime":4264.32,"endTime":4269.76,"body":"timing difference, and I know that you don't, and I know that you have reasons to not think that,"},{"startTime":4269.76,"endTime":4275.68,"body":"because you found grip strength, like you didn't see a correlation between grip strength"},{"startTime":4275.68,"endTime":4279.76,"body":"and comprehension. Yeah. Right. Yeah. Yeah. I mean,"},{"startTime":4279.76,"endTime":4285.84,"body":"every method has its weaknesses. And I suppose there could be some, some, you know,"},{"startTime":4285.84,"endTime":4292.64,"body":"groggy left hemisphere recovery that is underlying that ability. But I mean, I would expect more"},{"startTime":4292.64,"endTime":4299.04,"body":"more deficits and more people. But yeah, be …. I think the task is important too. I,"},{"startTime":4299.04,"endTime":4304.8,"body":"you know, like if you look at WAB comprehension, and my colleagues in South Carolina,"},{"startTime":4304.8,"endTime":4308.96,"body":"when I tell them that speech perception is bilateral, they laugh at me because they see"},{"startTime":4308.96,"endTime":4314.24,"body":"patients all the time who have dense single word comprehension deficits on the WAB."},{"startTime":4314.24,"endTime":4319.6,"body":"But the WAB is multiple pictures. There's semantic categories, and that's kind of bias"},{"startTime":4319.6,"endTime":4324.64,"body":"into the left hemisphere more. So, you know, I'd have to look at these other cases in your new study"},{"startTime":4324.64,"endTime":4329.04,"body":"that sounds really interesting what the task is. Oh, yeah, whether it'll ever be published, no,"},{"startTime":4329.04,"endTime":4334.64,"body":"I mean, it's clinical data. So, I'm, it's just what we've seen, and when we looked into it."},{"startTime":4334.64,"endTime":4341.12,"body":"Okay. Yeah. I wish it was, I wish it was a new study. But yeah, no, the Risse one is the one that I,"},{"startTime":4341.12,"endTime":4345.04,"body":"but like, yeah, like it's question, like they don't really, it's like an old clinical paper, right,"},{"startTime":4345.04,"endTime":4349.52,"body":"from 30 years ago. They're not really like language neuroscience people, and they don't really"},{"startTime":4349.52,"endTime":4355.6,"body":"describe their comprehension test in, in as much detail as we would like to, to have. So yeah,"},{"startTime":4355.6,"endTime":4360.72,"body":"no, I think it's like, I agree with, I mean, I conceptually I agree with you. Like obviously,"},{"startTime":4360.72,"endTime":4365.84,"body":"if you, if it was true that you could have anaesthetize a hemisphere and have single word comprehension"},{"startTime":4365.84,"endTime":4371.68,"body":"proceed normally, that would be unequivocal evidence that the right hemisphere can do it."},{"startTime":4371.68,"endTime":4380.56,"body":"I'm just not sure that that's quite been empirically shown yet. Okay. Fair enough. And coincidentally,"},{"startTime":4380.56,"endTime":4386.56,"body":"I'm also continuing to study this because yeah, we haven't convinced you and others yet. So, I'm"},{"startTime":4386.56,"endTime":4392.64,"body":"continuing, but yeah, I mean, the good thing is it's an empirical question. And honestly, I don't care"},{"startTime":4392.64,"endTime":4400.24,"body":"whether it's 80% lateralized or 20% or zero. I honestly don't care. Yeah. But the fact is that like"},{"startTime":4400.24,"endTime":4408.08,"body":"you know, predicting behavior, aphasic deficits from lesion location is notoriously impossible. Like"},{"startTime":4408.08,"endTime":4414.72,"body":"you almost never, I mean, exaggerating a bit, but it's very hard to do very, very,"},{"startTime":4414.72,"endTime":4422.56,"body":"lesion. No, Greg, I don't agree. I don't agree. Well, I mean, but I'll tell you what, you know what"},{"startTime":4422.56,"endTime":4429.68,"body":"the hardest deficit to predict is word comprehension. Comprehension, yeah. So word, no, word comprehension."},{"startTime":4429.68,"endTime":4434.08,"body":"Sentence comprehension is easy to predict. Word comprehension is very hard to predict. So I would,"},{"startTime":4434.08,"endTime":4438.64,"body":"so I would definitely grant you that, but I do think that we can make, we can do better on a lot"},{"startTime":4438.64,"endTime":4445.76,"body":"of other aspects of language. Yeah. So, what do you, what have you guys got going on to look"},{"startTime":4445.76,"endTime":4452.16,"body":"at, look further at this question? We're trying to get funding. Who knows if we'll get it to recruit"},{"startTime":4452.16,"endTime":4458.48,"body":"an unbiased sample of people with strokes left and right, give them a battery of tests and see"},{"startTime":4458.48,"endTime":4464.88,"body":"where their lesions are. And then do the reverse. So, what we do in in lesion symptom mapping, of course,"},{"startTime":4464.88,"endTime":4471.84,"body":"is identify a behavioral deficit and look for where in the brain we can predict that or correlate"},{"startTime":4471.84,"endTime":4477.84,"body":"damage with that deficit. I want to do the reverse and I want to see given an area that we think"},{"startTime":4477.84,"endTime":4484.24,"body":"is doing something for a function, look to see whether how many people would damage that area,"},{"startTime":4484.24,"endTime":4488.96,"body":"like complete damage to that area actually have the deficit we'd expect. We tried that with a"},{"startTime":4488.96,"endTime":4495.52,"body":"proxy of speech in our data set. First mapping the lesion location of apraxia of speech, which is like,"},{"startTime":4495.52,"endTime":4501.36,"body":"you know, sensory motor cortex. And then looking to see how many people who have complete damage"},{"startTime":4501.36,"endTime":4510.24,"body":"or a near complete damage to that area have it. And most do 70%, but 30% don't. And so my thinking is"},{"startTime":4510.24,"endTime":4516.16,"body":"that maybe some of that variance is due to people who have more bilateral organization."},{"startTime":4516.16,"endTime":4521.44,"body":"Oh, I completely agree. And like we see basically the same thing with apraxia of speech. I mean,"},{"startTime":4521.44,"endTime":4527.36,"body":"like it depends on what area you're thinking of like pre-central kind of issue. Yeah. So, I'd say in our"},{"startTime":4527.36,"endTime":4532.72,"body":"data set of the people that have damaged there, probably about half or a bit more than half have"},{"startTime":4532.72,"endTime":4538.88,"body":"apraxia of speech. And then a very significant minority simply don't. And including some people with"},{"startTime":4538.88,"endTime":4542.72,"body":"massive lesions where it's really not plausible that it could be like an adjacent region or that you"},{"startTime":4542.72,"endTime":4548.88,"body":"didn't hit the central thing. And so, and so I think I've kind of coming to the view that like actually"},{"startTime":4548.88,"endTime":4556.08,"body":"there are people in whom speech motor control can be subserved by the right hemisphere. And like you"},{"startTime":4556.08,"endTime":4562.72,"body":"said, 30% yeah, it could be about that. And I like the idea that you said before like the answers"},{"startTime":4562.72,"endTime":4568.0,"body":"to these questions are not going to be like, oh speech perception is bilateral or not. It's going"},{"startTime":4568.0,"endTime":4574.56,"body":"to be what's the distribution of the capacity of the non-dominant hemisphere across the population."},{"startTime":4574.56,"endTime":4578.72,"body":"And it's not going to be binary and it's not going to be the same for any individual. And that's"},{"startTime":4578.72,"endTime":4583.2,"body":"what our answers are going to look like. They're going to look like distributions in unbiased samples."},{"startTime":4583.2,"endTime":4589.12,"body":"So yeah, we're also start recruiting right hemisphere people now. So hopefully we'll be able to add"},{"startTime":4589.12,"endTime":4597.52,"body":"that to our left. Hemi people and have some, some answers that satisfy us all. But yeah,"},{"startTime":4597.52,"endTime":4600.32,"body":"I don't I don't think the right hemisphere people have too many deficits."},{"startTime":4600.32,"endTime":4606.48,"body":"No, no, I know. Yeah, yeah, I don't we found subtle ones in our sample."},{"startTime":4606.48,"endTime":4611.92,"body":"As did Kathy and her group. Yeah, but pretty subtle, right? So, I don't know that I don't think we're"},{"startTime":4611.92,"endTime":4615.68,"body":"going to be shocked by the right hemisphere data, but we I agree with you. We need to do the due"},{"startTime":4615.68,"endTime":4621.36,"body":"diligence and recruit those people as well. Yeah, yeah. And the people with no aphasia."},{"startTime":4621.36,"endTime":4624.8,"body":"Oh, absolutely. So yeah, that's how you know, that's how our lab works. It's like your, your"},{"startTime":4624.8,"endTime":4630.08,"body":"inclusion is based on your legion, not on whether you have aphasia or not. You have a left hemisphere"},{"startTime":4630.08,"endTime":4638.0,"body":"legion. We're coming to see you. And good. And, and yes, the Lily who is the lead SLP in my lab"},{"startTime":4638.0,"endTime":4644.56,"body":"is incredibly good at getting people to agree to be in our study. Like she takes it as a she takes"},{"startTime":4644.56,"endTime":4649.36,"body":"it as a personal affront if anybody ever declines consent. And like you'll literally like it'll"},{"startTime":4649.36,"endTime":4653.44,"body":"happen like once per year and you'll like, you know, lose sleep over it. And like why didn't they"},{"startTime":4653.44,"endTime":4663.28,"body":"consent? Yeah. So fascinating questions. And I mean, you know, I think you you put forward a really"},{"startTime":4663.28,"endTime":4670.24,"body":"strong hypothesis about the bilaterality of speech perception and comprehension. And I think"},{"startTime":4670.24,"endTime":4677.12,"body":"this is a lot of truth to it. And and I think that the facts about, you know, the overwhelmingly good"},{"startTime":4677.12,"endTime":4680.8,"body":"word comprehension in most people with aphasia is not one that should be like ignored."},{"startTime":4681.44,"endTime":4687.68,"body":"Oh, um, but yeah, we have to figure out the exact distribution of these phenomena."},{"startTime":4687.68,"endTime":4692.72,"body":"Yeah, I mean, we need to ask the different question is language left dominant or not?"},{"startTime":4692.72,"endTime":4697.28,"body":"Is the wrong question is like you were saying, it's what is the distribution? And that's kind of"},{"startTime":4697.28,"endTime":4703.6,"body":"very by function, very a lot in individuals. And that's just an empirical question that we that"},{"startTime":4703.6,"endTime":4709.2,"body":"we haven't the field hasn't yet started hasn't yet answered definitively. You started in your"},{"startTime":4709.2,"endTime":4715.84,"body":"paper. I think that was great. And I've tried, but there's a gaps in all of this. Yeah, no, there's"},{"startTime":4715.84,"endTime":4721.12,"body":"absolutely gaps. Yeah, I'm looking forward to the next 10 years. I think we will, I think we'll get to"},{"startTime":4721.12,"endTime":4726.0,"body":"the bottom of this in 10 years. Yeah, we will, we will, we'll be in complete agreement about whatever the"},{"startTime":4726.0,"endTime":4732.88,"body":"whatever the answer is. Well, that might results with you just so we can I can get the other"},{"startTime":4732.88,"endTime":4742.24,"body":"perspective. Yeah, or Julius or Argye or you know, or just about anyone else. Yeah. Sometimes I'm like,"},{"startTime":4742.24,"endTime":4747.68,"body":"oh, I'm maybe in like too like, you know, fiesty with Greg and I'm like, no, you're you're hearing"},{"startTime":4747.68,"endTime":4752.8,"body":"the same thing from your from your co-authors. So I'm not like too ashamed of it. And like I and like"},{"startTime":4752.8,"endTime":4756.56,"body":"you know, like I said, you like a good argument. And like, so I could share with our listeners that"},{"startTime":4756.56,"endTime":4763.2,"body":"yeah, like I was postdoc in your lab for about a year. And the way that it happened, the way that you"},{"startTime":4763.2,"endTime":4769.6,"body":"invited me to be a postdoc was that you reviewed one of my papers and largely disagreed with it."},{"startTime":4769.6,"endTime":4774.16,"body":"But we're like, and then you just emailed me after it's like, I reviewed your paper. I said, I said"},{"startTime":4774.16,"endTime":4779.68,"body":"except don't really agree with you, but would you like to do a postdoc? So, I think it's like,"},{"startTime":4779.68,"endTime":4786.88,"body":"that's just the right like that's the right attitude to like, you know, um, finding out the truth,"},{"startTime":4786.88,"endTime":4791.76,"body":"right? Is like you find somebody you don't agree with and you uh work with them. Yeah, totally."},{"startTime":4791.76,"endTime":4796.96,"body":"You need you need someone with a different opinion. So, I mean, there's nothing I have no stake in"},{"startTime":4796.96,"endTime":4801.92,"body":"the outcome. I just accept for I want to know how it works. What's you know, it's if we if the"},{"startTime":4801.92,"endTime":4807.04,"body":"motor system's involved in speech perception, so be it. Oh yeah. And well, it should be said that on"},{"startTime":4807.04,"endTime":4818.32,"body":"the question of that paper, um, you, you were right. Yeah. Okay. Well, um, I've taken a lot of your time."},{"startTime":4818.32,"endTime":4825.92,"body":"And I think we've gone through a lot of the big concepts of the book. Um, I hope that all the listeners"},{"startTime":4825.92,"endTime":4832.24,"body":"will want to read it. Um, I really enjoyed it. And yeah, congratulations on on on writing this."},{"startTime":4833.12,"endTime":4838.48,"body":"Yeah, really it's got I think it's going to be real seminal piece of work. Oh, thank you. I really"},{"startTime":4838.48,"endTime":4843.68,"body":"appreciate that and your opinion means much. And I always enjoy talking to you and debating you and"},{"startTime":4843.68,"endTime":4849.84,"body":"yeah, it's, it's a good time. Thank you so much. All right. We'll take care. Great to talk and, um,"},{"startTime":4849.84,"endTime":4857.36,"body":"look forward to seeing the book in print. Coming soon. All right. Bye. Take care. Bye. Okay. Well, that's it for"},{"startTime":4857.36,"endTime":4862.4,"body":"episode 35. Thank you, Greg, for the very fun conversation. I hope everyone enjoyed it as much as I"},{"startTime":4862.4,"endTime":4869.04,"body":"did. I've linked Greg's book on the podcast website at langneurosci.org/podcast and in the show notes"},{"startTime":4869.04,"endTime":4874.32,"body":"as well as a few of the other key papers we discussed. Like I said, I really highly recommend this book."},{"startTime":4874.32,"endTime":4878.8,"body":"Anyone who listens to this podcast is going to enjoy the book. All right. Thanks also to Marcia"},{"startTime":4878.8,"endTime":4891.76,"body":"Petyt for editing the transcript of this episode and thank you all for listening. Bye for now. See you next time."}]}