The Hippocampus as a Cognitive Map: Research Converation Part 2 with Lynn Nadel

Transcript:

The Hippocampus as a Cognitive Map and precursors to Active Inference

Andrea Hiott: [00:00:00] Okay. Hi, Lynn. We already said hi, but hello again. Um, so last time we got up to about UCL years and the book, that you were writing with John. And something I wanted to start with is you said something about teas that you had, because we had talked about your tea time in, in Montreal with Hebb, and you were going to tell me about some tea times at UCL that were even more daunting.

Oh,

Lynn Nadel: I'm kidding. I can't remember why I thought that was important, but actually we did, John and I did, this is London, so we went, we went for tea every day. This is, British life, so it's important. Three or four in the afternoon, you go for tea and we had two, we had two different habits, you might say.

One of them was to go to the kind of universe UCL tea room, which was a big room with a, with a big old lady with a monstrously large teapot pouring tea for people. It's a good image. It's [00:01:00] quite an image, actually. Really great. So that was one thing. That was the typical thing. And that would involve walking through parts of UCL.

Have you been to UCL? I have,

Andrea Hiott: yeah. Do you know

Lynn Nadel: where Jeremy Bentham is? That kind of thing with his bot whatever. Yes. I

Andrea Hiott: think so. Yes.

Lynn Nadel: We would walk from anatomy through the area past Jeremy Bentham into the tea room every day. So that was a habit. But the other habit was we would have tea regularly with the anatomy and physiology faculty.

in a room in, so anatomy and physiology were both in the same building in Gower, right? I don't know if you know the way that Gower Street is all that stuff facing on Gower Street. That's where the medical school is. On the other side is the hospital on one side. On the east side of Gower is the university.

On the west side of Gower is the hospital, right? Aspects of the hospital. And so the [00:02:00] anatomy and physiology shared one of the buildings on right on Gower Street, and they held joint tea. In in a kind of a big seminar room, the old style seminar rooms with lots of books, like a lot. You remember what books, books with libraries,

Andrea Hiott: oh, yeah. I still have a lot of books, actually.

Lynn Nadel: Stuff like that. I still, I do too, but like, what am I going to do? It's a real issue because I've already gotten rid of half of my books and I still have

Andrea Hiott: it's an issue for me too Because I live in Europe and half my books are still in states. And yeah,

Lynn Nadel: so we went to this team with physiology and anatomy and physiology at that point was populated by three Nobel Prize winners Ricardo Milady Burt Katz Katz Milady and and Huxley Andrew Huxley I think it was Andrew Huxley.

Um, and they, sat around and held court in tea every afternoon. So here was, here was me and John, a couple of brash Americans, [00:03:00] sitting around this table, and there are these three distinguished, properly dressed, which I never was, the properly dressed British, prize winners, sitting around, holding court, or talking about one thing or another, and that was really, Transformative actually in an interesting way.

I mean being in that kind of company It was it was a I mean, I my career has been extremely lucky So in that sense that you know at McGill I was surrounded by people like that. Yes, more or less. Yes high end No, I was and then luckily I mean in London. It was the same thing I mean, there were just people whose levels of achievement were such as to create a Let's say an aspirational goal.

I mean it was it was You know, John and I were, dealing with the best and we were, we had, there were no limits on what we thought we could do.

Andrea Hiott: And you had, were you writing the book during this time already or?

Lynn Nadel: Yeah. Yeah. writing the book. This is, this is during the time we were writing the book, we were constantly [00:04:00] interacting with those kinds of people.

And I think it had, must've had some sort of an effect and it was all around tea, which is kind of strange.

Andrea Hiott: Yeah. Well, I mean, for me, it's very fascinating.

Lynn Nadel: I don't, I thought that was important. But, but it's, it's a very, and I still, to this day, um, order extra strong Marks Spencer tea.

I still drink from that time back in London. Yeah, I got addicted to it and I drink it. I have, I have I have Marks and Spencer, which is wrong every day, still 50 years.

Andrea Hiott: That's really great. Did you ask them about questions? Did you talk to them about anything that you were writing about at that time?

Lynn Nadel: I don't know if John did.

I did not have substantive interactions with, with a number of them. I did with one other person in physiology who, who shared by name, interestingly enough, a woman, a physiologist who did some really in work, Lynn Bindman was her name. So I kind of interacted with her a little bit, but I didn't talk with, I mean, yes, I was inspired by these people to some level, but the other side of it was, these were your [00:05:00] average, these guys were your typical British pompous, British academic, I mean, they were, that, that was the other message

science is one thing, personality and kind of politics and stuff is the character or another thing. So I learned that lesson too, that, that,

Andrea Hiott: Did you also get the feeling that it's not as far away out of reach as you might have thought? I mean, I remember at a young age being around famous people or people who are really well accomplished and it gives you a kind of sense of, oh, they're human and it's possible.

Lynn Nadel: Absolutely. That's the point. That's the kind of point I'm trying to make. It's all, there's all, they're just, they put their pants on one leg at a time just like me.

Andrea Hiott: Yeah, exactly.

Lynn Nadel: Basically, anything's possible. If they could do what they did, I sure as hell can, and I'm sure John felt the same.

Andrea Hiott: Especially when you're young and you have all that energy still, it's like, you can do this. Right.

Lynn Nadel: Yeah. So our attitude in, in when we were writing the book and you, you, you actually said it in your email, we actually were [00:06:00] very consciously aware, maybe, delusionally at the time, but we, we were consciously aware because we talked about it that, that the, The theory that we were putting together at that time could serve as a fulcrum for organizing the way cognitive science deals with the brain going forward.

We were very aware of that at the time. That we were trying to, to, we were picking out sort of the most popular brain structure and we thought if we could put forward a meaningful theory of that structure. That was, that was based on multiple levels of evidence, anatomy, physiology, behavior, all of these things in, in sync to the, to whatever, to the best extent possible that that could be modeled for how to think about talking about, Brain incognition, essentially.

And so we, and that it could be the fulcrum because the hippocampus was so central that we could, if we could unlock that piece, we might actually create the beginning of how you could, that was, we had conversations [00:07:00] exactly like that.

Andrea Hiott: Oh, well.

Lynn Nadel: At that time. I did say that in the

Andrea Hiott: email. Because to me, from my perspective, having, Come a bit later and studied it.

It seems like the thing that I mean, of course, the, the story I'm telling starts in a way with that time period. I mean, you guys being in that environment of McGill that we talked about before, but then it sort of coming together in that book and as the fulcrum are almost like, everything kind of getting Channeled into that and then almost everything that I see now kind of seems relative to that.

I don't mean word for word exactly what the book says, but overall the framework, everyone just uses it, right?

Lynn Nadel: Exactly right. I think, I think that's the truth of it, and I think we thought we might be doing that at the time.

But we also had conversations along the lines of, when we published this thing, it could just sink like a lead, like a lead balloon.

Sure, yeah. I mean, we were conscious of the fact that it could just, many things do. [00:08:00] I'm not sure if I told you that this book that I recently published with Richard Lane that, on, on the neurobiology of psychotherapy, kind of very interesting stuff, basically. So trying to understand what's going on in the brain during therapy.

I can tell you more about that some other time. Yeah,

Andrea Hiott: I know you taught some classes on that.

Lynn Nadel: And I published on that and I actually, I've done a fair amount of, anyway, that book got published like, The week that COVID started.

Andrea Hiott: Oh no.

Lynn Nadel: And the book just sank like a stone. I mean, it's had virtually no, no pickup whatsoever.

Oh

Andrea Hiott: gosh. Anyway,

Lynn Nadel: we thought that that could happen with this. I mean, we were, we had two opposing views of what we were doing. Yeah. All the while trying to explain to our parents, or at least me to mine, and I think John to his, like, what are you doing? What have you been doing for the last five or six years?

You don't seem to publish much. I mean, what are you doing? Like what's taking so long? So we, we, we were aware of both of those possibilities, and we just did it because we were doing it.

Andrea Hiott: Well, this is [00:09:00] really, I'm glad we're here because I want to dig into this a bit because I'm trying to tell the story in a way that's accessible to people who don't know anything about brain science and in a way, so I want to get to that.

But also I just like the fact that you, so you, You were already thinking of of a framework. Were you thinking of a framework for cognition? For mind? Or were you thinking, okay, just for

Lynn Nadel: I think the mind, it would be too far to say mind, although John may have, John always He has all

Andrea Hiott: that philosophy going on.

Or you both do. I mean, the whole first part of the book is a deep dive. Yeah, but John

Lynn Nadel: had a real background in it. I didn't. John's wife is a philosopher. Got her PhD in philosophy.

Andrea Hiott: Eileen, right.

Lynn Nadel: So John really had, serious philosophical, I read a lot, but I didn't know, I had never no, no actual training.

Anyway, so,

Andrea Hiott: But were you thinking when you, when you were talking about it being a framework, were you thinking about for the study of the hippocampus kind of? Or were you thinking, because this was also a moment, I think it's so easy to forget, but Yeah. Yeah. Yeah. As we talked about in the first [00:10:00] conversation, it was all about memory and that wasn't that old, right?

The 50s, 60s, you were there when all of that was just right after the Milner, the HM, and that was the establishing hippocampus as memory. So you were just after that studying with those people. And then now we have navigation coming in. So in cognitive maps and Tolman and.

Lynn Nadel: Well, what we did when we, one of the key moves we made away from the, the broader framework of hippocampus memory was the notion of, of.

multiple memory systems. The notion that actually the hippocampus is responsible for only one kind of memory and other brain systems are responsible for other kinds of memory. So that's the broader framework. So we would put, we would be, looking at the board and we would write, hippocampus where?

All right. Hippocampus tells you where you are. All right. Well, you also need a part of the brain that tells you what you're interacting with. So, what's the what part of the brain? What's the why part of the brain? What's the who part of the brain? So, we began to sort of think, you could break down the brain [00:11:00] into these parts.

Into networks that we didn't talk about networks. We were not networking, but it regions which are responsible for different aspects of knowledge about the world and somehow memory emerges from all of that. So we were not saying the hippocampus was where memories were stored. We never said that, but we were saying it's it's focused on it's computationally structured to deal with the where part of what's of the world.

We, we were not, we understood the notion of sequences, but we didn't make a lot of it in the book. I mean, we talked about it as though we meant that, but we never really said, and the hippocampus generates C, like Boushaki is saying. I mean, we, we, we hadn't gone that route particularly, although John was quickly onto those kinds of things, and, Bayes procession, all that came out, came out later.

But in the book, we hadn't yet talked much about the role of the hippocampus in generating sequences and in temporal, but we did talk about spatio temporal, I mean, it was a bit mixed up, but the framework was a framework of if, if [00:12:00] we can solve the hippocampus as the where part of the brain, then we can start to use that to leverage, these other types of knowledge that the brain.

Somehow manages to represent and that would be a framework for thinking about how to link the brain to cognition that that we thought about but we, but there were a lot of pieces we didn't anticipate, and there were a lot of. Yeah, anyway, I mean that that was that part of it was was absolutely on our minds.

Andrea Hiott: Yeah, and the way it's. It's a bit of a brainstorm, the book. I mean, you do talk a lot about space and time. I like it that it's like that, that way, because you can see that it's not that you've decided anything for sure, but you're kind of illustrating. What I think now we can see a little bit more clearly, which it's not necessarily I mean, I didn't understand it maybe I'm wrong that you're saying that this part of the brain is only this or this or this but just this idea that We don't have to [00:13:00] have these separate categories Of like one kind of like there's memory and then there's navigation and then there's this and this and this

Lynn Nadel: We didn't I think you're right.

We did not realize it at the time but we were actually weighing in on a, on a significant debate about exactly this question of whether there are dividing lines between things like memory and perception and sensation and, mm-hmm. Navigation and decision making. We were weighing in on that debate without realizing it.

We were weighing in on the side of there are no dividing lines

Andrea Hiott: and you were showing that we could start to think of it. In a different way. I think that's the hard part, right? Is because it's easier to think in these categories and maybe we needed to back then because it was all just beginning,

Lynn Nadel: but then there followed from the 78, they followed 20 to 25 years of debate about that issue.

It sort of sort of emerged. And it was clear that our position put us on the side of the. Hippocampus does everything with regard to space and [00:14:00] navigation. It's not just long term memory or short term memory. I mean, it's the same system. Different states of the system are involved in different aspects of math, so on and so forth.

It took us a while to realize, and I then jumped in on that side of the equation. But I think that was inherent in the position we took right at the beginning, that, that we were actually weighing in on the, these, these distinctions, these textbook distinctions. Don't make much sense. We continued to use them ourself, because we had no other language.

But I think the, the, the framework we were putting together was a framework that, that, necessarily dissolved those boundaries once, once, once it, once it was fully developed.

Andrea Hiott: Yeah, you couldn't. I mean, it's like, you can't, you couldn't possibly see where we are right now. Back then, but in a way that's kind of opened the door for people to start thinking about it in that way.

And um, one thing was this idea of the model and the map, which of course we, it's Tolman, we can talk about Tolman and this idea of the cognitive map, but really making like, putting the, [00:15:00] looking at that instead of looking at these categories in a way. And then I guess what I want to try to understand is how you were thinking about, Model and maps and and so on because of course now everything is you know, there's that's what everything is about in a way And we're still trying to figure out are they really in brains and all this but it really generated a beautiful kind of sketchbook To think about all these big issues Beyond those categories.

Lynn Nadel: I mean, it's hard for me to actually Think about how to talk about this issue because I don't think I was ever in the other place. I think, as I described to you, because I went to undergrad in Canada, I mean, I don't think I was ever in the place, thinking that it wasn't like that. I mean, I always, I just started from where I had started.

And and you take under, if you take intro psych from head, you assume that the brain is creating representations of stuff in the world. I mean, that, that's it. And I never had another view. So well, that was necessarily going to be the position [00:16:00] we took when we went to the hippocampus because I, I, I couldn't, I couldn't.

think about the brain in any other way. And, and I think John was influenced a lot, prior to McGill by his working with ethologists. So he was very tied into thinking about, the real world. And so trying to record it, really moving animals. I mean, John's career was, was heavily influenced by the early work he did with, Danny Lehrman on, ethology on real behavior, real animals in the real world.

And that's what John did. He brought that into physiology, so to speak. So we, we, we knew from the beginning that we were, we were dealing, we were both of us because he was the same. He had worked as an ethologist, not, he was not in a psychology program, where he, where he was learning behaviorism when he was a man, he came to McGill.

Kind of like a blank slate almost, with philosophy in the background,

Andrea Hiott: and

Lynn Nadel: ethology, right? So, both of us, we never thought, well, let's see are we, are we saying something different here? We never even imagined it, we didn't [00:17:00] know there was another, I personally don't think that, I don't think I understood the depth of the theoretical positions taken by the people who I was ignoring.

At the time and any of them, I paid no attention to Skinner or the behaviorists or any of that stuff like it was just nonsense as far as, and I think I was unfair to them at the time but so I was totally in the representational camp already. Okay. So when, when we got going on this, I mean, we were obviously the, our notion was that, yeah, there's something like, there's an equivalent to something like a map in the brain.

So the brain forms these internal models. I mean, I, it couldn't be any other way, it seemed, I mean, how could, so again, this is straight head. I don't think there's anything, we were trained in that way of thinking and we went that way. And Tolman was, The other influence, which I don't, I only just recently realized this, this, um, George Miller.

Andrea Hiott: Like Brenda Milner.

Lynn Nadel: Not Brenda Milner. Miller.

Andrea Hiott: Miller. Oh, George [00:18:00] Miller. George

Lynn Nadel: Miller. Seven plus or minus two. That's George Miller.

Andrea Hiott: oh yeah, the number that you can hold in your working memory.

Lynn Nadel: That's George Miller, right? Okay. And George Miller wrote a book in 1960, which a lot of us read, called Plans and the Structure of Behavior.

Andrea Hiott: Oh.

Lynn Nadel: Do you know this book? Miller, Galanter Well, I,

Andrea Hiott: I, this sounds familiar. I definitely haven't read it, though.

Lynn Nadel: It's a very famous book. Miller, Galanter, and Freeboom.

What the three all right. And they proposed what they called the TOTE mechanism, test, operate test execute. They proposed a kind of a, um, what's the right word for it. I am, I'm having word finding trouble these days. My age is showing itself. They proposed a model if

mechanical model, more or less, of how the brain works. And it was very much anticipated the predictive story. We can, we'll get to that. You could say, um, but it, it, it was where they were talking about [00:19:00] it in a way that they said, that the brain creates an image. They were talking about images.

So they actually were talking about what is functionally the equivalent of Tolman's cognitive map within that model. They didn't use. So, so I had read that book. Everybody read that book in those years. Cause it was like one of the few books that was really trying to do something interesting. And, and I, I suspect that that might've influenced us as well.

That, that the general framework of that. Of that, which, which, which assumed that they were built in representations and assumed that those representations kind of influenced how you reacted in the world, and that the feedback from those, how you interacted in the world, then caused you to change.

I mean, all of that is very clearly kind of where we are right now. And the germs of that was in that were in that book. Even though it got, it's, it, book had a mixed fate, at the time. But, but it certainly, I think, influenced, again, further to think about, the brain as a [00:20:00] representational device.

So I don't think there was ever any chance that we would have approached this differently. I'm not sure how we ever could have come up, having seen those place cells, having read Tolman, having been trained by Hebb, there was only one, there was only one place to go. And the question was how, it was how deep we were going to go into it.

That was really, how are we going to, are we going to write a short paper on this and be done with it? Or are we going to take this, the whole, the whole 10 yards? What do

Andrea Hiott: you think was the deciding factor between going, going all the way?

Lynn Nadel: I

Andrea Hiott: just can't, you couldn't put it down or something.

I feel like I, you, you said at some point, there was so many interesting avenues or something.

Lynn Nadel: The thing, it just kept on expanding and we just, well, we're really, we should, we should add this piece. We can't forget that piece. And it did start out, I think, as I told you, it started out, we were going to just write a paper.

And I don't know what would have happened if we had ever written that paper and that, and then gone on, gone our separate ways [00:21:00] or something. I have no idea. I mean, we didn't

Andrea Hiott: tell the story, but that you were going to write the paper, right? But then you kind of upset the editor at the site. Well,

Lynn Nadel: I assume that we had.

Insult that I had insulted the editor of Site Review, so that was, that was no longer an option. So then we decided we'll write a small monograph. In those days, it was quite common for Oxford University Press to publish small monographs. Really small, 150 pages, something, like that.

So that's what we did, and we actually entered into a discussion with Oxford, and they thought it was a good idea. So we, okay, we'll do a small monograph. And we wrote, and we wrote a draft. of this small monograph by, it was in 1972, I think. When that first draft, it was either 72 or 73, and we had this draft, it was about, I think I told you, it was about 200 pages, maybe 200 to 300 pages, typewritten, so it would have been, 150 manuals, it would have been something of that order.

And I, [00:22:00] did I tell you this already? Without

Andrea Hiott: all the philosophy and everything. No,

Lynn Nadel: no, this had everything. This was a Oh, no, no.

Andrea Hiott: You didn't tell me that.

Lynn Nadel: This first draft had bits and pieces of everything that showed up in the Okay.

Andrea Hiott: In the

Lynn Nadel: book. It was already a kind of a version of the full book, um, although nowhere near as fleshed out.

Because we had already by then decided that if we're gonna tell this story, we're gonna have to situate it, in a context that demonstrates how important it is. So we had to situate them in this broader framework of this is a debate that's been going on in the, in, in the field. This is a debate that's been going on in scholarship for thousands of years, basically.

Andrea Hiott: What's that debate?

Lynn Nadel: Well, it's how does the brain, how does, how does the brain deal with the world? I mean, we had something to say about that, we thought, and we, and we, we wanted to situate it in the big debate about, for example, like, where does our spatial knowledge come from? I mean, so there was this big debate about innate versus, I mean, this [00:23:00] is, and the debate That's what the whole first chapter is about, is tracking this debate across time, I mean,

Andrea Hiott: it's almost the debate of space and time and absolute versus relative. That's it. It's that debate. It's these big debates that actually go back to, like, the first philosophers in a way.

Lynn Nadel: That's exactly right. So we wanted to situate it in that. That's why the philosophy section came first. We wanted to situate this story that we were telling.

We wanted to give it the importance we thought it deserved. That it should be situated, really at the nexus of these big debates. of this really big philosophical issue, Kant versus

Andrea Hiott: Leibniz, and Newton and Einstein and everybody's in there.

Lynn Nadel: And then I, exactly. So the whole, it was exciting.

I mean, it was,

Andrea Hiott: it is, it's still exciting. And in

Lynn Nadel: some weird way,

Andrea Hiott: it's kind of the question, that spans

Lynn Nadel: disciplines. It absolutely remains the question. So that was the way, so that, that we, we did this, we had this 200 to 300 page. It was 300 typewritten pages and we made 30 [00:24:00] copies, Xerox, 30 copies, and we sent them to people around the world.

We sent them to everybody we thought could give us some useful feedback, unsolicited. Half of them were people we didn't know, people in philosophy or linguistics, because there were parts of this thing that, et cetera. We sent this unbidden out, and we talked along about, the risk we were taking.

Andrea Hiott: Yeah, I think that's why it's so successful in a way is because it's it's looking at the problems. It's talking about the problems It's not necessarily saying here's all the answers But it's like showing there's different ways to explore it which for me becomes a bit the framework that we're trying to embrace this interdisciplinary idea of neuroscience cognitive science, I mean in a way you that's kind of the The start that I'm talking about, it's bringing in all the stuff that now that's what you study.

You study all that stuff.

Lynn Nadel: Right. Exactly. Right. And I think that's kind of where we were coming from basically.

Andrea Hiott: But I do wonder, um, [00:25:00] if you thought about, if memory and navigation needed to fit together somehow because of this one area of the brain and all of these different studies.

Lynn Nadel: No, we didn't.

I mean, and I still don't, I mean, I'm still, I think the field as a whole, and me certainly too, are still, is still struggling with, with this contingent fact that navigation and memory are wrapped up together in the brain. It's a fact, we know it. But why? Why? Did it have to be that way? Or did this just You know, I mean, why do we have two eyes in the front of our head?

Rather, I mean, there's all kinds of things that happened. They didn't have to happen, but they did. And that determined what came next in evolution. So why, why, why are these two things kind of so wrapped up together? And that, that remains a challenging question. Yeah. I do

Andrea Hiott: think that for me, that's part of the importance of all this too, is because And I'm not sure you will agree with this, you might actually disagree, but for me it's starting, we're starting to see that those aren't really different things, but it's different ways of looking at this process,

Lynn Nadel: that's part of it. That you can use

Andrea Hiott: the same model to look at.

Lynn Nadel: That's [00:26:00] part of it. The process

Andrea Hiott: from different angles, which is really hard to get it, to understand.

Lynn Nadel: Dissolving these bar, these, lines, these, these. All those categories. It has those, it has, it has that effect, exactly right. Yeah,

Andrea Hiott: I think we're still figuring out how to do that, and maybe it takes some new technology and maths and so on.

That for me is the exciting thing, is opening up to, it's not about calling one category memory and one navigation, but what are we trying to figure out, and then we might see different patterns in the same area.

Lynn Nadel: That's true. But it's important to remember that the kind of memory we're talking about is a specific kind of memory, right?

So it's not that navigation is entwined with all forms of memory. It's, it's entwined with a brain region that is, that is critical for a particular kind of memory. And other parts of the brain, are not connected to navigation in that way. So it's not that memory and navigation writ large are totally intertwined.

It's that there's an aspect of navigation and an aspect of, it's a Venn [00:27:00] diagram issue. Mm-Hmm, , there's, there's aspects of navigation and aspects of memory that over what we call memory that overlap. Right. And I've been, what, what I've been thinking, and I, and I I think, don't think we ever said anything about this in the book, is that it has to do with, and I may, we didn't really address the evolutionary issues in the book.

I've written about these,

Andrea Hiott: you've written about development. I wanted to ask you about that too.

Lynn Nadel: But the, but this is, this is phylogenetic development. The arguments, that I make now is that the evidence now showing that the hippocampal mapping system can be used for non spatial things is part of the debate.

Is this really a spatial system or not? Whatever. So the argument I'd like to make now is that evolutionarily, it started out as a purely spatial system. That what drove the, the evolution of this system was the need to effectively find your way around in space, I mean, which all terrestrial animals, not just terrestrial animals, all animals that [00:28:00] move.

If they move, they've got to figure their way around the space, unless they're one celled organisms that just drift with the water. I mean, there are kinds of animals that don't, even

Andrea Hiott: then they're still making their way. It's just making their way according to different ways,

Lynn Nadel: smell and things like that.

Right. So, so, so the idea is that life on this planet presented, finding your way in the world from an evolutionary perspective as a key problem that had to be solved in order to, to, to find food in order to find mates in order to find safety, all these ways, everything requires being able to move effectively in space.

Andrea Hiott: So Yeah, in a way that is life, right? It's day one, you're figuring it out. There's no choice.

Lynn Nadel: So the argument is that it started as a purely spatial system, but, but in order to do the job that it had to do to map space in some reasonably detailed way, so you could actually find your way around in the world, it had to, it had to be focused on details.

It had to actually be [00:29:00] focused on details. Now, if you put together a system that is basically noticing all the details in the world and, and sort of mapping them, if you will, or into some, onto some sort of a scaffold, that enables you to work out the spatial relations amongst them. If you do that, for a purely spatial purpose, you end up with a memory.

You end up with a memory of the details that existed in that space. So, argument goes, starts as a spatial system, needs to deal with details in order to, in order to function effectively as a spatial system, having evolved into computationally a system that can do that with details, this indexing mode of hippocampus.

Suddenly, it's a memory. This is great. Now we can use this as a memory. Right? And it's a memory for the place that I was in, context memory as a memory for where something is located. We can use it for memory. And then it expands in that way. And this [00:30:00] device, this kind of relatively flexible computational device that can take details and map them into a continuous manifold, which is really what a cognitive map is, can be good for things that are not spatial.

So, once you, Transcribed by https: otter. ai With enough jiggering in evolution, you might be able to map something else onto this system, like language, that can fit so on and so on and so on. So that was kind of where, where we were. That was what we were thinking.

Andrea Hiott: Yeah. I mean, that's what I, that would be kind of how I would propose it to in a way is that it starts with that system of, That you described, but even what we call spatial can change a little bit depending on where you're measuring it from when it comes to something like a language or an image representation.

Yeah, yeah, yeah.

Lynn Nadel: Space is by no means a, a unique, unequivocally simple thing. No. Space is just as complicated as memory. Right. So, so that would be.

Andrea Hiott: The same thing that, the same process that you're describing can actually kind of scale and nest at [00:31:00] different levels and it even doesn't even have to be only the hippocampus, but I mean there.

There's something about the process that you're describing that Yes.

Lynn Nadel: Anyway, so that was the framework. Now, the other piece of the framework, so the bigger, broader framework was that we, we think we can break the brain down into these systems. If we think about them the right way and the right way to think about them is the kind of knowledge that they convey to the organism.

Spatial knowledge, value, knowledge, the amygdala. Mm-hmm. , et cetera. You can, you can see where this is going. Yep. Well then what, what next? Well then the other piece of the puzzle that you've, that you've pointed out was that we bought in. Right away. Again, we didn't think about it as like there's an alternative here.

We bought in immediately to the idea that if you have such a thing, you can use it to make predictions. You basically use it to behave. You use it when you come to a choice point. You consult your map and it tells you if I turn left, I'm going to get this. I have left, right. If you turn left, you're going to get this.

If you turn right, you're going to get that. That was essential. That was essential to the model. [00:32:00] Right? And so we said that.

Andrea Hiott: So this whole idea of active inference, minimizing surprise, prediction error, all in there

Lynn Nadel: even though we didn't use any of those words.

Andrea Hiott: No, those words aren't there at all, but there's a similar idea that's going on.

You have some kind of Yeah, you have some kind of model you would have called it right or map with which you're I mean, I guess you aren't all Prediction is the word we could use now But in a way that's how you're moving in through the world in the way you described like the more so you move through the world You you notice patterns in the world.

You will align or fit to those patterns, whatever and literally your brain and Is doing that. And that is your kind of model which you then use to minimize, um, whatever might harm you.

Lynn Nadel: Exactly right. So the framework we were creating where we bought into Tolman's idea that what you learn about all the expectations.

Mm-Hmm. , you learned about these leads to that. Right. And you act on the base. Toman had it too. I mean, this is, we're not new to us. So we bought into that completely. And then, and then we said right [00:33:00] off the bat, one of the key things the math does is it makes predictions. And that we did say, we said predictions.

We did use that word there. We didn't say. The brain is a predictive device and we understand all that, none of that, but it's all, it's all implicit in the frame that we were, that we were creating, I think.

Andrea Hiott: Well, I think that's a strength for everyone, right? When you, in the same way you were just describing Miller, it's similar to Tolman, which is similar to Hebb.

There are different ways of trying to describe something that people are obviously seeing and have the technology to somehow try to point out. So I feel like in a way. the cognitive mapping and the predictive processing, you're in two different references and two different kind of ways of coming at it.

But aren't we sort of trying to basically understand how some sort of body with a nervous system processes its encounter in a way to survive? I mean,

Lynn Nadel: Absolutely. That's the key right there. That's the whole story, but, but of course it turns out to [00:34:00] be not so simple.

Andrea Hiott: Well, it's so rich and it's always changing and, weirdly in the way you describe the more we learn about it, the more it changes because it's all part of it.

Like one's process. Yeah, but um, I do wonder like how you really think about representations and models and so on, Tolman already there was this connection with knowledge and navigation and it's all already in all the stuff but when you study it, sometimes we still try to separate everything and say there is like a static representation in the brain.

Um, and are you saying that, or are you, is it more patterns based than parts based? Oh, it

Lynn Nadel: is. It is patterns. I mean, it, it, Wow. I mean, that's a tough one. That, these are the tough issues. These

Andrea Hiott: are tough, but you know, it's the kind of stuff that people need to talk about more.

Lynn Nadel: Absolutely. Absolutely. Here's what I, here's what I'm current. I mean, this really speaks to the question of what do you think a memory is

Andrea Hiott: among

Lynn Nadel: other things. You could say, what do you think of representation is, but let's say, let's talk about it in terms of, or [00:35:00] even a

Andrea Hiott: trace because it ends up, with your multiple traits, like people still can go around the same.

Theory, yeah. Or the same issue.

Lynn Nadel: Something changes in the brain as a function of our experience. Everyone accepts that,

Andrea Hiott: right? I mean, we've seen that in the studies, for sure.

Lynn Nadel: We know that things change, okay. Whatever that change is as a function of a, of a specific experience that I have, the changes that are, that occur in the brain that reflect that experience.

We can call that a representation of that experience. Let's do that for the moment. Now the question becomes, is that representation explicit in the way you're describing? Is it a static pattern that you could point to? If you just knew what to look for, you could say, aha, the activity of these 72, 000 neurons.

That means I'm thinking about a bird. I got versus, The idea that we don't actually have. I chose a bad example. Let's take an example of [00:36:00] again of a memory. So I have a sort of a memory for what I did yesterday, whatever, whatever happened in my brain changes that occurred today that stored information about what I did yesterday.

So the question is whether they are stored literally as a, as a kind of a memory, the way the way a recording is stored. Or whether they are stored in some other form, and then the information that is gained during that experience is somehow put together when you, when you are recalling it. Is memory always a constructive act of putting some things together?

Or is there some actual template that is the memory and all you have to do is ping it, basically?

Andrea Hiott: Like we could go lift it out of the brain or something rather than

Lynn Nadel: I'm veering in the other direction now. I think up to recently, people were of the Yeah. There are memories and you could find them, right?

And they are permanent. And we know that, blah, blah, you can change them and then reconsolidate. Then all of a sudden the dynamics of memory began to emerge, reconsolidation, whole bunch [00:37:00] of other things began to emerge that, the, sort of the dissolution of the line between perception and memory, the idea of their moment, all of that stuff conspires in all that

Andrea Hiott: stuff.

That's in. In the book, that got richer too. Yeah. Well that is

Lynn Nadel: kind of in the book or hinted at in the book and then you saw, well, does it make any sense to talk about memory that way anymore? Kind of the way the sort of medial temporal lobe memory system framework talked about memory, that you have memories and they're stored in this system?

Andrea Hiott: Yeah. I think you're already, in a way, what you're saying is. We don't have to talk about it that way anymore. I'm not sure it was ever that way, but we needed, that's why I bring it back to the book because it's similar to those categories and stuff. You need them up to a point. You need to believe them as real somehow like that.

You can pick them out of the brain, but maybe just don't need to believe that anymore. I don't think it actually changes the research that was done. It just changes the way we

Lynn Nadel: talk about

Andrea Hiott: it.

Lynn Nadel: Absolutely. I believe that's true. But for a while, I mean, the field of memory at least was dominated by the debate between those two [00:38:00] positions, right?

Andrea Hiott: Yeah. And I really understand it because you want to hold tight to that. And I just think it's more that we can't handle how to understand that it might not be there in some, you

Lynn Nadel: Totally. Static

Andrea Hiott: way. It doesn't mean it's not there. It's just more that a million things are, could be there depending on, again, what encounter are you in?

Lynn Nadel: When you think about, I mean, we're trying to work on these questions of how, what, what is actually there and, you know, how, how stable is it? I mean, what we know is that most of these things are not very stable. Yeah. I mean, the whole , so everything's up for grabs there, but my position is close to what my current position is, is what is very much what you're hinting at now, which is we don't need to talk about these things that way anymore.

Now, I, I prefer, I, I published a paper back in oh eight I think, which you may or may not have seen. It was called Update on Memory Systems. Said, so the work away and we should just use.

Andrea Hiott: We

Lynn Nadel: acquire knowledge of various kinds, and, and different systems are responsible for acquisition of different kinds of knowledge.

And then when [00:39:00] we retrieve a memory, we just access all the knowledge we have and put together that memory.

Andrea Hiott: Yeah, it's good you bring up that it actually has these real consequences. I mean, because we can get lost in trying to describe it, but actually it really matters in terms of if we, if we want to help people who have some issue with memory or something, so it's not, yeah.

Like, it, it matters the language we use, but what we really want to try to figure out, and what you're trying to figure out in your work, is how do you, like, figure out when and how those traces, or whatever we want to call them, representations, are activated. Not that, They need to be stored somewhere, but it's like, how do you, what, what, when something goes wrong, what's going wrong,

Lynn Nadel: yeah. Well, that's kind of what I'm interested in now,

And that's the predictive, that's the prediction error story. When something goes wrong, when your memory leads you astray, you make a prediction that doesn't get confirmed. Your memory no longer holds for the current situation. That's the, that's where the adaptive, [00:40:00] Story begins.

I mean, I don't know what happens now. How is the system structured such that it could take this faulty Prediction benefit from it. What happens now, right? So you got, you got to go back and you got to figure out, where did prediction come from in my brain and, and, how can I change that information in a way that I, in the future I can behave appropriately.

And so all those dynamics that now come in. Yeah, that's

Andrea Hiott: I think that's important too is that same notion of what why it's important to write books about this and to collaborate your career has been a big collaboration and to because a lot of it is this figuring out the story, it's The more that we, I mean this word trace is kind of loaded now that I talked about trace theory, but the more that we can sort of trace this development of how we understand all this research, because even our understanding of the research begins to change, the better maybe we [00:41:00] can start to kind of, model and understand how to do that, right?

Like, um, even just looking at that book and being able to read that book and, and all the papers too. It's one reason papers are still important. You can start to see um, patterns, right? That have held. And if you can reinterpret them in the way that you're doing now, you never know, it might be something very simple that suddenly can help us understand.

Um, how to keep better health in terms of whatever's going on. That's what we're all

Lynn Nadel: hoping for, that kind of little insight, that holy grail, that will, it'll all crystallize and it'll all look so simple. Oh, right. I'm sure it

Andrea Hiott: will at some point. That's how it goes.

Lynn Nadel: To me, that's the scientific enterprise.

And that indeed, the way the book up here, I mean, that's, in fact, a metaphor for how aspects of the book got put together. Yeah,

Andrea Hiott: the book is a bit of an example of that.

Lynn Nadel: But take, take it, take an area, say, okay, let's say we want to, we want to say something about development. So I just then went and read everything [00:42:00] that had ever been written about development of the hippocampus.

That was my job, right? And those sections of the book, which were all of the behavioral lesion sections, I just read everything. And it was pieces floating around everywhere and just around, and then suddenly they crystallize. Suddenly, what you just described happens. That you begin to see a pattern in all of that, that allows you to simplify it, and you rotate stuff and suddenly everything's lined up, and you actually have a story that makes very few assumptions, very few free parameters, but it actually accounts for a lot of the story.

So that process that I just described in 30 seconds replayed itself over and over and over again throughout the whole book, all the sections that I, I don't know, I don't know how John approached writing the physiology, he probably had nothing similar, but in writing all of the sections that I was primarily, the first drafter of, that [00:43:00] was the process, do exactly what you're saying.

Andrea Hiott: Yeah. And in a way, weirdly, this is kind of a good example of, of what we're trying to figure out because you were able to do that then because there were, I remember you telling me you kind of went back and bought all the books that you, or as many as you could. Yeah. There they are. Yeah. They're there with you.

There's one bookshelf

Lynn Nadel: right there. There's about 25 books.

Andrea Hiott: Right. Which is amazing. I mean, if you tried to do it today. Like, you need new technology, new ways of processing it in a way,

Lynn Nadel: but it's the patterns that are,

Andrea Hiott: are the same in a way you're still looking for patterns in the same way.

And the more deeply you go, cause you went very deeply at that time, the more they crystallize. It's just, we're trying to figure out how do we process so much more information in a deep way.

Lynn Nadel: That's a, that is a significant problem for students now. You know what I mean? I don't envy that, younger.

You and younger scientists have other younger scientists and trying to, trying to sort of distill the patterns because the data set is [00:44:00] so much more enormous, than it was before. So it's, um, it's tough, but you know, I, I think if you were there We much more

Andrea Hiott: technology and

Lynn Nadel: I mean, all of that is true, but you know, at every stage, I think the people who are living their, their scientific experiences at that particular moment in time, they can You know, they can think, there's all way more complex, but they've you always feel overwhelmed.

You find lots of overwhelming, information. But did you feel overwhelmed?

Andrea Hiott: Did you feel like that when you were trying to read all those books? Or did you think, oh, this is manageable?

Lynn Nadel: It was manageable. It was manageable at the point,

Andrea Hiott: you felt it

Lynn Nadel: because you, because this was, in early seventies.

Andrea Hiott: Yeah. There may have been a thousand of this

Lynn Nadel: couple thousand. I mean, there really wasn't that much. I mean, there was a lot, but there wasn't, so that we, I went, I read whatever I could read in other languages. I got translations. I mean, we went into every, we tried to track down everything that had been published on the hippocampus.

Andrea Hiott: Very exciting [00:45:00] as of 19 time

Lynn Nadel: and, and try to distill the patterns from that, but. Now there's a piece missing here which is if you do that and you start with no hypothesis whatsoever or no framework, you're, it's basically needle in a haystack time. You, you have to go, to the very first step of looking at this massive array of stuff.

You have to have some organizing principle in your head.

Andrea Hiott: That's a really important point because you already, as you said, had this, you, you took for granted that, We had a framework,

Lynn Nadel: we had a framework and an orientation that, basically pushed us in a certain direction, that facilitated crystallization of a certain sort.

I mean, without that, you could be basically moving around, space, the space of this problem, so to speak, forever. And we sort of made that point. I mean, John made that point about the units. He said, if you, if you may have read that somewhere, look, if you, if you, if you approach this thing, like you're going to, in a given experiment, you're going to explore one variable.

Right? You're just going to confine the [00:46:00] animal. You're going to really restrict this environment. You want to explore one variable. Really? Do you really think you're going to find the right one? Out of 14, 000 that you might have manipulated in that experiment? You have to have some idea what are, what are the right variables?

What are the things that are likely to tickle this brain structure? You have to have some idea to start with. And we did, so we had an idea. And with that idea, One could look at this literature and say, can that idea help us crystallize this mess, this steaming mess of data? And what you see in the book is the result of our attempts to sort of make sense out of this rather inchoate literature, all within the same frame.

Andrea Hiott: Has your, um, we have to go soon. So I just wondered if your views of, um, like behavior and cognition have changed at all. In the beginning you were just, I mean, do, do you really think of them as separate or do you, do you see, do you see it all as not a lot of

Lynn Nadel: behavior and [00:47:00] cognition?

Andrea Hiott: Yeah.

Lynn Nadel: Well, I mean, cogniti, I haven't even how to define cognition.

I mean, that's my first problem. I don't, I, I try to stay away from. I mean, and whenever I ask even very serious psychologists, can you give me a, a definition of cognition that does two things? One, it, it cleanly separates things that are cognitive from things that are not cognitive. That the definition allows me to do that.

Mm-Hmm. and two, it, it, it does, it lets, it lets me ask the question. Do other animals and plants have this? Mm hmm. Right? Right. I have yet to find a person who could come up with a definition that satisfied any of those requirements.

Andrea Hiott: Well, I have a definition, and I think it's actually one you just gave, and I think it's, if, if it's a body making its way through an encounter, um, that's a cognitive for me.

I mean, in a way, I think that's what I'm trying to get at. I feel like you guys sort of started this way of looking at what is cognitive as, you Um, a [00:48:00] particular kind of act, which layers, of course, I mean, it, a plant making its way is a completely different thing than a human who has learned representations and language and so forth.

Lynn Nadel: But plants have memory. I mean, I mean, a lot of the things that we assume, reflect cognition, if you look at definitions and. Right. And that's

Andrea Hiott: why I think that definition works for a plant. You don't say that it has human memory because it doesn't have a human body. It doesn't have a human nervous system, but it's still going to have memory for it.

Um,

Lynn Nadel: the typical human in the street says the word memory. They don't think about what a plant is doing, and that's the problem.

Andrea Hiott: That's the problem. Because if you say a plant has memory, they think you mean human memory. And, um, that's the problem with how we've defined cognition, But I think stuff like your book opens, opens it

Lynn Nadel: the book opens up and we certainly use the term, but I honestly don't know. A very sharp definition of cognition that allows me to say, this is not [00:49:00] cognition. So I, I don't, I don't spend my time doing that. I guess I like representations. On the other hand, I wrote a chapter.

Did you read that? Did I send you that chapter? I don't think so. No, but I would love to read it. This was 1984. So it's pretty out of date. Oh, wow. And it was a book that was came out of a conference that was held here in Arizona. It was actually the conference that I gave a talk in that led to me getting hired here.

So it played a role in my career. I can, I'll send you that chapter, but again, bear in mind that it's very simplistic. And because it was, it was before it was just at the. Cusp of the Connectionist Revolution. Oh, yeah. I would definitely want

Andrea Hiott: to read that.

Lynn Nadel: So, so it was, anyway, I'll send you that.

Andrea Hiott: Um, alright.

Lynn Nadel: You can download it.

Andrea Hiott: Yeah, well, just please, please just send it to me or at least send me the name of it. Um, we only have four minutes left, but I want to ask you, cause you, you've been doing all this hippocampal history stuff. When we saw each other in Arizona, you [00:50:00] were thinking about maybe still putting it in a book.

Are you still thinking about that? Or are you just going to

Lynn Nadel: I think that's over with. Let me, I'll, let me Send history. Send representation.

Andrea Hiott: Your Mastadon stuff, your hippocampus. Oh, I'm actually don't, I don't do my social media.

Lynn Nadel: The book, the book is that, that's not gonna happen. So every what's what, what the, the new development in that, in that sphere is that Mike Camo, who's the editor of Hippocampus, the Journal, hippocampus, is.

He had asked me to join him in helping to put together a special issue of the journal and nowadays a special issue means more than just one issue. It's a

Andrea Hiott: theme

Lynn Nadel: on the history of work on Hippocampus. Okay. He's invited about 20 or 30 people to write somewhat a little bit different in response to somewhat different questions than the one that I was posing to people, but nonetheless, and I'm joining him with that a lot of people are so there's going to be a kind of a series [00:51:00] of articles coming out of out in the Journal of Hippocampus over the next year or two, where people tell their year.

Their personal story about how they discovered what they discovered or how they did what they did or, so that's the that's the latest book on the history front. I've given up the idea of writing a book because I couldn't figure out how to do it that I was happy with. So I'm happy just to get this history out there.

But that's that's where it's at.

Andrea Hiott: I just want to make sure because you I know you were asking people all these really interesting questions and stuff and I just, first of all, I want to be able to cite it like. If when I'm writing the book, so I wanted to know, are you going to compile it somewhere other than

Lynn Nadel: I don't think I have any intention of doing anything more with it than what I've done with it.

Andrea Hiott: I mean,

Lynn Nadel: I've, I've put it, I've put everything out there for the, for the use of the public. It's all out there on Mastodon, which is not necessarily accessible to everybody, but it's out there so it's public and people can do whatever they want.

Andrea Hiott: And what about, didn't you do some interviews with Milner, Brenda Milner and stuff like [00:52:00] that?

Are you going to put those

Lynn Nadel: somewhere? That one's on Mastodon now as well. I broke it up. Oh, it is? Oh,

Andrea Hiott: okay, great.

Lynn Nadel: Go back to Mastodon. I, I added the, the Brenda Milner, I added the, um, the Moser interviews and the Brenda Milner interview. Okay. So, so recent. All right, great. Maybe a month ago or two. Yeah. That's really great.

I don't feel like we got to a lot of stuff. We didn't, we didn't

Andrea Hiott: even talk about Arizona. We didn't talk about the McNaughtons. We didn't talk about anything, but we at least talked about interesting stuff relative to the brain, because that is what I'm in a way trying to figure out how to,

Lynn Nadel: at that time period.

Where are in what you are you doing?

Andrea Hiott: I'm working on a different levels, right? So as a philosopher, I'm trying to find a, actually a way to, to really define what cognition is. And I feel like it's already there. So I'm kind of looking at stuff that you've done, but also in other, in biology and a lot of different places and trying to say, what's the pattern and the framework that everyone's already pointing out? But I'm also, as I told you, I just want to tell the story because I think these ideas [00:53:00] I think can be very helpful for everyday readers if it's told the story of the hippocampus is told in a accessible way.

And it's also, you're all just great characters. It's interesting. So I'm also writing that.

Lynn Nadel: Yeah, so so what's your timeline?

Andrea Hiott: Um, I already have the first draft of the seahorse one the book But there's just so much that I still wanna there's just so many interesting people.

Lynn Nadel: There are

Andrea Hiott: yeah, there's just so much It's like that's why I As you know, you could just go on and on telling the story of the seahorse, the hippocampus,

Lynn Nadel: yeah, have you talked to John? I doubt it, because John is

Andrea Hiott: I haven't even tried. I talked to him in Arizona , but I didn't even tell him I was writing the book.

Lynn Nadel: You'd be more interested in getting John to pay attention to you over email. No harm in trying, but I doubt it. I haven't tried yet.

Andrea Hiott: I would love to talk to him. I really want to hear about his philosophical years and, like, I actually want to ask him about Eileen and if they talked [00:54:00] about it.

Lynn Nadel: Why don't you send him an email and say these are the things you're interested in.

You're writing a book on the history of this and these are the things you're interested in. Would he be willing to spend some time to tell you the truth?

Andrea Hiott: Yeah, maybe I will. And you can

Lynn Nadel: say you've talked with me and he could check back with me.

He might check back with me and say, is this person legit or whatever.

Andrea Hiott: Okay. Yeah, I will then.

Lynn Nadel: I don't think you have any harm in trying.

Andrea Hiott: If you're going to write

Lynn Nadel: the story, it'd be a good idea to try. The other, another person I think you should think about talking to if you haven't done already is Gyuri Busaki.

Andrea Hiott: I have talked to him. He, I, I went and visited him at his office and stuff. So we've hung out some.

Lynn Nadel: Good. Yeah. Yuri is, Yuri is He's good. He's

Andrea Hiott: really interested in the philosophy side too. So that, That's why I'm

Lynn Nadel: thinking, good, I'm glad you've made that contact. I encourage what you're doing. If I can help in any further way, let me know. I'll send you that, I'll send you that, the representation chapter now. Okay. And if

Andrea Hiott: anything comes to mind that you think, hey, this is, [00:55:00] this, about you or about anyone that you think this is really important and it should be in a story about the, um,

Lynn Nadel: I don't know, I think it would help me if I saw what you were including.

I mean, if I saw what you were including, then I might say, oh, there's a missing piece here. Oh, I'll send you a draft

Andrea Hiott: of it before.

Lynn Nadel: Before it's public. If you want to read

Andrea Hiott: it, yeah, yeah.

Lynn Nadel: Well, I will at some point.

Andrea Hiott: If you don't mind reading yourself as a character, but I think you'll like it actually.

It's all very positive. It's, it's a positive thing.

Lynn Nadel: You might want to talk to Charan Ranganath also, by the way, he's just coming out with a book now on, on memory. He's gotten a lot of press in the last week. Oh, really? He did.

He was at my lab. I didn't know he had a Terry Gross interview. Oh, really? It just came out two weeks ago. Wow. Okay. Unremembered. Something like, Why Do We Remember? Whatever it is. Ranganath just came out within the last few weeks. He's been doing interviews. He's, he's going to go over to the UK apparently to do, I mean, he's, [00:56:00] it's a big, the public kind of book about memory and remembering and forgetting.

And so Charan is, Yeah, somebody you probably want to pay attention

Andrea Hiott: to. Yeah, that's good. I, I just haven't been paying attention to popular culture in the past couple of months, so I'll have to look at that. Thanks for telling me. Yeah. All right. Well, it's been great to talk to you, and I appreciate it, and I'll be in touch again.

Thank you. And you're still

Lynn Nadel: in Amsterdam.

Andrea Hiott: In Utrecht, yeah. Utrecht? Yeah,

Lynn Nadel: yeah, I've been in Utrecht.

Andrea Hiott: Nice. That's where we live. Good. Enjoy. All right. Be well. Thank you so much, Lynn. Bye bye. Bye. Thanks for everything.