Jonathan Peelle  0:03  
Hello, and welcome to The Brain Made Plain. I'm your host, Jonathan Peelle. And today I'll be speaking with Dr. Jessica Grohn. Jessica, welcome. It's so good to have you with me. 

Jessica Grahn  0:13  
Thank you for having me. 

Jonathan Peelle  0:14  
Yeah. Great. I wonder to start with, can you say a little bit about the kind of research you do in your lab? And maybe how you got interested in doing that? 

Jessica Grahn  0:23  
Yeah, absolutely. I think if you talk about music, and neuroscience, or music in the brain, that pretty much covers everything that's going on. In my lab, we have a lot of different areas of research, but nearly all of them relate to music. My core area of focus is probably rhythm I'm really interested in why it is that we extract a beat from rhythm. So this irregular pulse that we sort of feel in music, or even just in simple rhythms that don't have any melody, or harmony or anything else. And why does we tend to move to music, because there aren't a lot of other sounds in our environment that we move to. But there seems to be really something special about the link between music and movement. So a lot of the research in my lab is looking at what parts of the brain are involved in our understanding of rhythm and our responses to rhythm. How does musical training affect our brain responses? And then also looking a little bit at some applied stuff? So can we take what we know about the fact that music seems to make us move and use that to help people who have movement problems? So a lot of what I do falls into those major categories. One thing that always strikes me about probably any topic, but music is one of them, is that your music is such a broad term, right? And I know you're focusing on rhythm, but how does that, you know, how did you sort of get into the rhythm aspect of music? And what are the other facets that that other people kind of look at here, my interest in music came I think, like a lot of people's does, I learned to play piano when I was a little kid, I took up the cello as I got into junior high school really enjoyed that. And somewhere along the way, I don't I don't really know why. But somewhere I also found out was quite interested in the brain, I always enjoyed science overall. And the brain sort of felt like the study of the mysteries of people. So why does someone act like that? Or why are they good at math? Or why do they have this incredible musical talent, whatever it is, are the answers in the brain somewhere. So I was quite interested in the brain. And when I went to college, I thought, Okay, I want to go to a place as a neuroscience program, but I also really enjoying the musical side of my life, I was playing in a ton of orchestras. And I really enjoyed music. So I wanted to find a place I could do both, which I did. And I ended up going to Northwestern doing a degree in neuroscience and a degree in piano performance, playing cello on the side still, and had no intention of combining these things whatsoever. At the time, I was just interested in both independently. And it wasn't until I graduated and I started applying to graduate programs, I decided that I would make a much better amateur musician than I would an amateur scientist and that I was not going to have the skills to make it on the world stage as a pianist. So I would go the science route. And in my first year of graduate school, I really found I was thinking of questions about the brain. And so many of them seem to involve music, for example, music and memory. This is something that is a fascinating topic that other people study too. Why is it you can remember some song you haven't heard for 20 years. And not only do all the words come back immediately, but you can remember the people you used to hang out with at the time and a particular event associated with that. And it's a very rich type of memory that music can help us retrieve. And I had a really practical interest of well, how is it that, for example, a pianist can learn all of these really complicated motor sequences and produce them so rapidly? What how does the brain enable that to happen? And I was also really interested in Okay, is all this musical training that I've engaged with my whole life? Has that changed my brain in some way? Is that why I'm actually kind of fast at typing? Or is that related somehow?

So it was really clear over time that I had these interests and the PhD supervisor and I had at the time, we talked a lot about different questions that we could answer. And one of the things I talked about was rhythm in this relationship to movement, and he suddenly said, Oh, that's interesting, because I trained as a neurologist. And Parkinson's patients have often said that when they're having problems, initiating movement, getting movement going, that's one of the issues they can have. Sometimes a steady beat can help and I wonder if there's some relationship there in the brain. And that's basically how it happened was one conversation where the person I was working with and I sort of gelled and said, Okay, this is something we can both really sink our teeth into and as they say the rest is history.

Jonathan Peelle  5:02  
So before we go any further, I just wonder if you could try to paint a little bit of a picture about where the basal ganglia are. So the the cerebellum is a sort of big, lumpy part that hangs off the back and bottom of the brain. And it's interesting—is that an offensive description of the cerebellum?

Jessica Grahn  5:24  
It depends totally on who you're talking to you. But I absolutely agree the cerebellum is interes ting. And it is an odd, Lumpy thing kind of hanging off the back of the brain 

Jonathan Peelle  5:32  
so the basal ganglia where I mean, those are sort of deep in the middle of the brain, you know? Anyway, I guess I'm asking you because I sometimes have trouble, like finding them and identifying them. And so how would you how would you describe them to someone who doesn't know where where they are? 

Jessica Grahn  5:46  
This is a great question. So in the middle of your brain, right smack in the middle, you have some ventricles, which are sort of sacs that have cerebral spinal fluid in them, and they kind of support some of the the inner structures of the brain. And right alongside those sex, you have some parts of the basal ganglia. The basal ganglia are actually a cluster of different structures that have kind of been lumped together over history, but it has unique parts. So we were really interested in the parts of the basal ganglia that have been linked to movement. And those parts of the basal ganglia include the cordate, the putamen, and the pallidum. And these are each their own independent structures, but they're very interconnected, there are a lot of nerve fibers running between them. And so they're right smack in the middle of the brain. And they each have that colonnade on the left and accommodate on the right of putamen on the left and putamen on the right and pallidum on the left and pallidum on the right. And so these structures often stand out, if you're looking at, for example, an MRI scan, because they have a lot of nerve cell bodies or neuronal cell bodies. And those appear kind of gray on the MRI scan. And then they're surrounded by a lot of white matter tract, a lot of the descending motor pathways go right through and around the basal ganglia. So you see these gray blobs surrounded by white matter, which makes them easy to pick out on an MRI scan, which is very handy. And they actually receive, not surprisingly, a lot of inputs from motor areas of the brain that are on the top of the head in the cortex, like primary motor cortex, or supplementary or premotor cortex. 

Jonathan Peelle  7:27  
Great. Thanks for that, you know, I tend to try to describe brain areas by drawing them and it's actually hard to do it without a visual. So I thought that was really that was really helpful. 

Jessica Grahn  7:39  
No, it really is tricky, because what I often do is hold my hands together, each of them in a fist, and then put my knuckles together, they Okay, so imagine this is your brain, and then we open this up and look at the inside. But similarly, that doesn't work.

Jonathan Peelle  7:53  
If we can't see you, it's a little bit tricky. So you know, one of the things I wanted to talk to you about, which was, you know, one of your specific research studies, and the one that you suggested is actually the first one there, I think it's the first paper of yours that I that I read. And so this is a 2007 paper on rhythm and beat perception, and motor areas of the brain. And so I'd love just to kind of hear you talk a little bit about the study. But you know, you've said a little bit about this already. But maybe, you know, what was the I don't know, where was your sense of where the field was? And what made you think that this would be a good direction to go? And then maybe you could just talk about what you actually did in this study?

Jessica Grahn  8:36  
Yeah, absolutely. Yeah. So the first paper of mine, you read also the first paper I wrote pretty much. So this was what I spent the bulk of the first year and a half of my PhD, sweating blood over. So it has two parts to it. And the first part of the study was really just measuring rhythm behavior, to try and work out what is it in a rhythmic sequence that gives it a sense of beat. And then the second part, we then really wanted to look at, okay, and how is the brain responding to rhythmic sequences? And because of the way we'd set up the behavioral part, we're actually able to look at a couple different questions in the imaging part about, okay, what parts of the brain respond when there's a sequence of Tomes, but you can't find any beat in them, it's just irregular. And then what happens when you start to be able to perceive a beat in that sequence, and you can find that underlying regularity that you might, you know, want to tap your foot along to. And so we could really try to tease apart rhythm perception or there's perception of events in time, from perception of that underlying beat. So the behavioral part of the study we had to do because it actually turns out if you don't want to use real music, and you Just want to strip everything down to the bare essentials, which is what I wanted to do, because I really wanted to focus on the rhythmic aspect of the brain mechanisms. There are a number of ideas about how you can give a rhythm a beat, and one is you can just make the notes louder and longer on the beat you know: "DA-da-da-da DA-da-da-da". And that will definitely give people a beat. It's a very simplistic, easy one. What was more interesting to me was that people extract a beat even when you don't give them these hit you over the head type of cues like louder and longer notes on the beat. So if I just give you a little sequence like that, that that very quickly, people will say, Oh, yeah, I could tap along to that. So I snap my fingers, it might be that, that, that if I take those same time intervals between those little "da"s and kind of jumble them up. So "da...da...da......da" suddenly, you've got time intervals, but no underlying percept of a beat. And the way that feels to us is really different. It feels unpredictable. Some people find it more annoying to listen to, in part because it's unpredictable. And so what we wanted to do was really show what properties were necessary for me to be able to quickly and easily tap along to a rhythm. And so what we did is looked through the whole literature and took a couple ideas about how rhythms are constructed and said, Okay, if you have time intervals, that relate to each other in some simple way, that seems to be important. For example, if I have a rhythm that's composed of an interval that, say 250 milliseconds—a quarter of a second—and then the other intervals are twice that are three times that or four times that, that seems to be important for understanding, you're getting an underlying sense of regularity. And if you think about that, in musical notation, that's exactly how musical notation works. We have quarter notes, half notes, dotted half notes, which are three quarters, or a whole note, which is four quarters. So there is this sort of underlying kind of grid system, where they're nice, even fractions underlying most of the music that we listen to. So that seems to be important. But the other thing that people had said might be important, and hadn't been quantified very much is this idea of a perceptual accent. So some people call this the Tick Tock phenomenon. So if I give you "da da da da da da da" and I continue that on for a while. And then I asked you how you heard that. It's more often than not, that if you give people exactly the same tone, equally spaced like I tried to do there, they might hear "DA da DA da" and this structure that we impose seems to be something that we do to rhythms quite naturally. Another example of this is if I give you "da da da...da da da...da da da" and ask you to tap along to it, almost everybody will tap "da da da" [on the first syllable] that very few people will tap "da da da" [on the second syllable] at least in most Western cultures, there are some cultures that do do that.

Yet, those are both equally regular equal, you know, equally reasonable places to tap. And this idea is called perceptual accent that are something about those first and last tones in that grouping of three tones that that that that we feel are more prominent, and we still don't fully understand these rules that give rise to this prominence. But they are there and they're replicable. Similarly, if I give you "da da...da da...da da" people tend to hear the second one is more prominent, so that that does not get the data. So what we did is we constructed rhythms where those perceptual accents were evenly spaced, aligning with a beat, and we said, Okay, we're going to use these perceptual accents to, to help people find the beat, then we're going to give them sequences where we still have the relationships between the intervals, you know, corresponding to nice, even fractions, but we're not going to allow these perceptual accents to line up properly. Because in the literature at the time, there was a real debate about, do you just need that nice, regular set of fractions? Or do you also need perceptual accents. And so we wanted to tease this apart by allowing people to have the regularity or regularity plus regular accents. So we could see if the accents really mattered. And then sort of for control condition, we had a completely irregular sequence that nobody could ever fit a beat to the perceptual accents were also irregular. So that might be something, you know that, that, that, that, that, that that, you're never gonna be able to find a beat in that. And even if you're super trained musician, it just doesn't exist. And then to determine whether this made a difference, we had people listen to these sequences and reproduce them. And we found indeed, when you had these nice even fractions, and you had these regular perceptual accents, people were way better and more accurate at reproducing the rhythms. When you had those nice even fractions, but no regular perceptual accents, they were not nearly as good. They were, in fact, almost as bad as if the sequence was totally irregular. So this was a surprising finding, because it showed that we're actually pretty bad at perceiving some kinds of regularity, even when it's present, if we don't have these accents on top to really help point them out to us.

Jonathan Peelle  15:51  
I mean, maybe this is, you know, going a little far off field. But I mean, would it? Is it fair to say that, you know, from like an engineering standpoint, if you're looking at just these, you know, acoustic relationships or the timing relationships between the notes, you might think that, you know, these two conditions would be equal? Because because they are regularly spaced intervals between the beats, right, is that sort of the, the perspective that that you could almost imagine being equally able to tell these conditions apart? Because because of the regular spacing, but in fact, humans are doing something that is maybe not as obvious from the acoustic signal.

Jessica Grahn  16:33  
That is absolutely right. And in fact, there was a paper that inspired this, that study in which they had used the sort of fractional relationships, and made the claim that in fact, if there's a fractional relationship there, that's nice and simple, and regular, humans will detect it and be better at it. And what we showed is that is absolutely not true. So yes, you analyze the signal. And it should, it looks nice and regular. It's these are all, you know, simple ratios, things that, if you plotted them out, visually, would look nice, but we don't detect those. And so yes, there seems to be something special and not as easily explicable, or not as obvious that humans are doing when they perceive these. So no, that's absolutely true. So then we could get to our question of, okay, we now have two sets of rhythms that are really similar to each other, we have the same time intervals. But in one case, the way that we've set these intervals up the order that we put them in, gives rise to a beat percept. In the other case, we've got a rhythm that's the same length, the same total number of intervals, you have to remember, but because of the order of the intervals, is a little different. You don't feel a beat in it. And now we can take that into the brain. And we can say, Okay, we have things where the only difference between these sequences is that one gives a sense of beat, and the other does not. Now, what are we going to look for?

Jonathan Peelle  18:03  
And the nice thing about these stimuli that you have, right is that they're they're really well controlled is that the same number of notes, and the average spacing, or that kind of distribution of the spacing is the same across condition. But because because the order is in a particular way, you get a sense of beat, right? So we're always worrying about what are the other possible things that could be driving a brain response. And here, it's really hard to think of something else in the the acoustics that would be causing a difference. I think

Jessica Grahn  18:33  
that's exactly right. And that was part of where this sweating blood came from was trying to come up with these sequences that were so perfectly balanced in every other way. But reliably, one set gave it a beat percept Yeah, so then we were testing the brain mechanisms. And there are sort of two levels of hypothesis. One is, if a rhythm is irregular, we don't tend to move to it. So maybe the motor system only really engages when that rhythm has a beat. And when your timing sequences of sound, that don't have a beat, you'll get auditory cortex responses because auditory cortex processes sound, so of course, it will respond, but we wouldn't see anything beyond that. The other possibility is that we would see motor area responses for both types of sequences, because the motor system might not just be involved in tapping our foot to a beat, but might be doing something a little bit more fundamental in the processing of the timing itself, so that the tightening of the motor system is fantastic at processing sequences of time because all of our movements unfold over time. And they have to unfold very precisely in order for their movements to be accurate. So the motor system might just be very good at perceiving time sequences, in which case it might not matter so much whether the rhythm has a beat or not. And going back to what we were saying before about how there are all these different components of the Have the motor system, maybe some brain areas don't care whether there's a beat or not. And maybe some other brain areas do. And my PhD supervisor, in particular was interested in the basal ganglia, because that is the area in which Parkinson's patients have dysfunction. So they've got reduced input to the basal ganglia. And that's the rhythms used to help Parkinson's patients with movement, or at least some of them. So he was really interested in focusing on the basal ganglia and its relationship to beat perception. And it turns out his instincts were actually right on. So when we looked at how people's brains responded, when they were listening to these different sequences, what we find is that there are a number of areas that light up, no matter what kind of sequence you're listening to. So you get supplementary motor area, premotor, cortex, cerebellum, and the basal ganglia all responding as well as auditory cortex, because you're listening to sounds. So these respond to all sequences. But then what you find is that the sequences that have a beat the rhythms that you could tap along to if you wanted to, you get much more activity in the basal ganglia, and then also the supplementary motor area. So these areas seem to really care even more about rhythms that have a beat. And the crucial thing was that during the study, we made sure nobody was actually moving. So we instructed them not to move, we watched them while they were going through the scan. And then afterwards, we asked them if they were successfully able to not move. And actually, for a lot of these participants, I think the bigger trouble was staying awake, because they're sleep deprived undergraduates who are lying in a dark, kind of cozy space. And so they reported they had no trouble not moving. But really the trick, the trickier thing for them was staying awake.

Jonathan Peelle  22:00  
So that I think the other thing you looked at in that study was the effect of musical training, which is a bigger question. I mean, people are really interested in sort of how musical training affects lots of areas of cognition. But what yeah, what have you seen in kind of rhythm perception work?

Jessica Grahn  22:19  
Oh, yeah, this is this is an area I was also interested in, right? Like, I spent years of my life learning an instrument, Surely that is made my brain better in some way. So these questions turn out to be tricky to answer, especially when your study involves a musical task of some kind. So in that study, we did find that several of these motor areas, the supplementary motor area, which is one of the areas that also responded more to the beat, but then also premotor, cortex, and the cerebellum. All all of those motor areas were more active in people who had significant amounts of musical training more than five years, compared to people who had very little musical training under a year. And that's interesting. The problem is, it's not always clear what those sorts of activation differences mean. And I can just give you a little, maybe an an imitation of what musically trained and not musically trained subjects might typically do when they can participate in the study. So when a musician comes in to participate in the study, they know it's about rhythm, because that's in the recruitment materials. And we tell them, Okay, you're going to listen to these rhythms, and you're going to have to tap them back or in the scanner, you're going to be listening to these rhythms. And in the scanner, what we had them do is a discrimination task where they had to detect changes in the rhythm. And then after listening to the rhythms, they would tell us whether they detected a change. And they would do some practice trials, and then immediately say, I'm not sure if the sound is exactly the right level, I think I did detected a change here. But it might have been on the order of a tiny little onset shift, I'm not really sure. And is this rhythm in four, four time or three, four time, they would go into the scanner, and they would do the study, and they would be responding to the task very quickly on each trial. And then they would come out. And often what they would expect is that I had an instant readout of their brain activity. And unfortunately, as you know, fMRI scanning does not work that way. It took me many weeks to get anything remotely approaching a sense of what their brain was doing. So I have no idea what their brain is doing in the scanner, but they think I do that I have a machine that can process this all in real time. And what they're worried is I'm going to say, okay, James, I think you should sit down. I know you've been trading your whole life for a musical career and you've gotten into a very prestigious conservatory. But I've had a look at your brain activity, and I am afraid or you are not cut out for this because people think that brain activity is more real than the behavior and their abilities that they can observe. So musicians are very invested in this task. someone without musical training will come in and say, okay, rhythm. Yeah. And then I'll say no. And they'll often warn me like, Oh, I'm, I have two left feet, I'm no good on the dance floor, I really don't have any good musical skill. And I'll say, Don't worry, it's not a problem. All you have to do is listen to these sounds. And you know, tell me if this sequence of sounds is same or different from the sequence, okay. And they'll listen and do a few practice trials and think you got it? Yeah, I think so. One or two comments. Oh, that sounds a little like Morse code for some of the irregular sequences, but mostly unconcerned, often and ask a little question about, okay, so it's going to take two hours, and how much money do I get? Great. They'll go in, do the scan, come on out and say, Okay, I'm ready for my payment. CFX. Good luck with your work. So the level of engagement really potentially differs between people with musical training and not when they know they're being trained, this is a potential threat to them, to musicians that you're looking at their brain. And as I said, a lot of late understanding of brain responses, it's that there's somehow more real or more important than the behavior that we observe. So we're the musicians producing greater activity, because they were attentive, maybe even anxious, and very engaged. Or because there's something special about all the training that they had, that enabled their motor system, it was very practiced at responding to these kinds of rhythms, we just don't know. So that makes it hard to to tease apart sometimes.

Jonathan Peelle  26:29  
Yeah, and I, I would guess that there are sort of like social and economic and demographic factors, that also mean that some people are more likely to have had the opportunities for musical training than others. And so there might be, you know, kind of hard to quantify, you know, other aspects of people's lives might affect brain activity or development that aren't really captured just by looking at musical activity, or maybe, you know, that would correlate with that

Jessica Grahn  26:58  
completely, like if we're saying that the control group is just someone without musical training. It is often the case that yes, parents are more invested, your parents of kids with musical training are more invested, they have the resources to provide the training, the time to take the child to lessons, the time to make sure that the child is actually practicing. Making sure oh, maybe you should go study with this teacher who's who's really good. And that'll get you into this school. So it's absolutely the case that there are, are noted differences in socioeconomic status and other things, and, and even some interesting personality work that shows that things like neuroticism can be higher in those who have higher levels of musical training. So there's a host of differences, that that might be completely external to sort of socio economic, or proxies, they're more internal to the person but not related to the thing you're actually trying to study, which is musical training.

Jonathan Peelle  27:58  
I want to come back to, to the issue of training specifically, but it kind of raises this bigger picture of individual differences. And they're sort of, you know, many of us know, people who struggled to find a beat, you know, they're sort of either whether it's dancing, or just tapping along, some people do seem anecdotally to struggle with this more. And I wonder if we kind of put aside musical training for a moment, you know, how much variability is there in beat perception in the general population? And do you have any sense of what might contribute to that?

Jessica Grahn  28:38  
Yes, absolutely. Be perceptibility runs the whole gamut, which is interesting in and of itself, because it implies there's not sort of a, for example, single beat perception gene, where if you have one version of the gene, your normal, and your scores on, say, a beat perception ability test are all good. And then if you don't, you're completely at the bottom. So we don't have, for example, two separate distributions, one of people who are abysmal, and one of people who are great, and there's nobody in the middle, what we see is like many complex traits, a complete range, you can be fantastic. It'd be perception. Pretty good, good. Not so great, poor and absolutely terrible. And we've actually done some research, have a paper from 2012, where we try and tease apart some of the things that we think might go into this. And we find things like auditory short term memory ability can be important for your memory for rhythm and your ability to reproduce rhythms, as well as your beat perception ability and the way we try to isolate b perception abilities. We give people tests where they hear clip of music, and we ask them to tap along. And that's one easy way to get a sense of how accurately they can tap the beat. But you might have people who can hear the beat and hear Whether it's accurate, but maybe they have some motor problem where their output isn't very accurate, even though they can actually perceive it. So we have another way of testing people where we give them a clip of music. And over the music, we impose some beeps. So it's a bit like listening to a clip of music with a click track over it. And your job is to say whether these beeps are on or off the beat. And what we do is we miss align them, or we leave them nice and exactly where they should be. And we see if people can can tell the difference. And so when you use these perceptual tests, they correlate very highly with how well you can tap, it turns out, there aren't very many people out there who can perceive a great beat or perceive a beat very well, but can actually reproduce it accurately, mostly those things go together. But you see the whole range. musical training also goes into this. But surprisingly, when you do these kinds of tests, like tapping along to a beat or rhythm reproduction task where they hear rhythm and tap it back, you have many people with no musical training, who are excellent. And you have a surprising number of people who have had a fair amount of musical training, who really aren't very good at this. So musical training has an influence, but it is by no means the most important factor.

Jonathan Peelle  31:19  
But maybe it suggests that there is at least a predisposition somehow in the, you know, in the wiring of these regions in this network that that you kind of required to be excellent at it. And maybe you can modify it a little bit. But But there may be a genetic component. I wonder, when you kind of said there's no single gene for this, but is there any evidence about you know, so the bright, the fancy word is a poly genic? Kind of signature for this that might contribute to it? Or is it too early to say?

Jessica Grahn  31:53  
Yeah, there's actually some preliminary research going on one researcher, Raina Gordon, who's at Vanderbilt has really taken us on in the last few years, looking at some genome wide association studies on rhythm perception ability. And some of the work she has done has been looking at relationships between, for example, rhythm, abilities, and language abilities. And she definitely find some relationships there. And she indeed has found some associations with certain genes. It's very preliminary at the, at this stage, I think, basically, we're at the stage of trying to identify a series of candidate genes that might have an influence and learn more. But yes, this is this is an area of active research at the moment. I mean, I guess, you know, there's a practical application of if someone is a really lousy dancer, because they can't feel the beat, you know, how much better can they get? Right? I mean, yeah.

Yeah. And this is I think it's, it's unknown, because, because musical training, it's done in different ways in different cultures. And so you have people who have the experience that well, they were told to, to mouth the words in their school choir, because they were so out of tune. Or that yeah, you have two left feet. But very rarely do you have somebody going in and saying, oh, yeah, and so they tried to help me, it seems to be this like you get by the best you can. But unlike reading, where if you're falling behind, you're having trouble, someone's going to get you special help and really intervene, we just let it go. Because it's considered a sort of optional skill. So we actually know surprisingly little about how amenable rhythmic ability or musical ability is to some types of intervention. Certainly, I'm sure music teachers could tell us that, as you say, there are those who are predisposed and pick it up quite easily, and those who seem to really struggle. So I'm sure there is this variation, but it's not often that we force a child to really stick it out and get better at music when they when they struggle initially. So how how malleable this is, is not totally no.

Jonathan Peelle  33:55  
I also wonder too, like for language things, you know, there's there's increasingly a focus on early intervention, right. So if you have a young child, you know, two years old, who's having some difficulty, they typically get seen and get some kind of you no support with that. But you know, many people don't start music lessons until four or five or six or seven or older. And so if there is sort of like a kind of a preferred developmental window, it could be that that, you know, we're sort of missing it just by how we, you know, typically handled music education in at least in a lot of Western countries.

Jessica Grahn  34:35  
Yeah, absolutely. No, it's definitely the case that we we don't do the sort of early intervention for the most part. There are some, some music methods that seem to go earlier on and some that go later. So Suzuki, often, you know, where you're doing a lot of playing by ear, and students will start at two or three. But yeah, in many, particularly Western cultures, we do formal musical training much later?

Jonathan Peelle  35:02  
I'm thinking about my kids who are young and like, I want to make sure they they can dance when they're older. So I have to figure out how to, you know, encourage this?

Jessica Grahn  35:11  
Yeah, no, I know. And what's weird is something that I think a lot of Western cultures have lost is this sort of social music making aspect. So I think of things like square dancing and folk dancing and Cayley dancing, where music and moving to music forms essential part of a, an activity that you participate in from the time you're a small child, up through till the end of life. And right now, a lot of Western cultures do dancing is something that people are very socially self conscious about, and not likely to participate in, maybe a wedding reception where they've had a few glasses of wine is the main exception. But they need that to reduce their social self self consciousness about doing this. And I do think I wonder what we're missing there in terms of having a normalization of musical activity and music and dance activity. That's the understanding of these things is no Kaylee dancing, you don't have to be really good at it, or an expert. It's just something that everybody does for fun. And I think we're losing some of that, and a lot of the ways that we engage with music now.

Jonathan Peelle  36:24  
Oh, that's really interesting. I was kind of sort of, you know, I wanted to get back to patients with Parkinson's disease and sort of the the potential role that music and beat can have in their movement. But but that also kind of reminds me of what you're just saying that in, in some cultures, in some context, there's more of a connection between music and walking or dancing sort of these big motor movements, whereas, I mean, speaking for myself, you know, I have some musical background, but it's mostly sitting at a piano or sitting in a chair in an orchestra or band. And so there isn't that sort of full body, you know, movement component to it. So is there a sort of like a big picture where you see, you know, the link between music or beat, and, you know, these bigger, bigger motor movements that might be impacted in Parkinson's?

Jessica Grahn  37:21  
That is a great question. Yeah. So we've done a little bit of work, looking at musicians and dancers, who do tend to do these gross motor movements in response to music in a way that a lot of musicians, as you say, we're moving around our fingers, and that's about it, or fingers and arms.

And it does seem to be the case that there are links between these whole body things, musical training, you know, there are there's sway there are other things, and musicians do that. But we don't tend to train those things, the whole body movements, whereas dancers do. And it seems to be the case that dancers definitely show some benefits, in terms of that, oh, for the benefit, or whether they were predisposed, you can't do the causal thing there. But dancers do seem to show better processing of rhythm and beat. And if you look at our early responses, developmentally to rhythm, those tend to be bigger movements, we might clap, but little kids also love to jump up and down and dance. And so there seems to be if you look, before we get into how cultures are specific musical training might influence things, the inclination, in the way that we move to music tends to be gross motor movements, for sure.

So one of the neat things about this link between rhythm and music and movement is that it can be used to help movement. And, for example, I mentioned earlier about Parkinson's patients, and that my PhD supervisor was really interested in this link that had been observed where a steady beat might help some patients move. And he had interviewed some patients about this. And so the problem that Parkinson's patients have, and one of the more debilitating issues is a problem in initiating movement and walking, this comes out a lot that they might want to walk across the room to make a cup of tea, but their brain sends the command and nothing happens. And it can take many seconds before they find they're able to initiate movement, or while they're walking if they go through a doorframe or pass someone on the street, that can trigger freezing where their feet seem to be glued to the floor and it takes them a while to be able to get moving again. So the neat thing about oh, well, we see that rhythm really makes motor areas of the brain respond. Can we use that to actually help people with their movement seems to be the case. And so some of the work that we've been doing is looking at How rhythm can help patients with Parkinson's with walking. And one of the things that's interesting is, for example, what if you are a Parkinson's patient who has terrible beat perception? Are you still going to be helped by listening to rhythm? Or is this something that will really only be useful for somebody who has a good ability to feel the beat. And one of the neat things is, even though be perception ability runs the gamut. There are people who are great, and there are people who are terrible. The same is true of Parkinson's patients, there's those that are great at it, and there are those who are not so good. But that doesn't seem to break the link between music and movement. And you can see this when you look on a dance floor where you are getting a nice wide representation of people of all different musical training levels and skill levels. Those who are terrible at beat perception are not necessarily any less enthusiastic or induced to move, then those who are great at it. So there is something that is still a bit of a mystery to us. And it might go back to one of the findings in the 2007 paper, which is that any kind of sequence seems to elicit motor responses, even if it doesn't have a regular beat. And we did tend to see these motor responses even in people with no musical training whatsoever. So there does seem to be something about music and movement that does not rely on you necessarily being accurate in your synchronization for it to be effective.

Jonathan Peelle  41:28  
Well, it's kind of interesting, because you're sort of also hinting at these other effects may be about like, an effect or engagement or enthusiasm, right? That you can be a really enthusiastic dancer, even if you're not very good. And so, you know, when you think about kind of the effect on on patients, I mean, you know, how much of it is motor versus sort of like, you know, motivational.

Jessica Grahn  41:57  
Right. And this is one thing we're really interested in. So if I'm listening to music I love, we'd certainly know that that can help you exercise a little harder, walk a little faster, maybe run a little longer. Does this make a difference with Parkinson's patients. So we've been trying to do a series of studies where we look exactly at this, whether enjoyment of the music makes a difference to their walking capabilities. Surprisingly, for walking, we so far really don't find it makes a difference in terms of the quality of the walking, how stable they are, and how fast they are. But we definitely find it makes a difference in how willing and how much they enjoy doing the activity, which could be just as useful, but it doesn't seem to have quite the same effects, or it doesn't seem to enhance the effects that we see on. For example, reducing the amount of freezing or improving speed that seems to be doesn't really matter whether you really love the music or not. The other aspect that we measure something called groove. And groove just refers to how much the music makes you want to move. So it's, it's a, we've taken the word groove, which has all of these subtle musical meanings and associations and really boil it down to something very simple, which is does this make you want to tap your foot or not? And it turns out, that does matter. So you might not like the music. But if you kind of feel like it makes you want to move, then it's likely to affect your walking.

Jonathan Peelle  43:32  
And you have like in a serious scientific study that you have a measure called.

Jessica Grahn  43:39  
I know. Yeah, well, we didn't invent it, but it is absolutely captured what we're interested in and what seems to be important, so we're gonna stick with it for now. And then if you have low Groove Music, like chill out music, for example, or ambient music, or very slow classical music, that really does not help walking at all so, so in in how much you like, it doesn't seem to be quite as important as how much it makes you want to move.

Jonathan Peelle  44:10  
So one other thing I wanted to make sure to ask you is about, you know, non human animals. And, and music perception and beat perception. Many of us have seen videos of different kinds of animals that seem to be moving along to music on YouTube, or whatever. And I just wonder, like, where does that fit in?

Jessica Grahn  44:32  
Yes, the comparison across species I think is fascinating because a lot of species have pretty complex movement control systems, most of them that are closest evolutionary relatives do for sure. But when you look at non human primates, you don't see much spontaneous behavior that looks a lot like synchronizing to an auditory beat. There might be regular, rhythmic movements like drumming. or arm swinging, but there's a lot fewer observations of something of synchronizing to an auditory thing. And that seems to be what's special about music. However, you look in some species of birds, particularly birds that imitate like parents or cocktails, and you will often see this bobbing up and down to the beat. And so there are different ideas that you that this allows us to test. So what is it about bird brains that might be similar to human brains, where they both support this synchronization to sound that maybe is less prominent, and we can't say it's impossible in non human primates, we just don't have a lot of observations. So an absence of evidence is really the problem there. But one thing that's really similar with birds that can imitate in humans is this real linking communication between auditory and motor areas, which seems to be structurally less present in a lot of non human primates. But then this all kind of gets blown out of the water, in terms of trying to understand what the evolutionary you know, lineage might be, because so far, one of the most accurate examples we have documented in the non human literature is that of a sea lion named Ronan, who is exceptionally accurate of bobbing her head not just to a beat, but to music, and she can extrapolate to new music. And if you make the music skip so that suddenly the beat gets messed up. She can realign very, very quickly and the time course over which she realigns looks very similar to the way that humans would also realign to the beat. And we don't know a whole lot about sea lion brains yet. So there's this is an active area of research as well.

Jonathan Peelle  46:49  
Do you think we should get a MRI scan of a sea lion?

Jessica Grahn  46:54  
I have a feeling that this is the sort of thing that people are actually proposing.

Jonathan Peelle  46:59  
Yeah. Well, Jessica, thank you so much for joining us. It's been lovely talking to you and hearing about your work. And I wish you all the best as you continue this I'm sure we'll talk again soon.

Jessica Grahn  47:10  
Oh, absolutely. It's been a real pleasure to talk about some of the fun things that we're doing. Thanks for having me.

Jonathan Peelle  47:15  
Thanks. Okay, bye.

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