Music on the Brain: Jessica Grahn at TEDxWaterloo 2013

so yes I am a neuroscientist who studies how our brains respond to music my particular area of interest is rhythm now I might be a little bit biased but I believe that rhythm is the most important basic fundamental aspect of music you can take away all of the melodies and the harmonies forget about keys and don't worry about scales and what you have left is still undeniably music so forget about me I could just listen to that for the next couple of hours so what I'd really like to talk to you about today is our uniquely human response to rhythm and how it differs from other animals in the animal kingdom I'll also be talking about what goes on inside our brains when we're listening to rhythm now one of the most fascinating things about rhythm it is it's completely inextricably linked to movement so if you see someone with earbuds in if you catch even a little bit of a head nod or a toe tap you know immediately they're listening to music moving to music is also a cultural Universal it's found in every human society and I used to say that humans are the only species that has ever been shown to move spontaneously to music and then Along Came snowball snowball is a sulphur crested cockatoo his favorite band is the Backstreet Boys and his dancing has made him a little bit of a youtube star so I think you'll agree he's got some moves now that was actually a clip from an experiment conducted by neuroscientist Annie Patel and his colleagues and they wanted to scientifically record and analyze snoballs movement to see if he really was synchronizing to the beat the way that a human might and although it turns out much of the time snowball is very accurately tracking the beat there are also periods where he's not really on the beat at all in addition snowball really prefers speeds of about 125 beats per minute so if you slow the music down too much or speed it up too much he's no longer able to synchronize if it goes too far from that hundred 25 beats per minute so although this is probably the closest example that I know of of a nonhuman animal moving to music snowball still doesn't show the sort of flexibility or accuracy that a human does moving to music now apart from snowball there are other examples in the animal kingdom of synchronous rhythmic behavior thinking about chorusing frogs or flashing fireflies however these two also differ but differ in fundamental ways from what we do to music so if you think about what a cricket does for example its producing the same sound over and over again separated by roughly the same time interval what humans can synchronize to is far more complex take this example from FX twin there's another key difference and I eluded it to this a little bit with snowball and that's that most animal synchronous behavior only takes place within a very narrow range of rates whereas humans can synchronize to quite a wide range of rates so we're capable of putting our arms around our friends and swaying back and forth to a slow ballad or taking our lighter or our lighter app that we've downloaded to our phone and swaying that across and then we can turn around and jump up and down really quickly in time to a very fast techno beat the final difference and I think perhaps the most important one is that most animal synchronization takes place in the same modality so croaking sounds are synchronized with croaking sounds or light flashes are synchronized with other light flashes however what humans do crosses modality so we usually make a silent movement say your favorite dance move and we synchronize that to a sound our movement does not need to make a sound in order for us to be in sync we are perfectly capable of taking movement and synchronizing it to a sound without having to match modalities so this makes our behavior much more complex than that we see in other animals now I've been talking about frogs and crickets and birds these are all pretty far removed from us on the evolutionary tree if we want to know where our human response to rhythm comes from we probably be better off looking it more closely evolutionarily related animals such as monkeys now dr. Hugo merchant at the National University of Mexico has been doing exactly this he has been training monkeys to move to the beat now before we see how the monkeys do this I'd like to see how you a nice representative sample of human subjects do the same tasks that the monkeys do so it's a simple task we call synchronization continuation in the neuroscience literature all involves is you're going to hear some tones beep beep beep and what I want you to do is clap along to the tones as soon as you've got the beat that these tones are making you're going to clap along then after the tones finish I'd like you to carry on clapping for a little bit it's just even after the sound is finished maybe four or five claps now the trick here is to clap as soon as you've got the beat you don't want the tones we've already finished before you start clapping so are you ready you sure because if you do worse than the monkeys we're both going to look bad all right here we go very good you were so good you actually drowned out the beeps themselves which makes it a little bit harder to do the task but you did a fantastic job so now let's see what the monkeys do on this task now monkeys don't find clapping or even tapping very easy to do so in this task you'll see the monkeys hand is resting next to a lever and the sound will start and the monkey will when he's ready he's got the beat he'll pull the lever instead of clapping so here we see what the monkey does so you'll see that the monkey did the task in a very different way from how you did the task what the monkey does is react to each town so he uses the sound as a cue to initiate that movement which means by the time the movement actually occurs the sound itself is long gone and every beep is like this he never catches up and start synchronizing with the beat the way that you did what you did is something we call entrainment this is quite a special feature of human synchronization so as soon as you heard those tones you set up your own internal beat and then you use that internal representation to initiate your movement before any sound had occurred at all this meant that then you made the sound at the same time as the beeps you also carried on using that internal representation when you were clapping at the same rate after the beeps had stopped so we don't really know yet why it is that monkeys don't show entrainment in humans do however there are studies going on both in my lab and the labs of others to examine brain responses in both humans and monkeys to see if we can see where these differences come from however what we do know is this entrainment is completely crucial to your experience of music your entrainment is what allows us for example a saxophone player in a jazz ensemble to be a little bit ahead of the beat or a little bit behind the beat to give the music a different feel if you didn't have an idea of where that beat was supposed to be you would never know that the saxophone player was a little bit ahead or a little bit behind and you would never experience the emotion that that leading and lagging can induce now one of the neat things about our internal beat is its induced incredibly quickly you guys started clapping within 2 or 3 tones max and in music it happens just as quickly sometimes our internal beat is so strong we can feel it even when the music itself is almost silent this is a clip that was brought to my attention by musicologist just in London it's called hoochie coochie man as recorded by Muddy Waters I'm just going to play the beginning and I'd like you to pay attention see if you feel your internal beat in the silences and see how quickly it is that you feel the beat so within a few notes don'tdon't dumb we're all there now what's amazing about this is you didn't have to be trained to learn how to do this no one told you what this is what we're supposed to respond to when we hear music and you couldn't even explain to someone probably how it is you go about doing it yet it happens spontaneously and automatically in response to music so I was really interested in how it is that this response comes about so I used MRI scanning to look at brain activity in response to rhythms now we had people listen to rhythms while we were looking at their brain activity but because we really wanted them to pay attention to the rhythms and not be thinking about what they wanted to have for dinner that night we gave them a task to do and I'm going to give you the same task to try it involves listening to a rhythm that's presented once then hearing the same Rickett rhythm a second time and then deciding of the third rhythm is the same as the first two or different from the first two so the first two rhythms are always the same and then you decide if the third rhythm is same or different here we go so like you raise your hand if you think who's the same and raise your hand if you think it was different wow this is a good crowd that's correct so the third one was different and as you can see you have to really pay attention to the rhythms in order to make that distinction the other thing we told our participants was during the scan while they're listening to rhythms to stay absolutely still so no tapping or toe moving no counting along in their heads really what we wanted to see was the response to rhythm when people were staying completely still making no movement at all and this is what we found so on the right side of the screen you'll sort ly see a picture of the brain as if the top of the brain has been removed and there's auditory cortex activity now the auditory cortex located right by the ears is responsible for processing of sound this wasn't too surprising to us because we were playing our participant sounds so we would expect sound areas to be active however all the other areas that we saw did surprise us so here on the right side of the screen this is a view as if you just take in the forehead away and you're looking at a person straight on all of these other areas are areas that are responsible for the processing of movement so they're involved in the selection control and initiation of movement we call them motor areas now these motor areas are responding even though the participants are staying perfectly still and have no intention of moving they're just doing our task this was really surprising to us and we thought this was quite an interesting finding suggesting that rhythm is driving movement areas in the brain even when people aren't moving so we wanted to see if this was the seat the same thing that was going on in music I did spend a lot of time making those rhythms but if I'm honest with myself I can acknowledge I'll never make the Billboard Top 100 so how do we know that the response we're seeing during these rhythms would be the same response when people are listening to real music so we did a comparison so first people heard rhythms just like the ones you heard before here's a reminder and this is the brain response that we saw so this is if you just take in the front of the brain or the front of the head off moved it to the side and you're looking straight on the person and we see motor areas again we see the supplementary motor area in the middle premotor cortex off to the side and the basal ganglia deep within the brain then we played our subjects music and this is an example of the sort of Clips we used and this is the response that we saw the exact same motor areas are responding so rhythm seems to drive motor area responses whether it's in the context of tone sequences or in the context of music the suggest that music is not just about sound but also fundamentally about movement now the neat thing about this is this means we can actually take music turn out the whole thing on its head and use music to change activity in motor areas of the brain this has a potential for therapeutic applications so motor areas of the brain are commonly affected both by stroke and by degenerative disease one example of this is Parkinson's disease so Parkinson's patients have difficulty initiating movements and they often freeze in the midst of making a movement in addition their movements can be unsteady or slow now people have tried to use music to help Parkinson's patients movements in the past and there is some benefit however the benefit seems to be very variable some patients show a big improvement and some patients show hardly any improvement at all in my lab we think this is probably because our individual responses to music are also highly individual or very variable the thing that gets me out onto the dance floor might not even get a toe tap from you so we're currently allowing patients to select their own music based on their ratings of how much it makes them want to move we're also looking at the importance of how familiar the music is whether it's enjoyable and even whether the particular genres that certain patients really prefer to move to and the last video that I'd like to show you today I think demonstrates why we're so excited about this research it just shows a patient who's uploaded a video of himself up to YouTube he's moving around in his living room and you can see some of the symptoms of Parkinson's disease that this patient has for example freezing in the midst of movements in the beginning of the clip there's silence and then he goes and puts on some music that he himself has selected so there's some freezing right there so I think you'll agree the effects of music on movement can be very powerful so next time you're listening to some tunes and you maybe feel like getting your inner wiggle on I say go for it you'll be celebrating something that makes you as a human unique thank you you

Channel: TEDx Talks

Views: 135,235

Rating: 4.8571429 out of 5

Keywords: tedx talk, tedx talks, Technology, Canada, ted talks, animals, Body, neuroscience, ted x, brain, Mind, Science, tedx, music, tedxwaterloo, Control, Jessica Grahn, ted, 2013, ted talk, English, parkinsons, research, Health

Id: u1vlTI0EsPk

Length: 16min 28sec (988 seconds)

Published: Thu May 30 2013