Theodore Zanto, PhD, wouldn't call himself a musician. But he knows an awful lot about how the human brain processes music. A neuroscientist at the University of California, San Francisco (UCSF), Dr Zanto studies the neural mechanisms behind attention, perception, memory, and rhythm. Medscape recently spoke with him about his research on how the brain tunes into rhythm and how drumming has therapeutic potential in the aging brain.
Medscape: How did you get interested in this area of research in the first place?
Dr Zanto: It goes back to when I went to grad school. I was always interested in how the brain gives rise to cognition, attention, and memory—things of that nature. In grad school, I worked with Ed Large, who was studying music in the brain. He was interested in how the brain processes music, and I was interested in working with him because music is really a good window into the fundamental nature of how the brain works.
Everything that we do, everything that is processed in our brains—and this is true for all of nature, really—is very rhythmic: the way we speak, the way we walk, the way we chew, the way the stars move. You can find rhythm in pretty much everything.
The brain is also very rhythmic. It communicates using rhythms—neural oscillations, as we call them. I thought it would be interesting to study music as a window into, first, why we like music; and second, how rhythms can underlie other cognitive functions.
When I was working with Ed in grad school, I was studying neural correlates of the beat. When you listen to a song, you intrinsically know where the beat is. You tap your foot, you bob your head, you snap your fingers. You can dance to it. It's what really enables you to synchronize with other musicians if you're playing or if you're singing or dancing.
I was looking at how the brain gives rise to this feeling of the beat, and we were using EEG really to look at the oscillations and the rhythms of the brain. We were also using functional MRI (fMRI) to get an idea of where things happen in the brain. EEG can tell you when things happen; fMRI tells you where. We're using these two techniques to really address the question of how the brain gives rise to this feeling of the beat.
For example, in one of our fMRI studies, participants were asked to listen to a rhythm, memorize it, and then tap it out. What we saw was that motor regions of the brain—regions that typically are engaged when we move—were lighting up, even when they weren't moving. The brain seemed to be recruiting the motor areas of the brain in order to track the rhythm, to keep the beat.
We thought that was really interesting!
Medscape: How about your EEG work? What did that show?
Dr Zanto: If you look at the EEG signatures of people tracking a beat or rhythm, you see these high-frequency bursts of neural activity in the brain right where the beat was expected to be. There doesn't even have to be a sounded event for these brain oscillations to occur. Otherwise, you could argue that it's just the brain responding to the music or the sound. But in fact, these pulses of neural activity actually occur where you expect the beat to lie even in the absence of a sound.
For example, if you hum a melody, the notes in that melody don't necessarily fall on each beat. But your brain will keep the beat in the background. So the idea is that you can have this neural signature that tracks the beat.
The Timing of Distraction
Dr Zanto: A caveat to all of this is that this work was part of my bigger project, which was studying how the brain tracks rhythm in the context of attention and memory. When I came to UCSF, I began working with Adam Gazzaley and started studying how attention and memory changed as we get older. I moved away from the music stuff until I got to a point in my research where I realized that older adults seem to have these timing problems—that a lot of age-related declines in memory seem to be stemming from attentional problems, such as orienting attention in time.
Specifically, they're not preparing for distraction. Say we bring our older adults into the laboratory and ask them to remember a bunch of items. They generally do pretty well, oftentimes on par with a 20-year-old. We're talking about "older adults" as being 60 to 80 years old or so.
What's interesting is that once we introduce distraction, all of a sudden memory seems to really decline. When we look at their neural activity during distraction, what we see is that they're not suppressing this irrelevant information. If we later on ask them about the irrelevant distractions, older adults actually remember the distractions better than the younger adults, meaning that they're really encoding everything that's coming into their environment and overloading their limited memory storage.
It's even more interesting if you tell older adults, look, there's going to be a distraction here. Just ignore it. Or, conversely, if we let them know when a target is going to appear, or to pay attention to here and not here, older adults don't really seem to capitalize on these predictive cues.
If you look at neural activity in anticipation of a "to be attended" stimulus, younger adults will ramp up neural activity in anticipation of what they're going to pay attention to. So that way, when they see it, they process it with a lot more efficiency and then they can remember it better. Conversely, if they know they're going to be distracted, they can ignore that area in space or that point in time. They can shut down neural regions and suppress the neural activity so that this distracting information doesn't interfere with their memory.
Timing Is Everything
Medscape: And you found that timing ability plays into attention as well, correct?
Dr Zanto: Yes. I thought, why don't we see whether this stems from a more fundamental problem with timing in general? We know from other research that as you get older, your timing ability becomes more variable and less precise. One of the leading theories of cognition is that there is a slowing of processing speed as well as more neural noise as we age, which is going to generally impair brain rhythms. This then has a cascade of effects on attention and memory abilities.
What I was hoping to do is train timing abilities in older adults to try to improve a fundamental feature of how the brain works. In order for brain regions to communicate, they need to be synchronously time-locked to each other in certain ways. We're hoping that we can improve attention and memory by training timing abilities.
What I'm doing right now is a kind of training program where we give tablets to older adults in the Bay Area. They play a drumming game, much like a simpler version of the popular Rock Band and Guitar Hero video games. When the cue hits a line, you have to tap on one side of the screen to match the beat. We give them different patterns to tap, so we're titrating the difficulty on the basis of performance.
The idea is that we're hoping to improve timing abilities so that they now start to engage their environment in more of an anticipatory, predictive way. As I said before, older adults aren't using predictive cues, which is directly related to their ability to deploy attention and time or predict future events. Here, we're trying to train that ability using rhythm, because rhythm by definition is predictable. In order to move with music, you need to be able to anticipate the beat, and so that's exactly what we're exercising here.
Music (and Drumming) as Medicine
Medscape: What are you seeing in terms of results?
Dr Zanto: We're hoping that by improving our patients' attentional capacity, or their ability to really focus on specific points in time, that they will concurrently be able to ignore other points in time or other points in space. Hopefully their ability to focus their attention should improve, which will subsequently improve memory ability.
So far, we're about halfway through a rhythm training study, so it's a little bit too early to say anything. But we're cautiously optimistic and have done other studies leading up to this that would indicate this is going to work. And to be clear, when we do these studies, we're not looking to see whether people get better at the rhythm game itself, but better at other tasks involving attention and memory.
We've already completed one study looking at the same outcome measures as the training study, in both musicians and nonmusicians, to see whether there is a musicianship advantage. Our research, as other labs have shown, indicated that by training musical abilities, you will get some boost in performance on attention and memory abilities. That's why when we recruit older adults for this rhythm training study, we make sure that they're all nonmusicians.
Medscape: Are there data showing that musicians have better memories or attention capacities?
Dr Zanto: I wouldn't say it's really well known, because there isn't a whole lot of music research out there. But more and more data are gathering indicating that there is a musicianship advantage in multiple cognitive domains, including memory and attention abilities. This is true across the lifespan. You can see it in kids, in adults, and in older adults as well. Along with those measures of improvements in performance, you can also see changes in the gray and white matter of the brain. Musicians show increased gray- and white-matter tracts in multiple brain regions, including parts of the prefrontal cortex, cerebellum, and parietal regions.
Medscape: Can you speak to the various forms of music therapy out there? What does the evidence show about their efficacy?
Dr Zanto: There are a lot of people doing music therapy, particularly at hospitals. But there haven't been that many intervention approaches, which is part of the rationale behind our work. We really need intervention studies that say, you know what? Let's just take a group of people who by all means we can see are roughly equivalent, and then randomize them into two groups: one that doesn't get the musical exposure or training and one that does. Through those approaches, you can really start seeing the advantages of music as a therapeutic.
These studies are slowly cropping up and showing that you can take younger adults, children, and even older adults and randomize them to a group and see these benefits. It's still unclear how much they benefit, and it's still unclear how long you have to engage in the training in order to reach those benefits.
The therapeutics going on in hospitals are a little different from what's going on in the context of research. Everything that I've been talking about is considering music as therapeutic in a research context. We're just taking healthy adults and assigning them to a group. Hospitals are of course more interested in treating their patients. And there are a lot of people out there, not just in a hospital, but in clinics and in private practice, who are deploying music therapy under the assumption or under word of mouth that it can help. And also on the basis of anecdotal evidence from their own experience.
Maybe they have tons of evidence that it works. But in the end, there aren't many published studies with proper controls showing efficacy.
Medscape: There are many reported cases of music helping patients with dementia recover memories. What do you make of these?
Dr Zanto: There is definitely more and more mounting evidence here, but I wouldn't say that there's a consensus as to the efficacy of it. There definitely are studies out there that would indicate there's a benefit of music therapy in improving quality of life, as well as improving some memory abilities in patients with Alzheimer disease. At the other end of the life spectrum, there are also at least a dozen, maybe two dozen, studies on the utility of music therapy in prenatal care.
Premature infants can have high levels of stress and high heart rates that can lead to lots of problems. I've seen several studies now—and they're pretty well controlled—indicating that music therapy can help premature infants calm down so that they can grow properly while they're in the intensive care unit. It's pretty well-documented, and intuitive, that music can have a calming effect. And perhaps not surprisingly, the most effective music at calming infants is that sung by their mothers.
Getting back to older people, in terms of Alzheimer disease, preferred music seems to be the most efficacious. For example, if you were to play a popular song today to a person who grew up in the 1930s, 1940s, or 1950s, it's probably not going to have that much therapeutic value. Whereas when you present music they're familiar with, say from their teenage years, all of a sudden they're able to jog memories from those years and have a much more pleasant and relaxing response to it. I think the essence of music therapy is that it can jog memories and can create these associations that you had with previous points in your life, which can be relaxing and contribute to overall well-being.
Medscape: One practice gaining popularity with the public is drum therapy. Can you speculate on the potential effects on the brain of drumming in particular?
Dr Zanto: This is one of the things I'm trying to get at, as are a few other labs. Music and rhythm itself are not necessarily dissociable, right? When I say "music," there's always this rhythmic component to it. I'm not entirely sure whether there are any good randomized controlled trials on drumming itself, but I certainly could see it as having meditative-like benefits on mental health. I can see how it could be incredibly beneficial because, as I said at the very beginning, the brain is rhythmic. So when you are drumming, you're not just training the brain through the sound waves that your brain is processing. Every time you hit the drum, there is a representation of that sound in your brain.
This is true of playing all music to a degree. But drumming, especially drumming, has this concussive and rhythmic effect that you can feel with your body. Now you have these two streams of input—the sound and the physical sensation—that are really entraining your neural oscillations at particular frequencies. I could see this being therapeutic in the sense that it could help induce trance-like states and could be seen as a form of meditation that can give you a feeling of relaxation or entrainment with your environment, which I think is kind of the essence of a trance—it's entrainment with your environment in a broad sense.
Although much research is needed to understand the therapeutic potential of drumming, I would not be surprised to see future studies validating its efficacy. In addition to the relaxing effects that drumming may have on well-being, music-therapy research has provided some preliminary evidence that it can help people with movement disorders, such as Parkinson disease, in which rhythmic body movements (eg, walking) can be negatively affected. As we and other labs have observed, music—and in particular rhythm—engages regions of the brain involved in controlling movement. Therefore, I could see drumming as having great therapeutic potential in helping entrain motor regions of the brain and help people with Parkinson disease produce rhythmic body movements, such as walking.
Medscape: Last question: Are you a musician?
Dr Zanto: I took piano for 10 or so years, played the sax and the tuba for a few years, and tried to teach myself the guitar. To be honest, I'm not very good at any of them, but I try.
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Cite this: The Therapeutic Potential of Drumming and Rhythm - Medscape - Oct 12, 2017.