The musical instrument you play, or played as a child, likely has a big impact on how you perceive music every day. In a novel new study looking at beatboxers and guitarists, cognitive neuroscientists found that areas of the brain that control movement were activated in the musicians’ brains but not in non-musicians’ brains.
Past neuroimaging studies have observed common patterns of brain activity for both the perception and production of music in classical musicians – with motor systems being recruited during musical perception, and auditory systems recruited during musical production. “A tight coupling between auditory and motor systems is more frequently observed in musicians rather than non-musicians, and has been argued to represent a signature of musical expertise,” says Saloni Krishnan of the University of Oxford, lead author on the new study in Cerebral Cortex. “However, many of these studies have tended to group together different kinds of musicians, such as pianists, violinists, etc., implicitly suggesting that formal musical training is what differentiates musicians from non-musicians.”
Krishnan and her colleagues at University College Londonwanted to test that conclusion and to more broadly explore how the experience of playing an instrument affected brain activity when listening to music. “We thought activity in sensorimotor regions of the brain might explain how musicians can make quick judgments about how technical the piece was when listening to an instrument they play,” she explains. So, she and her colleagues designed the study to examine groups of musicians who produce music using different body parts – representing one of the few studies to test non-classical musicians.
CNS spoke with Krishnan about the study’s unique design and what it can tell us about music perception in the brain.
CNS: How did you become personally interested in this research area?
Krishnan: I’m fascinated by how humans coordinate and sequence complex mouth motor movements in service of speech, as talking is one of the most complex motor actions we perform. Via Sophie Scott, I had seen videos of Reeps One (Harry Yeff) and was taken aback by his ability to make complex sounds for beatboxing. His oral movements were completely unique and self-taught, occurring in novel combinations and patterns, but for music rather than speech. I thought beatboxing offered us a completely new insight on how oral motor systems are instantiated in the brain. Consequently, I was keen to study the neural bases of beatbox expertise.
CNS: So why pair up beatboxers with guitarists in the new study?
Krishnan: Beatboxers primarily use their mouth vocal tract to make music, while guitarists use their hands. In the brain, there is a strip of cortex representing the different parts of the human body, such as hands, legs, the mouth etc. These regions are active when we move that specific body part. We were curious about whether we could elicit activity in these motor regions when musicians listened to music from their genre, rather than when they played their instrument.
I believe our approach of comparing different groups of musicians to each other, and to non-musicians, is the way forward. This approach allows us to demonstrate a one size fits all approach doesn’t work for musicians.
CNS: What are some novel aspects of your study design?
Krishnan: Relative to other studies of musical perception, three things were different about our study. First, we used novel music that was completely unfamiliar to our participants. This allowed us to explore if long-term experience would allow musicians to recruit motor regions for completely unfamiliar music. Second, we used a naturalistic listening paradigm, which elicits little to no motor activity for perception in non-musicians. Finally, most fMRI studies on musicianship have tended to compare musicians to non-musicians. I believe our approach of comparing different groups of musicians to each other, and to non-musicians, is the way forward. This approach allows us to demonstrate a one size fits all approach doesn’t work for musicians. We only see changes in neural activity when musicians listen to a style of music they can produce.
CNS: What were your most excited to find?
Krishnan: Initially, when I was piloting the study, with non-musicians or amateurs, I saw no evidence of sensorimotor activity for listening to beatbox or guitar music. I was disappointed that the study didn’t seem to be working but had no scientific reason to change our design. However, on testing just a few professional musicians, I saw robust sensorimotor activity when they listened to the genre of music they could produce. I remember cheering in the lab the day I looked at this data!
It turns out that most studies reporting motor activity for musical listening use an active task, which elicits sensorimotor activity even in non-musicians. When using a naturalistic listening task, this sensorimotor activity is only seen in musicians. The other feature that was really unique is that the recruitment of sensorimotor regions for music the musician could produce was observable at the individual level, something that doesn’t often happen in fMRI studies. This made me feel very confident about our results.
CNS: What do you most want people to understand about this work?
Krishnan: That experience shapes the way we perceive sound! I believe this might be crucial to understanding why sensorimotor regions are recruited during perception. Given that most adults are experts at speech, this should be something we consider when we think about the neural bases of speech perception.
The other key message is that considering mechanisms of transfer is important. In our study, we found that musicians specifically engaged sensorimotor areas for the style of music they could produce, but resembled non-musicians for the other style. If the effects of training are so specific, I wonder what the implications are for studies which suggest that musical training will prove advantageous for speech.
Many talented beatboxers, including MC Zani, the Hobbit, Bass6, Bellatrix, Grace Savage, participated in our study, and I have learned so much from the experience of working with. They’ve also changed my experience of the scanner’s helium pump forever!
CNS: What’s next for this line of work?
Krishnan: We want to probe what advantage sensorimotor activity during listening might provide. Does it allow musicians to learn or imitate new sequences more easily? Is it simply epiphenomenal? By conducting behavioral and perhaps TMS [transcranial magnetic stimulation] studies, we can address these questions.
I’m also interested in determining how new vocal representations emerge in the brain. I’m keen to conduct a study where we scan novice beatboxers as they learn new skills, and see how their vocal representations change as they build a new repertoire of sounds.
CNS: Anything else you’d like to add?
Krishnan: One of the most fun things about this study was working with musicians. I used to email musicians with a form asking about their years of professional experience, and one guitarist wrote back saying he was nominated for a Grammy and would that count? Sadly, we didn’t end up scanning him! We were also very lucky that the London beatbox community gave us their support. Many talented beatboxers, including MC Zani, the Hobbit, Bass6, Bellatrix, Grace Savage, participated in our study, and I have learned so much from the experience of working with. They’ve also changed my experience of the scanner’s helium pump forever!
-Lisa M.P. Munoz
