New research is shedding light on what we know about how the brain interacts with music, but it also highlights how challenging it is to study effectively due to the highly personalized nature of how we interpret it.A growing number of researchers examining the effects of music on the brain could lead to new therapeutic treatments in the future. (Christine Daniloff/MIT)This is an excerpt from Second Opinion, a weekly roundup of eclectic and under-the-radar health and medical science news emailed to subscribers every Saturday morning. If you haven’t subscribed yet, you can do that by clicking here. This week: Studying how the brain interacts with music isn’t as easy as you might think. Microwaves are more dangerous for children than previously thought. How doctors are fighting the anti-vaccination movement with facts. New research is shedding light on how the brain interacts with music. It also highlights how challenging it is to study the issue effectively due to the highly personalized nature of how we interpret it. “Music is very subjective,” says Dr. Daniel Levitin, a professor of neuroscience and music at McGill University in Montreal and author of the bestselling book This is Your Brain on Music. “People have their own preferences and their own experience and to some extent baggage that they bring to all of this — it is challenging.” Levitin says there are more researchers studying the neurological effects of music now than ever before. From 1998 to 2008 there were only four media reports of evidence-based uses of music in research, while from 2009 to 2019 there were 185, Levitin said in a recent paper for the journal Music and Medicine. It’s a “great time for music and brain research” because more people are well-trained and skilled at conducting rigorous experiments, according to Levitin. Emerging research reveals challenges A new study by researchers in Germany and Norway used artificial intelligence to analyze levels of “uncertainty” and “surprise” in 80,000 chords from 745 commercially successful pop songs on the U.S. Billboard charts. The research, published Thursday in Current Biology, found that chords provided more pleasure to the listener both when there is uncertainty in anticipating what comes next, and from the surprise the music elicits when the chords deviate from expectations. “The ‘uncertainty’ is about saying how much you know what’s going to happen next, whereas the ‘surprise’ is actually comparing what you expected and what you actually heard,” says lead author Vincent Cheung of the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany. Last month, researchers at McGill University published a similar study in The Journal of Neuroscience that found that people are more attracted to songs that sound familiar, but are still unpredictable. That unpredictable nature of music can have “strong emotional effects” on us, yet the research shows we still prefer music with “expected musical outcomes in more uncertain contexts.” Sound complicated? Welcome to the world of studying music and the brain. How do we study something so personal? The problem is that there are often external factors that are difficult to control that could affect the results of these studies — including the background, age and musical experience of the participants themselves. In the case of the Current Biology study, the songs that were selected range in date from 1958 to 1991, but the median age of the study’s participants was around 25. Neuroscientist Daniel Levitin says musical therapy for dementia patients is an exciting area of research, but we’re still learning how it works. (Arsenio Corôa) Levitin says that presents obvious challenges to a listener’s familiarity with the music, and the study authors admit that other factors such as a listener’s cultural background, the musical genre and style could affect how surprising chords are to them. A study published in Scientific Reports last week by researchers at University College London looked at how quickly the brain can recall a “familiar” song — much like the “name that tune” games radio hosts play on air. The researchers — led by Maria Chait, lead study author and a neuroscientist at the UCL Ear Institute in London, England — wondered whether they could measure how quickly the brain can recognize familiar songs, even when someone isn’t trying to. The researchers asked participants to list five songs that they’ve frequently listened to that have a personal, positive meaning to them, then selected one song from the list and matched it with an unknown yet structurally similar song. Both were played for the listener. The participants’ brain activity and pupils were analyzed, and researchers concluded they were able to react to the familiar songs incredibly quickly — within 100 to 300 milliseconds. Defining ‘familiar music’ isn’t simple But our individual perceptions of “familiar music” highlights the inherent challenges with this type of research. A listener could be familiar with a certain song that their child plays over and over, for example, but not necessarily enjoy that song at all, Chait says. “You need to control for the type of familiarity, you need to find controls for the songs that you’re using and that ended up being quite complicated,” Chait said. One criticism Levitin had of the study is that participants knew they would get one of the five songs they submitted, which left those songs “primed in their memory.” New research reveals the effect music has on the brain, but experts say there is still much we don’t know. (Albert Leung/CBC) Another controversial factor involved the control group in the study. To find a group of people unfamiliar with all 20 songs in the experiment, the researchers recruited international students. Chait said the control group was predominantly made up of people from Asian backgrounds, who were “unfamiliar with popular Western music.” “If you grow up in a different musical language environment, so to speak, your brain responds to other genres other music cultures very, very differently,” says Michael Thaut, a professor of music and neuroscience at the University of Toronto. This means the control group participants may have responded “much slower” because they were unfamiliar with the “melodic and harmonic language of Western music,” he said. Could ‘familiar music’ help treat Alzheimer’s disease? Thaut is part of a group of researchers at U of T and St. Michael’s Hospital in Toronto that are using “familiar music” in a different way — with people who have Alzheimer’s disease. “We would see patients who really couldn’t do anything — didn’t know where they were, didn’t know their name, couldn’t speak, yet could play the piano or could compose a song,” says Dr. Corinne Fischer, a geriatric psychiatrist and one of the researchers of the study. “So that realization that patients could have this immense cognitive reserve related to these specific abilities made us interested in the question.” They studied 20 patients with either early-stage Alzheimer’s or mild cognitive impairment to figure out what was occurring in their brains while they listened to familiar music, compared with music they had never heard before while undergoing MRI scans. What they found was that when participants listened to songs they knew well, dating back at least 20 years, there was much more brain activity in several additional areas of the brain compared with the unknown songs. “For years we were pursuing the idea that music is a very good cognitive enhancer,” says Dr. Luis Fornazzari, a behavioural neurologist and researcher on the study. “So it confirmed that music, even in the passive way like listening, is a very important brain activator.” The medical applications of musical therapy on dementia patients is something Levitin sees potential in, especially given that it’s an inexpensive therapy seemingly without side effects. But more research needs to be done to identify the specific nature of its benefits, he said. “In order for Health Canada to endorse this as a therapy, we need to understand how it works and we don’t know the mechanisms,” he said. “There are questions — does music do this uniquely? Would a comedy record do it? A book on tape? A good television show? There’s an enormous amount we don’t know.” To read the entire Second Opinion newsletter every Saturday morning, please subscribe.