Memory is more than what connects us to the past. For neuroscientists, memory is what enables us to function on a daily basis, to organize our thinking, and shape ideas. Short-term memory helps us, for example, to remember a phone number for a few seconds just before dialing it, or the quantity of flour indicated in a recipe.
This “working memory” allows us to prioritize our thoughts. It also helps dictate our behaviour, which is perhaps one of the differences that clearly distinguishes humans from animals," explains Robert Zatorre. "And it’s linked to creativity."
For nearly 40 years, this researcher from the Montreal Neurological Institute and Hospital has been studying brain function and memory through the lens of music. "We use musical training as a model,” he says. Hearing, planning, motor control and, of course, short and long-term memory: music mobilizes our grey matter on all levels. “Today, we want to understand whether music training can improve our performance in other areas,” the researcher explains.
If we know that learning an instrument promotes, among other things, the development of motor skills, language, and stress management, one question remains: is learning music "transferable" to other cognitive functions? In other words, does playing the piano make us better at mental math, for example? "This is controversial," notes Zatorre.
To examine the issue, his team launched a project in collaboration with the Hebrew University of Jerusalem, funded by IDRC in partnership with the Azrieli Foundation, the Canadian Institutes of Health Research, and the Israel Science Foundation as part of the Joint Canada-Israel Health Research Program. "The goal was to train people to perform either a simple mental task or a complex task requiring working memory. Our hypothesis was that people who trained their working memory should be able to more easily transfer their skills than others," explains Philippe Albouy, a postdoctoral researcher who designed the study and analyzed results as part of Zatorre's team.
Forty students participated in the study, undergoing functional magnetic resonance imaging that allows for real-time detection of activated areas of the brain. Participants were assigned the simple mental task of comparing two melodies with minute variations in tone to determine whether or not they were identical. "At first, the tone variations were imperceptible. Then, through training, they improved their ability to perceive the nuances," explains the young researcher.
As for the complex task requiring working memory, it called for the participants to listen to three notes and then asked them to mentally switch the notes in a precise order (for example, the third note became the first, followed by the first and the second). "Then they listened to the three notes again and were asked to determine whether the order corresponded to the expected permutation. This task, which requires complex mental manipulation, is processed through a vast network of neurons called the dorsal stream. This is required in high-level mechanisms, such as making a mental calculation or imagining the rotation of an object in 3D," explains Philippe Albouy. The volunteers then had to complete 40 one-hour online training sessions from home for either the simple or complex task. Back in the lab, they were subjected to a battery of exercises and the researchers once more examined their brains.
"What we were able to demonstrate is that participants who had trained in the complex task were better at performing another task for which they had not been trained, which consisted of reciting a list of numbers in reverse order," says the researcher, whose results will be published soon. As for the group that had practised listening to the notes, they were simply better at discriminating between notes, but not at performing more complex tasks.” Conclusion? "There is indeed a malleability related to training."
With this in mind, the Israeli-Canadian team is proceeding to the next step: to see whether this type of exercise can help people with dyslexia improve their reading performance. "We know that most people with dyslexia have difficulty performing certain simple auditory tasks," explains Merav Ahissar, researcher in psychology at the Hebrew University of Jerusalem. But the manipulation and memorization of sounds is crucial for reading. "We hope to better understand how to modify training protocols, including for reading, so that these weaknesses are no longer major obstacles," she adds.
For Robert Zatorre, who was an organist before becoming a neuropsychologist, music has the potential to help those with learning difficulties. "We know that in underprivileged areas, which are often very noisy, children have attention disorders due to difficulty in distinguishing the teacher's voice from the noise. An American pilot project has shown that music training can improve their listening, in addition to their social skills," he says.
Indeed, several studies have shown that people with dyslexia also have a hearing deficiency in noisy environments, altering their comprehension of speech. And, in 2015, French researchers found that weekly sessions of rhythmic music over a few months significantly improved the reading skills of children with dyslexia. It’s a path that deserves to be explored.
The original French version of this article was published in the January 2018 issue of Québec Science.