The brain, alive with imagined music and the sound of silence
Music has the power to move us. The flow of a melody and the dramatic pauses mid-tune can affect us like very little else in life. But what happens inside our brains as we experience music or think about our favourite songs? According to research supported in part by the EU-funded NEUME project, imagining a song triggers similar brain activity as those moments of silence in the middle of a melody. Even when no music is playing, our brain continues to respond to it. The results of the research provide us with a deeper understanding of human sensory predictions – the brain’s ability to use sensory information from the environment to make predictions about future events. When listening to music, our brain is constantly trying to predict what will happen next. It uses the rhythm of the music to interpret and anticipate the ongoing melody. Anything unexpected, such as a dissonant chord, increases brain activity. The research team sought to isolate the brain’s prediction signal from the signal it produces when actually listening to music. To do this, they used electroencephalograms (EEGs) to study how the brain responds to the silent intervals found here and there in music. They therefore measured the brain activity of professional musicians as they listened to or imagined Bach piano melodies. The musicians’ brain activity was found to be of the same type during silent intervals – when a note was expected but none was played – and when imagining music. However, when listening to music, their brain activity had an inverse electrical polarity to both silence and imagined music, which points to different brain activations.
Not just a sensory experience
“There is no sensory input during silence and imagined music, so the neural activity we discovered is coming purely from the brain’s predictions e.g. the brain’s internal model of music,” notes Asst. Prof. in Intelligent Systems Giovanni Di Liberto of Trinity College Dublin in a news release posted on ‘ScienceDaily’. “Even though the silent time-intervals do not have an input sound, we found consistent patterns of neural activity in those intervals, indicating that the brain reacts to both notes and silences of music.” So what does this imply? “Ultimately, this underlines that music is more than a sensory experience for the brain as it engages the brain in a continuous attempt of predicting upcoming musical events,” explains Asst. Prof. Di Liberto. “Our study has isolated the neural activity produced by that prediction process. And our results suggest that such prediction processes are at the foundation of both music listening and imagery.” According to the researcher, while the team’s purpose was to explore sound processing and sensory prediction mechanisms, their findings “have wider implications,” even finding use in clinical research. “For example, imagine a cognitive assessment protocol involving music listening,” he comments. “From a few minutes of EEG recordings during music listening, we could derive several useful cognitive indicators, as music engages a variety of brain functions, from sensory and prediction processes to emotions. Furthermore, consider that music listening is much more pleasant than existing tasks.” Two related studies, ‘The Music of Silence: Part I’ and ‘Part II’, have resulted from the research co-funded by NEUME (Neuroplasticity and the Musical Experience). Both studies have been published in the ‘Journal of Neuroscience’. For more information, please see: NEUME project
Keywords
NEUME, music, silence, brain, brain activity, sensory, prediction, listening