This is how your brain knows when the beat is about to drop

We may finally know how the brain processes a beat drop: people use two distinct brain networks to anticipate and identify transitions between segments in a piece of music.

Musical boundaries, the moments when one section of a composition ends and another begins, are important to our enjoyment of music, particularly from the Western tradition. Otherwise, your favourite hit would sound like a monotonous stream of random sounds, “similar to reading a text with no punctuation”, says Iballa Burunat Perez at the University of Jyväskylä in Finland.

To understand how the brain processes musical boundaries, she and her colleagues analysed brain activity in 36 adults while they listened to three instrumental works from different genres: the Argentinian nuevo tango composition Adiós Nonino by Astor Piazzolla, the US progressive metal piece Stream of Consciousness by Dream Theater and the Russian ballet classic The Rite of Spring by Igor Stravinsky. All of the listeners attended school in Finland, and half considered themselves semi-professional or professional musicians.

The researchers found that, right before a musical boundary, a brain network they called the early auditory network activates in anticipation of the musical phrase ending. This network primarily involves auditory areas in the posterior, or back, of the brain’s outer region, called the cortex.

A different network then activates during and after musical transitions. Dubbed the boundary transition network, it is characterised by increased activity in auditory areas toward the middle and anterior, or front, of the cortex. Perez says the shift in brain activity between these two areas is similar to how our brains understand the differences between sentences in language.

Several brain regions deactivate during and after musical boundaries, including the right ventrolateral prefrontal cortex, which is involved in complex cognitive tasks and decision-making. This suggests that, as a new segment begins, the brain redirects attention and resources towards integrating the new musical information, says Perez.

Musicians and non-musicians engage these two brain networks differently as well. For instance, musicians relied on brain areas important for higher-level auditory processing and integration. This may reflect a more specialised approach towards understanding musical boundaries, says Perez. Non-musicians, on the other hand, showed greater connectivity across broader brain regions, indicating a more generalised approach.

In addition to clarifying how the brain processes music, these findings may also help develop music-based therapies for people who have difficulties comprehending language, says Perez. For instance, incorporating elements of musical boundaries into language transitions – perhaps by setting syllables to a melody – may make sentences easier to understand, she says.