How your brain knows when the beat is about to drop

We may finally understand how the brain processes beat drops: People use two distinct brain networks to predict and identify the transitions between musical segments.

Musical boundaries — the moments when one part of a composition ends and another begins — are important to enjoying music, especially traditional Western music. Without them, your favorite hits would sound like a monotonous, random stream of notes, “like reading a text without punctuation,” says Ibarra Burnat-Peres of the University of Jyväskylä in Finland.

To understand how the brain processes musical boundaries, she and her colleagues analyzed brain activity while listening to 36 adults listen to instrumental pieces from three different genres: Adios Nonino Astor Piazzolla, an American progressive metal band Stream of consciousness Dream Theater and Russian Ballet Classics of The Rite of Spring Works by Igor Stravinsky. All of the listeners had attended school in Finland, and half of them considered themselves semi-professional or professional musicians.

The researchers found that just before musical boundaries, a brain network they call the early auditory network activates in anticipation of the end of a musical phrase. This network primarily involves auditory regions located in the posterior, or back, outer region of the brain called the cortex.

Another network becomes active during and after musical transitions. This network, called the border-transition network, is characterized by increased activity in auditory areas toward the middle and anterior, or front, parts of the cortex. Perez says that this change in brain activity between the two regions is similar to how the brain understands the difference between sentences in a language.

During and after the musical boundary, several brain regions, including the right ventrolateral prefrontal cortex, which is involved in complex cognitive tasks and decision-making, deactivate, suggesting that the brain redirects attention and resources to integrating new musical information as a new segment begins, Perez says.

Musicians and non-musicians also used the two brain networks differently. For example, musicians relied on brain regions important for higher-order auditory processing and integration, which may reflect a more specialized approach to understanding musical boundaries, Perez says. Non-musicians, on the other hand, showed greater connectivity across broader brain regions, indicating a more general approach.

In addition to shedding light on how the brain processes music, Perez says, these findings could also help develop music therapy for people who have difficulty comprehending language. For example, incorporating elements of musical boundaries into speech transitions (such as matching syllables to a melody) might make sentences easier to understand, she says.