In a new study, New York University researchers isolated the rhythms in the brain that can coordinate with music. However, only the brain oscillations of musicians were able to synchronize with the unusually slow music clips used in the experiments, say the NYU researchers — the brain waves of non-musicians could not match the unhurried tempo.

“We show that musical training strengthens oscillatory mechanisms designed for processing temporal structure in music,” wrote the researchers in their published study.

Wavelengths

The neurons in your brain communicate via electricity and the pulsing of this charged activity is a brainwave, Scientific American explains. Categorized into four distinct types, brainwaves range from low amplitude, high frequency beta waves to high amplitude, low frequency delta waves. Beta waves would be the signature of an active, engaged mind, while a person ruminating on the past or meditating is most likely in an alpha state. Daydreaming allows us to dip into our theta brainwaves, while deep dreamless sleep plunges us into the low frequency of delta waves.

Though one brainwave state will dominate at any given moment, the other three remain in the mix at all times. Meanwhile, our minds respond to the sound waves around them.

“For any rhythmic sound, the brain seems to align its own rhythms to that of the sound so that they are both ‘on the same wavelength,’” Keith Doelling, the lead author and a Ph.D. candidate at NYU, told Medical Daily.

Specifically, previous research has shown how our brain rhythms coordinate with speech, enabling us to isolate the syllables, words, and phrases from continuous, spoken word streams, Doelling and his co-authors explained. But what about music — do our brains parse individual notes within a stream of music? 

To come up with some answers, the NYU research team conducted three experiments using magnetoencephalography (MEG), which measures the tiny magnetic fields generated by brain activity. After enlisting 39 volunteers, the researchers divided them into two groups: musicians (12) and non-musicians (27). Next, participants listened to 13-second clips of classical piano music which varied in tempo (from half a note per second to eight notes per second). In each run, participants were asked to detect short pitch distortions in the sound clips.

So how did the participants compare? The brain oscillations of all the participants synchronized with the note rate of any musical clip when the tempo was faster than one note per second, observed the researchers. However, only the musicians’ brains could align their oscillations with an unusually slow tempo. According to the researchers, this difference suggests the non-musicians are less capable of processing music as a continuous melody (perhaps instead their brains cling too much to individual notes).

When we are able to align our brain waves with “the temporal structure of music,” this allows our brains “better access to other aspects of musical processing as well (certainly pitch, and potentially things like melody and harmony),” Doelling explained.

Ultimately, our brain rhythms strive to align with and group any sound, whether music or speech, into small chunks to be analyzed. 

“We seem to use rhythm as a type of carrier signal to facilitate the transfer of information… that can be decoded in the brain further down the processing pathway,” said Doelling.

Source:  Doelling KB, Poeppel D. Cortical entrainment to music and its modulation by expertise. PNAS. 2015.