Science finds the part of your brain that responds to singing

Music is universal across cultures and is a kind of information input unlike any other. Despite this, scientists are just beginning to understand how the brain processes music.

A few years ago, a team of neuroscientists at the Massachusetts Institute of Technology approached a group of patients undergoing electrocardiography — an invasive form of brain monitoring where a surgeon removes the top of the skull and places electrodes on the surface of the brain to record electrical activity — and asked if they could study how their brains process music.

The resultant study, published last month in Current Biology, identifies, for the first time, a group of neurons that are “song-selective,” responding specifically to singing, but not to instrumental music or speech. It is a finding that could have resonance; every clue is a part of a larger quest to map the human mind.

What’s New — The researchers located a “song-selective” hotspot in the middle of the superior temporal gyrus, the part of the brain that contains its sound-processing center, the auditory cortex. This particular song-selective region has stronger speech responses than the larger area that is sensitive to music and is linked to mechanisms for emotions and memories.

“I do think music provides an ideal domain to study lots of different, more general aspects of perception.”

This neural wiring makes sense, the study notes, as “[v]ocal melodies are better remembered than instrumental melodies, which may reflect greater salience for sung compared with instrumental music.”

How They Did It — The same MIT team completed a 2015 study that first identified a segment in the auditory cortex that responds to music, but not to other sounds. That study utilized functional magnetic resonance imaging (fMRI), which monitors brain activity by following small movements of blood.

“We knew very little about how representations of speech and music are structured within those areas,” lead author Samuel Norman-Haignere tells Inverse.

Electrocorticography gave them a chance to go deeper into the brain for even more specialized inquiry. They found 15 volunteers among the patients undergoing epilepsy surgery at the Albany Medical Center.

The researchers played for them 165 sounds, among them: a car horn, a dripping faucet, a dog barking, a person typing, a human chewing, a woman speaking, a man speaking, a man speaking in English, and a man speaking in a language the subjects could not understand. Each has a different meaning to a person and lit up a slightly different region of the brain, allowing the researchers to map out how the brain processes sound of varying significances. (They did the same for their 2015 study and the findings were mostly the same.)

They also had a selection of music, snippets of instrumental tracks, and 11 songs with vocals. Purposefully, they were from different genres: reggae, punk, heavy metal, soul, hip-hop, modern rock, classic rock, etc. “All 11 of them produced high responses” in one region of the music-sensitive brain area, says Norman-Haignere. “And all of the other instrumental music and all of the speech produce low responses.”

Why It Matters — You engage many functions of your brain when you listen to a pop song. You are processing the language, including subtexts and subtleties conveyed by pitch and tone — think of the difference between Bob Dylan’s pensive “All Along the Watchtower” and Jimi Hendrix’s urgent-sounding version. You are processing the emotion. You are understanding each bit as a larger work of art. You may be engaging with the memory of when you first heard that song. All of that is encoded in neural networks.

“I do think music provides an ideal domain to study lots of different, more general aspects of perception,” says Norman-Haignere. “I think comparing what you observe for music — and other sounds, like speeches — is a functional area of research that can be used to reveal more mechanisms.”

There is also the question of which of those neural pathways are music-specific and which process many kinds of information. “One of the key findings from this work,” says Norman-Haignere, “is at least some neural population in the brain that are actually pretty specific, and there's a big open question as to why.”

What’s Next — There are many questions further research can answer, says Norman-Haignere.

“At the moment, we know this [neural] population exists. We don't know exactly what it's responding to. We don't know, for example, if it’s responding to particular patterns of pitch over time in the melody, or whether it's also responding to particular patterns of what's being said, in conjunction with the way in which the pitch is modulating. We also don't know, kind of why this neural population exists, if it’s there because people simply listen to a lot of music or there's some role in evolution.”