Scientists find part of brain responds selectively to sound of singing

Scientists say they have found an unexpected response in the brain of a person who sings in a musical.

Researchers say they have found groups of cells that respond to the sound of singing.

A team of scientists in the US made their discovery by recording electrical activity in the brains of 15 people who were undergoing surgery for epileptic seizures.

The team recorded electrical activity in response to 165 different sounds, from pieces of instrumental music to speech and sounds such as dogs barking. They combined the results with the data from fMRI brain scans to map the location of the patterns in the brain.

Dr Samuel Norman-Haignere, a co-author of the study based at the University of Rochester, said that the team decided to combine the data from different approaches to overcome their weaknesses.

fMRI is one of the workhorses of human cognitive neuroscience, but it is very coarse. He said that intracranial data has poor spatial coverage.

fMRI scans have shown that some neurons respond to speech or music in a different way. The populations of neurons that respond to the sound of singing appear to be weak, showing only weak responses to other types of music or speech.

The team wrote that the results suggest that representations of music are fractionated into subpopulations for different types of music, one of which is specialized for the analysis of song.

The work shows that the song-specific neurons sit in the superior temporal gyrus, close to areas previously identified as responding to music or speech.

The authors believe that the song-selective neurons were not spotted in previous work using fMRI scans alone, since the use of electrodes allows for a better measure of the activity of neurons.

The researchers want to understand what it is about singing that certain areas of the brain are responding to, for example whether it is pitch and timbre, or melody and rhythms.

The authors write that the study presents a first step towards answering the questions.

They point out that songs can evoke specific emotions or memories and that there are areas of the brain that can be studied.

A professor at University College London who was not involved in the research welcomed the study.

The singing voice is the only musical instrument that almost everyone is born with, so one might expect us to have a different relationship with human song, relative to other kinds of music.

Some of the differences between the brain systems that control how we speak and those that control how we sing can be seen when we listen to human song.

Dr Ediz Sohoglu said the findings were striking.

One of the questions that arises is why the brain has evolved or been shaped by experience. He said that it would be better to use the same neurons in a multi-purpose fashion.

It's possible that having specialized neurons helps a person focus on certain sounds. If I am listening to my favourite singer in a concert, I might find it easier to ignore the loud conversation behind me, which would be represented in a different part of my brain.