The brain is a highly organized and complex organ that functions as the coordinating center of sensation and intellectual and nervous activity. Each area of the brain directly corresponds to a very specific function (emotions, movement, visual processing, memory, etc.), but, up until two days ago, scientists were unable to decipher exactly which area of the brain corresponded to music perception. On December 16th, Massachusetts Institute of Technology (MIT) announced that neuroscientists at the university were able to identify a neural population highly selective for music … for the first time ever!
In analyzing the human auditory cortex, researchers identified six respective neural populations that process and separate noise stimulus (or sounds) into categories: music, speech, and then functional categories like frequency and pitch. According to one of the scientists working on this case, Josh McDermott, “One of the core debates surrounding music is to what extent it has dedicated mechanisms in the brain and to what extent it piggybacks off of mechanisms that primarily serve other functions.”
This was the area in question that had researchers most curious. So they decided to map the entire brain’s auditory system using an fMRI (functional magnetic resonance imaging used to catalogue neural activity by charting blood flow; an incredibly difficult task to conquer with such minute spatial resolution).
The scientists observed ten people by sampling their neural responses to 165 samples of recorded sound (the closing of a door, the flush of a toilet, the beat of a drum, etc.) They measured the activity in voxels, the smallest unit of measurement to reflect the response of hundreds of thousands or millions of neurons. Using this system, the team was able to observe and draw up a visual map of exactly where the brain activity took place.
Contrary to normal everyday sounds, “the music result is notable because people had not been able to clearly see highly selective responses to music before,” says Sam Norman-Haignere, a postdoc at MIT’s McGovern Institute for Brain Research. He continues, “We think this provides evidence that there’s a hierarchy of processing where there are responses to relatively simple acoustic dimensions in this primary auditory area. That’s followed by a second stage of processing that represents more abstract properties of sound related to speech and music.” So this means that we are able to register, process, and encode music differently than the way we respond to other noise stimuli.
With said neural populations responding specifically to music, their findings provide evidence that music corresponds to its own music-selective neural environment —a discovery not yet proven by any research to date. The researchers are now investigating whether there are sub-populations of neurons that respond directly to specific aspects of music (rhythm, melody, beat, etc.), and also hope to find how musical training might affect this newly discovered neural population.
Watch more about how researchers identified a neural population in the human auditory cortex that responds specifically to music:
[Via MIT News]