MUSIC SCIENCE DISCOVERIES
Los Angeles Times Headlines, December 13, 2002
Music Leaves Its Mark on the Brain
If it's pleasing to the ears, it's tied to rewired circuits that find notes harmonious,
By Robert Lee Hotz, Times Staff Writer
NEW YORK — From Mozart to Miles Davis, the harmonies of Western music
rewire the brain, creating patterns of neural activity at the confluence of emotion
and memory that strengthen with each new melody, research made public Thursday
By monitoring the brains of people listening to classical scales and key progressions,
scientists at Dartmouth College glimpsed the biology of the hit-making machinery
of popular song. Focusing on the structure of Western music, researchers show
how the musical mind hears the flat notes in Flatt and Scruggs, the sharps of
the Harmonicats and all five octaves in pop diva Mariah Carey's repertoire.
The flash-dance of these brain circuits, which process the harmonic relationship
of musical notes, is shaped by a human craving for melody that drives people to
spend more every year on music than on prescription drugs. The circuits center
in a brain region that responds equally to the musical patterns of Eminem's hip-hop
busta rhymes and Bach's baroque fugues.
"Music is not necessary for human survival, yet something inside us craves
it," said Dartmouth music psychologist Petr Janata, who led the global research
team. "Our minds have internalized the music."
Whatever the reason, the effect on the individual brain is measurable.
Among expert musicians, certain areas of the cortex are up to 5% larger than
in people with little or no musical training, recent research shows. In musicians
who started their training in early childhood, the neural bridge that links the
brain's hemispheres, called the corpus callosum, is up to 15% larger. A professional
musician's auditory cortex — the part of the brain associated with hearing
— contains 130% more gray matter than that of non-musicians.
The new study, published today in Science, shows for the first time that the
abstract knowledge about the harmonic relationships in music inscribes itself
on the human cortex, guiding expectations of how musical notes should relate to
one another as they are played. Through constant exposure, synapses are trained
to respond like a series of tuning forks to the tones characteristic of Western
music, several experts said. So far, no one has tested the music of other cultures,
but researchers speculate that all music should have the same effect.
The pattern in the music literally becomes a pattern in the brain. "It
shows this link between music theory and perception and brain function,"
said Frances H. Rauscher, an expert in music cognition at the University of Wisconsin
at Oshkosh. "No one had looked before."
The Dartmouth group scanned eight people with a functional magnetic resonance
imager as they listened to an eight-minute melody specially composed to move continuously
through all 24 major and minor musical keys. The volunteers, who each had about
12 years of musical training, performed several music-related tasks while they
listened in the scanner.
The scanner, which records changes in blood flow associated with mental processing,
allowed the scientists to watch this meandering of keys as the music traced a
path across the surface of the cortex.
Although music activated many parts of the brain, the researchers discovered
that everyone had just one area in common that tracked and processed melodies.
That brain region, near the center of the forehead, is called the rostromedial
prefrontal cortex. This region, which links to short and long-term memory and
emotions, is different from areas involved in more basic sound processing.
"In the same way that tracing the path of a car allows one to infer the
underlying map of a city's streets, the path traced by the keys along the cortex
allowed the researchers to see the underlying structure," explained David
Huron, head of the cognitive and systematic musicology laboratory at Ohio State
"It is beautiful."
Since the first primitive human ancestor carved a flute from a bear bone more
than 50,000 years ago, melody, harmony and rhythm have stirred people of every
culture. No one knows how or why music evolved to become such an important human
activity. "Music is really popular, but what does it do for the brain?"
asked Janata. "Why is it we have the emotional responses we do to music?
Why is it that melodies run spontaneously through our heads?"
Music may be as much in the genes as in the soul.
Perfect pitch, for example, appears to be inherited, only to be lost if not
reinforced by practice. By 4 months of age, babies already prefer the more musical
intervals of major and minor thirds to the more dissonant sounds of minor seconds,
researchers have shown.
Gordon Shaw and Mark Bodner, brain experts at the Music Intelligence Neural
Development Institute in Irvine, emphasized, however, that there is nothing special
about Western music, at least as far as brain anatomy and neural networks are
concerned. These distinctive musical circuits in the cortex could be just as easily
tuned by exposure to the music of the Aborigine didgeridoo, Tuvan throat-singing
or Japanese court gagaku.
"This is a brain structure that has adapted to the way the music is,"
Huron said. "This is a manifestation of Western culture that is appearing
on the cortex, not some innate structure."
Within this brain region, however, a melody creates a slightly different pattern
of neural activity every time it is heard, as if the laser reading the digital
pattern of a compact disc recording varied the pattern slightly each time the
music was played.
This dynamic map may be the key to understanding why a piece of music might
elicit a certain behavior one time, such as dancing, and something different another
time, such as smiling when remembering a dance, the researchers said.
"We think it might explain why when you hear a piece of music one time,
it might move you to dance," said Janata. "When you hear it another
time, you might instead remember the party or the feelings you had there."
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