Theos-Talk Archives (December 2002 Message tt00525)

And the program also reverses the procedure.
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december 13, 2002 Los angeles times 
front page

music Leaves its mark on the brain

if it's pleasing to the ears, it's tied to rewired circuits that find notes 
harmonious, study says.
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 shows.


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 university.
"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."