HARVARD GAZETTE ARCHIVES
Music on the brain:
Researchers explore the biology of music
By William J. Cromie
Babies come into the world with musical preferences. They begin to respond to music while still in the womb. At the age of 4 months, dissonant notes at the end of a melody will cause them to squirm and turn away. If they like a tune, they may coo.
Scientists cite such responses as evidence that certain rules for music are wired into the brain, and musicians violate them at the risk of making their audiences squirm. Even the Smashing Pumpkins, a hard-rock group, play by some of the same rules of harmony that Johann Sebastian Bach did in the 18th century.
"Music is in our genes," says Mark Jude Tramo, a musician, prolific songwriter, and neuroscientist at the Harvard Medical School. "Many researchers like myself are trying to understand melody, harmony, rhythm, and the feelings they produce, at the level of individual brain cells. At this level, there may be a universal set of rules that governs how a limited number of sounds can be combined in an infinite number of ways."
"All humans come into the world with an innate capability for music," agrees Kay Shelemay, professor of music at Harvard. "At a very early age, this capability is shaped by the music system of the culture in which a child is raised. That culture affects the construction of instruments, the way people sound when they sing, and even the way they hear sound. By combining research on what goes on in the brain with a cultural understanding of music, I expect we'll learn a lot more than we would by either approach alone."
Besides increasing basic understanding, Tramo believes that studying the biology of music can lead to practical applications related to learning, deafness, and personal improvement. For example, there's evidence that music can help lower blood pressure and ease pain.
Looking for a music center
A human brain is divided into two hemispheres, and the right hemisphere has been traditionally identified as the seat of music appreciation. However, no one has found a "music center" there, or anywhere else. Studies of musical understanding in people who have damage to either hemisphere, as well as brain scans of people taken while listening to tunes, reveal that music perception emerges from the interplay of activity in both sides of the brain.
Some brain circuits respond specifically to music; but, as you would expect, parts of these circuits participate in other forms of sound processing. For example, the region of the brain dedicated to perfect pitch is also involved in speech perception.
Music and other sounds entering the ears go to the auditory cortex, assemblages of cells just above both ears. The right side of the cortex is crucial for perceiving pitch as well as certain aspects of melody, harmony, timbre, and rhythm. (All the people tested were right-handed, so brain preferences may differ in lefties.)
The left side of the brain in most people excels at processing rapid changes in frequency and intensity, both in music and words. Such rapid changes occur when someone plucks a violin string versus running a bow across it.
Both left and right sides are necessary for complete perception of rhythm. For example, both hemispheres need to be working to tell the difference between three-quarter and four-quarter time.
The front part of your brain (frontal cortex), where working memories are stored, also plays a role in rhythm and melody perception.
"It's not clear what, if any, part these hearing centers play in 'feeling' music," Tramo notes. "Other areas of the brain deal with emotion and pleasure. There is a great deal of effort going on to map connections between the auditory cortex and parts of the brain that participate in emotion."
Researchers have found activity in brain regions that control movement even when people just listen to music without moving any parts of their bodies. "If you're just thinking about tapping out a rhythm, parts of the motor system in your brain light up," Tramo notes.
"Music is as inherently motor as it is auditory," he continues. "Many of us 'conduct' while listening to classical music, hum along with show tunes, or dance to popular music. Add the contributions of facial expressions, stage lights, and emotions, and you appreciate the complexity of what our brain puts together while we listen and interact with music in a concert hall or mosh pit."
Understanding the biology of music could allow people to use it better in medical and other areas where evidence indicates music produces benefits beyond entertainment.
Following heart bypass surgery, patients often experience erratic changes in blood pressure. Such changes are treated with drugs. Studies show that those in intensive care units where background music is played need lower doses of these drugs compared with patients in units where no music is played.
Scientists and medical doctors are investigating the value of musiclike games to aid dyslexics. When dyslexics play a game that calls for responses to tones that come very fast, it reportedly helps them to read better. "The approach is controversial," Tramo admits, "but there's enough favorable evidence for researchers to continue testing it."
Some hospitals play soft background music in intensive care units for premature babies. Researchers have found that such music, as well as a nurse's or mother's humming, helps babies to gain weight faster and to leave the unit earlier than premies who don't hear these sounds.
On the other end of the age scale, music has been used to calm Alzheimer's patients. At mealtime in nursing homes or hospitals these people may be difficult to organize. Fights even occur. The right kind of music, it has been demonstrated, reduces confusion and disagreements.
Investigators have also found that music lowers blood pressure in certain situations, and it seems to increase the efficiency of oxygen consumption by the heart. "One study showed that the heart muscle of people exercising on treadmills didn't work as hard when people listened to music as it did when they exercised in silence," Tramo notes.
Then there are endless anecdotes about athletes using music to enhance their performance. Pitcher Trevor Hoffman of the San Diego Padres, for example, listens to AC/DC to get psyched up in a game. Tramo ran to "Brown Sugar" by the Rolling Stones when he won a gold medal in the 100-yard dash in high school. To determine how much difference music makes, however, the performance of an athlete who listens to music would have to be compared with that in games when he or she didn't listen.
Tramo believes that music and dancing preceded language. Archaeologists have discovered flutes made from animal bones by Neanderthals living in Eastern Europe more than 50,000 years ago. No human culture is known that does not have music.
"Despite this, large gaps exist in our knowledge about the underlying biology," Tramo points out. We don't know how the brain decides if music is consonant and dissonant. We don't know whether practicing music helps people master other skills such as math or reading diagrams, although evidence that merely listening to Mozart in the womb improves IQ scores is weak or nonexistent.
Tramo made a choice between composing music and studying its biology at the end of medical school. When he and his roommate at Yale recorded a demonstration album called "Men With Tales," both RCA and Columbia Records said they wanted to hear more. But Tramo decided to stay with medicine. He didn't quit music though. Recently, he and his band recorded a song, "Living in Fantasy," which ranks in the top 40 of MP3 (accessible by computer) recordings made in Boston.
"I'm working on the neurobiology of harmony," Tramo says, "but I find time to compose and play music. Bringing the two together is like bringing together work and play."