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MONDAY, Aug. 4, 2003 (HealthDayNews) -- Armed with brain scans, British researchers say they're learning how humans detect delicate variations in the sounds that make up music and the human voice.
The scientists theorize that different parts of the human brain are in charge of interpreting the two dimensions of pitch -- its place on the scale (such as B or F) and its octave level (such as high or low, or soprano or baritone).
"We are basically saying that there is a mapping of pitch in the brain like a piano keyboard," says study co-author Dr. Timothy Griffiths, a senior clinical fellow at Newcastle University Medical School in the United Kingdom.
According to Griffiths, some researchers have suggested the brain processes a pitch in one giant piece. Griffith and his colleagues decided to test that theory by using functional magnetic resonance imaging (fMRI) scanners to analyze brain activity when humans listened to various tones.
At issue is "how does a musician tell [a note] is a G, and secondly, how does the musician know which G it is -- high, middle or low?" explains Christine Beckett, a professor of music at Concordia University in Montreal.
The researchers report their findings in this week's online issue of the Proceedings of the National Academy of Sciences.
They found one part of the brain near the auditory center lit up when the subjects heard notes that differed by location on the scale. Another part lit up in reaction to the octave of a note.
In other words, when the brain hears a B sung by a tenor, one part picks up the B part while another detects that a tenor is involved.
"In other words, there is a mechanism in the brain, at a very high level in the cortex, for representing both [dimensions of a note]," Griffiths says.
So why is this information important? It's a small piece of a big puzzle, and will contribute to an ongoing project to map out the brain, Beckett says.
"You could say it is the neural equivalent of the human genome project, the importance of which is undisputed," Beckett says. "To know how this fascinating organ deals with life in general, we have to know how it deals with all the little bits, and break it down into manageable components."
Understanding how the brain processes music is at the "cutting edge" of efforts to tap into the brain's secrets, she says.
More information
Some lucky people develop perfect pitch. If you have it, researchers at the University of California at San Francisco want to hear from you. Check out their perfect pitch Web site and take an online test to find out if you're tone-sensitive -- or tone-deaf. You can also learn about pitch from this Web site, which features excerpts from easily recognized rock and pop songs.
