Conductors single out sour side notes.

Experienced classical-music conductors wield their batons like master anglers, pulling musical keepers out of an orchestra's pool of instrumentalists. This impressive feat--which occurs only after many practice sessions leading up to a concert--requires maestros to monitor both the orchestra's overall performance and the contributions of specific violinists, oboists, trumpeters, and so on.

Skilled conductors sort through the symphonic cacophony by homing in on subtle changes in sounds originating from precise locations to the side as well as in front of them, a new study finds. Measurements of the brain's electrical activity indicate that conductors allocate just as much attention to peripheral sounds as to centrally located sounds, a team of neuropsychologists reports in the Feb. 1 NATURE.

Neither nonmusicians nor classical pianists possess this acoustic side-scanning ability, underscoring its key role in orchestra conducting, say Thomas F. Munte of the University of Magdeburg in Germany and his colleagues.

"Our findings provide [an] example of how extensive training can shape cognitive processes and their neural underpinnings," the scientists conclude.

Munte's team studied three groups: classical-music conductors who had an average of 19 years of conducting experience, classical pianists who had played professionally for an average of 16 years, and people who had no musical training of any kind. Each group consisted of six men and one woman.

Each participant sat in a chair facing a set of three loudspeakers. Another set of three speakers stood on the person's far right. Both arrays of speakers simultaneously delivered bursts of electronic noise that fell within a narrow range of acoustic frequencies. At random times, a single central or peripheral speaker emitted a burst outside of the usual frequency range.

All three groups showed about the same accuracy in noting the deviant sounds from the central speakers. However, conductors made markedly fewer errors that the other groups in identifying the deviant peripheral sounds, the researchers say.

Electrical activity in the conductors brains--measured by electrodes placed on the scalp during testing--exhibited a pattern asscociated with heightened attention when they heard either central or peripheral sound deviations. The other two groups showed attention-related brain activity only when they heard deviant central sounds.

Conductors who had as little as 6 years of experience on the podium located deviant peripheral sounds as well as their colleagues who had brandished their batons for nearly 30 years, Munte notes. "I suspect that conductors acquire the ability to localize peripheral sounds within the first few years of professional experience," he says.

Robert J. Zatorre, a neuroscientist at Montreal Neurological Hospital who studies music perception, is intrigued by the new results "Conductors are responsible for fine-tuning the way in which each member of an orchestra plays a musical composition," Zatorre holds. "The ability to identify the source of peripheral sounds is crucial for conductors."

Music schools typically attempt to teach aspiring conductors to pinpoint errors by having musicians intentionally play a wrong note from various sections of the orchestra, Zatorre adds. Fledgling conductors who are initially able to identify the source of peripheral sounds with at least fair accuracy may benefit the most from further experience he suggests.