Going with the flow of musical brains.

Some musicians afflicted with extensive brain damage experience a tragic loss of both verbal and musical skills. In one poignant case, French composer Maurice Ravel developed a progressive brain disease of unknown origin that first robbed him of the ability to write and to perform many basic motor skills. Ravel then lost the capacity to read and play music, as well as his formidable gift for composition. Yet he could still play scales on the piano, and until his death in 1937, he derived the same joy as always from listening to music.

Scientists who use imaging technology to study the brains of performing musicians now offer a likely reason for Ravel's particular lapses, as well as the first solid clues to the regions of the brain involved in musical performance.

When an accomplished pianist reads musical notation and plays the composition on a keyboard, a network of areas throughout the brain springs into action, report psychologist Justine Sergent of McGill University in Montreal and her colleagues in the July 3 SCIENCE. These brain structures perform functions distinct from the duties of the far-flung cerebral regions crucial for language (SN: 4/30/88, p.280), but the two brain systems lie adjacent to one another. Thus, widespread brain damage often blocks various language and musical skills, as in Ravel's case, the Canadian researchers assert.

Sergent's group recruited 10 right-handed, classical pianists, each with at least 15 years of musical training. The scientists mapped blood-flow increases in the brain, which indicate greater brain activity, by injecting each participant with water containing a minute amount of a radioactively labeled oxygen compound. A positron emission tomography (PET) scanner measured gamma rays emitted by the rapidly decaying radioactive marker.

PET imaging lasted for one minute while volunteers reclined and read a musical score for the right hand, displayed on a television monitor. Another one-minute PET session took place while they played the same score on a small electronic keyboard within easy reach.

The researchers isolated areas involved in the two musical tasks by removing PET data on blood-flow activity generated during control trials involving visual fixation on a blank screen, manual responses to dots shown on the screen, and listening to and playing musical scales.

Sergent's group superimposed PET images over magnetic resonance imaging (MRI) views of volunteers' brains to pinpoint areas of greatest blood flow. The results indicate that sight-reading and piano performance activate parts of all four lobes of the brain's outer layer, or cortex, and the cerebellum, which sits at the base of the cortex. Many brain areas involved in word processing brush against cerebral nodes in the musical network, although musical performance also activates areas that handle the spatial information embodied in notes on a musical staff, according to Sergent.

"Sight-reading and piano playing with the right hand are only a fraction of musical experience, and we are still far from understanding the pleasure and emotions elicited by music, as well as the composer's mind," Sergent says.