Riff Riders: Brain scans tune in to jazz improvisers

It would come as no surprise to the late saxophonist and improvisational master John Coltrane, but when accomplished jazz musicians play free-form, their brain activity suggests a release of self-expression from conscious monitoring and self-censorship.

Such neural activity may lie at the heart of musical improvisation and perhaps other improvisational feats, propose auditory scientist Charles J. Limb of Johns Hopkins Hospital in Baltimore and neurologist Allen R. Braun of the National Institute on Deafness and Other Communication Disorders in Bethesda, Md.

“What we think is happening is that when you’re telling your own musical story, you’re shutting down neural impulses that might impede the flow of novel ideas,” says Limb, himself a trained jazz saxophonist.

Moreover, jazz musicians immersed in improvisation display heightened brain activity in all sensory areas and in adjacent motor regions, the researchers say. Improvisers’ brains “ramped up” to translate incoming sensations into novel musical performances, Limb suggests.

For the new study, published online in the February PLoS ONE, the researchers recruited six professional jazz pianists. Limb and Braun designed a plastic keyboard for the musicians to prop on their laps and play while lying inside a functional magnetic resonance imaging (fMRI) machine. They heard what they played through in-ear speakers.

By measuring rises and falls in the rate of blood flow throughout the brain, fMRI indirectly reads increases and decreases in neural activity in different brain regions.

In one exercise, pianists first played notes of the C-major scale in order, then improvised a melody with the same notes.

In a second exercise, musicians first played a memorized jazz composition note-for-note while listening to a recorded jazz quartet accompaniment. Pianists then improvised tunes while listening to the same background music.

Both exercises stimulated comparable brain activity unique to improvisation, the researchers say. The part of the frontal brain that has been linked to planning and self-censorship saw a marked decline in activity. At the same time, activity spiked in a small frontal structure that has been linked to being able to tell a story about oneself.

The researchers plan to look for the same frontal responses during improvisation by other types of artists, such as poets or painters. Even the ability to converse in one’s native tongue is unscripted and may depend on the brain’s improvisational mechanisms, Limb proposes.

Further research could help determine whether the observed frontal responses contribute to altered states of consciousness often reported during jazz improvisation.

Neuroscientist Fredrik Ullén of the Karolinska Institute in Stockholm regards the widespread deactivation of planning-related frontal areas during jazz improvisation as “the most fascinating new finding.” In a 2007 fMRI study of classical pianists, Ullén found more frontal-brain activation during improvisation than Limb and Braun did. However, classical pianists lack the improvisational experience of jazz pianists, he says.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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