This is your brain on jazz: researchers use MRI to study spontaneity, creativity

A pair of Johns Hopkins and government scientists have discovered that when jazz musicians improvise, their brains turn off areas linked to self-censoring and inhibition, and turn on those that let self-expression flow.

The joint research, using functional magnetic resonance imaging, or fMRI, and musician volunteers from the Johns Hopkins University's Peabody Institute, sheds light on the creative improvisation that artists and non-artists use in everyday life, the investigators say.

It appears, they conclude, that jazz musicians create their unique improvised riffs by turning off inhibition and turning up creativity.

In a report published 27 February in Public Library of Science (PLoS) ONE, the scientists from the University's School of Medicine and the National Institute on Deafness and Other Communications Disorders describe their curiosity about the possible neurological underpinnings of the almost trance-like state jazz artists enter during spontaneous improvisation.

'When jazz musicians improvise, they often play with eyes closed in a distinctive, personal style that transcends traditional rules of melody and rhythm,' says Charles J. Limb, M.D., assistant professor in the Department of Otolaryngology-Head and Neck Surgery at the Johns Hopkins School of Medicine and a trained jazz saxophonist himself. 'It's a remarkable frame of mind,' he adds, 'during which, all of a sudden, the musician is generating music that has never been heard, thought, practised or played before. What comes out is completely spontaneous.'

Though many recent studies have focused on understanding what parts of a person's brain are active when listening to music, Limb says few have delved into brain activity while music is being spontaneously composed.

Curious about his own 'brain on jazz,' he and a colleague, Allen R. Braun, M.D., of NIDCD, devised a plan to view in real time the brain functions of musicians improvising.

For the study, they recruited six trained jazz pianists, three from the Peabody Institute, a music conservatory where Limb holds a joint faculty appointment. Other volunteers learned about the study by word of mouth through the local jazz community.

The researchers designed a special keyboard to allow the pianists to play inside a functional magnetic resonance imaging (fMRI) machine, a brain-scanner that illuminates areas of the brain responding to various stimuli, identifying which areas are active while a person is involved in some mental task, for example.

Because fMRI uses powerful magnets, the researchers designed the unconventional keyboard with no iron-containing metal parts that the magnet could attract. They also used fMRI-compatible headphones that would allow musicians to hear the music they generate while they're playing it.

Each musician first took part in four different exercises designed to separate out the brain activity involved in playing simple memorised piano pieces and activity while improvising their music. While lying in the fMRI machine with the special keyboard propped on their laps, the pianists all began by playing the C-major scale, a well-memorised order of notes that every beginner learns. With the sound of a metronome playing over the headphones, the musicians were instructed to play the scale, making sure that each volunteer played the same notes with the same timing.

In the second exercise, the pianists were asked to improvise in time with the metronome. They were asked to use quarter notes on the C-major scale, but could play any of these notes that they wanted.

Next, the musicians were asked to play an original blues melody that they all memorised in advance, while a recorded jazz quartet that complemented the tune played in the background. In the last exercise, the musicians were told to improvise their own tunes with the same recorded jazz quartet.

Limb and Braun then analysed the brain scans. Since the brain areas activated during memorised playing are parts that tend to be active during any kind of piano playing, the researchers subtracted those images from ones taken during improvisation. Left only with brain activity unique to improvisation, the scientists saw strikingly similar patterns, regardless of whether the musicians were doing simple improvisation on the C-major scale or playing more complex tunes with the jazz quartet.

The scientists found that a region of the brain known as the dorsolateral prefrontal cortex, a broad portion of the front of the brain that extends to the sides, showed a slowdown in activity during improvisation. This area has been linked to planned actions and self-censoring, such as carefully deciding what words you might say at a job interview. Shutting down this area could lead to lowered inhibitions, Limb suggests.

The researchers also saw increased activity in the medial prefrontal cortex, which sits in the centre of the brain's frontal lobe. This area has been linked with self-expression and activities that convey individuality, such as telling a story about yourself.

'Jazz is often described as being an extremely individualistic art form. You can figure out which jazz musician is playing because one person's improvisation sounds only like him or her,' says Limb. 'What we think is happening is when you're telling your own musical story, you're shutting down impulses that might impede the flow of novel ideas.'

Limb notes that this type of brain activity may also be present during other types of improvisational behaviour that are integral parts of life for artists and non-artists alike. For example, he notes, people are continually improvising words in conversations and improvising solutions to problems on the spot. 'Without this type of creativity, humans wouldn't have advanced as a species. It's an integral part of who we are,' Limb says.

He and Braun plan to use similar techniques to see whether the improvisational brain activity they identified matches that in other types of artists, such as poets or visual artists, as well as non-artists asked to improvise.

This research was funded by the Division of Intramural Research, National Institute on Deafness and Other Communication Disorders, National Institutes of Health.