Two researchers at the National Institutes of Health, Charles Limb and Allen Braun, asked six jazz pianists to improvise at the keyboard, while their heads were inside a brain scanner known as a functional magnetic resonance imaging (fMRI) machine. The brain scanner is immense–it fills up an entire room–and to get your brain scanned, you have to be lying down so that the immense donut shaped scanning ring can be moved into place around your head. So the researchers designed a special keyboard that could be propped up in the pianist’s lap.
Then they had each of the six pianists play four different exercises, two that were not improvised and two that were. The first exercise was a simple C major scale (not improvised); in the second exercise, they were asked to improvise on the C major scale (using only quarter notes and in time with a metronome); in the third exercise, they played a blues melody that they had all memorized in advance (not improvised); and for the fourth, they were asked to improvise their own tune.
To figure out which areas of the brain are unique to improvisation, you’d want to see which brain areas were active only for the second and fourth exercises. So the researchers “subtracted” the images while the brain was not improvising, from the brain images during improvisation–leaving only the areas that were different during improvisation. In both of the improvised activities, there was a particular region that slowed down during improvisation: the dorsolateral prefrontal cortex. This area is associated with planned actions and self-censoring. The researchers hypothesized that lower activity in this area should be associated with lower inhibitions.
And, there was another brain region that showed increased activity: the medial prefrontal cortex, an area associated with self-expression.
What’s perhaps most important about this research is that these findings aren’t unique to jazz pianists. The researchers point out that the same brain patterns should be found in any improvised behavior, including everyday activities like telling a story for the first time, or improvising your way through the neighborhoods to get around a traffic jam. The key is a combination of reduced inhibition and heightened self-expression.