Brain scan showed distinct activity differences in the jazz musicians and that difference was greater in those with longer jazz histories. Past improvisation experience increased the functional bilateral connectivity of the dorsal premotor cortex, the pre-supplemental motor areas of cortex, and the dorsolateral prefrontal cortices. Decreased activity connectivity was noted in executive control frontal-parietal areas. Thus, it would seem that creativity training, in jazz at least, changes the brain at a network level. Presumably, these connectivity changes were created by past histories in learning jazz and no doubt facilitated improvisation by automating some of the neural functions needed to perform it.
How do we interpret the decreased activity in executive-control areas of cortex? Multiple other brain-scan studies in other contexts have indicated that as a brain becomes proficient in a certain task, apparently less neural tissue is needed to perform the task. Decreased activity can therefore indicate task mastery.
Scientists have known for a decade or more that learning and memory in general change both brain anatomy and function. Such changes are typically linked to the neural requirements for performing specific kinds of tasks. This study of classical and jazz musicians follows on prior studies showing that musical training does change the brain. For example, violin players have enhanced neural activity in the motor cortex controlling hand movements. The relative size of the left and right motor cortex differs between piano and string players.
The importance of this present study is that it demonstrates that the brain change depends on the kind of musical training and appears to be selective for improvisation. Moreover, musical improvisational training affects more than just control over movements and extends to cognitive functions needed to improvise. Improvisation is a creative act that apparently recruits cortical circuits to support it and in the process rewires the brain to facilitate improvisation.
Improvisation relies heavily on memory of previously learned musical patterns and implementation strategies. Jazz players call this "musical vocabulary." Thus, jazz players have to become musicians first, then learn how to improvise. Because memory is a "process in a population, not a thing in a place," neural representation of musical vocabulary is probably widely distributed, and the brain must learn how to recruit connections from multiple brain areas and integrate them in real time in the prefrontal and movement-control parts of the brain, which apparently generate creative ideas and implement them.
Pinho, A. L. et al. (2014) Connecting to create: expertise in musical improvisation is associated with increased functional connectivity between premotor and prefrontal areas. J. Neuroscience. 34 (18): 6156-6163. doi: 10.1523/JNEUROSCI.4769.13-2014.