A significant number of recent studies have used functional neuroimaging methods to investigate the perception of musical stimuli by the human brain –. The broad appeal of these studies is likely to be related to the universal nature of music throughout history and across cultures, as well as the intrinsic relationship between music and language. Fewer studies, however, have examined the central mechanisms that give rise to music performance ,  while, to our knowledge, only one other study  has examined the neural substrates that give rise to the spontaneous production of novel musical material, a process that extends well beyond the technical or physical requirements of musical production per se. Spontaneous musical performance, whether through singing or playing an instrument, can be defined as the immediate, on-line improvisation of novel melodic, harmonic, and rhythmic musical elements within a relevant musical context. Most importantly, the study of spontaneous musical improvisation may provide insights into the neural correlates of the creative process.
Creativity is a quintessential feature of human behavior, but the neural substrates that give rise to it remain largely unidentified. Spontaneous artistic creativity is often considered one of the most mysterious forms of creative behavior, frequently described as occurring in an altered state of mind beyond conscious awareness or control – while its neurophysiological basis remains obscure. Here we use functional neuroimaging methods to examine musical improvisation as a prototypical form of spontaneous creative behavior, with the assumption that the process is neither mysterious nor obscure, but is instead predicated on novel combinations of ordinary mental processes. It has been suggested that the prefrontal cortex is a region of critical importance that enables the creative process (which includes self-reflection and sensory processing as integral components) . We hypothesized that spontaneous musical improvisation would be associated with discrete changes in prefrontal activity that provide a biological substrate for actions that are characterized by creative self-expression in the absence of conscious self-monitoring. Furthermore, we hypothesized that alterations in prefrontal cortical activity would be associated with top-down changes in other systems, particularly sensorimotor areas needed to organize the on-line execution of musical ideas and behaviors, as well as limbic structures needed to regulate memory and emotional tone.
In this study, we used functional MRI to study improvisation, which is the hallmark of jazz music . During a jazz performance, musicians utilize a composition's underlying chord structure and melody as the contextual framework and basis upon which a novel solo is extemporaneously improvised. Hence, no two jazz improvisations are identical. The process of improvisation is involved in many aspects of human behavior beyond those of a musical nature, including adaptation to changing environments, problem solving and perhaps most importantly, the use of natural language, all of which are unscripted behaviors that capitalize on the generative capacity of the brain.
Since musical improvisation is an extraordinarily complex human behavior, we felt that it should be examined using paradigms that, while amenable to experimental constraint, are of high ecological validity (as argued by Burgess and colleagues; see , . We therefore designed such a paradigm—that of professional jazz pianists improvising on a piano keyboard during image acquisition, alone and with the musical accompaniment of a jazz quartet—using tasks of similar ecological validity to control for the perceptual and motor features of performance. Six highly skilled professional jazz musicians underwent functional MR brain scans (3 Tesla) during which they played a non-ferromagnetic piano keyboard specially designed for use in an fMRI setting (Fig. 1, upper). Because musical improvisation incorporates a broad range of melodic, harmonic, and rhythmic invention that is intrinsically difficult to control (while retaining musical integrity), we designed two paradigms, one that was relatively low (which we have termed Scale) and one that was high (which we have termed Jazz) in musical complexity. Both utilized musical control tasks designed to engage the same sensorimotor circuits but to generate pre-determined, over-learned output.
Limb CJ, Braun AR (2008) Neural Substrates of Spontaneous Musical Performance: An fMRI Study of Jazz Improvisation. PLoS ONE 3(2): e1679. doi:10.1371/journal.pone.0001679