Measuring creativity in an improvised jazz context: a preliminary tDCS study

Musical improvisation involves the generation of original and contextually appropriate musical sequences. This investigation focused on whether brain stimulation applied to the motor cortex influences creativity and technical fluency in musical improvisations. Previous research on creativity has examined two important brain networks: the dorsolateral prefrontal cortex (DLPFC), which underpins attention and monitoring, and the medial prefrontal cortex (MPFC), which regulates mind wandering and mental simulation. Other research on music has examined the significance of the premotor cortices, which include the ventral and dorsal pre-motor cortex (vPMD & dPMD,respectively) and the pre-supplementary motor area (pre-SMA) that aid in the generation of musical sequences and high level of motor planning and execution. To date, the primary motor cortex (M1)has not been explored in musical creativity. The M1 mediates movement of the hand, and is also involved in the consolidation and acquisition of motor skills. This investigation examined the role of the M1 regions in creativity, motor performance and technical fluency in a jazz improvisation context. The relationship between creativity and technical fluency was also assessed. The role of the M1 regions was evaluated with transcranial direct current stimulation (tDCS), which is a non-invasive, safe and painless form of brain stimulation that modulates the neural activity over the desired area. Minute electrical currents are delivered through two saline-soaked electrodes: the positive (anodal) electrode stimulates neural activity, whilst the negative (cathodal) electrodes inhibits neural activity. Bi-hemispheric, online tDCS was applied to the M1 region of proficient musicians. Two tDCS groups were used, Anodal-Left M1/Cathodal-Right M1 (n = 4) and Cathodal-Left M1/Anodal-Right M1 (n = 4) whilst they completed a sight reading and improvisation task. The level of creativity and technical fluency of the performances were assessed by an expert adjudicator (n = 1). It was hypothesised that applying excitatory tDCS over the M1 region of proficient musicians will enhance both creativity and technical fluency compared to inhibitory tDCS. The results from the preliminary study illustrates a trend that excitatory tDCS over the M1 region enhances creativity (p =.07). Furthermore, excitatory tDCS also significantly enhanced technical fluency (p =.05) when compared to inhibitory tDCS. These preliminary results provide some evidence that the M1 region is a brain area that aids in the enhancement of creativity, technical fluency, and motor performance in an improvised jazz context with proficient musicians.