Neural Correlates of Lyrical Improvisation: An fMRI Study of Freestyle Rap
Siyuan Liu, Ho Ming Chow, Yisheng Xu, Michael G. Erkkinen, Katherine E. Swett, Michael W. Eagle, Daniel A. Rizik-Baer & Allen R. Braun
doi:10.1038/srep00834
Received: 20 June 2012
Accepted: 19 October 2012
Published online: 15 November 2012
Abstract
The neural correlates of creativity are poorly understood. Freestyle rap provides a unique opportunity to study spontaneous lyrical improvisation, a multidimensional form of creativity at the interface of music and language. Here we use functional magnetic resonance imaging to characterize this process. Task contrast analyses indicate that improvised performance is characterized by dissociated activity in medial and dorsolateral prefrontal cortices, providing a context in which stimulus-independent behaviors may unfold in the absence of conscious monitoring and volitional control. Connectivity analyses reveal widespread improvisation-related correlations between medial prefrontal, cingulate motor, perisylvian cortices and amygdala, suggesting the emergence of a network linking motivation, language, affect and movement. Lyrical improvisation appears to be characterized by altered relationships between regions coupling intention and action, in which conventional executive control may be bypassed and motor control directed by cingulate motor mechanisms. These functional reorganizations may facilitate the initial improvisatory phase of creative behavior.
Introduction
Hip-Hop music, in particular rap, has had a huge cultural impact in western society, especially among the young, since its appearance four decades ago. Freestyle rap, a popular form, requires an artist to freely improvise rhyming lyrics and novel rhythmic patterns, guided by the instrumental beat – a particularly challenging form of spontaneous artistic creativity.
It has been proposed that artistic creativity is itself a twofold process, in which an initial improvisatory phase, characterized by spontaneous generation of novel material, is followed by a period of focused re-evaluation and revision1. The neural correlates of the improvisatory phase are poorly understood1,2,3,4,5,6,7,8 Freestyle rap thus provides a unique opportunity to study this initial, improvisatory phase at the interface of music and language.
In an attempt to identify the neural correlates of spontaneous lyrical improvisation in this context we compared freestyle (improvised) to conventional (rehearsed) performance, using functional magnetic resonance imaging (fMRI). Utilizing spatial independent component analysis (sICA) methods9 recently developed in this laboratory to effectively remove imaging artifacts associated with connected speech or song, has made it possible to study this unique genre using fMRI for the first time. Importantly, in order to study spontaneous lyrical improvisation in its most natural form, our design evaluated the natural and ecologically valid process: freestyle artists producing freestyle rap, unencumbered by unrelated cognitive demands.
Spontaneous improvisation is a complex cognitive process that shares features with what has been characterized as a ‘flow’ state10. It has been suggested that the frontal lobe, may play a central role in the improvisatory process, although the nature of its contributions is unclear2. On this basis, in addition to its other characteristics, we expected the neural correlates of lyrical improvisation to include changes in prefrontal activity that might enable spontaneous creative activity through effects on systems that regulate attention, affect, language and motor control.
Our results support these predictions and provide a novel model for improvisation characterized by functional changes within a large-scale network that is anchored in the frontal lobe. This pattern – activation of medial and deactivation of dorsolateral cortices – may provide a context in which self-generated action is freed from the conventional constraints of supervisory attention and executive control, facilitating the generation of novel ideas11. Importantly, altered relationships within the prefrontal cortex appear to have widespread functional consequences, affecting motivation, emotion, language as well as motor control, and may generalize to other forms of spontaneous creative behavior.
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