Impairment under DAF (and other altered auditory feedback paradigms) has been interpreted as evidence for a sensory guidance hypothesis, i.e., disruption of sensorimotor integration (e.g. Finney & Warren, 2002; Havlicek, 1968; Lee, 1950). Musical performance is a complex sensorimotor task that on most instruments involves a sequenced execution of finger movements, which in turn produces an intended sequence of sounds. The sound output and motor plan are coordinated, with the auditory feedback serving as a continuous guide to ongoing musical performance (Zatorre et al., 2007). Put simply, the predicted consequence of a motor command is compared to the actual sensory feedback; incongruences between prediction and feedback lead to motor commands that attempt to correct for this mismatch. Impairment under DAF can thus be interpreted as corrective motor commands to prediction-feedback mismatch – but in the case of DAF, the feedback itself is incorrect.
The present study investigates the executive functions that might modulate sensorimotor integration in musical performance, and in particular, whether working memory might have a role in musical performance under DAF. Working memory is a limited-capacity brain system responsible for the temporary storage and manipulation of information for ongoing tasks (Baddeley & Hitch, 1974). There exists already a body of literature suggesting that working memory exerts a top-down influence on sensorimotor integration during speech production. Li et al. (2015) trained the working memory of healthy participants and measured their cortical event related potential (ERP) responses to pitch-shifted auditory feedback; ERPs known as the N1-P2 complex were modulated by prediction-feedback mismatches. Their results suggest that participants who received working memory training exhibited better detection and correction of feedback errors. In a later study, the same group replicated their earlier findings, and further found that employment of working memory resources decreased the participant’s ability to detect and correct for altered feedback (Guo et al., 2017). The authors suggest that working memory exerts top-down modulations on sensorimotor integration for speech control by facilitating the processing of feedback errors, including a role in inhibiting the compensatory adjustments of incorrect auditory feedback.
To the best of the authors’ knowledge, such a relationship between working memory and sensorimotor integration of musical performance has yet to be established. Nevertheless, a link between working memory and musical performance has been demonstrated previously. For instance, Maes et al. (2015) found that engagement of working memory resources impaired the rhythmicity of cellists’ bow strokes. Meinz and Hambrick (2010) found that working memory capacity was a better predictor of piano sight-reading ability than years of experience or weekly hours of practice. However, these studies only indicate a link between working memory and musical performance in general, and not sensorimotor integration during musical performance specifically.
Perhaps more presciently, there is an overlap between the neuroarchitecture engaged in tonal working memory and that engaged during musical performance under altered auditory feedback. In participants undertaking pitch memory tasks, functional imaging found increased activation in the supramarginal gyrus, superior and inferior parietal lobules (IPL, SPL), area Sylvian-parietal-temporal (Spt), insula, superior temporal gyrus (STG), inferior frontal gyrus (IFG), premotor cortex, supplementary motor area (SMA), and Broca’s area (Gaab et al., 2003; Zatorre et al., 1994). Pfordresher et al. (2014) used fMRI to measure brain activity in pianists playing under normal and altered (DAF and pitch-shifted) auditory feedback. Altered auditory feedback was associated with increased activity across similar regions of frontal (IFG, SMA, Broca’s area), posterior parietal (IPL, Spt), and superior temporal (STG) cortical regions, as well as the insula and cerebellum. In other words, it appears that both working memory and musical performance under DAF draw upon similar neural networks.
The present study seeks to further demonstrate a connection between working memory and sensorimotor integration in musical performance. We separately measured the working memory capacity and piano performance under DAF of healthy participants. Based on the existing literature, we hypothesised that participants with greater working memory capacity will also be better able to compensate for the deleterious effect of DAF on musical performance.