Neural mechanisms for auditory-motor integration and learning: prediction and reward

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This research program will probe the neural systems underlying prediction and reward in auditory-motor learning. It is based on anatomical and physiological models of music and speech which propose that there is an auditory dorsal stream in the human brain that predictively links sound and action. Objective 1 aims to dissociate the role of dorsal stream structures in auditory-motor learning, and to identify the generators and oscillatory signatures of predictive motor responses. Prediction is also critical in musical reward or pleasure which emerges from the tension between expectations and outcomes, and is mediated by dopamine-modulated striatal networks. Importantly, striatal reward mechanisms are also crucial for learning, but the link between musical pleasure and learning has not been explored. Thus Objective 2 will examine the impact of predictability and pleasure on learning to play a melody. Finally, models of musical pleasure propose that striatal reward networks interact with cortical systems. In Objective 3 we aim for the first time to identify interactions between dorsal-stream sensorimotor prediction networks and striatal reward networks in the context of musical groove - the pleasurable desire to move to music. We have developed a series of novel paradigms in our lab and will combine them with converging brain imaging and neuro-stimulation methods to address the following hypotheses: (1) The role dorsal- and ventral premotor cortex in acquiring auditory-motor associations will be tested using repetitive TMS. Further, we hypothesize that predictive auditory-motor associations are encoded in dorsal stream oscillatory networks. We will test this by combining single-pulse TMS with EEG and MEG. (2) We have shown that melodic predictability and pleasure modulate auditory-motor learning. We hypothesize that this learning results from the combined contributions of dorsal stream and reward networks and we will test this using fMRI. (3) We will use MEG and fMRI to test the hypothesis that interactions between the dorsal stream and reward networks underlie musical groove. This work is innovative in exploring the interaction between neural systems for predictive control of action and those mediating reward, and in examining the underlying brain oscillatory mechanisms. The results will advance our understanding of dorsal stream contributions to auditory-motor integration, prediction and learning. They will also serve to refine models of the oscillatory mechanisms that link auditory and motor information for predictive control of action. Objectives 2 and 3 are original in testing the interaction between dorsal stream prediction and learning mechanisms and striatal reward mechanisms. This will provide critical insights into the impact of intrinsic reward on motor learning, and will contribute to identifying the neural mechanisms underlying the strong link between sound, action and pleasure that characterize human interactions with music.