1 Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada; indiana.wollman@mail.mcgill.ca.
2 Center for Interdisciplinary Research in Music Media and Technology, Schulich School of Music, McGill University, Montreal, QC H3A 1E3, Canada.
3 International Laboratory for Brain, Music and Sound Research, Montreal, QC H2V 2J2, Canada.
4 Laboratory for Motor Learning and Neural Plasticity, Department of Psychology, Concordia University, Montreal, QC H4B 1R6, Canada.
5 Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada.
6 CNRS, Institut de Recherche et Coordination Acoustique/Musique, Sorbonne Université, UMR 9912 Sciences et Technologies de la Musique et du Son, 75004 Paris, France.

The auditory and motor neural systems are closely intertwined, enabling people to carry out tasks such as playing a musical instrument whose mapping between action and sound is extremely sophisticated. While the dorsal auditory stream has been shown to mediate these audio-motor transformations, little is known about how such mapping emerges with training. Here, we use longitudinal training on a cello as a model for brain plasticity during the acquisition of specific complex skills, including continuous and many-to-one audio-motor mapping, and we investigate individual differences in learning. We trained participants with no musical background to play on a specially designed MRI-compatible cello and scanned them before and after 1 and 4 wk of training. Activation of the auditory-to-motor dorsal cortical stream emerged rapidly during the training and was similarly activated during passive listening and cello performance of trained melodies. This network activation was independent of performance accuracy and therefore appears to be a prerequisite of music playing. In contrast, greater recruitment of regions involved in auditory encoding and motor control over the training was related to better musical proficiency. Additionally, pre-supplementary motor area activity and its connectivity with the auditory cortex during passive listening before training was predictive of final training success, revealing the integrative function of this network in auditory-motor information processing. Together, these results clarify the critical role of the dorsal stream and its interaction with auditory areas in complex audio-motor learning.