Neural ensembles for music production recruit more language instruments as rhythmic complexity increases.

Language and music, two core forms of human communication, both rely on rhythmic control. To date, the neural ensembles supporting their real-time production are not fully characterized. Using rapid phase-encoded fMRI, we mapped the spatiotemporal brain dynamics of overt language and music production under varying rhythm control demands. We observed overlapping hemodynamic traveling waves across domains, with auditory-motor regions activated earlier, followed by visual, posterior parietal, and Sylvian parietal-temporal (Spt) regions, supporting sensorimotor transformation and online monitoring of production. Increasing rhythmic complexity elicited slower and stronger activations in both domains: compared with baseline, regular rhythm control elicited delayed and amplified responses, while irregular rhythm control produced the slowest and strongest responses. During music production, rhythm-related activity expanded into frontal and temporal language regions, suggesting that higher rhythmic demands engage language resources. These findings reveal dynamic neural ensembles that can flexibly reconfigure shared resources to support temporal precision in sequence production.