Manifolds in the Medial Premotor Cortex During Switching From Attending to Tapping to a Metronome.

Animals synchronize their movements with external rhythms to coordinate perception and action, but the neural population mechanisms that allow them to attend and then initiate and sustain these rhythms remain unclear. Using recordings from the medial premotor cortex (MPC) of two macaque monkeys, we investigated neural dynamics during an attend-then-synchronize tapping task with visual metronomes. We found low-dimensional neural manifolds that captured neural population trajectories. During the attention epoch, trajectories exhibited increasing amplitude and oscillatory strength with the successive stimuli, which is consistent with a dynamic system using a resonant mechanism. Then, the transition from perception to tapping synchronization was marked by a reliable shift into a distinct manifold subspace with rotatory dynamics, enabling accurate decoding of the switch in behavior. In addition, correct tapping trials were characterized by a more robust oscillatory structure not seen in incorrect trials. These findings demonstrate that the geometry and coherence of MPC neural trajectories encode different perceptual and motor aspects of tapping synchronization.