Data for "Infra-Delta Oscillatory Signatures and Gesture Density in Expert Piano Performance"

The repertoire featured Contrapunctus I (BWV 1080) by Bach and an excerpt from Chopin’s Ballade No. 1, Op. 23, performed from memory based on urtext editions. Key-press onset events were annotated per hand to quantify note and gesture counts, excluding legato transitions without discrete attacks.

Both performances exhibited a convergent low-frequency periodicity in beat-level timing variability (tactus imprecision), oscillating at approximately 0.36 Hz. This slow temporal modulation aligns with the delta-band range of neural oscillations and may reflect a shared endogenous timing scaffold, plausibly motor in origin, underlying expressive control in skilled performance.