Proactive neural preparation across individual handwriting strokes: links to tool properties and cognitive performance

Handwriting is a hierarchical cognitive–motor skill governed by proactive and reactive control. Despite being inherently tool-mediated, it remains unclear how the physical properties of a handwriting tool are integrated into this hierarchy during handwriting and whether such tool-dependent control relates to cognitive performance. By achieving high-precision time synchronization between electroencephalography and tablet-recorded digital pen logs, we examined whether neural activity during handwriting tasks tunes to pen-tip friction on a stroke-by-stroke basis and how this relates to movement efficiency and cognitive performance. Handwriting exhibited theta/alpha inter-trial coherence surrounding pen-down events, whereas line drawing did not; this phase alignment did not differ by pen-tip friction. Pen-tip effects were most evident in the pre–pen-down activity; the medium-friction tip, typically judged to be similar to the participants’ usual pen, produced the largest pre–pen-down amplitude. Larger pre–pen-down activity was associated with shorter stroke duration and higher maximum stroke velocity. In addition, larger pre–pen-down and smaller post–pen-down activities in the calculation task were associated with higher accuracy. These results demonstrate stroke-level anticipatory tuning to tool physical properties and indicate that proactive processing links pen-surface mechanics to efficient handwriting and cognitive performance.