Orthographic character complexity modulates dynamic neural activity in skilled handwriting

Area of Science:

• Neuroscience
• Cognitive Science
• Motor Control

Background:

• Handwriting is a complex fine motor skill with incompletely understood neural mechanisms.
• Continuous handwriting production involves intricate neural processes that are challenging to study.

Purpose of the Study:

• To investigate the neural and behavioral effects of orthographic character complexity during continuous handwriting.
• To explore the relationship between Chinese character stroke number and motor control signals.

Main Methods:

• Utilized electroencephalography (EEG) during a naturalistic sentence-handwriting task with 102 adult native Chinese speakers.
• Analyzed inter-character intervals and event-related potential (ERP) amplitudes.
• Employed linear mixed models to assess the impact of character complexity and confounding factors.

Main Results:

• Character complexity significantly increased the time taken between writing characters (inter-character interval).
• Character complexity modulated ERP amplitudes in both pre- and post-onset time windows.
• A dipole-like activation in the left motor cortex was observed, with amplitude increasing with character complexity.

Conclusions:

• Character complexity influences both behavioral aspects (writing speed) and neural activity during handwriting.
• EEG-based analysis of naturalistic handwriting is feasible for studying neurocognitive processes.
• Findings extend understanding of the dynamic neural patterns underlying handwriting motor control.