# Brain-hemispheric differences in the premotor area for motor planning: An approach based on corticomuscular connectivity during motor decision-making

## TL;DR

This study shows that the brain's hemispheres differ in how they plan hand movements, with the right hemisphere playing a key role in decision-making.

## Contribution

A novel approach using corticomuscular coherence in short time intervals reveals hemispheric differences in motor planning.

## Key findings

- Significant beta-band CMC was found between the anterior deltoid and contralateral PMA before stimulus onset.
- Left anterior deltoid showed significant CMC with the right PMA during motor planning, linked to shorter planning times.
- Right-hand motor planning lacked this pattern, suggesting more complex cognitive processes.

## Abstract

•Motor planning of the hand movements are not symmetrical across brain hemispheres.•The premotor area plays a critical role in motor decision-making.•A novel approach to exploring motor planning through functional connectivity within very short time intervals.

Motor planning of the hand movements are not symmetrical across brain hemispheres.

The premotor area plays a critical role in motor decision-making.

A novel approach to exploring motor planning through functional connectivity within very short time intervals.

This study investigates the role of the premotor area (PMA) in motor planning during decision-making, focusing on differences between brain hemispheres. A cross-sectional assessment was conducted involving seventeen right-handed participants who performed tasks requiring responses with either hand to visual stimuli. Motion capture, EEG and EMG signals were collected to analyze corticomuscular coherence (CMC) in the beta and gamma bands across four motor-related cortical areas. Findings revealed significant beta-band CMC between anterior deltoids and contralateral PMA before stimulus onset in simple reaction tasks. Moreover, significant beta-band CMC was observed between the left anterior deltoid and the right PMA during the motor planning phase, prior to the onset of muscle contraction, corresponding with shorter planning times. This connectivity pattern was consistent across both simple and complex reaction tasks, indicating that the PMA plays a crucial role during decision-making. Notably, motor planning for the right hand did not exhibit the same connectivity pattern, suggesting more complex cognitive processes. These results emphasize the distinct functional roles of the left and right hemispheres in motor planning and underscore the importance of CMC in understanding the neural mechanisms underlying motor control. This study contributes to the theoretical framework of motor decision-making and offers insights for future research on motor planning and rehabilitation strategies.