The temporal coupling effect: Preparation and execution of bimanual reaching movements

Area of Science:

• Neuroscience
• Motor Control
• Human Movement Science

Background:

• Bimanual movements exhibit coupling, a lack of independence between hands affecting spatial and temporal domains.
• The electro-cortical activity underlying temporal bimanual coupling, particularly during motor preparation, remains understudied.

Purpose of the Study:

• To investigate the electro-cortical activity associated with the temporal bimanual coupling effect during motor preparation.
• To examine how movement difficulty influences bimanual coordination and motor preparation.

Main Methods:

• Participants performed congruent and incongruent bimanual movements towards easy or difficult targets.
• Motor Related Cortical Potentials (MRCPs) were recorded to analyze electro-cortical activity.
• Behavioral data on movement synchronization and timing were collected.

Main Results:

• No significant effect of conditions or difficulty was observed in the early phase of MRCPs (posterior and anterior BP).
• Hands were prepared simultaneously, indicating a single motor program for bimanual actions.
• Behavioral data revealed strong hand synchronization, with movement difficulty impacting activity at and after movement onset.
• Difficult movements, especially involving the right hand towards a difficult target, elicited a prominent Post-motor potential (N4).

Conclusions:

• Bimanual movements are planned and programmed as a unified motor program.
• Movement difficulty primarily influences the execution phase of bimanual actions, rather than the initial preparation.
• The findings provide insights into the neural mechanisms of bimanual coordination and the emergence of difficulty in action execution.