Distribution of control during bimanual movement and stabilization

Area of Science:

• Neuroscience
• Motor Control
• Human Movement Science

Background:

• The brain's control of bimanual actions is complex, with theories suggesting hemispheric specialization for distinct roles.
• Hemispheric specialization theory posits dominant hemispheres handle ballistic control and non-dominant hemispheres manage postural stabilization.

Purpose of the Study:

• To investigate how the brain allocates control between dominant and non-dominant arms during bimanual reaching and postural stabilization.
• To test the prediction that arm control division aligns with hemispheric specialization during complex tasks.

Main Methods:

• Participants performed bimanual reaching tasks with hands virtually linked, encountering an unstable force field.
• Measurements included power grasp force to assess postural stability and movement kinematics to analyze control allocation.

Main Results:

• Postural stability, indicated by power grasp force, was equally high in both arms at movement termination.
• The dominant arm, or the arm with stronger flexor muscles, was preferentially used for initial movement acceleration.
• Control allocation was task-dependent, not strictly adhering to hemispheric specialization.

Conclusions:

• The brain flexibly assigns arm control based on task goals and muscle strength, rather than rigid hemispheric specialization.
• Motor control strategies adapt dynamically, demonstrating a flexible allocation of resources during bimanual actions.