Respiratory and Cardiac Phase Coupling With Voluntary Actions Across Motor Tasks.

Area of Science:

• Neuroscience
• Human motor control
• Respiratory physiology

Background:

• Bodily rhythms, including breathing and heartbeat, impact perception and motor control.
• Previous research suggests breathing phases, especially exhalation, synchronize with voluntary actions, potentially indicating a role in motor intention.
• The extent of this synchronization may vary depending on the effector and movement direction.

Purpose of the Study:

• To investigate respiratory synchronization across various voluntary motor tasks.
• To examine the interplay between stimulus-driven and action-driven respiratory coupling.
• To assess cardiac synchronization with voluntary actions.

Main Methods:

• 32 healthy participants completed two tasks: a modified Libet clock task (key press/release) and an elbow flexion-extension task using a joystick.
• Respiratory and cardiac activity were monitored during voluntary actions.
• Analysis focused on the timing of voluntary actions relative to respiratory and cardiac phases.

Main Results:

• Voluntary actions demonstrated a general tendency to occur during exhalation across different effectors (finger, elbow) and movement directions (flexion, extension).
• Stimulus-locked respiratory phase influenced subsequent action timing, suggesting trial structure modulates respiration-action coupling.
• No consistent cardiac phase modulation of voluntary action timing was observed, though a minor trend emerged in specific conditions.

Conclusions:

• Respiration-action coupling is supported across diverse voluntary motor tasks.
• Stimulus-locked respiratory dynamics may contribute to the timing of voluntary actions.
• Cardiac influence on voluntary action timing appears minimal in this context.