Force illusions and drifts observed during muscle vibration

Area of Science:

• Neuroscience
• Motor Control
• Somatosensation

Background:

• Proprioception and efferent signals are crucial for position and force perception.
• Muscle vibration can induce kinesthetic illusions by altering afferent and efferent feedback.
• Understanding these mechanisms is key to explaining sensory-motor control.

Purpose of the Study:

• To investigate how muscle vibration affects finger force perception and production.
• To test a scheme where force perception relies on proprioceptive signals within an efferent reference frame.
• To determine if vibration-induced illusions are mediated by changes in afferent and efferent kinesthesia.

Main Methods:

• Healthy subjects performed steady force production tasks with visual feedback.
• Force matching tasks were used to assess perceived force magnitude.
• High-frequency vibration was applied to forearm/hand extensors during force tasks.

Main Results:

• Without visual feedback, finger force production decreased, but less so with forearm vibration.
• Vibration of one forearm led to perceived higher force in the non-vibrated matching hand.
• Findings suggest vibration shifts both proprioceptive signals and the efferent reference coordinate.

Conclusions:

• Muscle vibration consistently alters finger force perception, supporting a combined kinematic-kinetic perception model.
• Vibration induces shifts in the referent coordinate and potentially coactivation commands.
• These findings highlight the dynamic interplay between sensory feedback and motor commands in force perception.