Sensorimotor incongruence alters limb perception and movement

Area of Science:

• Neuroscience
• Psychophysics
• Human Motor Control

Background:

• Altered limb ownership and heaviness are reported in various neurological conditions.
• Sensorimotor incongruence is hypothesized to cause these sensations, but empirical verification is limited.
• The impact of subjective limb perception on motor execution remains unclear.

Purpose of the Study:

• To systematically investigate the relationship between sensorimotor integration and subjective limb perception (ownership, heaviness).
• To examine how altered subjective limb perception affects movement execution.
• To elucidate the mechanisms underlying sensorimotor incongruence.

Main Methods:

• A psychophysical experiment involving 39 healthy participants.
• Systematic induction of sensorimotor incongruence using visual feedback delay (0-600ms) during wrist movements.
• Electromyography (EMG) recorded muscle activity; movement speed, integral, and peak frequency analyzed. Subjective perceptions measured via Likert scale.

Main Results:

• Altered limb ownership and heaviness increased proportionally with visual feedback delay.
• Muscle activity and movement speed decreased with increasing visual feedback delay.
• No significant correlation was found between subjective limb perception and objective measures of muscle activity or movement speed.

Conclusions:

• Sensorimotor incongruence systematically alters subjective limb perception and motor execution independently.
• Distinct neural mechanisms likely govern subjective limb perception and motor control.
• Future research should explore rehabilitation strategies targeting sensorimotor incongruence.