Vestibular contribution to combined arm and trunk motion

Area of Science:

• Neuroscience
• Motor Control
• Human Movement Science

Background:

• Arm-trunk coordination is crucial for accurate reaching movements.
• The vestibular system's role in compensating for trunk motion during reaching is under investigation.
• Galvanic vestibular stimulation (GVS) has been shown to influence pointing movements when body motion is restrained.

Purpose of the Study:

• To investigate the effects of GVS on arm-trunk coordination during reaching movements.
• To determine if vestibular signals influence arm posture and movement during trunk-assisted reaching.

Main Methods:

• Subjects performed reaching or posture-maintenance tasks while moving their trunk forward with eyes closed.
• Galvanic vestibular stimulation (GVS) was applied during these tasks.
• Hand and trunk kinematics were analyzed to assess movement deviations.

Main Results:

• GVS application resulted in deviations of the final hand position in both lateral and sagittal directions.
• These deviations were attributed to independent effects on trunk trajectory and arm position relative to the trunk.
• Both reaching and posture-maintenance tasks showed GVS-induced modulations in arm-trunk coordination.

Conclusions:

• The vestibular system is directly involved in controlling trunk motion during reaching.
• Vestibular signals contribute to arm-trunk coordination during trunk-assisted reaching movements.
• GVS provides a tool to probe the neural mechanisms underlying complex motor behaviors.