Digit displacement, not object compliance, underlies task dependent modulations in human corticomuscular coherence

Area of Science:

• Neuroscience
• Motor Control
• Human Sensorimotor System

Background:

• Human sensorimotor electroencephalography (EEG) exhibits 10 and 20 Hz oscillations, with the latter coherent with contralateral electromyography (EMG).
• The precise functional role of this corticomuscular coherence remains unclear.
• Previous studies indicated a link between corticomuscular coherence and object compliance, but confounded digit displacement.

Purpose of the Study:

• To differentiate whether corticomuscular coherence is modulated by object compliance or digit displacement.
• To investigate the relationship between corticomuscular coherence and parameters of a precision grip task.

Main Methods:

• Subjects performed a precision grip task with computer-controlled manipulandum simulating varying lever compliance.
• EEG and EMG data were recorded during hold-ramp-hold displacement profiles under visual feedback.
• Corticomuscular coherence was analyzed between sensorimotor EEG and hand/forearm EMG during the hold phase.

Main Results:

• Corticomuscular coherence magnitude demonstrated a clear dependence on the extent of digit displacement.
• When lever compliance changed during the task, coherence modulated with preceding digit displacement, not the altered compliance in the hold phase.

Conclusions:

• Human corticomuscular coherence is directly associated with digit displacement during the preceding movement.
• Findings suggest corticomuscular coherence may not reflect object compliance directly but rather sensorimotor recalibration post-movement.