Enhanced Descending Corticomuscular Coupling During Hand Grip With Static Force Compared With Enhancing Force.

Area of Science:

• Neuroscience
• Motor Control
• Rehabilitation Engineering

Background:

• Corticomuscular coupling, involving descending and ascending pathways, is key to motor control but its role in different force states remains unclear.
• Understanding corticomuscular coupling dynamics is essential for optimizing brain-computer interface (BCI) applications in hand motor rehabilitation.

Purpose of the Study:

• To quantitatively investigate corticomuscular coupling during hand motor tasks involving enhancing and steady-state force.
• To compare the influence of static versus enhancing force on neural pathways between the brain and muscles.

Main Methods:

• Twenty healthy subjects performed precision grip tasks with static and enhancing force, with visual feedback.
• Electroencephalography (EEG) from the primary motor cortex and electromyography (EMG) were recorded.
• Mutual information and Granger causal connectivity were analyzed in specific frequency bands (alpha, beta).

Main Results:

• Mutual information was significantly higher for static force in the beta and alpha bands.
• Granger causal connectivity from cortex to muscle was significantly stronger for static force in the beta and high alpha bands (10-20 Hz).
• Static force engagement led to increased corticomuscular coupling, suggesting greater attentional demands.

Conclusions:

• Hand grip with static force enhances corticomuscular coupling compared to enhancing force.
• These findings provide valuable insights for designing more effective motor rehabilitation therapies using BCI.
• The results highlight the importance of force state in modulating neural control of hand movements.