Modulation of Corticomuscular Coupling With Split-Belt Locomotor Adaptation in Healthy Young Males.

Both alpha and beta CMC temporarily decreased immediately following application of the split-belt perturbation compared to normal walking.

• CMC was recorded using EEG and EMG from the tibialis anterior muscle
• Alpha band was defined as 8-12 Hz and beta band as 12-32 Hz
• The decrease occurred immediately following application of the perturbation, suggesting disruption of established corticomuscular coupling
• The split-belt paradigm was used as the locomotor adaptation paradigm

Both alpha and beta CMC temporarily decreased immediately following removal of the split-belt perturbation compared to normal walking.

• This decrease mirrored the pattern seen at perturbation onset
• The decrease at perturbation removal also suggests disruption of established corticomuscular coupling
• This occurred at the transition from the adaptation phase back to normal belt conditions

During the adaptation process, alpha CMC in the slow leg's heel contact phase significantly increased toward normal walking levels.

• The increase was specific to the alpha band (8-12 Hz) rather than the beta band during adaptation
• The increase was phase-specific, occurring during the heel contact phase of the slow leg
• This pattern suggests enhanced corticomuscular coupling during the active adjustment of gait patterns
• The increase was directionally toward normal walking levels, suggesting a recovery or recalibration process

During de-adaptation, both alpha and beta CMC increased, and CMC in all gait phases returned to normal walking levels.

• Unlike during adaptation (where only alpha CMC increased), both alpha (8-12 Hz) and beta (12-32 Hz) CMC increased during de-adaptation
• CMC eventually returned to normal walking levels across all gait phases by the end of de-adaptation
• This broader band increase during de-adaptation suggests a different neural mechanism compared to the adaptation phase
• The return to normal walking levels indicates re-establishment of the original corticomuscular coupling pattern

The study characterized CMC modulation across distinct phases of split-belt locomotor adaptation using simultaneous EEG and EMG recordings in healthy young males.

• Participants were healthy young males
• EEG and EMG were recorded simultaneously during the split-belt locomotor adaptation paradigm
• EMG was recorded from the tibialis anterior muscle
• CMC was calculated in both alpha (8-12 Hz) and beta (12-32 Hz) frequency bands
• The paradigm included baseline normal walking, perturbation (split-belt), and de-adaptation phases

Locomotor adaptation is driven by sensory prediction errors and involves supraspinal structures, but the role of oscillatory coupling between the sensorimotor cortex and spinal motor neurons had previously been unclear.

• CMC was used as an index of oscillatory coupling between the sensorimotor cortex and spinal motor neurons
• Prior to this study, how CMC is involved in locomotor adaptation remained unclear
• The supraspinal involvement in locomotor adaptation was already known from prior literature
• The split-belt paradigm was used to induce locomotor adaptation driven by sensory prediction errors