Sensorimotor Oscillatory Phase-Power Interaction Gates Resting Human Corticospinal Output.

Area of Science:

• Neuroscience
• Motor Control
• Brain Oscillations

Background:

• Sensorimotor networks exhibit time-varying oscillatory activity in phase and power.
• The combined influence of oscillatory phase and power on corticospinal output remains unclear.
• Understanding these interactions is crucial for deciphering human motor function regulation.

Purpose of the Study:

• To investigate the interaction between sensorimotor oscillatory phase and power on human corticospinal excitability.
• To determine if phase-dependency of motor evoked potentials is modulated by oscillatory power.

Main Methods:

• Transcranial magnetic stimulation (TMS) delivered to the motor cortex during electroencephalography (EEG) recordings.
• Motor evoked potentials (MEPs) analyzed offline based on concurrent mu (8-12 Hz) and beta (13-30 Hz) oscillation phase and power.
• Linear mixed-effects models used to assess phase-dependency across varying power levels.

Main Results:

• A significant interaction between mu oscillation phase and power was observed (P = 0.002).
• The direction of corticospinal excitability's phase-dependency reversed with changes in mu power.
• No significant phase-power interaction was found for beta oscillations (P > 0.11).

Conclusions:

• The interaction between mu oscillatory phase and power critically gates human corticospinal output.
• This interaction explains variability in corticospinal excitability beyond phase or power alone.
• Findings highlight the complex interplay of neural oscillations in motor control.