From Motivation to Action: Action Cost Better Predicts Changes in Premovement Beta-Band Activity than Speed

Area of Science:

• Neuroscience
• Motor Control
• Computational Neuroscience

Background:

• Premovement beta-band event-related desynchronization (β-ERD) is modulated by movement speed, but the relationship is not strictly monotonic.
• β-ERD is hypothesized to enhance neural information encoding capacity.

Purpose of the Study:

• To test if β-ERD relates to the neurocomputational cost of movement (action cost), rather than solely movement speed.
• To investigate the role of action cost in modulating β-ERD during a reaching task.

Main Methods:

• Thirty-one participants performed a speed-controlled reaching task while electroencephalography (EEG) was recorded.
• Analysis involved assessing β-ERD modulations across different movement speeds and modeling action cost.
• Linear mixed models were used to compare the predictive power of action cost versus speed on β-ERD.

Main Results:

• β-ERD was significantly greater for both high and low speeds compared to medium speed.
• Participants preferred medium-speed movements, suggesting they were perceived as less costly.
• Estimated action cost patterns mirrored β-ERD modulations and predicted β-ERD variations better than speed.
• This relationship was specific to the beta band, not observed in mu or gamma bands.

Conclusions:

• Premovement β-ERD is better explained by the neurocomputational cost of action than by movement speed alone.
• Increased β-ERD may facilitate motor preparation for movements with higher action costs (slow or fast).
• This suggests β-ERD reflects neural resource allocation for flexible motor planning, relevant for conditions like Parkinson's disease and brain-computer interfaces.