Relationship Between Non-invasive Brain Stimulation-induced Plasticity and Capacity for Motor Learning

Area of Science:

• Neuroscience
• Motor Control
• Rehabilitation

Background:

• Cortical plasticity is crucial for motor learning (ML).
• Non-invasive brain stimulation (NIBS) modulates motor cortex plasticity to enhance ML.
• The link between NIBS-induced plasticity and ML capacity remains unclear.

Purpose of the Study:

• To investigate the relationship between NIBS-induced changes in motor evoked potentials (MEPs) and ML capacity.
• To determine if different NIBS protocols elicit varying effects on ML.

Main Methods:

• 56 participants underwent three NIBS protocols: paired associative stimulation (PAS), anodal transcranial direct current stimulation (AtDCS), and intermittent theta-burst stimulation (iTBS).
• Participants completed three lab-based ML tasks: serial reaction time (SRTT), visuomotor adaptation (VAT), and sequential visual isometric pinch task (SVIPT).
• Response patterns to NIBS were clustered, and ML variables were compared; regression and correlation analyses explored the relationship between MEP changes and ML capacity.

Main Results:

• No significant differences in ML variables were found between NIBS response clusters.
• Higher response to NIBS potentially predicted poorer performance in specific blocks of the VAT.
• "Responders" to AtDCS and iTBS demonstrated faster reaction times than "non-responders," though physiological significance is uncertain.

Conclusions:

• MEP changes in the motor cortex (M1) induced by PAS, AtDCS, and iTBS show minimal association with ML capacity across SRTT, VAT, and SVIPT.
• NIBS-induced cortical excitability changes in M1 may correlate with reaction time and skill retention in certain ML tasks.