Differences in motor learning success are associated with differences in M1 excitability.

Area of Science:

• Neuroscience
• Motor Control
• Motor Learning

Background:

• The primary motor cortex (M1) is implicated in motor learning, but its precise role and associated neural plasticity remain incompletely understood.
• Augmented feedback is crucial for motor skill acquisition, yet optimal feedback schedules for promoting learning and plasticity are debated.

Purpose of the Study:

• To investigate the relationship between augmented feedback frequency and motor learning.
• To examine the impact of different feedback schedules on primary motor cortex (M1) plasticity during motor skill acquisition and retention.

Main Methods:

• Two groups of participants (n=10 each) performed a wrist tracking task with either 100% or 50% augmented feedback.
• Transcranial magnetic stimulation (TMS) was used to assess M1 cortical excitability, including short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), before, after, and 24 hours post-training.

Main Results:

• The 50% feedback group demonstrated superior retention performance compared to the 100% feedback group, indicating enhanced motor learning with reduced feedback frequency.
• While cortical excitability did not change during acquisition, the 50% feedback group showed elevated M1 excitability at retention.
• Reduced SICI was observed post-practice, suggesting decreased intracortical inhibition during motor skill acquisition, while ICF remained unchanged.

Conclusions:

• The frequency of augmented feedback significantly influences motor learning and M1 plasticity.
• Enhanced M1 excitability during retention suggests its role in consolidating newly acquired motor skills.
• The findings highlight that M1 modulation during motor skill learning is dependent on task complexity and feedback parameters.