Motor Learning in a Complex Motor Task Is Unaffected by Three Consecutive Days of Transcranial Alternating Current...

Area of Science:

• Neuroscience
• Motor Control
• Rehabilitation

Background:

• Transcranial alternating current stimulation (tACS) can enhance motor learning in simple tasks by increasing cortical excitability and entraining neural activity.
• The effectiveness of tACS for complex motor skill acquisition, particularly over multiple sessions, remains less understood.

Purpose of the Study:

• To investigate the impact of three consecutive days of M1 tACS on motor learning of a challenging overhand throwing task in young adults.
• To assess the influence of M1 tACS on primary motor cortex (M1) excitability during motor skill practice.

Main Methods:

• A double-blind, randomized, SHAM-controlled, between-subjects design was employed with 24 healthy young adults.
• Participants underwent three experimental sessions involving overhand throwing practice with concurrent M1 tACS or SHAM stimulation.
• Motor learning was quantified by endpoint error in throwing, and M1 excitability was measured using motor evoked potentials (MEPs) via TMS.

Main Results:

• Overall, endpoint error decreased significantly from pre- to post-tests across both groups, indicating motor learning occurred.
• No statistically significant difference in the reduction of endpoint error was observed between the tACS and SHAM groups.
• MEP amplitudes increased from pre- to post-tests, but this change did not differ significantly between the tACS and SHAM groups.

Conclusions:

• Multi-day application of tACS to the primary motor cortex does not significantly enhance motor learning of a complex motor task beyond the effects of practice alone.
• tACS did not lead to greater changes in M1 excitability compared to SHAM stimulation in the context of this complex motor learning task.