Purpose: This study explored the effects of motor learning training combined with repetitive transcranial magnetic stimulation (rTMS) on motor performance in healthy subjects.
Methods: Twenty-seven right-handed subjects were randomized to three groups: ipsilateral rTMS (IS group), contralateral rTMS (CS group), and sham rTMS (SS group). rTMS was applied for 10 minutes (1 Hz, 90% motor threshold) prior to training. Training involved 10 minutes of finger tracking with the right hand. Tracking performance was tested before, during and after training.
Results: Improvement in tracking performance over the posttests was not significantly different between the CS and SS groups, whereas it was significantly lower for the IS group compared to the SS group. No difference was found across groups at retention tests.
Conclusion: These findings indicate that rTMS interfered with motor performance transiently when applied ipsilateral to the training hand and had no effect when applied contralaterally. These results invite further work to determine whether the disruptive effect of ipsilateral rTMS observed here in healthy subjects, with presumably balanced interhemispheric inhibition, might translate differently to subjects with abnormal interhemispheric inhibition (stroke patients) in a way that disinhibits the ipsilesional hemisphere and improves performance in the paretic hand.