Concurrent TMS to the primary motor cortex augments slow motor learning.

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Cognitive Science

Background:

• Transcranial magnetic stimulation (TMS) is an FDA-approved neuromodulation technique.
• Repetitive physical, cognitive, and behavioral therapies aim to alter neural network properties via Hebbian learning.
• The efficacy of TMS as an adjuvant therapy for these repetitive learning paradigms is under investigation.

Purpose of the Study:

• To test the hypothesis that adjuvant TMS enhances motor learning compared to sham TMS.
• To investigate the effects of TMS on neural plasticity during a slow motor learning task.
• To examine changes in cerebral blood flow (CBF) associated with TMS-augmented motor practice.

Main Methods:

• Healthy participants performed a 4-week daily digit sequence motor task with their non-dominant hand.
• Participants received either 5 Hz TMS or sham TMS over the right primary motor cortex (M1).
• Sequence performance was measured daily, and resting CBF was assessed using H2(15)O PET at baseline and post-intervention.

Main Results:

• Both TMS and sham groups showed significant improvements in sequence performance.
• The TMS group exhibited a significantly greater rate of skill acquisition compared to the sham group.
• The TMS group demonstrated increased resting CBF in motor learning-associated regions (M1, cingulate cortex, putamen, hippocampus, cerebellum).

Conclusions:

• Adjuvant TMS significantly augments the behavioral effects of motor practice, enhancing skill acquisition.
• TMS concurrently promotes neural plasticity within the motor sequence learning network.
• These findings support the application of TMS in neurorehabilitation alongside physical therapy to improve motor learning outcomes.