EFFECTS OF TRANSCRANIAL STATIC MAGNETIC STIMULATION OVER THE PRIMARY MOTOR CORTEX ON MOVEMENT-RELATED SENSORIMOTOR OSCILLATORY ACTIVITY

Transcranial static magnetic stimulation (tSMS) is a non-invasive brain stimulation technique known to reduce cortical excitability by placing a small but strong neodymium magnet over the scalp. The aim of this study was to investigate whether movement-related sensorimotor oscillations are modulated by application of tSMS over the primary motor cortex (M1). Electroencephalograms were recorded from eighteen healthy young adults while they performed precision force control tasks before and after application of tSMS or sham stimulation over the left M1. Event-related desynchronization (ERD) during movement and event-related synchronization (ERS) after movement in the left M1 were quantitatively compared between pre- and post-stimulation sessions to evaluate changes in sensorimotor cortical activity. The results showed that behavioral variables, including mean force error and force variability, were not significantly affected by tSMS. On the other hand, beta-band ERD during movement was reduced, whereas post-movement beta-band ERS was enhanced following tSMS, suggesting altered modulation of motor-related beta oscillations. Additionally, alpha-band ERD increased after sham stimulation, which may reflect practice-related effects, as repeated motor execution and progressive motor learning are known to enhance alpha-band ERD over the sensorimotor regions. These findings suggest that tSMS modulates sensorimotor cortical oscillatory activity during and after movement without inducing measurable changes in task performance.