Effects of a Single Session 400 Hz Transcranial Pulsed Current Stimulation on Corticospinal and Corticocortical...

The effects of 400 Hz anodal and cathodal transcranial pulsed current stimulation of the primary motor cortex (400 Hz a-tPCS_M1, 400 Hz c-tPCS_M1) on corticospinal excitability (CSE) and corticocortical excitability (CCE) and hand dexterity remain underexplored. This study examined the effects of a single session of 400 Hz a-tPCS_M1, 400 Hz c-tPCS_M1, and sham stimulation on CSE, CCE, and hand dexterity, providing insights for potential clinical applications in motor deficits. In this double-blinded, randomized, counterbalanced crossover trial, 26 healthy young adults completed three experimental sessions: 400 Hz a-tPCS_M1, 400 Hz c-tPCS_M1, and sham stimulation, spaced 48 h apart. Transcranial magnetic stimulation assessed CSE and CCE, while the Purdue Pegboard Test (PPT) evaluated hand dexterity. The results showed polarity-specific effects. A single session of 400 Hz a-tPCS_M1 significantly increased CSE and improved hand dexterity, evidenced by faster PPT completion times (p < 0.05). Conversely, 400 Hz c-tPCS_M1 reduced CSE but did not influence PPT performance (p > 0.05). Sham stimulation showed no significant changes. These findings suggest that 400 Hz a-tPCS_M1 enhances motor excitability and dexterity, while 400 Hz c-tPCS_M1 selectively reduces CSE. This study lays a foundation for exploring high-frequency tPCS in clinical motor rehabilitation.