Intensity-Dependent Effects of 4-week Transcranial Direct Current Stimulation on Motor Learning in Healthy Young Adults

The intervention will be conducted using a battery-powered stimulator (TCS-E2000, Shenzhen Yingchi Technology Co., Ltd) through a pair of saline-soaked sponge electrodes (5 cm × 7 cm).The stimulation intensity will be set at 3 mA. The stimulation will last for 20 minutes each time, with a 10 s fade-in period at the start and a 10-s fade-out period at the end of stimulation. The participants will receive intervention lasting for four weeks(10 sessions).The anodal electrode will be placed over the primary motor cortex (M1), and the reference electrode will be positioned at the center of the forehead.

The intervention will be conducted using a battery-powered stimulator (TCS-E2000, Shenzhen Yingchi Technology Co., Ltd) through a pair of saline-soaked sponge electrodes (5 cm × 7 cm).The stimulation intensity will be set at 2 mA. The stimulation will last for 20 minutes each time, with a 10 s fade-in period at the start and a 10-s fade-out period at the end of stimulation. The participants will receive intervention lasting for four weeks(10 sessions).The anodal electrode will be placed over the primary motor cortex (M1), and the reference electrode will be positioned at the center of the forehead.

The intervention will be conducted using a battery-powered stimulator (TCS-E2000, Shenzhen Yingchi Technology Co., Ltd) through a pair of saline-soaked sponge electrodes (5 cm × 7 cm).The stimulation intensity will be set at 1 mA. The stimulation will last for 20 minutes each time, with a 10 s fade-in period at the start and a 10-s fade-out period at the end of stimulation. The participants will receive intervention lasting for four weeks(10 sessions).The anodal electrode will be placed over the primary motor cortex (M1), and the reference electrode will be positioned at the center of the forehead.

The intervention will be conducted using a battery-powered stimulator (TCS-E2000, Shenzhen Yingchi Technology Co., Ltd) through a pair of saline-soaked sponge electrodes (5 cm × 7 cm).The intervention will last for 20 minutes each time, with a 10 s fade-in period at the start and a 10-s fade-out period at the end of stimulation，but there is not current in between. The participants will receive intervention lasting for four weeks(10 sessions).The anodal electrode will be placed over the primary motor cortex (M1), and the reference electrode will be positioned at the center of the forehead.