Transcranial direct current electrical stimulation (tDCS)
CORTEX
Two-channel battery-driven stimulators (NeuroStim 2, Medina Tebgostar, Tehran, Iran) were used to apply tDCS over the target brain areas during the 3rd to 6th experimental sessions (two devices were used). Four carbon electrodes covered by saline-soaked surface sponges (NaCl 140 mmol dissolved in Milli-Q water) were used as anodes (5 × 4; 20 cmStrength and radial component of the electric field induced by tDCS. Finite Element Models derived from Magnetic Resonance Imaging in a head model (MNI152) of the strength and radial (normal to the cortical surface) component of the electric field (EF) induced by tDCS. Electrode montage targeting the simultaneous stimulation with anodal tDCS of the representation of the lower limbs in the primary motor cortex and the left dorsolateral prefrontal cortex (Two channels of the tDCS device were used for the simultaneous stimulation of these two regions. For anodal stimulation, the current was gradually ramped up for 30 s, maintained at 2 mA for 20 min, and then progressively ramped down for 30 s. In the sham condition (sh-tDCS), the same electrode position was applied, and the current was ramped up for 30 s, but the 2-mA current was only maintained for 30 s, and then ramped down for 30 s remaining off the rest of the time. This protocol has been shown to be adequate for blinding participants in tDCS studies