Fig. 1

Schematic representation of the experimental procedure and design. A Time course of the study design. This study consisted of the following three phases: Pre-assessment, Assessment, and Post-assessment. The assessment phase consisted of three sessions: baseline, online, and offline. Navy blue shows the 20-min tDCS stimulation period. B The protocol in each of the three assessment sessions consisted of four repetitions of the two subtests of the PPT, the left-handed peg task and left-handed assembly task. Data from the first trial was removed from analysis, considering the possibility of generating large variation in task performance. C Schematic illustration of active and sham stimulation. The left figure shows active stimulation, a sustained 2-mA current delivered for 20 min. The right figure shows sham stimulation, a ramp up to 2 mA followed by an immediate ramp down. PPT Purdue Pegboard Test, tDCS transcranial direct current stimulation