Data Analysis: Mean change in each outcome from baseline to post-training to follow-up will be compared between tDCS and sham (two-way repeated-measure ANOVA for factors "stimulation type" and "evaluation time point"). Two-way repeated-measures ANOVA for factors "stimulation type" and "training block" will explore the interaction between tDCS and training with or without feedback for each outcome. Any decay in PPT score in either sham or anodal tDCS groups will be evaluated using a paired-tDCS. Medical students and specialty residents will be evaluated independently. Level of training of residents will be factored retroactively into our analysis.