Mean premotor reaction time (ms) during free-choice trials.

<p>A) Reaction times collapsed across hand are shown in pre- and post-tDCS blocks for each stimulation polarity (anode left, anode right, and sham). Error bars denote standard error. Note that when collapsed across stimulation polarity there is a significant difference between pre- and post-tDCS blocks (<i>p</i> = .048). B) Boxplots of premotor reaction time in pre- and post-tDCS blocks for each stimulation polarity (collapsed across response hand) where the small square indicates the mean, the horizontal line within the rectangular box indicates the median, and the boundaries of the rectangular box indicate the 25th and 75th percentiles.