Figure 4.

Emotional face identification: number of correct trials. Baseline-standardized mean number of correct trials are depicted during, and after anodal, cathodal, and placebo tDCS (p1–3; p1 = immediately and 5 min after tDCS, p2 = 10 and 20 min after tDCS, p3 = 30 and 60 min after tDCS). The number of correct trials increases during the course of the experiment, thus indicating learning of the task in all stimulation and emotional conditions. This effect is significant for negative facial expressions under anodal and placebo tDCS conditions for the whole course of the experiment, but not for cathodal tDCS. For positive facial expressions, anodal tDCS caused a significant improvement as compared to baseline in the last two measures, and placebo tDCS in the last measure. Again under cathodal tDCS facial recognition did not improve significantly. Filled symbols indicate significant reaction time differences as compared to baseline values (paired, two-tailed t-tests, p < 0.05). Vertical bars indicate standard error of mean. a, anodal tDCS; c, cathodal tDCS; p, placebo tDCS; pos, positive emotional facial expression; neg, negative emotional facial expression.