Modulation of the cognitive event-related potential P3 by transcranial direct current stimulation: Systematic review and meta-analysis

[Display omitted] •Meta-analysis about the tDCS effect on P3 elicited by cognitive tasks.•Anodal frontal tDCS significantly increases parietal P3 amplitude during oddball and n-back tasks.•No tDCS effect was detected on P3 latency, however, few studies analyzed this marker.•P3 brain potential may be useful to assess the effects of tDCS during attention and memory processes. Transcranial direct current stimulation (tDCS) has been widely used to modulate cognition and behavior. However, only a few studies have been probing the brain mechanism underlying the effects of tDCS on cognitive processing, especially throughout electrophysiological markers, such as the P3. This meta-analysis assessed the effects of tDCS in P3 amplitude and latency during an oddball, n-back, and Go/No-Go tasks, as well as during emotional processing. A total of 36 studies were identified, but only 23 were included in the quantitative analysis. The results show that the parietal P3 amplitude increased during oddball and n-back tasks, mostly after anodal stimulation over the left dorsolateral prefrontal cortex (p = 0.018, SMD = 0.4) and right inferior frontal gyrus (p < 0.001, SMD = 0.669) respectively. These findings suggest the potential usefulness of the parietal P3 ERP as a marker of tDCS-induced effects during task performance. Nonetheless, this study had a low number of studies and the presence of considerable risk of bias, highlighting issues to be addressed in the future.