Ambiguous tDCS: variability of the brain response to transcranial direct current stimulation in reinforcement learning task

Transcranial electrical stimulation (TES) is a popular approach for studying and modulating cortical function. Currently, numerous studies use TES in behavioral experiments with no physiological control. The authors of such studies rely on the assumption of fairness and complete predictability of their stimulation models. However, control reveals the actual effect induced by the stimulation rarely matches the one previously modeled. Our study illuminates diverse effects caused by tDCS and brings up the importance of physiological control when including TES in the research design.