Transcranial Direct Current Stimulation (tDCS)

Abstract This overview introduces the methodology, history, mechanisms, and applications of transcranial Direct Current Stimulation (tDCS). This includes tracing the historical origins of tDCS along related transcranial Electrical Stimulation (tES) techniques such as Electrosleep, Cranial Electrotherapy Stimulation, and Limoge Current. tDCS terminology and tDCS dosaging is defined. How tDCS is customized to given applications is explained (the origins of tDCS specificity) and includes anatomical, activity-selective, and input-bias mechanisms. Preparation methods for tDCS are reviewed that include selecting and preparing electrodes and contact medium, selecting and preparing electrode placement, common montages, and the use of computational models to optimize dose. We review safety considerations for tDCS and important efficacy trials.