This study shows that the effects of an anodal stimulation on T3 with a cathodal stimulation on the right shoulder significantly boosted audio-pitch perception. The subjects were given bilateral anodal, cathodal, and “sham” (sham stimulation is a generic term to indicate an inactive form of stimulation) tDCS in a randomized counterbalanced order. The effects were staggering, with anodal stimulation the Random Gap Detection Test (RGDT) scores improved 22.5% while cathodal decreased it by 54.5%.
The subjects were given 2 milliamps of current throughout the study.
Siever, D. (2013). Transcranial DC Stimulation. Neuroconnections, Spring Issue, 33-40. http://www.mindalive.com/1_0/article%2010.pdf.