Currently it is assumed that cathodal stimulation (in transcranial direct current stimulation, tDCS) degrades the neural firing rate, and thus it is believed to degrade cognitive performance. Here we challenge this assumption by predicting that under high competition the cathodal stimulation might act as a noise filter, leading to an improved performance. We presented auditory targets with different emotional valence using a dichotic listening paradigm. We found that cathodal, but not anodal stimulation of the right IFG generated better prosody comprehension. Cathodal stimulation in competitive situations, such as the dichotic listening paradigm, can act like a noise filter, and may in fact enhance cognitive performance. This study contributes to understanding the way the IFG is engaged with prosody functions, and explains the cathodal effects of tDCS. This might lead to the development of more efficient brain stimulation protocols.
Alexander, T., Avirame, K., & Lavidor, M. (2012). Improving emotional prosody detection in the attending ear by cathodal tDCS suppression of the competing channel. Neuroscience letters, 508(1), 52-55. https://doi.org/10.1016/j.neulet.2011.12.017