Stimulating somatosensory psychophysics: a double-blind, sham-controlled study of the neurobiological mechanisms of tDCS

Abstract

In this study, the influence of tDCS on vibrotactile adaptation is investigated. Double-blind tDCS (Anodal/Sham) of 1 mA was delivered for 600 s to electrodes positioned in a somatosensory/contralateral orbit montage. Stimulation was applied between blocks of the implemented amplitude discrimination tasks. Amplitude discrimination thresholds were significantly degraded during adaptation trials, compared to those achieved at baseline but tDCS failed to modify task performance. Using Bayesian statistics, this finding was revealed to constitute substantial evidence for the null hypothesis. The failure of DC stimulation to alter performance is discussed in the context of several factors that may have confounded the induction of changes in cortical plasticity