Concurrent Transcranial Direct Current Stimulation (TDCS) and Functional MRI Reveals Modulatory Effects on Brain Activation During a Simple Motor Task

Peter Dechent¹, Rafael Polania², Carsten Schmidt-Samoa¹, Walter Paulus², Andrea Antal²

Anodal/cathodal tDCS have facilitatory/inhibitory effects, respectively, on the stimulated cortical networks. Here we used concurrent tDCS-fMRI to test whether anodal/cathodal tDCS result in BOLD-fMRI signal changes during a resting condition. Furthermore, we examined tDCS-effects on brain activation during voluntary finger tapping. Anodal/cathodal tDCS over left M1 induced no detectable BOLD signal change. However, anodal/cathodal tDCS combined with finger tapping resulted in a decreased BOLD response in SMA, but not M1, in comparison to voluntary finger tapping without stimulation. This suggests that in contrast to the rest condition the combination of neuronal polarization and motor activation induces inhibition in remote brain areas.