Transcranial direct current stimulation (tDCS) of the inferior frontal gyrus disrupts interpersonal motor resonance

Interpersonal motor resonance (IMR) is presumed to result from activity within the human mirror neuron system, which itself is thought to comprise the inferior parietal lobule (IPL) and inferior frontal gyrus (IFG). Twenty healthy adults underwent anodal, cathodal, and sham transcranial direct current stimulation (tDCS) to either IPL or IFG immediately before the assessment of IMR (using transcranial magnetic stimulation). IMR (i.e., motor-evoked potential amplitude during transitive action observation relative to static observation) was significantly reduced following both anodal and cathodal stimulation of IFG (relative to sham), but there was no effect of stimulation for IPL. These data support the role of IFG, a presumed mirror neuron region, in IMR.