Fig. 5

The modulation effects of dual-tDCS and its responsiveness prediction model. a The summarized modulation effects of dual-transcranial direct current stimulation (tDCS) in anodal and cathodal polarities in healthy controls and stroke survivors. b The dual-tDCS responsiveness in paretic hand of subacute stroke survivors could be predicted from baseline ipsilateral silent period (iSP) ratio. In linear regression analysis, the baseline iSP ratio, i.e. contralesional / ipsilesional hemispheric iSP before tDCS, could significantly and negatively predict changes of normalized motor evoked potentials (MEP), i.e. MEP post tDCS / MEP before tDCS in real relative to sham stimulation. α-ERS: Alpha band event related synchronization; NH: non-dominant hemisphere; DH: dominant hemisphere; IH: ipsilesional hemisphere; CH: contralesional hemisphere