Fig. 4
Target regions of interests (ROI) of the sensorimotor network and tDCS-related functional connectivity changes involved in motor recovery after stroke. A Anatomical illustration of the 12 ROIs. The orange circles are the primary sensorimotor cortices, while the yellow circles are explorative network hubs. Rectangles illustrate the projected placements of the anode (red) and cathode (blue). B The significant relationships between changes in functional connectivity (△FC) and changes in FMA-UE (△FMA-UE) after 2-week real versus sham tDCS (△T2–T1). Scatter plots represent the actual observed △FMA-UE (y-axis) and the estimated △FMA-UE (x-axis) from the multiple regression model. C The significant relationships between △FC and △FMA-UE after 12 weeks post-stroke (△T3–T1). Dark red lines connecting ROIs and △FC in formulas indicate positive correlations between △FC and △FMA-UE, whereas dark blue lines (△FC) indicate negative correlations. Circles and triangles represent the real and sham tDCS group, respectively. Solid symbols indicate participants with preserved motor evoked potential (MEP +), while hollow symbols indicate absent MEP (MEP −). aR2, adjusted R squared; tDCS, transcranial direct current stimulation; FMA-UE, Fugl-Meyer Assessment of Upper Extremity