Effects of tDCS on the amplitudes of motor evoked potentials (contour plots). X-axis: sagittal coordinates, Y-axis coronal coordinates, Z-axis: intensities of corticomotor responses. Coordinates of stimulation are established using the stereotactic frame. Responses are expressed as % of baseline. Upper left: control rat; upper right: Ringer's; lower left: b78; lower right: b96.11.