FIG 3. Two-dimensional scatter plots of the COGs in the 12 subjects (two sessions per subject) in the contralateral M1. Small dots represent individual COGs, and large dots indicate the mean COGs. Note the separate subdivisions for the foot, arm, and tongue and the clear somatotopic gradients within the arm representations in both the axial and coronal planes. The x, y, and z coordinates corresponding to those in Talairach space (21). Left, Axial plane with approximate contour of the precentral gyrus. Right, Coronal plane with the cortical surface and limited to the white matter.