FIG 4. Two-dimensional scatter plots of within-forearm COGs in contralateral M1 in the 12 subjects. COGs plane for the fingers, hand, wrist, and elbow are displayed in the axial plane.

A, First experimental session. The approximate contour of the precentral gyrus is outlined (as in Fig 3 left image, with the same colors as in Fig 3). The width x of each rectangle is 20 mm and the height y is 18 mm in Talairach space. Note the preserved somatotopic gradient in all 12 individual hand and forearm representations.

B, Second experimental session. Note the highly similar distribution and preserved somatotopic gradient of within-forearm COGs in almost all subjects compared with those of first session.