Figure 4: The ratio of the cerebral cortex area with significant activation to that of the entire imaged portion of the hemisphere (the extent ratio) of all subjects. During normal hand grasping of healthy subjects and unaffected-hand grasping of patients, the contralateral hemisphere was predominantly activated. In contrast, the ipsilateral hemisphere was extensively activated during moderately paretic hand grasping. C, contralateral hemisphere; I, ipsilateral hemisphere; Lt, left; Rt, right; Filled squares, patients with bilateral activation; Filled triangles, patients with ipsilateralpredominant activation.