Fig 4. Case 4. A 71-year-old woman with metastatic brain tumor located inside the right-sided premotor area.

A-1, Preoperative MR imaging displays heterogeneously enhancing tumor in the premotor area.

A-2, Postoperative MR imaging shows no residual tumor in the premotor area.

B, fMRI images activated by right hand clenching (blue) and left hand clenching (red) before surgery,

C, fMRI images activated by right hand clenching (blue) and left hand clenching (orange) after surgery. Both left and right hand clenching activated the right temporal and frontal lobes before surgery. After surgery, left and right hand clenching activated the anterior temporal lobe (C-1,-2,-3), and left hand clenching activated a relatively small area of contralateral M1 (C-6). Because both preoperative and postoperative fMRI show similar atypical results such as no activation in the left hand M1 during right hand clenching, it seems that this result was not artifactual. It is not clear why there is no activation in the left M1 during right hand clenching, but the right hemisphere might be mainly activated by both right and left hand clenching in the case of severe paresis, possibly because of the preferential processing of spatial information in the right hemisphere.