Figure 2.

The left hemisphere interaction sites in the four experiments. A, Cortical regions more active (colored red to yellow) during the observation of grasping performed with a mechanical implement than during the observation of the same action done by hand, each relative to its static control, rendered on lateral views of the left hemisphere of standard (MNI) human brain (experiment 1, n = 20, random effects analysis). B, Cortical regions active in the contrast observation of screwdriver versus hand actions, relative to their static controls (experiment 2, n = 21, random effects analysis). C, SPMs showing significant voxels in the interaction observation of rake vs hand actions (experiment 3, n = 8, fixed effects analysis), relative to their static control. D, Same for experiment 4 (observation of actions with pliers, n = 8, fixed effects). In all four interactions threshold is p < 0.001 uncorrected. E, Conjunction of the interactions in the four experiments; threshold for each interaction p < 0.005 uncorrected, yielding the core of aSMG. Purple arrows indicate left aSMG.