Fig. 5.

Pairwise comparisons of the differences between mean activation evoked by the 3 intact stimulus categories using a d′ index for parietal cortex ROIs. The d′ index is a measure of the separability of the distributions, across subjects, of evoked responses for 2 different stimulus categories. The comparison of tools and animals (A) confirmed the general tool bias in the topographic regions of the parietal cortex, as well as hPGR and tAIPS. The comparisons of tools and graspable objects (B) and graspable objects and animals (C) revealed a response profile gradient along the posterior-to-anterior extent of the topographic regions of the IPS, most clearly in the left hemisphere. Graspable objects evoked significantly stronger response than animals, but not tools, in posterior regions and significantly weaker responses than tools, but not animals, in anterior regions. *P < 0.05, significantly different from zero. †P < 0.003, significant linear trend across ROIs. CI, confidence interval.