Figure 7.

Condition preferences based on mean activity changes. Series of PCA biplots spanning all eight STS subregions are displayed for the right (top) and left (bottom) hemispheres. Each PCA biplot shows voxel coefficients as blue vectors, with orange circles representing the scaled principal component scores for each experimental condition. Conditions are labeled on the left-most plots for each hemisphere and these labels apply to the neighboring plots located to the right. On each plot, the first principal dimension is represented along the abscissa and the second principal dimension along the ordinate. The range of the axes (labeled on the bottom left plot) is identical for all 16 plots. Voxel coefficient vectors point toward the condition(s) preferred in terms of mean activity; shorter vectors correspond to voxels that did not exhibit a strong preference. These results clearly demonstrate a functional-anatomic gradient of activation preferences transitioning from visual (subregions 6–8) to audiovisual (subregions 4–5) to auditory (subregions 1–3) moving posterior to anterior.