Figure 2.

Neural effects of visual processing

(A) In the fMRI-scanner, subjects saw a silhouette for a short period of time and were instructed to infer a plan for the construction of that silhouette. Sometimes trials were followed by a catch trial, in which subjects had to indicate whether blocks were part of the construction of the previous silhouette.

(B) In the scanner, subjects received (known) basic building blocks (first row), hierarchical building blocks (second row), or novel and previously unseen compounds as construction trials. The novel compound silhouettes were either built with two basic building blocks on top of each other (third and fourth row) or beside each other (fifth and sixth row) or with two hierarchical building blocks on top (seventh and eighth) or beside (ninth and tenth) each other.

(C) We found that activity in the lateral occipital, superior parietal, and precentral gyrus covaried with the number of elements in a compound, providing an approximation to construction difficulty (left). We also found effects for (absolute) changes in the number of elements between consecutive silhouettes in the lateral occipital cortex (middle). We did not detect any significant effects for differences in visual shape (pixels) but detected effects in superior parietal and frontal cortex reflecting differences in size between the individual silhouettes.