Figure 5.

Model network of interregional connections and experimental inputs. Chosen and alternate network models for DCM model comparison are shown. Regions were connected with stimulus inputs entering fusiform (FUS) and parietal (iPS) visual processing streams. Models assumed unidirectional inputs from FUS and iPS to all other regions. The red arrows and arrowheads highlight defining organizational features for each network model: Chosen Model, Inputs from all other regions converge onto sTS and iFG; Alternate Model 1, all other regions are bidirectionally connected; Alternate Model 2, posterior regions (iPL, sTS) send unidirectional input to anterior regions (PRE, iFG); and Alternate Model 3, regions are connected in separate streams between iPL and PRE, and between sTS and iFG. Alternate Model 4 is a fully interconnected network. Task-specific modulatory effects were assessed at every interregional connection for the chosen model. SYN, Semantic task input; LET, visual task input.