Figure 4.

Model comparison. Original and alternative models for the DCM model comparison. Thick black arrows represent connections that are allowed to be modulated by both SMALL and LARGE. Dashed arrows are intrinsic connections not allowed to be modulated. All driving inputs are the instruction cues (INPUT) that triggered the preparation of the appropriate motor program. The INPUT is fed into V3A. The resulting perturbation is allowed to propagate throughout the model via interconnections from V3A to V6A, terminating in the PMd, and from V3A to AIP, terminating in PMv. In the original model, we tested whether the forward connections in this model were differentially modulated by object size (SMALL or LARGE) during the execution of the movement. The alternative models are described in detail in Materials and Methods, Model selection.