Fig. 4.

Histogram comparing the precision of V1 maps generated from VP voxels. The x-axis indicates the difference between the receptive field locations of VP voxels and the weighted average of the receptive fields in corresponding V1 connectivity maps. Since the actual functional connectivity between V1 and VP is known to preserve retinotopy, each VP voxel and its learned V1 connectivity map should have similar receptive field locations. The y-axis shows the fraction of VP voxels in each difference bin spanning 1.2° of visual angle. Red bars (back) show results for regularized maps (λ = 10³,k = 10), which demonstrate significantly smaller differences than blue bars (front), which show results for non-regularized maps (λ = 0). The dotted lines compare the median difference of both methods to a loose lower bound, based on the uncertainty in our receptive field estimates.