Figure 6. Model simulations reproduce empirical observations.

We varied the independent variable in the model—the surface area of the model visual cortex, to investigate its influence on the model’s outputs—the discrimination threshold and contextual modulation magnitude. When the model visual cortex expanded in surface area, the cortical representation of visual field location expanded accordingly, and the cortical representation of orientation expanded as well through an increase in either the number or the size of orientation hypercolumns (the simulation results of which were marked with black and grey colour, respectively). Mirroring the empirical observations, the model simulations revealed a tradeoff between discrimination sensitivity and contextual modulation magnitude that correlated with the surface area of the model visual cortex. This tradeoff and its correlation with the model visual cortical surface area were only evident in the domain of orientation or visual field location and were not observed in the domain of luminance or contrast. Each point represents a single simulation (N=10) and the line is the best-fitting linear regression. Statistical values reflect Spearman’s rho and its bootstrap confidence interval with FDR correction for multiple comparisons (α=0.025).