Coupled n -ECPs as dimension-reducing solutions of the EN model. Coupled n-ECP are displayed in visual space showing simultaneously the distortion of the RM and the OPM (σ/Λ = 0.3 (η = 0.028), η
= η, circular stimulus ensemble). The distorted grid represents a the cortical square array of cells. Each grid intersection is at the receptive field center of the corresponding cell. Preferred stimulus orientations are color-coded as in Figure 2a. As in Figure 4, n and i enumerate the number of nonzero wave vectors and nonequivalent configurations of wave vectors with the same n, respectively. The coupled 1-ECP is a pinwheel-free stripe pattern without retinotopic distortion. Only the most anisotropic and the most isotropic coupled n-ECPs are shown for each n. Note that for all ECPs, high gradients within the orientation mapping coincide with low gradients of the retinotopic mapping and vice versa. Retinotopic distortions are displayed on a fivefold magnified scale for visualization purposes.