Figure 27

The EN model with deterministic annealing and stimuli, distributed on a grid in feature space. (a) OPMs (left) and RMs (right) for N = 20 × 20 × 8 (upper row), N = 50 × 50 × 8 (middle row) and N = 100 × 100 × 8 (lower row) stimuli and nonperiodic boundary conditions (annealing rate χ = 0.999). β is the continuity parameter in the conventional definition of the EN model (see 'Methods' section, Equation (46)) and is scaled, such that a comparable number of columns emerges in all simulation for each N. (b) Pinwheel densities of EN solutions for different numbers of stimuli (annealing rate χ = 0.999). Crosses mark individual simulations, red line indicates average values. (c) Statistics of nearest neighbor pinwheel distances for pinwheels of (upper left) arbitrary and (upper right) opposite and equal charge for 100×100×8 stimuli and nonperiodic boundary conditions, averaged over four simulations (red curves). Black curves represent fits to the experimental data from [38]. Lower left: SD of pinwheel densities estimated from randomly selected regions in the OPM. Black dashed curve indicates SD for a two-dimensional Poisson process of equal density.