Fig 2. Dictionary Φ and local connections.

(A) Feature vectors learned by training the model on natural images resemble localized Gabor filters. Features are ordered according to their orientation, which was estimated by fitting a Gabor function. Only a subset of the total set of N = 1024 dictionary elements is shown. (B) Units with overlapping input fields have strong short-range connections. The sign of the coupling is determined by the arrangement of on/off regions of the input fields: opposite phases correspond to excitatory connections (red) and matching phases to inhibitory connections (blue).