Feedforward weights after training for the MNIST and natural image patch datasets.

a: Weights learned from the MNIST dataset. Each square in the grid represents the incoming weights to a single hidden unit; weights to the first 100 hidden units are shown. Weights from visible neurons which receive OFF inputs are subtracted from the weights from visible neurons which receive ON inputs. Then, weights to each neuron are normalized by dividing by the largest absolute value. b: Same as (a), but for the natural image patch dataset.