Highly activated weights for example image presentations in the two datasets.

a: Weights for the MNIST dataset. First column shows 5 example inputs. Next 10 columns show the receptive fields of the 10 hidden units most activated for that input. Opacity codes the relative strength of the hidden unit’s responses with respect to the most active hidden unit; weakly activated hidden units are drawn nearly transparent. Final column shows the network’s attempted construction as measured by the late-time spike count. b: Same as (a), but for the the natural image patch dataset.