Fig. 2.

Model. A: motion energy model (adapted from Adelson and Bergen 1985). The stimulus is processed by 2 spatial filters and the resulting outputs are convolved with several temporal filters, recombined, squared, summed, and passed through a square root operation prior to the computation of an opponent stage. See methods for details. The end-stopped stage is added at the initial stage (dotted box, top right). B: middle temporal (MT) model. The MT cell receives input from a population of primary visual cortex (V1) cells with spatially shifted receptive fields. The output is determined by summing over these inputs with SoftMax weighting.