Network architecture for the gated difference memory.

This system loads and stores a two-dimensional value in a working memory; when the “gate” signal is on (closed), the system maintains its current value through recurrent activity, and when the “gate” is off (open), the system replaces its current representation with the input value. Gray circles are LIF populations while blue circles are detailed neuron populations. The green connection is trained by osNEF to compute f(x) = x, while the purple connection is trained to compute f(x) = −x. The orange connection directly inhibits neurons in “diff” using fixed negative weights.