The afferent and lateral connections of a single neuron in the LISSOM network are shown. All connection weights are positive.
The LISSOM network is a sheet of interconnected neurons. Through afferent connections, each neuron receives input from two ``retinas''. In addition, each neuron has reciprocal excitatory and inhibitory lateral connections with other neurons. Lateral excitatory connections are short-range, connecting only close neighbors. Lateral inhibitory connections run for long distances, and may even implement full connectivity between neurons in the network.
Neurons receive afferent connections from broad overlapping patches on the retina called anatomical receptive fields, or RFs. The NxN network is projected on to each retina of RxR receptors, and each neuron is connected to receptors in a square area of side s around the projections. Thus, neurons receive afferents from corresponding regions of each retina. Depending on location of the projection, the number of afferents to a neuron from each retina could vary from 0.5s x 0.5s (at the corners) to s x s (at the center).