The model consists of a cyclic lattice of units characterized by a voltage variable .
Additional input is provided by an independent external current .
Center surround connectivity pattern. During a particular simulation, the connectivity pattern is fixed, although the exact synaptic weight varies stochastically. Based on physiological evidence, the pattern of local excitatory and inhibitory connections is center-surround , for the validity of this assumption can be found. Likewise, N inhibitory connections per unit are chosen from a uniform probability distribution on a ring eight to nine lattice constants away. The weight of the excitation and inhibition, in units of voltage threshold, is and .