Equations and parameters used in the neural network model. Ei(t) and Ii(t) are electrical activities of excitatory and inhibitory units, respectively; Δ is the rate of change; KE and KI are gains of the sigmoid functions; TE and TI are the input thresholds; N(t) is the random activity term; δ is the decay rate; and wEE, wIE, and wEI are the weights (excitatory-to-excitatory, inhibitory-to-excitatory, and excitatory-to-inhibitory). iniE(t) and iniI(t) are the total inputs coming from other areas into the excitatory and inhibitory units at time t.