Figure $P 1.2$ represents a neural net, where the fiber marked $v_{i \Delta}$ is connected to a souree which generates stimuli of values 0 or 1 at times $t_w \dagger$ A large eircle represents a neuron. The output of a neuron at time $t$, is stimulated (i.e., assumes the value 1) if and only if the number of its stimulated "excitatory inputs" (indicated by heavy dots) minus the number of its "inhibitory inputs" (indieated by small circles) at time $t_{v-1}$ equals or exceeds its "threshold" (the integer written inside the large circle). $\left(x: v_{\text {iu }} \quad z: v_{\text {out }}\right)$
(FIGURE CAN'T COPY)