Table 1.

Effect of ′up′ and ′dn′ signals on the post-synaptic terminal potential which in turn determines the type of plasticity event induced on pre-synaptic spikes.

Plasticity signal	Vpost	Plasticity event	Open switches	Closed switches
′up′ = 0 and ′dn′ = 0	3.0	No change	S4, S5, S7	S6, S8
′up′ = 1 and ′dn′ = 0	4.5	Potentiate	S4, S6, S7	S5, S8
′up′ = 0 and ′dn′ = 1	0.5	Depress	S8, S5, S6	S4, S7

Shown are the open and closed switches in each case. The switches are controlled by the ′up′ and ′dn′ signals.