Long-Term Memory, Simulated Qubits, Physical Qubits - Brain Theory from a Circuits and Systems Perspective - page 70

Fig. 4.11 Excitory/inhibitory toggling circuit
Fig. 4.12 AND/XOR toggle circuit
that there is no multivibration and permits normal triggering. Multivibration is
triggered with S2. However, if multivibration is in progress, the gate U3 detects this
and stops the cycling pulse via an XOR gate U2 whose output is made to be logic
zero. Weak synapses S1, S2, and S3, by the way, are assumed to have insignificant
delay. U1 and U3 are assumed to have identical delays so that pulses arrive
simultaneously at U2.