Figure 25.

STDP-like learning memristive Pavlov’s dog implementation. (a): The electrical schematic diagram: N1—the first pre-neuron, spiking after the “food”-related stimulus; N2—the second pre-neuron, spiking after the “bell” stimulus; N3—the post-neuron, which spikes when the total input current exceeds the threshold; R—a resistor with a constant resistance value of R = 2 kΩ; M—a memristive element, initially in the R_off = 20 kΩ resistive state. A post-spike is generated unconditionally after a spike comes from N1 and under the condition that the memristor current exceeds I_th after a spike comes from N2. (b): An example of the spike pattern applied to the inputs of the scheme: 1—the initial pulse (first Epoch) on the resistor (R) (unconditioned stimulus), resulting in post-spike (P) 2, which in turn comes to the memristive device (M) as pulse 3 (dashed) in the inverted form; 4—the pulse on the memristive device, initially without post-neuron activity; 5—simultaneous pulses on the resistor and the memristive device, which result in post-spike 6 leading to the training pulse 7 (dashed); 8—a post-spike as a result of the conditioned stimulus when the training is completed (Epoch n, where n is equal to or above the number of epochs required for successful conditioning) [136]. Reproduced from A.A. Minnekhanov, A.V. Emelyanov, D.A. Lapkin, K.E. Nikiruy, B.S. Shvetsov, A.A. Nesmelov, V.V. Rylkov, V.A. Demin, and V.V. Erokhin, “Parylene based memristive devices with multilevel resistive switching for neuromorphic applications”, Sci. Rep., 9, 10800 (2019).