(a): Shapes of pre-synaptic (red line) and post-synaptic (black line) potential pulses. (b): Resulting voltage across the memristive element for the specific Δt = 200 s value [174]. Reprinted from Microelectronic Engineering, Vol. 185, D.A. Lapkin, A.V. Emelyanov, V.A. Demin, T.S. Berzina, and V.V. Erokhin, “Spike-timing-dependent plasticity of polyaniline-based memristive element”, pages 43–47, Copyright (2018), with permission from Elsevier; (c): STDP window for the memristive-device-related conductance changes for different ∆t delay values. The inset shows the shapes of pre-synaptic (black) and post-synaptic (red) potential pulses [143]. Reproduced with permission from N.V. Prudnikov, D.A. Lapkin, A.V. Emelyanov, A.A. Minnekhanov, Y.N. Malakhova, S.N. Chvalun, V.A. Demin, and V.V. Erokhin, “Associative STDP-like learning of neuromorphic circuits based on polyaniline memristive microdevices”, J. Phys. D: Appl. Phys., 53, 414001 (2020). Copyright (2020) IOP Publishing, Ltd.