Fig. 5.

Capacitance-dependent operating regimes in a tonic VO₂ active memristor neuron. a Diagram of operating regimes determined by the values of C₁ and C₂ membrane capacitors. When C₂ > C₁, the neuron exhibits Class 2 excitable spiking and subthreshold oscillations (see (b)). When C₂ < C₁, the neuron exhibits Class 1 excitable spiking (see (c)). When C₂ < 0.35C₁, the neuron exhibits Class 1 excitable bursting (see (d)). Various combinations of C₁ and C₂ are sampled (colored dots) by measuring time dependence of neuron output with a linearly ramped input current. (b–d) Typical neuron input and output vs. time (top panels), and the current-dependence of instantaneous spike frequency (bottom panels) sampled from Class 2 excitable spiking, Class 1 excitable spiking, and Class 1 excitable bursting regimes, respectively