An oscillator circuit that includes a voltage source, a resistor, a capacitor, and a nonlinear device. The capacitor and the nonlinear device may be coupled in parallel with one another. The resistor may be coupled in series with the capacitor and the nonlinear device. The voltage source may be coupled in series with the resistor. The voltage source may supply the oscillator circuit with a direct current input signal. The nonlinear device may include an active layer coupled to a first electrode and a second electrode. In response to the direct current input signal, the oscillator circuit may output a spike train including a spike bunch.