Fig. 3: Measured spiking activities of transneurons in different regimes under varying external voltage and temperature.

Left column A–E: Measured response of the transneuron in a PRR-like regime; the plots present measurements of current, I, in milliamperes (mA) versus time in seconds (s) at applied voltages, V, measured in volts (V) from 0.6 to 1.3 V. Within this voltage interval, we observe evolution of regular isolated spikes. Spiking appears at the voltages above 0.6 V, grows more intensive for 0.7 V and 1 V, then decreases for 1.1 V and stops for 1.3 V. (In these measurements, the external resistance was 68 kΩ and the capacitance was 10 nF. The memristor was fabricated using Method 1; see ‘Methods’.) Middle column F–J: Bursting behaviour of voltage spikes is shown at intermediate voltages (1–1.9 V). Bursting appears at the voltage of about 1 V, develops with the increasing voltage (1.3 and 1.4 V), followed by depletion of spiking in bursts at 1.5 V, and disappears at about 1.9 V. (In this transneuron, the external resistance was R_ext= 65 KΩ and the external capacitance was C = 50 nF. The sample was fabricated using Method 2.) Right column (top three panels, K–M): MT-like spiking of a transneuron (R_ext=65Kohm and C = 50 nF, fabricated using Method 2). Here, spiking starts at a relatively high voltage threshold of about 2.2 V. Then spiking frequency grows as external voltage increases to 2.2 V and 3 V. The bottom two panels (N, O) at right show the influence of temperature on spiking (for temperatures, T₀, measured in degrees of Celsius, °C, from 20 to 40 °C), resulting in a further rise of spiking intensity in this transneuron (with R_ext = 60 kΩ, C = 20 nF, fabricated by Method 2).