NbO x -based memristor has been fabricated operating at a low voltage range of 0.5/1.5 V, exhibiting coexistence of resistive switching (RS) and threshold switching (TS) characteristics depending on the range of the low resistance state (LRS). Additionally, the device demonstrates self-rectification behavior. It achieves synaptic plasticity and emulates the leaky integrate-and-fire (LIF) artificial neuron, capable of high-frequency operation at 6.7 MHz and displaying firing saturation. This device may hold significant importance in the realm of information processing, adaptability, and energy efficiency within the intricate dynamics of neuromorphic systems.