In this study, the synaptic functionalities of artificial synaptic transistors were improved by nanowire-type polysilicon channel structures. The channel conductance, which is interpreted as synaptic plasticity, is efficiently modulated due to a high surface-to-volume ratio of the nanowire channel. As a result, the hysteresis window of the nanowire-type synaptic transistors was larger than that of the film-type synaptic transistors even in the same gate voltage sweeping range. In addition, the NW-type synaptic transistors were found to have superior short-term facilitation properties than the film-type ones through the measured PPF characteristics and frequency-dependent EPSC characteristics.