Abstract: The phonotaxis of bushcrickets demonstrates that they have good capability of reocgnizing conspecific songs and locating the sound source,which bases on complicated auditory mechanisms of the central nervous system (CNS).This article describes the response characteristics of AN3,an auditory ascending neuron in the prothoracic ganglion,and its projections within the brain.The AN3,with a quasi-tonic discharge pattern,has high sensitivity,directionality and ability to encode sound intensity.Therefore,it plays an important role in auditory information processing of CNS.Its projections in brain are mainly concentrated in the lateral part of the deutocerebrum,there synaptically connecting with local auditory interneurons in brain.