Complex sound perception by laboratory mice

Abstract

Although mice are known to produce vocalizations with varying spectrotemporal characteristics, exactly how they are using these vocalizations for communication is still not entirely known. Ultrasonic vocalizations (USVs) are produced by male and female mice of many strains and researchers have parsed these USVs into different categories. Whether or not these USV categories are meaningful to the mice has been the subject of many preference and playback studies, which have weaknesses. Using an operant conditioning nose poke paradigm, we have trained laboratory mice to detect, discriminate, and identify simple and complex stimuli, including USVs used for communication. We have found that USVs are easier to detect than pure tones, although noise, aging, and blast trauma disrupts this process. Like humans listening to words, the beginnings of USVs appear to hold more importance than the middle or ends of USVs. Mice can discriminate amongst USVs, and there is evidence for categorization of at least some USVs, but this ability is much worse than that of other animals tested on similar tasks. Psychophysical experiments with awake trained mice are important for determining the perceptual limitations of the mouse auditory system and using these rodents as models for human communication disorders.