Dilation of the inferior colliculus and hypersensitivity to sound in Wnt1-cre and Wnt1-GAL4 double-transgenic mice

The processing of sound information is mediated by the cochlea and the central auditory system. Among the central auditory system, the inferior colliculus (IC) has leading roles in the acoustic processing. In a previous study, we demonstrated psychiatric disorder-related behavioral abnormalities in a genetically modified animal of Wnt1-cre and Wnt1-GAL4 double-transgenic (dTg) mouse. Here we report an abnormal morphology of the IC and dysacusis in the dTg mice. The IC in the brain of the dTg mice is dilated in appearance and histologic analysis revealed a high cell-density in the IC. Also, the dTg mice showed high scores in a startle response test using a click box that emits a 20-kHz sound. Auditory brainstem response (ABR) test revealed lower ABR thresholds of the dTg mice at a test-stimulus frequency of 32 kHz, but not at 4-16 kHz. These findings suggest that the dTg mice could be a useful animal model for studying the physiologic function of the IC and the pathophysiology of psychiatric disorder-related dysacusis.