In the control rat, sound signals are transmitted to the brain via inhibitory neuron, medial nucleus of trapezoid body (MNTB). In the autism model rat, MNTB neurons are impaired and the transmitted sound signals cannot be suppressed. Thus, it causes auditory hypersensitivity. Since MNTB is known to be involved in exploring the direction of the sounds, impairment of MNTB suggests that new approach such as "Does your child seem to know where the sound comes from?" would be useful for the diagnosis of autism.