Auditory sensitivity shift by attention in Mongolian gerbil

Abstract

Mongolian gerbil, Meriones unguiculatus, communicate with others by various sounds. About 80% of those sounds range over 20 kHz. A threshold of hearing in this range, however, was about 20 dB higher than their most sensitive frequency (1 to 16 kHz). We proposed a hypothesis that the auditory sensitivity heightened when gerbils communicated with others. In order to test the idea, a cochlear microphonics (CM) was recorded under various behavioral context as a measure of auditory sensitivity. Under paired condition, a subject was set with another gerbil. The condition simulated the subject gerbils in their group, and the subject was considered to pay attention to sounds of the company. The CM response under the situation was higher than under single situation. Then, we investigated if the CM increase was specific under the situation. Subject was trained to pay attention to a sound of conditioned stimulus by electric shock as a negative reinforcer. The sound worked as an alarm sound for gerbils. The CM response increased while the gerbil was paying attention to the sound. Those results suggest that the sensitivity of auditory periphery is raised by attention in various behavioral contexts.