Behavioral assessments of auditory sensitivity in transgenic mice

This report summarizes positive reinforcement conditioning procedures for assessing sensory function in transgenic mice. To illustrate these behavioral methods auditory sensitivity was measured in mice lacking alpha9 acetylcholine receptor subunits (alpha9 knock-out mice). These receptors are known to play an important role in the efferent pathways that modify cochlear responses to sound stimuli. The strategies of parameter manipulation that led these subjects through their preliminary training stages to stable threshold performances are described in detail. Techniques for estimating and interpreting sensory thresholds are discussed from the perspective of signal detection analyses. This study found no significant differences between alpha9 knock-out mice and control subjects when hearing thresholds were measured under quiet conditions, as predicted by previous behavioral and electrophysiological evidence.